Toxicity and bacterial anti-motility activities of the hydroethanolic extract of Acacia senegal (L.) Willd (Fabaceae) leaves.

BACKGROUND: Acacia senegal is a plant traditionally used for its various properties, including the treatment of infectious diseases. Recently, our team has demonstrated the ability of the hydroethanolic extract of the leaves to increase the activity of phenicol antibiotics against multi-resistant bacteria. The aim of this work is to determine the toxicological effects of the extract and its capacity to inhibit the bacterial mobility of Gram-negative bacteria, in order to evaluate the level of safety use of this plant. METHODS: The cytotoxicity test was performed using the neutral red absorption method. Acute and sub-acute oral toxicity were conducted on NMRI mice and Wistar rats. The behaviour and adverse effects were recorded during the 14 days of the acute study. For the subacute test, biochemical parameters, food and water consumption, and morphological parameters were determined. The anti-motility activities were evaluated on Pseudomonas aeruginosa PA01 and Escherichia coli AG100, using specific concentrations of Agar as required by the method. RESULTS: HEASG induced inhibition of keratinocytes cell growth with an IC50 of 1302 ± 60 µg/mL. For the acute toxicity study in mice, the single dose of extract of 2000 mg/kg body weight caused no deaths and no behavioural changes were observed; therefore, the median lethal dose (LD50) of HEASG was calculated to 5000 mg/kg body weight. In Wistar rats, no mortality was observed at 250, 500 and 1000 mg/kg/day during the 28-day subacute oral toxicity study. The weights of both females and males increased globally over time, regardless of the batch. No statistically significant differences were registered for organ weights and biochemical parameters, except for chloride for biochemical parameters. Water and food consumption did not change significantly. Furthermore, no macroscopic changes in organ appearance were observed. Regarding anti-motility activity, the extract has reduced the swarming motility of PA01 and AG100 significantly at the concentration of 32 µg/mL (P < 0.001). The extract has reduced the swimming motility (P < 0.01) of PA01 but not AG100. CONCLUSIONS: The results suggest that hydroethanolic extract of A. senegal leaves has significant activity against bacterial motility and relatively low toxicity.

Enhanced photoemission from laser-excited plasmonic nano-objects in periodic arrays.

The process of photoelectron emission from gold surfaces covered with nano-objects that are organized in the form of a periodic array is addressed in the short laser pulse regime ([Formula: see text] fs) at moderate intensities [Formula: see text] W cm(-2) and for various laser wavelengths. The emission spectrum from a gold single crystal measured under the same conditions is used for reference. The comparison of the photo-emission yield and the energy of the ejected electrons with their counterparts from the (more simple) reference system shows that the periodic conditions imposed on the target surface drastically enhance both quantities. In addition to the standard mechanism of Coulomb explosion, a second mechanism comes into play, driven by surface plasmon excitation. This can be clearly demonstrated by varying the laser wavelength. This interpretation of the experimental data is supported by predictions from model calculations that account both for the primary quantum electron emission and for the subsequent surface-plasmon-driven acceleration in the vacuum. Despite the fact that the incident laser intensity is as low as [Formula: see text] W cm(-2), such a structured target permits generating electrons with energies as high as 300 eV. Experiments with two incident laser beams of different wavelengths with an adjustable delay, have also been carried out. The results show that there exist various channels for the decay of the photo-emission signal, depending on the target type. These observations are shedding light on the various relaxation mechanisms that take place on different timescales.

Multi-channel electronic and vibrational dynamics in polyatomic resonant high-order harmonic generation.

High-order harmonic generation in polyatomic molecules generally involves multiple channels of ionization. Their relative contribution can be strongly influenced by the presence of resonances, whose assignment remains a major challenge for high-harmonic spectroscopy. Here we present a multi-modal approach for the investigation of unaligned polyatomic molecules, using SF6 as an example. We combine methods from extreme-ultraviolet spectroscopy, above-threshold ionization and attosecond metrology. Fragment-resolved above-threshold ionization measurements reveal that strong-field ionization opens at least three channels. A shape resonance in one of them is found to dominate the signal in the 20-26 eV range. This resonance induces a phase jump in the harmonic emission, a switch in the polarization state and different dynamical responses to molecular vibrations. This study demonstrates a method for extending high-harmonic spectroscopy to polyatomic molecules, where complex attosecond dynamics are expected.

Corpus callosotomy for control of intractable epilepsy in children.

Cerebral commissurotomy has often been reported to control seizures in patients suffering from intractable epilepsy. However, in adults, division of the corpus callosum alone has been shown to be equally effective while considerably reducing the surgical morbidity. The present study of nine epileptic callosotomized patients suggests that callosal section can also be performed successfully and safely in children. Neurologic and concomitant psychological improvements are described.

Adjunctive therapy with oxcarbazepine in children with partial seizures. The Oxcarbazepine Pediatric Study Group.

OBJECTIVE: To evaluate the safety and efficacy of oxcarbazepine (OXC) as adjunctive therapy in children with inadequately controlled partial seizures on one or two concomitant antiepileptic drugs (AEDs). BACKGROUND: OXC has shown antiepileptic activity in several comparative monotherapy trials in newly diagnosed patients with epilepsy, and in a placebo-controlled monotherapy trial in hospitalized patients evaluated for epilepsy surgery. DESIGN: A total of 267 patients were evaluated in a multicenter, randomized, placebo-controlled trial consisting of three phases: 1) a 56-day baseline phase (patients maintained on their current AEDs); 2) a 112-day double-blind treatment phase (patients received either OXC 30-46 mg/kg/day orally or placebo); and 3) an open-label extension phase. Data are reported only from the double-blind treatment phase; the open-label extension phase is ongoing. METHODS: Children (3 to 17 years old) with inadequately controlled partial seizures (simple, complex, and partial seizures evolving to secondarily generalized seizures) were enrolled. RESULTS: Patients treated with OXC experienced a significantly greater median percent reduction from baseline in partial seizure frequency than patients treated with placebo (p = 0.0001; 35% versus 9%, respectively). Forty-one percent of patients treated with OXC experienced a > or =50% reduction from baseline in partial seizure frequency per 28 days compared with 22% of patients treated with placebo (p = 0.0005). Ninety-one percent of the group treated with OXC and 82% of the group treated with placebo reported > or =1 adverse event; vomiting, somnolence, dizziness, and nausea occurred more frequently (twofold or greater) in the group treated with OXC. CONCLUSION: OXC adjunctive therapy administered in a dose range of 6 to 51 mg/kg/day (median 31.4 mg/kg/day) is safe, effective, and well tolerated in children with partial seizures.

Sound localization in hemispherectomized patients.

In order to precisely evaluate the consequences of cortical damage on free-field sound localization in humans, the present study examined response accuracy to auditory targets in three hemispherectomized patients and IQ-matched controls. Listeners reported sound location by pointing with their dominant hand to the apparent sound location in an anechoic chamber. Two conditions were tested: (i) localization of a fixed-sound source and (ii) localization of the beginning and the end of a simulated moving stimulus. In both conditions, the responses of the patients were less accurate than those of the controls in the hemifield contralateral to their removed hemisphere. Moreover, the single-case analyses revealed that the performances obtained with fixed sources were generally more precise than those obtained with moving sources. This result is discussed in terms of a differential involvement of cortical and subcortical pathways in the processing of stationary and moving sounds. Finally, the age at surgery and the post-surgical interval were related with the magnitude of the deficits, suggesting the possible influences of functional reorganization and cerebral plasticity.

Absence of disconnexion syndrome in callosal agenesis and early callosotomy: brain reorganization or lack of structural specificity during ontogeny?

Four acallosal subjects, one child, aged 5, and three adults, as well as five epileptic patients who underwent callosotomy between the ages of 6-21 years, were tested on a variety of intra- and intermanual tasks in a study aimed at elucidating the developmental aspects of callosal plasticity. The performance of the clinical sample was compared to that of 48 normal children, aged 5-12 years, an age span generally considered to coincide with the final stages of callosal maturation. As previously reported, interhemispheric integration improved with increasing age in the normal sample. The two patients having undergone callosotomy in childhood performed as well as their normal peers, whereas the three others who had the operation in late adolescence or adulthood showed the typical disconnexion deficits reported in the literature. The acallosal subjects, including the youngest one, outperformed all groups. We speculate that the remarkable plasticity seen in the acallosals and the young callosotomized patients may be related to a critical period in development coinciding with a phase of synaptic overproduction and redundancy that would favor the reinforcement of alternative neural pathways. The compensatory mechanisms appear to become more limited in late adolescence when synaptic distribution presumably assumes adult patterns.

Reye's syndrome: relapses and neurological sequelae.

Twenty-two children aged 2 months to 11 years were seen at our institution from January 1970 to March 1975 with clinical, laboratory, and/or histological features consistent with the diagnosis of Reye's syndrome. There were three pairs of siblings. Severity of the illness ranged from relatively benign to rapidly fatal forms. Five received live attenuated vaccines within the three weeks prior to admission. Four relapsed 1 to 21 months after the initial episode, and in one there were multiple recurrences. Six developed major neurological sequelae. All patients graded levels IV and V by EEGs on admission subsequently died in contrast to none from grades 1 and 2. Peritoneal dialysis was carried out in the more severely affected patients. The procedure did not influence final outcome as predicted by the first EEG and is thought to be of limited value.

Case study: dreamy state and temporal lobe dysfunction in a migrainous adolescent.

Symptoms of migraine can be very atypical during childhood and adolescence. This article describes a case in which the symptoms of migraine were mainly psychiatric: dreamy state, intermittent confusion, partial amnesia, and childlike regressive behavior with depressive features. Although the results from neurological examinations and electroencephalographic recordings were normal when the individual was symptomatic or not, temporal lobe dysfunction, determined by 99mTc-hexamethyl-propyleneamine oxamine single-photon emission computed tomography, was evident during the migraine.

Extent and limits of cerebral adjustment to early section or congenital absence of the corpus callosum.

The ability to effect inter- and intrahemispheric comparisons of visual and tactile stimuli was studied in 4 callosotomized patients and 6 callosal agenesis subjects using response accuracy and response times to determine the extent of cerebral adjustment to functional or congenital absence of the corpus callosum. The visual tasks involved within- and between-fields presentation of pairs of colours and shapes. The tactile tasks required uni- and bimanual comparisons of 3 categories of stimuli (size, shape and texture) of increasing difficulty. Older callosotomized children showed disconnection deficits similar to those reported in adult split-brain patients, whereas both acallosal subjects and our youngest patient with complete callosal transection demonstrated a high level of accuracy in the interhemispheric tasks. However, all patients required considerably more time to accomplish the cross-integration of relatively complex visual and tactile information which seems to be one of the major limitations of the compensatory mechanisms. The results also indicate that the quality of transfer differs between the acallosal and early-callosotomized patients in relation to the sensory modality studied. Thus, visual cross-matching was found to be superior to bimanual matching for the callosotomized group, whereas intermanual comparisons proved to be more efficient than visual integration in the acallosals. These divergent findings suggest not only that different compensatory mechanisms may be operating in visual and tactile transfer, but also that the same mechanisms may be utilized differently by the two populations deprived of the use of callosal connections.

Neurological findings in HIV-infected children: a review of 49 cases.

Many HIV-infected children have neurological involvement. We present our observations in 49 cases, 58% of which had some form of clinical neurological impairment. Most of the patients affected (71%) presented with progressive encephalopathy, characterized by developmental delay with loss of acquisitions and cognitive decline, an impaired growth curve, microcephaly and corticospinal dysfunction. CT-scan imaging shows cerebral atrophy in all cases and basal ganglia calcifications in 29%. Non-specific abnormalities are found on the EEG in two-thirds of cases and in the CSF in slightly less than half the cases. Pathological studies sometime revealed HIV encephalitis or lateral corticospinal tracts degeneration. Neurological impairment secondary to vascular events, neoplasms or opportunistic infections were rare, especially when compared with the adult HIV population.

[Brain tumors in children in a French Canadian environment]. / Tumeurs Cerebrales de l'enfant en milieu Canadien-Français.

Between 1964 and 1976, we have seen 197 cases of cerebral tumors in children. We have studied the frequency of each histological group of tumors, their localization, the results of the clinical investigation, their clinical manifestations and the prognosis for each group. This study has confirmed that in children brain tumors are more frequently localized in the posterior fossa (56.4%). As in other series, tumors derived from the glia represent nearly 80% of the total. Clinically, increased intro-cranial pressure is the most frequent manifestation of posterior fossa lesion (75% of cases) while cerebellar involvement was seen in 60% of these children. Brain lesions and supratentorial tumors are more insidious in their presentation and their clinical manifestations more diversified. The EEG appeared useful in the investigation of brain tumors and showed irregularities in 78% of our patients. However, a more specific diagnosis requirelography. As in previous series, the mortality rate remained high in the children we have followed, particularly for some groups of tumors (glioblastoma, medulloblastoma, brain stem lesions). It is to be hoped that with the introduction of the CT Scan, the improvement of neurosurgical techniques and the use of immuno and chemotherapy, the prognosis may be improved.

Scoliosis assessment in Friedreich's ataxia by means of intrinsic parameters.

Spinal deformities have been evaluated in a five year retrospective study where 28 boys and 25 girls all having Friedreich's ataxia were on the average assessed once a year in a multidisciplinary clinic. Scoliosis seems somewhat more progressive in girls than in boys and more severe in non-ambulatory than ambulatory patients. Some of those scolioses are very progressive reaching 60 degrees to 100 degrees Cobb angle values requiring spinal surgery while other progress less rapidly and do well on their own. In addition it was shown that the intrinsic geometric spine curve parameters namely that of curvature and torsion are a powerful diagnostic tool in the assessment of evolutive scoliosis.

Serum and platelet lipoamide dehydrogenase in Friedreich's ataxia.

Pyruvate dehydrogenase (PDH), alpha-keto glutarate dehydrogenase (alpha-KGDH) and lipoamide dehydrogenase (LAD) were measured in platelets of 11 patients with typical Friedreich's ataxia and 10 normal control subjects. Serum LAD was also evaluated in the same patients. No statistically significant changes were found in platelets for the group as a whole, although some patients had low values (more than one standard deviation below control mean). Serum LAD was significantly reduced in the patients with Friedreich's ataxia. This was not due to associated diabetes.

Platelet taurine uptake in spinocerebellar degeneration.

The uptake of 14C-taurine was studied in the platelets of 20 ataxic patients and 20 age-matched normal control subjects. No significant differences were found in uptake or kinetics of taurine between the two groups of subjects. If a transport defect in taurine exists in Friedreich's ataxia, it is not present in all tissues. Preliminary indication was obtained in favor of heterogenity of the uptake pattern between ataxic individuals.

A progressive neurological syndrome associated with an isolated vitamin E deficiency.

Several authors have recently reported a neurological disorder associated with chronic vitamin E deficiency in man. Except in one patient, this deficiency has always been secondary to an underlying disease resulting in lipid malabsorption. We report a second case of such a neurological syndrome in a patient in whom vitamin E deficiency was an isolated finding. The clinical picture in our patient was characterized by a diffuse muscle weakness most prominent distally and in the lower limbs, generalized areflexia, a decrease in proprioception and vibration sense and slight limb and gait ataxia. His condition improved on alpha tocopherol therapy so that it is very likely that vitamin E deficiency is responsible for his neurological deficit. Since in our patient as well as in several other reported cases this condition has been treatable, it is important that this syndrome be recognized in children presenting a suggestive clinical picture even if they do not have lipid malabsorption.

Evaluation of foot deformity using a three-dimensional geometric model.

A three-dimensional geometric model of the foot's bony structure based on the use of a stereoradiographic technique is presented. To illustrate the potential of such a model it has been applied here to the study of cavus foot in a patient having Friedreich's ataxia. This model permits an accurate evaluation of this complex spatial foot deformity.

Intermittent treatment of febrile convulsions with nitrazepam.

Intermittent oral or rectal administration of diazepam for the prophylactic treatment of febrile convulsions has given results comparable to the continuous use of phenobarbital while limiting side effects and risks of toxicity. Since we believe that nitrazepam is a better anticonvulsant than diazepam, we performed a study to evaluate the effectiveness of this medication in the prophylactic treatment of febrile convulsions. Nitrazepam was given only when the children had fever and almost exclusively in children with a high risk of recurrence (less than 12 months of age at first convulsion; atypical convulsion; one or several previous convulsions). Thirty one children with a high risk of recurrence received nitrazepam. The rate of recurrence in this group was 19.3% after a follow-up of 16 months, compared to 45.8% in 24 children who also had a high risk of recurrence but in whom the parents refused the medication or gave it inadequately (p less than 0.05). Fifty one children with a low risk of recurrence also were evaluated and followed for at least 12 months (mean 15.4 months). Six were treated with nitrazepam, mostly because of parental anxiety, and none had a recurrence; of the 45 untreated children in this group, 6 (13.6%) had another convulsion. These results show the efficiency of nitrazepam in the prophylactic treatment of febrile convulsions.

Kinematics of the foot.

Orthogonal stereoradiographs are frequently utilized in determining three-dimensional geometrical parameters of human body segments. They have been applied here in the estimation of the length and elongation of the ligaments of the normal foot. Three small spherical metallic markers were respectively encrusted into the tibia and fibula, the seven bones of the tarsus and into the five metatarsals of an amputated lower limb to identify uniquely their spatial location. The foot was then positioned on a rotating platform. Standardized antero-posterior and lateral radiographs were taken. Afterwards the foot was dissected and the proximal and distal insertions of most of its ligaments were located by means of spherical markers. A second series of orthogonal radiographs were taken of each of the fourteen bones. The radiographs were digitized. The length of each ligament and elongation for a simple and complex movements were calculated by means of a computer program. The results of a simple movement of rotation representing a normal 20 degree dorsiflexion at the talocrural joint and of complex movements of rotation stimulating an abnormal high arch such as encountered in Friedreich's ataxia are presented and discussed.

Origin of Friedreich's disease in Quebec.

We have been able to trace 40 cases of classical Friedreich's disease from 14 previously unrelated French Canadian kindreds to one common ancestral couple arriving in New France in 1634: Jean Guyon and Mathurine Robin. One member of this couple presumably introduced one gene for Friedreich's disease into the French Canadian population. This gene has now been traced over 12 generations to both parents of the present cases. We plan to use this knowledge to study the spectrum of clinical manifestations of this gene and to carry out gene chromosomal localization studies, using the techniques of linkage and of molecular biology. Such studies in rare autosomal recessive disorders have previously been judged to be almost impossible.