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Biomedical subjects

M Taleb

Publications and source records attributed to M Taleb.

At least 19 recordsLinked to original sources
PubMed2005

Variation in nerve autograft length increases fibre misdirection and decreases pruning effectiveness: an experimental study in the rat median nerve.

OBJECTIVES: In the clinical set, autologus nerve grafts are the current option for reconstruction of nerve tissue losses. The length of the nerve graft has been suggested to affect outcomes. Experiments were performed in the rat in order to test this assumption and to detect a possible mechanism to explain differences in recovery. METHODS: The rat median nerve was repaired by ulnar nerve grafts of different lengths. Rats were evaluated for 12 months by behavioural assessment and histological studies, including ATPase myofibrillary histochemistry and retrograde neuronal labelling. RESULTS: It was demonstrated that graft length interferes in behavioural functional recovery that here correlates to muscle weight recovery. Short nerve grafts recovered faster and better. Reinnervation was not specific either at the trunk level or in the muscle itself. The normal mosaic pattern of Type I muscle fibres was never restored and their number remained largely augmented. An increment in the number of motor fibres was observed after the nerve grafting in a predominantly sensory branch in all groups. This increment was more pronounced in the long graft group. In the postoperative period, about a 20% reduction in the number of misdirected motor fibres occurred in the short nerve graft group only. CONCLUSION: Variation in the length of nerve grafts interferes in behavioural recovery and increases motor fibres misdirection. Early recovery onset was related to a better outcome, which occurs in the short graft group.

Adenosine Triphosphatases↗
PubMed2001

Reperfusion demonstrated by apparent diffusion coefficient mapping after local intra-arterial thrombolysis for ischaemic stroke.

Diffusion-weighted MRI (DWI) is becoming important for diagnosis and investigation of acute cerebral ischaemia. It has been reported that apparent diffusion coefficient (ADC) maps could be an indicator of reperfusion. Our aim was to use echo-planar technology to investigate this phenomenon. We report 19 patients treated by local intra-arterial thrombolysis for middle cerebral artery stroke within 6 h of the onset of symptoms, in whom we performed follow-up DWI. ADC were found to be higher in the patients with angiographically proven reperfusion.

Adult↗
PubMed1998

Selective restoration of sensation by peripheral nerve grafts directly implanted into the contralateral C7 dorsal root ganglion: an experimental study in rat brachial plexus.

OBJECTIVE: In brachial plexus injuries, when the dorsal root ganglion (DRG) is avulsed from the spinal cord there is no possibility of direct repair. Therefore, in the present report the median nerve was connected directly to the contralateral C7 DRG, to restore forepaw sensation. METHODS: The ulnar nerve was sectioned, and a 15-mm segment of nerve was removed. The median nerve was sectioned, transposed dorsally, and repaired using a sural nerve graft directly implanted into the C7 contralateral DRG. Rats were then assessed 6 and 12 months later by behavioral, histological, and plasma extravasion techniques. RESULTS: All animals recovered sensation in the forepaw. Retrogradely labeled sensory neurons were demonstrated in the C7 DRG, and the whole forepaw was labeled after plasma extravasion induction by median nerve antidromic stimulation. Several myelinated and positively neurofilament-stained fibers were demonstrated in the grafted median nerve. CONCLUSION: The surgical strategy proposed might be a useful alternative to selective sensory repair in the emerging field of brachial plexus reconstruction by direct spinal cord surgery.

Animals↗
PubMed1996

Cross-cultural study of schizophrenia.

Researchers have used a variety of approaches to assess schizophrenic disorders across cultures. Of the possible ways of studying cultural variations, the one most typically employed involves the accumulation of data in geographically isolated settings and indigenous situations. Another method is through comparative studies of people of various backgrounds living in the same social and geographical environment. This opportunity is provided by immigrants of diverse origins living in the same community. Ninety schizophrenic patients (according to DSM-III-kappa criteria) participated in this study, aged between 18 and 35 years. Three groups were constituted. The first population consisted of second-generation North Africans living and raised in France, the second of native French patients, and the third population consisted of schizophrenic patients living and being raised in North Africa (Algeria), their native country. This study showed that, for the symptoms evaluated, schizophrenic patients from Maghreb have few clinical differences from patients of French origin. Thus, cultural origins do not seem to be of major influence. These results are in concordance with those of the International Pilot Study of Schizophrenia based on a larger international population.

Adolescent↗
PubMed1995

The rat brachial plexus and its terminal branches: an experimental model for the study of peripheral nerve regeneration.

Despite the introduction of microsurgical techniques into clinical practice, the results of surgical procedures involving the brachial plexus and peripheral nerves are still far from spectacular. We therefore studied the rat brachial plexus and its terminal branches in 203 rats. Detailed anatomic and morphologic analyses of the biceps brachii and musculocutaneous nerve, finger flexors, flexor carpi radialis, and the median nerve were performed. Various sources of conventional and vascularized nerve grafts were explored. After musculocutaneous nerve section or median nerve section, there were no articular contractures or automutilations, which constitutes an advantage for these experimental models over the sciatic nerve model. The brachial plexus and its terminal branches provide a good experimental model which can be used to assess the development and normal control of muscle function, examine the mechanisms underlying functional recovery, and test the effects of treatments to enhance recovery.

Animals↗
PubMed1984

[The blood-testis barrier].

The blood-testis barrier in man is mainly due to the tight junctions of Sertoli cells. It creates favorable conditions for the spermatogenesis and sperm survival in the testicular fluid. It prevents the occurrence of autoimmunity after puberty. The alteration of the blood-testis barrier allows the production of antisperm antibodies and may lead to infertility.

Antibody Formation↗
PubMed1983

[Inhibin: its origin, nature and role].

Inhibin is a protein secreted by the Sertoli cells in men and by the granulosa cells in women. It inhibits the synthesis and release of the follicle-stimulating hormone in the pituitary gland and reduces the hypothalamic LH - releasing hormone content. It also inhibits the multiplication of spermatogonias in male gonads and the production of progesterone by the ovaries. Inhibin determinations in biological fluids may help to understand the pathophysiology of puberty, ovulation, menopause and various types of infertility.

Female↗
PubMed1977

[Primary vaginal cancer in adults. Apropos of 72 cases treated at the Fondation Curie from 1956 to 1968].

Primary vaginal cancer are infrequent and amount to 2 or 3 per cent of the gynecological cancers. Their diagnosis is difficult, because many other cancers metastasize in the vagina. The primary vaginal cancer arise mostly after climateric. Adjuvant causes would be a total hysterectomy in the past, prolapsus, prolonged use a pessary or a previous irradiation. The squamous-cell carcinomas, by far the most frequent (91%), are mostly situated in the upper third of the vagina on the anterior and posterior walls. Surgery, being difficult and mutilating is rarely indicated. So the treatment is mainly radiotherapic: external irradiation and intracavitary curietherapy. The radiation techniques are a little different according to the site of the lesion in the lower third or not. The upper lesion can be treated like a cervix cancer. The lower ones are more difficult to handle; for curietherapy, one must use molded apparatus, loaded with Iridium wire, adapted to each special case. The therapeutic results are rather poor:43 per cent for the 5-year cure rate and 36 per cent for the 10-year cure rate: less than for the cervix uteri. The upper lesions have a better prognosis than the lower ones. Results should be improved with an earlier diagnosis, a more accurate radiotherapy and a more precise dosimetry. The non-squamous-cell cancers (adenocarcinomas, sarcomas, mallignant melanomas) are generally rather radio-resistant. They are rare and their prognosis is very poor.

Adult↗
PubMedDate not supplied

Influence of paraoxon (POX) and parathion (PAT) on apoptosis: a possible mechanism for toxicity in low-dose exposure.

The acute effects of poisoning with organophosphorus compounds (OPCs) are well known and have been described extensively. Most of the clinical symptoms are due to inhibition of acetylcholinesterase. Although acute OPC poisoning is a well-established clinical entity, the existence of chronic poisoning due to exposure to low levels of OPC (below the threshold required for cholinergic clinical symptoms) is a hotly debated issue. Recent studies have suggested the involvement of OPCs in apoptotic processes. However, the mechanisms by which they modulate this process are poorly investigated. In the present study we evaluated the toxic effect of different concentrations of paraoxon (POX) and parathion (PAT) in murine EL4 T lymphocytes. We examined cellular responses, including induction of apoptosis, involvement of a caspase cascade, the activity of effector caspase (caspase-3) and the biochemical and morphological changes that are the hallmarks of classical apoptosis. The results of our study indicate that at doses below IC(50) POX is a potent inducer of apoptosis, as opposed to PAT that shows little apoptotic effect.

Animals↗