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Biomedical subjects

J Soudant

Publications and source records attributed to J Soudant.

At least 55 records · Page 3Linked to original sources
PubMed1993

[Electrophysiological study of hemifacial spasm].

Hemifacial spasm is characterized by intermittent involuntary contractions of one or several groups of muscles innervated by the facial nerve. The possible causal mechanisms have been the subject of numerous publications. The pre-eminent work of Moller and Jannetta implicates the compression of the facial nerve at its point of entry into the central nervous system, the Root Entry Zone, while the physiopathology is poorly understood, two principle hypotheses emerge: 1) ephaptic transmission between injured fibers; 2) hyper excitability of the facial motor nucleus. Using standard electromyographic techniques and blink reflex studies, we were able to demonstrate hyperexcitability of the facial nucleus. The cause of this hyperexcitability remains unexplained. It could be the result of a permanent antidromic stimulation from a peripheral ectopic center of excitation.

Adult↗
PubMed1993

[Demonstration and electrophysiological analysis of the blinking reflex in the rat. Value of the animal model].

The authors have developed an animal model for the electrophysiological investigation of the blink reflex. The justification for such investigations and the experimental protocol were presented. The authors studied the blick reflex with electromyographic recordings obtained after the stimulation of the supra orbital nerve (V1) in the awake rat and in the anaesthesized rat. Two components of the reflex, R1 and R2 were observed. The early component, R1 was ipsilateral to the stimulus. It was observed whatever the degree of anaesthesia. The R2 component came later and was only observed in awake or weakly anaesthesized rats. It appeared to be isolated and unprecedented by an R1 component when the contralateral supra orbital nerve was stimulated. The R1 responses were facilitated by prior ipsilateral or contralateral stimulation of V1.

Anastomosis, Surgical↗
PubMed1992

Redirection of the hypoglossal nerve to facial muscles alters central connectivity in human brainstem.

Functional motor control requires perfect matching of central connectivity of motoneurones with their peripheral connections. However, it is not known to what extent central circuitry is influenced by target muscles, either during development or following a lesion. Surgical interventions aimed at restoring function following peripheral nerve lesions provide an opportunity for studying this interaction in the mature human nervous system. We have followed 8 patients in whom the hypoglossal nerve was anastomosed into a lesioned facial nerve, allowing voluntary contractions of the previously paralyzed muscles. We show that, in addition to replacing the facial neurons at peripheral synapses, a new short-latency trigemino-hypoglossal reflex, of the R1 blink reflex type, can be demonstrated in patients showing recovery, implying a sprouting of trigeminal neurons towards hypoglossal motoneurones, over a distance of at least 0.5 cm. These surprising results show an unexpected influence of the periphery in remodelling central connectivity in man.

Adult↗
PubMed1992

Monoclonal antibody-coated magnetite particles as contrast agents for MR imaging and laser therapy of human tumors.

Attempts to improve human tumor detection by non-radioactive magnetic resonance techniques have led several investigators to develop antibody-linked paramagnetic contrast agents. Initial studies focused on gadolinium conjugated to monoclonal antibodies. However, very high levels of this contrast agent were needed to significantly reduce proton relaxation times and obtain improved MR images. The use of magnetite (Fe 3O 4) as an MR contrast agent provides a magnetic moment that is approximately one order of magnitude larger than gadolinium. In this study monoclonal antibodies 44 x 14 (specific for squamous cell carcinoma) and 436G10 (specific for melanoma) were obtained from ammonium sulfate precipitation of tumor ascitic fluid. Equal volumes of magnetite solution (1.87 mg Fe/ml) and antibody solution 44 x 14 (5.24 mg protein/ml) and 436G10 (0.64 mg protein/ml) were mixed and sonicated. The 44 x 14-magnetite and 436G10-magnetite solutions were then added to equal volumes of M20 and P3 squamous cell carcinoma cell lines. T1 and T2 values were obtained on a Praxis II NMR spectrometer equipped with a 10 mm probe and 0.25 Tesla permanent magnet. The T2 relaxation times of the magnetite-antibody-cell mixtures were 31 ms with an R = 0.985 for both experimental samples. Our results demonstrate a significant decrease in T2 by binding of the magnetite-coated antibodies to these melanoma and carcinoma cells in vitro. The possibility of detecting subclinical local and metastatic disease with magnetite linked to monoclonal antibodies followed by MRI guided laser tumor ablation therapy may render this technique clinically attractive for treatment of deep-seated tumors.

Antibodies, Monoclonal↗
PubMed1992

Laser and daunomycin chemophototherapy of human carcinoma cells.

Adriamycin and daunomycin anticancer drugs are detectable in leukemias and solid tumors by cell fluorescence. We observed initial cytoplasmic fluorescence followed by slow nuclear localization of adriamycin and daunomycin after incubation with cultured human squamous cell (P3, FADU) and adenocarcinoma (HT29, SW620) lines by digital video imaging microscopy. Tumor cells incubated with 10 mug/ml of these drugs exhibited increased uptake for more than 3 h with intracellular levels in the range 0.5-2.5 mug/10 6 cells measured by dimethyl sulfoxide (DMSO) extraction and fluorescence spectrophotometry. Daunomycin had 10- to 100-fold higher toxicity for these carcinoma cells than for normal human epithelial keratinocytes measured by in vitro MTT tetrazolium assays. The viability of daunomycin-sensitized carcinoma cells was decreased 2- to 10-fold further by argon laser illumination at 488 nm (5W, T max = 8 degrees C) for 2-3 minutes. The results suggest that adriamycin derivatives may be useful targeting agents for adjuvant treatment and chemophototherapy of human solid tumors by MR-guided laser fiberoptic endoscopy.

Adenocarcinoma↗
PubMed1992

Metastatic head and neck malignancy treated using MRI guided interstitial laser phototherapy: an initial case report.

Interstitial laser phototherapy (ILP) guided by magnetic resonance imaging (MRI) may become an attractive adjunctive modality for the treatment of deep and surgically inaccessible tumors of the head and neck when accurate methods of laser dosimetry and "real-time" monitoring techniques with the MRI are introduced. We recently demonstrated in ex vivo and in vivo models, a linear relationship between levels of laser energies, thermal profiles, MR signal intensity changes, and histopathological tissue damage. Results of treatment in a patient with an unresectable large right jugulodigastric metastatic squamous carcinoma using new approach of MRI guided ILP are now reported. The patient complained of significant right-sided neck pain and headaches secondary to a rapidly growing metastatic lymphadenopathy which recurred after previous surgery, radiation, and chemotherapy. Two treatment sessions were used at an interval of 2 weeks. Each treatment was performed in the MRI suite under heavy sedation. Using a 600-microns bare fiber of the Nd:YAG laser implanted interstitially under MR guidance, the metastatic node was treated at three sites. T1- and T2-weighted images were performed prior to, immediately after, 24 and 48 hours, and 4, 5, 7, 9, 16, and 25 days post-treatment. Successful relief of pain and growth arrest of this node was observed after the second treatment and at the 3-month follow-up. These results demonstrate that this technique of ILP guided by MRI may be feasible in humans, and will become clinically practical when appropriate methods of dosimetry and instrumentation are developed.

Aluminum Silicates↗
PubMed1992

Laser dyes for experimental phototherapy of human cancer: comparison of three rhodamines.

The mitochondrial dye Rhodamine 123 (Rh-123) has been shown to be an effective photosensitizer for argon-laser irradiation of some types of human cancer cells in vitro. We reported that 514.5-nm laser illumination of Rh-123 sensitized human melanoma, and squamous carcinoma cells strongly inhibited tumor-cell proliferation as measured by decreased 3H-thymidine (3H-T) uptake in vitro and may eradicate some tumors when grown as transplants in nude mice. However, several other human tumors were resistant to Rh-123 laser therapy in vitro and in vivo. In the current study, it was possible to obtain 100- to 1000-fold increased sensitivity to 514.5-nm laser illumination by replacement of Rh-123 with the cationic rhodamine dyes Rh-3G and Rh-6G. Cell viability was decreased over 95% and 3H-T incorporation reduced at least 80% by laser phototherapy after sensitizing tumor cells with 1 micrograms/mL Rh-123, 0.01 microgram/mL Rh-3G, or 0.001 microgram/mL Rh-6G. However, Rh-123 alone did not decrease 3H-T uptake significantly unless present at over 10- to 100-fold higher levels than Rh-3G, respectively. The tumor cell dye uptake level was measured by N-butanol extraction and absorption scans at 400 to 600 nm. The results revealed that dye uptake was more rapid, and retention of Rh-3G and Rh-6G was 5- to 10-fold higher than for Rh-123 in the human tumor cells. The data suggest that Rh-3G and Rh-6G may be highly sensitive chromophores for laser phototherapy of human cancer cells.

Adenocarcinoma↗
PubMed1992

Visual improvement after transethmoid-sphenoid decompression in optic nerve injuries.

Transethmoid-sphenoid decompression has been performed on 11 patients with indirect optic nerve injury. Visual improvement occurred in 8 patients, including 4 patients with initial total blindness. Optic neuropathy improved even when there was a long interval, up to 92 days, between trauma and decompression. There is still controversy about the treatment of traumatic optic neuropathy. Our results suggest that surgery can be helpful in the management of this condition. Transethmoid-sphenoid optic nerve decompression is a minimally invasive procedure that gave, in this series, satisfactory results with low morbidity.

Adolescent↗
PubMed1992

[Surgical decompression of the optic nerve in intracanal injuries. Indications and results].

Fifteen patients with traumatic optic neuropathy (anatomical section excluded) underwent surgical anterior decompression of the optic nerve, via the trans ethmoid-sphenoid approach. Improvement of visual function assessed by visual acuity and visual field measurements, was obtained in 10 patients. Results remained stable for a follow-up period of at least 6 months. There was a delay of several weeks before improvement in some of the patients. Thus a long follow-up period seems recommended. Trans ethmoid-sphenoid optic nerve decompression is a reliable procedure with low morbidity, and represents a promising therapy for indirect injuries of the optic nerve.

Adolescent↗
PubMed1992

[X-ray computed tomography in surgical indication of physiological section of the optic nerve. Apropos of 15 cases].

Optic nerve trauma induces loss of vision and absence of direct pupillary light reflex. Persistence of consensual pupillary light reflex excludes anatomical section. Trans ethmoidal-sphenoidal decompression relieves the optic nerve and allows an improvement of visual function. Ten patients among 15 surgical decompressions recovered visual function. There is a good correlation between improvement and the release of an anatomical nerve compression. Recognition of direct or indirect computed tomographic signs of optic nerve compression are essential in the surgical indications. The prognosis post-surgical improvement is dependent on the sensitivity of computed tomography scan.

Craniocerebral Trauma↗
PubMed1991

Future directions of laser phototherapy for diagnosis and treatment of malignancies: fantasy, fallacy, or reality?

A new and highly promising adjunctive modality for the diagnosis and therapy of malignancies is under development using lasers and tumor targeting dyes. To reach the eventual goal of clinical treatment, several current "fantasies and fallacies" regarding laser applications in medicine must be identified and their problems clearly outlined. A multidisciplinary scientific approach is also required to enable the clinical practicality of this laser targeting approach. Many new dyes and laser wavelengths are being tested to improve specific tumor uptake and/or retention, lower systemic toxicity, increase tissue penetration, and identify fluorochromes with synergistic properties to further enhance laser tumoricidal effects. Rapid technological advancements in magnetic resonance imaging may now provide an extremely sensitive way to detect and monitor laser-tissue effects, and allow efficient interstitial laser phototherapy of deep and sometimes inaccessible tumors. The current and future prospectives of the emerging field of laser phototherapy are described.

Coloring Agents↗
PubMed1991

[Chronic maxillary sinusitis of dental origin and nasosinusal aspergillosis. How to manage intrasinusal foreign bodies?].

About a series of 33 patients operated in the ENT Depart. Prof. Soudant-La Pitié-Salpêtrière Hospital-Paris. Any emphasis was put on 11 cases of aspergillosis sinusitis. Most of the time, clinical signs are non specific. But X rays studies are of great help for the diagnosis. Treatment of chronic sinusitis of dental origin, particularly aspergillosis, remains surgical: caldwell-luc operation or endonasal approach. As a conclusion, the authors suggest systematic removal of all intrasinusal foreign body.

Adult↗
PubMed1990

[The temporomandibular joint: anatomy, physiology, clinical review].

The temporomandibular joint (TM joint) is a synovial joint with two condylar surfaces and an intra-articular cartilaginous disc. Its development has two origins. Its physiology is complex and intimately related to dental occlusion, which is why we talk about the temporomandibular and dental joint. Recent neurophysiological data allow a better approach to TM joint dysfunction. The lateral pterygoid muscle plays decisive role in the pathogenesis of TM joint dysfunction.

Humans↗
PubMed1990

[Neurinoma of the 8th cranial nerve. Surgical indications in neurofibromatosis].

There are two types of neurofibromatosis, i.e. peripheral neurofibromatosis (type 1) and central neurofibromatosis (type 2). Neurinomas of the acoustic nerve are basically seen in central neurofibromatosis, in which case they are generally bilateral. Surgical indications for neurinoma are rare and 5 patients will be discussed: 2 of these underwent an operation on the neurinoma by the posterior route on several occasions, while 1 patient was operated by the trans-labyrinth route. Nuclear magnetic resonance remains the best means of monitoring.

Adult↗
PubMed1990

[Amyloidosis disclosed by ORL manifestations].

Amylosis is characterized by an infiltration of acellular substance into the tissues. This substance is mainly made of protein molecules. This disease is primary or secondary to general disorders. Its anatomical polymorphism can well involve the ENT system. Its clinical pictures are well known by the ENT specialist. About tow amyloid tumors diagnosed because of oropharyngeous signs, the authors remind the main symptoms at the upper airway and ENT tracts; the local, regional and general treatment will be discussed.

Aged↗
PubMed1990

[Post-traumatic decompression of the optic nerve. Ophthalmologic and x-ray computed tomographic evaluation. Results in a series of 23 cases].

Post traumatic optic nerve compression gives a Clinic picture of physiological section. CT Scan is consistent with optic canal lesion when considering direct signs (bony fragments compressing the nerve) or indirect (fractures and hematoma of posterior orbital wall, of posterior ethmoid, and sphenoid). 23 patients had a surgical decompression through transethmoidosphenoidal approach. A lesion of optic canal was found in 22 out of 23 cases. Improvement of vision was noted in 12 cases.

Adolescent↗