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Biomedical subjects

H Mansour

Publications and source records attributed to H Mansour.

At least 37 records · Page 2Linked to original sources
PubMed1989

Locomotion in rats transplanted with noradrenergic neurons.

It is known that catecholaminergic drugs can induce both locomotion and a late flexion reflex in spinalized animals. We studied spinal reflexes and locomotor activity in five adult spinal rats which had received a suspension of fetal noradrenergic (NA) neurons below the transection and in three control spinal rats. A rhythmical activity similar to the one of locomotion was regularly observed in three of the grafted rats held above a moving belt. In two of them, the step frequency was increased when the velocity of the moving belt was increased. This was not observed in control rats. A late flexion reflex was obtained in grafted rats that displayed locomotor activity, as well as in two controls. In the two rats which exhibited locomotor activity, analysis showed numerous immunoreactivite (against NA) cells and processes with terminals concentrated around the perikarya of motoneurones.

Animals↗
PubMed1989

Intraspinal transplants of serotonergic neurons in the adult rat.

Adult male Sprague-Dawley rats were made paraplegic by a complete transection of the spinal cord at lower thoracic level. One week later they were transplanted, below the level of the section, with a cell suspension prepared from the raphe region of 14-day embryos. After survival periods of 10 days to 1 year, the animals were sacrificed and the spinal cord processed for the immunocytochemical detection of 5-HT. Axons from grafted cells grew extensively into the grey matter of the host, and established axosomatic and axodendritic synapses in the anterior horn and intermediolateral column, similar to those of the intact animal. In addition, a group of transplanted animals was tested for sexual reflexes which are under the control of serotonin. It was found that ejaculation reflexes, which are absent in paraplegic rats, are restored in transplanted animals.

Animals↗
PubMed1988

[Value of postoperative radiotherapy in various tumors of the pituitary gland].

Already advocated by Cushing to complement surgery of pituitary adenomas, radiotherapy remains useful in these benign tumours despite controversies concerning long-term results, pituitary cell resistance and potential harmful effects on the optic nerve, glands and skin. Radiotherapy was applied to 36.6 p. 100 of 150 patients with pituitary tumours operated upon by the same surgical team. Some very good results were obtained, notably in invasive and recurrent tumours. In a case of chromophobe adenoma operated twice at 1 year interval, radiotherapy (4,500 rads) after the second operation resulted in complete cure confirmed by computerized tomography 15 years later. Similarly, in an 8-year old girl reoperated upon for severe recurrent suprasellar craniopharyngioma 3 years after the initial excision, post-operative radiotherapy (5,000 rads) produced excellent remission which persists after 19 years. Thus, even with the modern diagnostic and microneurosurgical procedures, radiotherapy remains, for many authors, a useful and safe method to improve the prognosis of pituitary tumours.

Adenoma↗
PubMed1988

Treatment and recurrences in 135 pituitary adenomas.

In 135 operated pituitary adenomas of different histological nature, seen over 20 years, the initial treatment was surgical, by trans-sphenoidal or transcranial approach depending on the tumour extent, followed by radiotherapy if necessary. In spite of modern investigation methods, diagnosis is still often made late, so that 118 of our cases already had visual symptoms. After surgery alone (87 cases) made by the same team recurrences occurred in 16%. Reoperations (14 cases) were generally more difficult and could also be followed by new recurrences needing finally radiotherapy with still positive results. Two cases had initial radiotherapy, the other 46 cases were treated by surgery and radiotherapy with a recurrence level of 8.3%. These results indicate the need to use immediate postoperative radiotherapy in every pituitary adenoma showing even the slightest invasive potential because radical surgery is hypothetical and recurrences possible. The recurrence of pituitary adenomas remains a difficult problem of anticipation and of curative management. Our position in terms of these benign tumours is to adopt readily this therapeutic course: surgery followed by radiotherapy, which provides the best prognosis without major risks.

Adenoma↗
PubMed1988

Protective effect of beta-naphthoflavone against NO2 toxicity in mice with genetically inducible lung cytochrome P450.

The effects of the cytochrome P450 inducer beta-naphthoflavone (BNF) on NO2 toxicity were studied in two strains of mice. In one strain (C57B1/6J), cytochrome P450 could be induced by the aromatic hydrocarbon, while in the other strain (DBA/2J) cytochrome P450 was not inducible by this compound. Mice were treated with BNF before and during 4 days of exposure to 20 ppm NO2. The body growth of NO2-exposed mice improved only in BNF-treated C57B1/6J mice. In this strain, BNF reduced both pulmonary edema (as measured by wet and dry lung weights or as assessed by histological studies) and lung peroxidation (as measured by malondialdehyde). This protective effect of BNF on NO2 toxicity in C57B1/6J mice was associated with an increase in the components of the cytochrome P450 system (cytochrome P450 and cytochrome b5), whereas the activities of pulmonary antioxidant enzymes (superoxide dismutase, glutathione peroxidase, and glutathione reductase) were not significantly increased. These data suggest that the induction of the cytochrome P450 system may be important in promoting NO2 tolerance in those strains of mice in which the cytochrome P450 system is genetically inducible.

Animals↗
PubMed1988

Genetic differences in response to pulmonary cytochrome P-450 inducers and oxygen toxicity.

The effects of cytochrome P-450 inducers on O2 toxicity were studied in mice. We first examined three cytochrome P-450 inducers, which differ by their specific tissue affinity: phenobarbital sodium (PB), essentially active in the liver, and 3-methylcholanthrene (3-MC) and beta-naphthoflavone (BNF), which are also active in the lung. Both BNF and 3-MC increased the survival rate and significantly decreased pulmonary edema (pulmonary water and wet-to-dry weight ratio) in C57BL/6J mice exposed to hyperoxia (O2 greater than or equal to 95%), whereas PB had no protective effect. In the second part of this study, we compared the action of BNF in two strains of mice. In one (C57BL/6J), cytochrome P-450 can be induced by aromatic hydrocarbons, whereas in the other (DBA/2J) cytochrome P-450 is not inducible by these compounds. Protection against O2 toxicity was assessed in terms of lethality and pulmonary edema and of lung lipid peroxidation (assessed by measuring malondialdehyde). BNF only protected against O2 toxicity in the inducible strain. This protective effect of BNF on O2 toxicity in C57BL/6J mice was associated mainly with a large increase in the components of the cytochrome P-450 system (cytochrome P-450 and cytochrome b5) in the lung. The activity of pulmonary superoxide dismutase was also slightly increased, but the enhancement was not statistically significant. In contrast, in DBA/2J mice neither the components of the cytochrome P-450 system nor the activity of superoxide dismutase showed any increase.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Protection of rat from oxygen toxicity by inducers of cytochrome P-450 system.

Rats were pretreated with various inducers of cytochrome P-450 before being exposed to pure normobaric oxygen (O2) in order to determine whether the inducers interfere with toxicity. The pulmonary and liver inducers beta-naphthoflavone (beta NF) and 3-methylcholanthrene (3MC) increased the survival rate and decreased the amount of pleural and lung fluid accumulation in adult rats exposed to oxygen. Phenobarbital (PB), which is essentially active in the hepatic microsomal cytochrome P-450, was less effective in counteracting oxygen toxicity. After 7 days of exposure to oxygen, none of the untreated rats survived, whereas 40, 73, and 90% survival was observed in rats treated with PB, 3MC, and beta NF, respectively. After 60 h of O2 exposure, significantly less pleural and lung fluid accumulation was observed in beta NF- and 3MC-treated rats than in untreated or PB-treated rats (p less than 0.001). Both beta NF and 3MC prevented the increase of lung peroxidation (assessed by measuring of malondialdehyde) and that of hydrogen peroxide production by lung microsomes induced by O2 exposure. These protective effects are associated with a large increase in the components of the pulmonary cytochrome P-450 system and its peroxidase activity and with an increased response to hyperoxia by lung antioxidant enzyme activities. In contrast, in control rats, the activities of the antioxidant enzymes were not increased, and both the quantity and the peroxidase activity of cytochrome P-450 were significantly decreased by O2 exposure. We conclude that in the rat, pretreatment by inducers of pulmonary cytochrome P-450 results in marked protection against O2 toxicity and an increase of antioxidant enzyme response to hyperoxia.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

[Radicular evoked potential. Peroperative recording in lumbar disk hernias].

The evoked compound action potential of lumbar nerve roots after posterior tibial nerve stimulation at the ankle during operation were studied in 10 patients with lumbar disc herniation. The recording needle electrode was inserted into compressed the nerve root before and after excision of disc herniation. The evoked nerve root action potentials consisted of a positive-negative complex. Before excision, this predominant positive complex was recorded in every patient with a mean peak latency of P1 at 16.64 +/- 1.69 msec, and a mean peak to peak amplitude of P1-N1 of 1.94 +/- 0.52 microv. In three cases with migratory disc herniation, the P1-N1 complex was followed by smaller negative component. After excision of disc herniation, the amplitude of the P1-N1 complex decreased significantly with no significant latency modification. The second negative component was not recorded in the three cases with migratory disc herniation. The recording of nerve root evoked potential during operation is of interest for diagnostic purposes. In addition, it allows electrophysiological monitoring of nerve root traumatism during operation procedures.

Adult↗
PubMed1987

[Role of cerebral echography in the diagnosis of aneurysms of the vein of Galen].

Cerebral ultrasound imaging by a transfontanelle approach is now a common investigation during the first year of life. This exploratory procedure is non-invasive, non-irradiating, requires no sedation and can be carried out at the infant's bedside. In addition, the classical apparatus can be completed by deep Doppler allowing deep cerebral vessels to be studied. Three cases are reported of aneurysm of Galen's ampulla detected by ultrasound imaging during the neonatal period. Images demonstrated the presence of an abnormal fluid mass in the region of Galen's ampulla, confirmed as of vascular origin by Doppler, and allowed assessment of degree of subjacent ventricular dilatation and possible secondary ischemic lesions. In massive neonatal forms this exploration may be sufficient since prognosis is poor, but in lesions of moderate size CT scan and angiographic examinations and perhaps MR imaging are required. This technique allows detection of this malformation in the fetus and could therefore influence therapy.

Cerebral Veins↗
PubMed1987

[Brown-Séquard syndrome caused by foramen and calcified disk herniation, responsible for direct compression of Adamkiewicz's artery].

The thoracic discal hernia is a rare affection whose prognosis has been transformed by the present diagnostic means and the technical progress of surgery. A case history has been reported of a thoracic discal hernia, T9-T10, with Brown-Sequard Syndrome and vertebral CT Scanning showed a left lateral localization. A posterior access remains indicated in lateral localization of those hernias, and it confirms clinical and neuroradiological findings showing a direct compression of the Adamkiewicz artery in the intervertebral foramen.

Arterial Occlusive Diseases↗
PubMed1986

Transplantation of dissociated foetal serotonin neurons into the transected spinal cord of adult rats.

Twenty adult rats underwent a complete section of the spinal cord at the lower thoracic level. One week later, 15 of them received a cell suspension obtained from raphe nuclei of 14-day-old foetuses into the distal fragment of the spinal cord. They were sacrificed after survival periods of 10-60 days, and vibratome sections of the spinal cord were processed for immunocytochemical detection of serotonin (5-HT). The control, non-transplanted animals showed a total absence of 5-HT immunoreactivity below the section, whereas the transplanted rats showed many immunoreactive 5-HT perikarya in the graft region, some at a distance of up to 10 mm, and a progressive innervation of the whole grey matter extending at least over 20 mm from the graft site.

Animals↗
PubMed1986

A new strategy for clinical decision making: censors and neuroendocrinological diseases.

A patient rarely has a single, isolated disease. The situation is usually much more complex since the different parts of the human organism and its metabolism interact with each other on multiple levels and follow several feedback patterns. These interactions and feedback patterns become even more complex when the effects of the external environment are considered. When several diseases are present, the first steps in medical diagnosis are to determine whether one of the diseases interacts with ("Censors") or changes the significant symptoms, signs, or results of the laboratory tests of the other diseases. We will try, within this paper, to go beyond the scope of the first generation of Artificial Intelligence systems in medicine to determine the effects of two diseases on each other. One important part of the effect of two diseases on each other is the effect of Censors. In addition, causal reasoning, reasoning by analogy, and learning from precedents are important and necessary for a human-like expert in medicine. Their application to thyroid diseases, with an implemented system, are considered in this paper.

Artificial Intelligence↗
PubMed1986

Diethyldithiocarbamate provides partial protection against pulmonary and lymphoid oxygen toxicity.

Prolonged exposure of C57B16 mice to pure O2 at 1 ATA induced pulmonary edema associated with involution of lymphoid system and depressed immunity. The consequences of these toxic events were evaluated by 1) mortality rate, 2) determination of pulmonary water, 3) thymic and splenic cellularity, and 4) humoral (primary antibodies) and cellular (mitogenic) immune responses. Pretreatment of mice with 125 mg kg-1 of diethyldithiocarbamate (DDC) several days before exposure to O2 resulted in 1) an increase in animal survival (92-100% vs. 59% O2 controls), 2) a reduction in pulmonary edema, 3) partial stabilization of thymus and spleen lymphocyte populations, and 4) restoration of the humoral response (specific antibodies appeared earlier than in O2 control animals) and improvement of the mitogenic proliferative response of the spleen cells after hyperoxia. None of these effects were observed when DDC treatment coincided with the beginning of exposure. Our results indicated that DDC protects mice from both pulmonary and lymphoid hyperoxic injury, but only in a partial manner. It is suggested that the mechanism of this antioxidative property is indirect.

Animals↗
PubMed1986

[Protection of the pulmonary toxic effects of normobaric oxygen by inducers of cytochrome P450-linked monooxygenases].

Inducers of cytochrome P450-linked mono-oxygenases increase the normobaric oxygen tolerance of the adult rat. Pulmonary inducers, as 3-methylcholanthrene and beta-naphthoflavone permit the rat survival and simultaneously a decrease of pulmonary edema. Phenobarbital, an hepatic inducer had lesser effects both on survival rate and on pulmonary and lymphoïd oxygen toxicity.

Animals↗
PubMed1986

[Transplantation of fetal neurons into the spinal cord after section].

The transection of spinal cord can be seen as an interruption of the continuity in between the control command and the peripheral reception. The consequence is an anarchic reorganization of the distal spinal cord often responsible of spasticity and painful rigidity. We have, in a first step, sectioned the spinal cord at lower thoracic level in adult rats. Knowing the modulatory role of aminergic neurotransmitters, we have then one week later transplanted foetal 5-HT neurons into the distal segment of the cord, in half of the transsected animals. Functional results suggest the constitution of sphincteral autonomy in the grafted animals whereas the controls showed either an acute urine retention leading to death within two to three weeks after the section, or an absence of sphincteral control. Immunocytochemical study with specific 5-HT antibodies showed adult-looking neurons extending processes towards the intermediolateral nucleus and the anterior horn. Ultrastructural immunocytochemistry disclosed afferent and efferent synapses to the grafted neurons.

Animals↗