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A Chabli

Publications and source records attributed to A Chabli.

18 recordsLinked to original sources
PubMed2006

Prenatal diagnosis of some metabolic diseases using early amniotic fluid samples: report of a 15 years, experience.

BACKGROUND: In the present study, we report the results of 132 prenatal diagnoses performed on chorionic villi and cell-free amniotic fluid obtained simultaneously at 12-13 weeks of gestation. In addition, we report the result of 59 prenatal diagnoses performed at 12-13th week using amniotic fluid only. METHODS AND RESULTS: A total of one fetal loss (1/191) was observed when a sample of amniotic fluid was obtained at around 12-13 weeks, whereas three losses (3/82) were observed after midtrimester amniocentesis. We attribute this finding to the fact that only a very small volume of amniotic fluid was sampled using a very small needle. CONCLUSION: From these data it appears that when a couple is facing a high risk of recurrence of some metabolic diseases, the study of chorionic villus and amniotic fluid sampled simultaneously offers a safe and reliable method of early prenatal diagnosis.

Abortion, Spontaneous↗
PubMed2002

Improving the prenatal diagnosis of citrullinemia using citrulline/ornithine+arginine ratio in amniotic fluid.

Prenatal diagnosis of citrullinemia is performed using a direct argininosuccinate synthetase (ASS) assay on chorionic villi (CV) and citrulline concentration measurement in early amniotic fluid (AF). Here we report the results of 40 prenatal diagnoses performed using this method, discuss the difficulties encountered in interpreting the results, and propose the use of the citrulline/ornithine+arginine ratio (which is more discriminatory than citrulline concentration alone) when performing prenatal diagnosis of citrullinemia.

Amniocentesis↗
PubMed2000

Arm restlessness in patients with restless legs syndrome.

Restless legs syndrome (RLS) is a neurologic disorder characterized principally by leg paresthesia and motor restlessness. Several clinical reports indicated that many patients with RLS also have arm paresthesia and restlessness. In the present study, the incidence of arm restlessness was assessed by questionnaire in 230 patients diagnosed with idiopathic RLS. Arm restlessness was reported by 48.7% of the patients. Patients with and without arm restlessness were compared with regard to clinical and polysomnographic parameters. No between-group differences were found for age at onset of RLS, duration of illness, gender, presence of a family history of RLS, sleep latency, total sleep time, sleep efficiency, and periodic leg movements index during sleep. However, arm restlessness was more frequent in patients with severe RLS. Interestingly, the polysomnographic data failed to differentiate the patients with arm restlessness from those without arm restlessness, except for sleep efficiency, which tended to be lower in patients with arm restlessness. In conclusion, the results of the present study are in agreement with clinical observations that a large proportion of patients with RLS have arm restlessness.

Adult↗
PubMed2000

Cross-correlated and oscillatory visual responses of superficial-layer and tecto-reticular neurones in cat superior colliculus.

The present study examined, in the superior colliculus (SC) of anaesthetised cats, the functional connectivity between superficial-layer neurones (SLNs) and tectoreticular neurones (TRNs: collicular output cells). TRNs were antidromically identified by electrical stimulation of the predorsal bundle. The auto- and cross-correlation histograms of visual responses of both types of neurones were recorded and analysed. A delayed, sharp peak in cross-correlograms allowed us to verify whether SLN and TRN cells were coupled; in addition, oscillatory activities were compared to verify if rhythmic responses of SLN sites were transmitted to TRN sites. We found that oscillatory activity was rarely observed in spontaneous activity of superficial (1/74) and TRN sites (1/48). Moving light bars induced oscillation in 31% (23/74) of the superficial-layer and in 23% (11/48) of the TRN sites. The strength of the rhythmic responses was determined by specific ranges of stimulus velocity in 83% (19/23) and 64% (7/11) of oscillating SLN and TRN sites, respectively. Frequencies of oscillations ranged between 5 and 125 Hz and were confined, for 53% of the cells, to the 5-20 Hz band. Thus, the band-width of frequencies of the stimulus-related oscillations in the superior colliculus was broader than the gamma range. Analysis of cross-correlation histograms revealed a significant predominant peak with a mean delay of 2.7+/-0.9 ms in 46% (17/37) of SLN-TRN pairs. Most correlated SLN-TRN pairs (88%: 15/17) had superimposed receptive fields, suggesting they were functionally interconnected. However, individual oscillatory frequencies of correlated and oscillatory SLN and TRN cells were never the same (0/8). Together, these results suggest that the neurones in collicular superficial layer contact TRNs and, consequently, support the idea that the superficial layers contribute to collicular outputs producing eye- and head-orienting movements.

Animals↗
PubMed2000

Periodic arm movements in patients with the restless legs syndrome.

A high proportion of patients with restless legs syndrome (RLS) also complain of arm paresthesia but the presence of periodic arm movements (PAM) has never been documented in a sleep laboratory in these patients. We investigated the prevalence of PAM during nocturnal sleep and awakenings in 22 RLS patients. Fifteen patients had a PAM index >5 movements per hour during wakefulness and among them only 3 had a PAM index >5 during sleep. Twenty patients had a periodic leg movement (PLM) index >5 during wakefulness and 17 had a PLM index >5 during sleep. In 42.8% of cases, PAM showed temporal relationship with PLM during wakefulness. These results show that PAM is frequent in RLS and suggest that the basic neurological dysfunction responsible for RLS is probably not located exclusively at the level of the lumbar spinal cord but involves neuronal systems located at upper levels.

Adult↗
PubMed1999

Maturation of visual receptive field properties in the rat superior colliculus.

Visually responsive neurons were recorded in the superficial layers of rat superior colliculus from postnatal day 12 to 28. Receptive field properties such as size, type (ON, OFF, ON-OFF and motion sensitive) and direction selectivity were analyzed to disclose changes during maturation. Although some aspects of sensory properties are modified during development (latency, receptive field sizes, and proportions of receptive field types), a high level of sophistication is also present in young animals even before eyelid opening. For instance, direction selective and direction biased cells, which require complex synaptic relations, are already observed when the first light evoked responses emerge in the superior colliculus (P13), strongly suggesting that this property develops without visual experience. Furthermore, direction selectivity is present in the colliculus prior to the appearance of visually evoked activity in the cortex. This indicates that direction selectivity can not be attributable to incoming cortical afferents. This study provides the first direct evidence that, unlike the cat, the rat's cortico-tectal pathway is only weakly involved in the establishment of direction selectivity in collicular neurons.

Aging↗
PubMed1999

Response component analysis of simple and complex cells of area 18 during depression of area 17.

Simple and complex cells of visual areas of cats may be reliably classified according to the modulatory index (MI) of their responses. This investigation is aimed at analysing the MI in area 18 when a small region (about 200-400 microm in diameter) of area 17 was inactivated with a microinjection of GABA, in anesthetized cats. Cells were stimulated with sine-wave gratings whose orientation, spatial, and temporal frequencies were optimal for the studied unit. The AC and DC response components, and the MI were computed along with fast Fourier transforms of evoked discharges recorded as peristimulus time histograms. Results showed that these response components were relatively unaffected in simple cells, whereas complex cells exhibited large changes when area 17 was silenced. In particular, a large proportion of complex cells showed a MI greater than 1, thereby adopting a response pattern resembling simple cells. It is suggested that this subpopulation of complex cells receives a direct input from geniculate X cells.

Animals↗
PubMed1998

Influences of area 17 on neuronal activity of simple and complex cells of area 18 in cats.

To understand the influence of the ascending path linking area 17 to area 18 of visual cortices, experiments were carried out in which a small neuronal population of area 17 was inactivated with GABA, while unitary responses were recorded in area 18. In the latter, cells are identified as belonging to the simple or complex family according to their firing pattern evoked in response to sine-wave gratings scrolling through the receptive fields. Anesthetized cats were prepared for single-cell recordings. In area 17, a GABA-containing pipette was placed in superficial layers in order to inactivate reversibly a small neuronal population. Prior to blockade, the orientation tuning curves were obtained in both areas and the difference in optimal orientation between areas 17 and 18 was recorded. In area 18, cells were classified as simple or complex. The strategy was to study the reaction of neurons in area 18 prior to, during and after area 17 depression. In most simple cells, whenever the difference in orientation was in the iso-range, that is when the difference in optimal orientations of the injected site (in area 17) and of the neuron in area 18 was less than 30 degrees, the GABA application produced a decline of the evoked discharges, whereas GABA injection augmented the evoked firing rate when the difference was in the cross-range (>60 degrees). In contrast to simple cells, GABA depression enhanced the responses in the majority of complex cells with like orientations in both areas. When the difference between recording sites was in the cross-range, then area 17 depression produced weaker evoked firing. A tangential penetration of the injecting pipette, allowing injection of different orientation sites while testing the same unit in area 18, revealed that the latter could react with an enhancement or a decline of the responses as the injecting pipette shifted from iso (or cross) to cross (or iso) disparity in optimal orientations between areas 17 and 18. These results suggest that the path connecting area 17 to area 18 may be functionally discriminated on the basis of the orientation domain and cell types. In addition, our data suggest that the ascending visual streams are required to generate orientation specificity in area 18.

Animals↗
PubMed1997

Spatial frequency properties in area 18 during inactivation of area 17 in cats.

The aim of this investigation was to understand the functions of long horizontal connections projecting from area 17 to area 18 in cats. The animals were anesthetized and prepared for recording single-cell responses to sine-wave gratings in area 18. Neuronal activity was analyzed under three conditions: prior to, during, and after inactivation of a circumscribed region of area 17. The latter was depressed with micro-injections of GABA. Cells in both areas were in close retinotopic correspondence. Cells were classified as simple and complex types. Globally, simple cells were less affected than complex units, and those which were affected shifted their optimal spatial frequency to higher values. Complex neurons were more often influenced by the interruption of area 17 input. Namely, the peaks of the tuning curves were displaced on the x-axis to a new optimal spatial frequency. This effect was obtained by a dual change: a decline in the discharge strength to the optimal spatial frequency and an enhancement to nonoptimal spatial frequency. Contrast sensitivity function disclosed similar shifts of optimal spatial frequencies. Likewise bandwith, spatial resolution, high cutoff, and low cutoff were modified to a greater extent in complex cells. It appears that there is no relationship between areas 17/18 orientation difference and the modifications observed in tuning curves to spatial frequencies. The results suggest that neurons of area 18 may carry multiple-frequency channels and that area 17 facilitates the emergence of one particular spatial frequency.

Animals↗
PubMed1994

Application of a new protocol for nested PCR to the detection of minimal residual bcr/abl transcripts.

Nested PCR (NPCR), a two-step procedure in which the products of a first PCR using 'outer' primers are reamplified using 'inner primers', has been successfully used to test for the chronic myeloid leukemia (CML)-specific bcr-abl transcripts. A major drawback of the conventional nesting strategy is linked to the opening of the reaction tube between the two successive PCR reactions, giving a risk of contaminating the second mix with amplicons. In this paper, the application of a new protocol for NPCR without reopening the reaction tube between the two steps of the procedure is described for the research of residual leukemic cells in the peripheral blood of 14 CML patients treated by bone marrow transplantation (BMT) or interferon (IFN). This assay which is both highly specific and sensitive, offers several advantages over the use of conventional NPCR: it is more sensitive, faster and decreases the risk of false-positive results. In addition, chemiluminescent detection of amplified DNA after transfer onto a nylon membrane, although comparable with radioactive hybridization in terms of sensitivity and speed, is more advantageous in safety and convenience. In conclusion, this assay could be adapted to a number of clinical diagnostic uses.

Base Sequence↗
PubMed1993

Fast, manual, nonradioactive method for DNA sequencing.

We describe a protocol that allows nonradioactive detection of sequencing products after manual, direct, solid-phase sequencing of polymerase chain reaction-amplified DNA. The amplified DNA fragment to be studied is biotinylated at the 5' end of one of the two oligonucleotide primers used for amplification, allowing coupling to streptavidin-coated magnetic beads. The immobilized double-stranded DNA is then separated into single strands by alkaline treatment. A 5'-biotinylated sequencing primer is used after saturating with a biotin solution any possible remaining affinity sites on the streptavidin-coated magnetic beads. Sequencing is performed by using T7 DNA polymerase, and the sequencing products are electrophoresed in denaturing polyacrylamide sequencing gel. After transfer of the products to a nylon membrane, the sequencing pattern is revealed by chemiluminescence. Biotinylated alkaline phosphatase is bound to the 5' end of the sequencing primer via a streptavidin bridge and catalyzes the reaction by cleaving a phosphate group from a chemiluminescent substrate. The emitted photons are detected by exposing the membrane to x-ray film. This method is simple, rapid, and consistently successful and reproducible.

Base Sequence↗
PubMed1991

Bisexual behavior in the male rat: influence of masculine sexual activity on the display of lordosis behavior.

Sexually inexperienced male Wistar rats (strain WI in our colony) known to very infrequently display spontaneous lordosis behavior (Schaeffer et al., 1990b) were used. A first group was tested four times at 5-day intervals for lordosis with vigorous stimulus males (heterotypic sexual behavior), immediately following testing for masculine sexual activity with highly receptive females (homotypic sexual behavior). A small number of animals displayed lordosis during the first test, but more and more animals displayed this behavior from the first to the fourth test. There was no relationship between the degree of masculine sexual activity--intromission without ejaculation or ejaculation--and the occurrence of lordosis behavior. A second group was tested only once for both masculine sexual activity and lordosis behavior as above and afterwards three times at 5-day intervals for lordosis behavior in the absence of any previous testing for masculine sexual activity. A few animals displayed lordosis during their first test. As compared to the first group, the animals which had not displayed lordosis in the first test never showed lordosis responses in the following tests. It is concluded that both homotypic and heterotypic sexual interactions are required for the display of lordosis behavior in the strain of Wistar rats used in this study.

Animals↗
PubMed1989

Lordosis inhibiting effects of endogenous progesterone in the male rat primed with estrogen.

The aim of this study was to investigate the mechanisms involved in the inhibitory action of progesterone on estrogen-induced facilitatory effects of estradiol benzoate on lordosis behavior in the male rat. Intact adult male rats were given 1) 25 micrograms estradiol benzoate (EB) and 100 micrograms progesterone (P) at an interval of 42 hr. EB injected animals served as controls 2) EB followed by 3 doses of 400 micrograms dexamethasone (DEXA) and P as above. EB + DEXA injected animals served as controls. Testing for lordosis behavior was performed by 50 +/- hr after EB injection. A significant decrease in the number of the males displaying lordosis in response to the mounts of stimulus males resulted from P injection following EB treatment as compared to EB controls. DEXA treatment significantly reduced the number of EB animals showing lordosis responses but completely prevented the inhibitory effects of exogenous P to occur. Blood P values appeared to be significantly lower in EB + DEXA males than in their EB counterparts. The results provide evidence that endogenous P is involved in the display of lordosis behavior by EB-treated intact males. They mainly suggest that the effects of exogenous P on estrogen-induced lordosis behavior in the intact male rat result from sequential inhibitory mechanisms involving exposure of the animals to the successive action of endogenous and exogenous P.

Animals↗
PubMed1987

Effects of ventromedial nucleus lesions on the display of lordosis behavior in the male rat. Interactions with facilitory effects of male urine.

Previous observations showed that exposure to the odor of male urine prior to mating could enhance the display of lordosis behavior in male rats feminized with ovarian hormones. This study was performed to determine in feminized male rats whether the control of lordosis behavior by the olfactory system was mediated by the ventromedial nucleus (VMN) of the hypothalamus. Male rats were orchidectomized (ORCH) as adults and primed with 25 micrograms estradiol benzoate (EB) and 150 micrograms progesterone (P) 40 hr apart. Lordosis behavior was tested 9 +/- 1 hr after P injection. VMN lesions were shown to completely suppress the display of lordosis behavior as compared to sham VMN operated and dorsomedial nucleus (DMN) lesioned animals. Exposure of feminized rats to the odor of male urine by 9 +/- 1 hr before mating significantly increased the proportion of ORCH rats that displayed lordosis behavior in response to male mounts. This effect was abolished by VMN lesions but was maintained in the sham VMN operated and DMN lesioned animals. These results were discussed in the light of the present knowledge on the neuroendocrine and olfactory structures which mediate lordosis behavior in the male rat.

Animals↗
PubMed1986

Endogenous progesterone and lordosis behavior in male rats given estrogen alone.

Male rats castrated as adults were given successive doses of estradiol benzoate (EB) combined or not, with dexamethasone (DEXA) at the end of estrogen treatment. Two experiments were done to determine if progesterone (P) of adrenocortical origin was involved in the display of lordosis behavior under these experimental circumstances. There was a significant rise in blood P concentration in animals given 0.5 and 1.0 microgram EB when compared with oil-control injected animals, an effect which was completely suppressed by DEXA treatment. An increase in the proportion of estrogen treated animals displaying lordosis responses to male mounts was found with increasing doses of EB and paralleled the effects of EB on P adrenocortical secretion. However, the number of feminized animals given 1 microgram EB + DEXA was reduced to the level corresponding to the effects of 0.5 microgram EB on lordosis behavior. These data show that the secretion of P by the adrenals is involved in the expression of lordosis behavior in castrated male rats primed with repeated doses of estrogen.

Animals↗
PubMed1985

Hormonal control of the perception of the olfactory signals which facilitate lordosis behavior in the male rat.

This study was designed to evaluate in the male rat the hormonal requirements for the facilitation of feminine behavior by the odor of male urine. Wistar rats from the WI and WII strains in our colony were orchidectomized (ORCH) as adults. A first group was given a single dose of 75 micrograms estradiol benzoate (EB) and tested for lordosis behavior 48 hr later. Exposure to the odor of male urine by 9 +/- 1 hr before the behavioral session did not increase the number of animals showing lordosis behavior as compared to non exposed controls. A second group of WI rats was given 0.5 micrograms EB every day for 4 to 8 days. A similar number of animals displayed lordosis behavior irrespective of whether they were exposed to the odor of urine before testing. A third group of WI rats was injected with 75 micrograms EB and 1 mg progesterone (P) 39 hr apart. Exposure to the odor of urine during estrogen treatment remained ineffective but significantly increased the number of animals showing lordosis behavior when performed at the time of P injection. A last group of WII rats was given 25 micrograms EB and 100 micrograms or 150 micrograms P 39 hr apart. Although uncapable as such to facilitate lordosis behavior the dose of 100 micrograms P rendered the animals responsive to the odor of urine. It was concluded that (1) the perception by feminized males of olfactory signals from the male was dependent on P; (2) an interaction between hormonal and sensory mechanisms was involved in the facilitation of lordosis behavior in the male rat.

Animals↗
PubMedDate not supplied

Connections between areas 17 and 18 depend on orientation and cell type.

The functional relationships between areas 17 and 18 are still incompletely understood; many experiments indicate that cells sharing like properties are linked together, whereas other studies suggest a deviation from this principle. Here we report the effect of using GABA to block circumscribed area 17 neuronal populations with known orientation preferences. We studied the interaction of this treatment on the responses of simple and complex neurons in area 18. The data suggest that these interactions follow different rules for simple and complex cells: specifically, an iso-orientation linkage appears to hold for simple cells while a cross-orientation linkage appears to hold for complex cells.

Animals↗