Search PubMed⌕ Search

Biomedical subjects

P Mares

Publications and source records attributed to P Mares.

At least 109 records · Page 6Linked to original sources
PubMed1998

Pudendal nerve motor latency correlation by age and sex.

This study was a prospective study, it was undertaken on 172 subjects who had no prior central or peripheral nerve supply pathology and who had not an antecedent of anal surgery. The subjects had a normal value of the sacral reflex latency to be included in this study. In this population the value of the pudendal motor nerve latency was compared by age and sex in order to determine precise norms. There was 92 men whose age adveraged 36 +/- 14.57 years and 80 women with an average age of 55.03 +/- 15.7. The motor latency was obtained by stimulating the nerve by rectal or vaginal tuch-near the sciatic spine with a St Mark's electrod and taking a reading in the intemediate part of the external anal sphincter muscle. The intensity of the stimulation was 70 to 80 mA. The stimulation and the recording was repeteded five both on each side and the shorter latency whose choised. The value of the motor latency taken at the positive peak was analysed statiscally. The average value was 5.52 +/- 1.9 ms on right pudendal nerve and 5.74 +/- 1.6 ms on the left in male subjects and 6.16 +/- 1.8 in the right pudendal nerve and 6.42 +/- 1.96 on the left in female subjects. The values on right pudendal nerve latency varied from 4.9 +/- 1.28 ms in men and 4.76 +/- 1.6 ms. in women at under 28 years and to 5.06 +/- 2.06 ms in men and 7.7 +/- 1.8 ms in women at over 70 years. The values on the left side varied from 5.53 +/- 1.5 ms in men and 4.78 +/- 1.35 ms in women at under 28 years and to 5.06 +/- 2.06 ms in men and 8.47 +/- 1.95 ms in women at over 70 years. In men population, the value of the motor latency of the pudendal nerve is not correlated with age. In women population, the value is correlated with age.

Adult↗
PubMed1997

Non-NMDA receptor antagonist GYKI 52466 suppresses cortical afterdischarges in immature rats.

GYKI 52466 (1-(4-aminophenyl)-4-methyl-7,8-methylendioxy-5H-2,3-benzo-diaz epi ne), a non-competitive non-NMDA receptor antagonist, was tested against epileptic afterdischarges elicited by cortical stimulation in 12-, 18- and 25-day-old rats with implanted electrodes. Shortening of afterdischarges and a decrease in intensity of clonic movements accompanying both stimulation and afterdischarges were induced by the 20 mg/kg dose of GYKI 52466 in 18- and 25-day-old animals, whereas 12-day-old rat pups exhibited only shortening of electroencephalographic afterdischarges. The 10 mg/kg dose of GYKI 52466 did not significantly change afterdischarges in any age group. Motor skills were compromised after the 20 mg/kg dose of GYKI 52466. This effect was again more marked in 18- and 25-day-old animals than in the youngest group. In addition, anxiolytic-like action was observed in the jumping down test in 25-day-old rats. This effect was not influenced by a benzodiazepine antagonist flumazenil. On the contrary, the anticonvulsant action of GYKI 52466 was partly blocked by flumazenil, indicating thus multiple mechanisms of action of GYKI 52466.

Animals↗
PubMed1997

Inhibition of glutamate decarboxylase activity by 3-mercaptopropionic acid has different time course in the immature and adult rat brains.

It has been found that the latency of epileptic seizures caused by glutamate decarboxylase (GAD) inhibitor 3-mercaptopropionate (3-MPA) is markedly longer in immature rats than in the adults. Time course of rat brain GAD inhibition was studied in 12-day-old and adult (90-day-old) animals following 3-MPA (70 mg/kg i.p.). GAD activity was determined by quantification of 14CO2 liberated from [1-(14)C]glutamate by supernatant 20,000 x g of brain homogenate prepared from rats killed at different intervals after 3-MPA administration. In adult rats, the enzyme activity decreased significantly by 14.1% even 1 min after 3-MPA administration and was decreasing gradually till the onset of seizures. In immature rats, GAD activity decrease after 1 min was by 41.4% and further decrease was smaller. Comparison of the time profiles of GAD changes in both groups confirmed our findings that in spite of delayed seizure onset, GAD inhibition in immature rats is more pronounced, probably due to immaturity of the blood-brain barrier.

3-Mercaptopropionic Acid↗
PubMed1997

Excitatory amino acid antagonists and pentylenetetrazol-induced seizures during ontogenesis. IV. Effects of CGP 39551.

We determined anticonvulsant effects of CGP 39551 [(E)-2-amino-4-methyl-5-phosphono-3-pentenoic acid 1-ethylester] against pentylenetetrazol-induced seizures in developing, 7-90 day old, rats. The rats received CGP 39551 in doses of 10, 20 or 40 mg/kg IP 30 min prior to the pentylenetetrazol administration (100 mg/kg s.c.). In addition, the 20 mg/kg dose of CGP 39551 was injected 120 min prior to pentylenetetrazol. In adult rats, all doses of CGP 39551 blocked generalized tonic-clonic pentylenetetrazol-induced seizures. In younger rats, higher doses of CGP 39551 and/or a longer delay between the CGP 39551 pretreatment and pentylenetetrazol administration was necessary for similar anticonvulsant effects against tonic-clonic seizures. In contrast, there was no effect of CGP on pentylenetetrazol-induced clonic seizures. The results indicate that CGP 39551 has anticonvulsant features similar to other competitive NMDA receptor antagonists. High doses of CGP 39551 and long pretreatment latency which are necessary in young rats for anticonvulsant effects may reflect the overexpression of NMDA transmission during the second and third postnatal week of the rat. Alternatively in adult rats, we can speculate an anticonvulsant role of a CGP 39551 metabolite or maturation of brain uptake mechanism for CGP 39551.

2-Amino-5-phosphonovalerate↗
PubMed1997

Synaptic vesicle size and shape profile in the kindling model of epileptogenesis.

Excitatory synapses were studied in the dentate gyrus ipsilateral to stimulated entorhinal cortex in fully kindled rats 2 weeks after the last (3rd) stage 5 seizure. In previous studies of the same model marked redistribution of synaptic vesicles to a 'strategic position' in the vicinity of the synaptic cleft and a significant enlargement of postsynaptic element were described. In this study the size and shape of synaptic vesicles were evaluated in three zones parallel to the presynaptic membrane of the synaptic cleft. The first zone (0.1 micron) directly adjoined the active zone of presynaptic membrane, the second was from 0.1 to 0.2 micron and the third from 0.2 to 0.3 micron from the presynaptic membrane. The vesicles of both the experimental and control animals were significantly smaller in zone I than in zone II and III and, in the control animals there was a tendency of vesicles to diminish towards the active zone. Such a tendency was not observed in the experimental animals, the largest vesicles were in the middle of zone II and were significantly more rounded in comparison to the vesicles in the controls. On the contrary, the vesicles in zone I and III were more elongated in the experimental animals than in controls. Our results may be taken as a sign of active reconstruction of synaptic apparatus in relation to increased functional readiness of the synapses. Possible mechanisms as well as significance for the kindling and epileptogenesis are discussed.

Animals↗
PubMed1997

Effects of a subconvulsant dose of kainic acid on afterdischarges elicited by cortical stimulation in rats.

The aim of this study was to test the hypothesis that nonconvulsive seizures elicited by a low dose of kainic acid may induce acute as well as chronic changes in brain function. Cortical epileptic afterdischarges (ADs) characterized by spike-and-wave rhythm and clonic seizures of facial and forelimb muscles were elicited in adult male rats with chronically implanted electrodes. Four stimulations were given in each of four weekly sessions. In the second session, 26 animals were injected with kainic acid (6 mg/kg i.p.) and 19 rats received no injection. The acute effects of kainic acid were to increase the intensity of movements accompanying stimulation and abruptly prolong ADs. Epileptic ADs were followed by a depression of electrocorticographic activity in both noninjected and kainic acid groups. In addition, when kainate was administered, interictal spike activity was registered mostly in the occipital region. One and two weeks after kainate administration, i.e. in the third and fourth stimulation sessions, there was an increased incidence of transitions from spike-and-wave ADs to another, limbic type of afterdischarge. This functional change persisted although no obvious neuronal death was found in the hippocampi of 12 other rats that received the same dose of kainic acid.

Animals↗
PubMed1997

[Electrophysiologic studies in the descending perineum in women].

Seventy five female patients (mean age: 55 +/- 13 years) were included into the study. Electromyography of the perineum with study of the intramuscular activity of the external anal sphincter was done and measures of the sacral reflex latency were obtained by stimulation of the cavernous nerve of the clitoris, recording in the external anal sphincter muscle. Neurogenic syndromes of pudendal nerve either isolated or associated with muscular disorders have been shown to be correlated with descending perineum. In our study, we investigated whether a history of obstetrical or surgical interventions is related to the occurrence of this syndrome. We did not find any significant relationship.

Adult↗
PubMed1997

Anticonvulsant action of gabapentin during postnatal development in rats.

PURPOSE: To study the anticonvulsant effects of gabapentin (GBP) in immature animals. METHODS: Motor seizures were induced by pentylenetetrazol in 7-, 12-, 18-, 25-day-old, and adult rats. Animals pretreated with GBP (15, 30, or 60 mg/kg i.p.) were compared with controls. The incidence and latency of two types of seizures [minimal (i.e., clonic)] and generalized tonic-clonic (GTCS) were recorded, and seizure severity was scored. RESULTS: GBP suppressed or at least restricted the tonic phase of GTCS at all the developmental stages studied. In addition, minimal seizures were suppressed in 18-day-old rats. Both effects exhibited a tendency to a U-shaped dose-response curve. CONCLUSIONS: Anticonvulsant effects of GBP were demonstrated in immature and in adult rats.

Acetates↗
PubMed1997

Convulsant action of D,L-homocysteic acid and its stereoisomers in immature rats.

PURPOSE: We wished to characterize the convulsant effect of homocysteic acid (HCA) in developing rats. METHODS: Seizures were induced in 7-, 12-, 18-, and 25-day-old rats by intraperitoneal (i.p.) administration of D,L-HCA and in 12-day-old rats by i.p. injection of L- and D-stereoisomers of HCA. The animals were observed for 30 min after injection. The incidence, latencies, pattern of motor seizures, and all behavioral phenomena were noted. Fifty percent convulsant dose (CD50) values were calculated by probit analysis. Electrocorticograms (ECoG) were recorded after injection. RESULTS: HCA did not elicit minimal clonic seizures whereas generalized tonic-clonic seizures (GTCS) occurred in all the age groups studied. Flexion (emprosthotonic) convulsions occurred to postnatal day 18. ECoG recordings exhibited delta activity in younger pups and sharp graphoelements in older pups, but electroclinical correlation was poor. Young animals were more sensitive to the convulsant effect of D,L-HCA. In addition, D-HCA was significantly more effective than L-HCA in inducing both flexion and generalized seizures. CONCLUSIONS: Our data clearly indicate that seizures induced by HCA differ from those evoked by homocysteine. There are no qualitative differences in the motor pattern of seizures induced by the two stereoisomers of HCA, but marked differences were apparent in the very first signs of their action. These differences might be due to interaction with different glutamate receptor subtypes.

Animals↗
PubMed1997

Anticonvulsant action of 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo(f)quinoxaline in immature rats: comparison with the effects on motor performance.

Anticonvulsant action of 2,3-dihydroxy-6-nitro-7-sulfamoylbenzo(f)quinoxaline (NBQX), a competitive antagonist at non-N-methyl-D-aspartate receptors for excitatory amino acids, was studied in a model of cortical epileptic afterdischarges (ADs) in 12-, 18- and 25-day-old rat pups with implanted electrodes. Electrical stimulation of sensorimotor cortex was repeated four times with 20-min intervals, NBQX (in doses of 10, 30, 60 or 90 mg/kg i.p.) or solvent (dimethyl sulfoxide, 1 ml/kg i.p.) were injected 10 min after the first afterdischarge. Dimethyl sulfoxide did not change the phenomena recorded; NBQX shortened ADs or at least blocked progressive prolongation observed under control conditions. Intensity of movements accompanying stimulation decreased after NBQX, and clonic movements accompanying ADs were suppressed in a dose-dependent manner. The highest dose of NBQX disabled the animals; therefore, the action of this drug on motor skills was studied in another group of animals. Even the dose of 30 mg/kg NBQX interfered with motor performance in 12- and 18-day-old rat pups, 25-day-old rat pups were more resistant to this action. NBQX exhibited only moderate antiepileptic action (suppression of progressive lengthening of ADs) at doses where unwanted side effects were absent.

Animals↗
PubMed1997

Two models of epileptic spike-and-wave rhythm in rats are differently influenced by ethosuximide.

Epileptic afterdischarges induced by electrical stimulation of the sensorimotor cortex as well as minimal metrazol seizures are characterized by EEG spike-and-wave rhythm and nearly the same motor pattern of clonic seizures. The action of ethosuximide on these two models was tested in adult rats with implanted electrodes. Cortical afterdischarges remained practically uninfluenced by ethosuximide (62.5 or 125 mg/kg i.p.) whereas minimal metrazol seizures were suppressed in a dose-dependent manner (doses of 31.25, 62.5 and 125 mg/kg i.p. were used). Present results in connection with recent data on the abolition of spike-and-wave rhythm elicited by low systemic doses of pentylenetetrazol suggest that spike-and-wave rhythm does not represent a single entity.

Animals↗
PubMed1997

Anticonvulsant effect of progabide in rats during ontogenesis.

The action of progabide against motor seizures elicited by pentylenetetrazol was studied in 7-, 12-, 18-, 25-day-old and adult rats. Progabide (dissolved in dimethylsulfoxide) was injected in doses from 12.5 to 150 mg/kg i.p. 30 min before pentylenetetrazol. Minimal seizures were not affected by solvent or progabide pretreatment. The action of progabide against major, i.e. generalized tonic-clonic seizures, changed with age: adult rats exhibited a tendency to suppression of whole major seizures, whereas specific suppression of the tonic phase was observed in rat pups during the first three weeks of life. The only effect seen in 25-day-old animals was prolongation of the latency of major seizures after the highest dose of progabide.

Aging↗
PubMed1997

Anticonvulsant effect of SL 75 102 in adult and immature rats.

The anticonvulsant action of SL 75 102, a metabolite of Progabide, was studied in a model of pentylenetetrazol-induced motor seizures in adult and 12-day-old rats. SL 75 102 suppressed generalized tonic-clonic seizures in adult rats and restricted the tonic phase of these seizures in rat pups. SL 75 102 was less effective than Progabide. In addition, some minor differences in anticonvulsant actions of these two drugs were observed.

Aging↗
PubMed1996

[Magnetic resonance imaging of the pelvis].

Magnetic resonance imaging (MRI) is particularly well suited to pelvic explorations. Normal uterine zonal anatomy and its variations within the menstrual cycle are well codified. MRI is the best preoperative imaging modality for the localization of fibroids. MRI allows a good approach to tissue characterization in benign ovarian tumors and a precise loco-regional assessment in malignant tumors. It could eventually replace the surgical second look after therapy. In prostate cancer, MRI is the most accurate imaging modality to assess capsular invasion.

Female↗
PubMed1996

Suppression of cortical epileptic afterdischarges in developing rats by anticonvulsants increasing GABAergic inhibition.

The anticonvulsant action of three drugs facilitating GABAergic inhibition by different mechanisms (valproate, phenobarbital and progabide) was studied in 229 young rats (12, 18 and 25 days old) with implanted electrodes. Epileptic afterdischarges (ADs) elicited by electrical stimulation of the sensorimotor cortex were used as a model. All three drugs were able to suppress ADs, even the lowest doses used blocked the prolongation seen with repeated stimulations under control conditions. In addition to these general effects, some differences among the three drugs were observed: phenobarbital (10, 20, and 40 mg/kg i.p.) exhibited marked anticonvulsant action in all three age groups whereas valproate (200 and 400 mg/kg i.p.) was somewhat less effective in the youngest rats studied than in the two older groups. Progabide exhibited an effect similar to valproate when a higher dose (150 mg/kg i.p.) was taken into account, but the lower dose (75 mg/kg i.p.) was most efficient in 12 day old rat pups. Our data support the possibility that cortical ADs represent a model of human myoclonic seizures. In addition, they suggest an uneven development of individual components of the GABAergic inhibitory system.

Animals↗
PubMed1996

Influence of prostaglandin E1 on tissue ischemia during surgical repair of the abdominal aorta.

OBJECTIVE: To evaluate tissue protection by PGE1 during leg ischemia in patients undergoing aortic surgery. DESIGN: Randomized, controlled prospective clinical trial. SETTING: Single university hospital. PARTICIPANTS: 19 consecutive patients undergoing abdominal aortic aneurysm repair. INTERVENTIONS: Patients received infusions of 30 ng/kg/min of PGE1 or saline. MEASUREMENTS AND MAIN RESULTS: Hemodynamic variables, lactate, creatine phosphokinase, and thromboxane B2 (TXB2) were measured. In the control group, the decrease in cardiac index (CI) after aortic cross-clamping (AXC) persisted until unclamping together with a decrease in femoral venous O2 content (CfvO2). In the PGE1 group, CI returned to baseline with a trend toward greater CfvO2 levels. During reperfusion in the PGE1 group, O2 consumption and lactate levels exceeded preclamp values. Pulmonary hypertension occurred equally in both groups but did not correlate with TXB2, which was not altered by surgery or by PGE1 infusion. CONCLUSIONS: Intraoperative PGE1 treatment offers no benefit and may exacerbate tissue ischemia during AXC by redistributing microcirculatory flow or limiting cellular oxygen utilization in a manner that overwhelms any possible protective effect.

Aged↗
PubMed1996

Pharmacology of cortical epileptic afterdischarges in rats.

Afterdischarges (ADs) elicited by electrical stimulation of the sensorimotor cortical area are characterized by rhythmic spikes and spike-wave complexes in the EEG and by clonic face and forelimb seizures. We studied the sensitivity of such ADs to phenytoin (PHT), carbamazepine (CBZ), phenobarbital (PB), primidone (PRM), and valproate (VPA) in 78 adult male Wistar rats with implanted electrodes. Neither PHT (30 and 60 mg/kg intraperitoneally, i.p.) nor CBZ (25 and 50 mg/kg i.p.) suppressed cortical ADs. Indeed, ADs were prolonged by higher doses of both drugs. PRM had a similar effect: A dose of 40 mg/kg transiently shortened ADs, but a dose of 80 mg/kg prolonged ADs. PB (20 and 40 mg/kg) and VPA (200 and 400 mg/kg) were effective in suppressing ADs. Higher doses of VPA and PB reduced the intensity of motor phenomena related to the stimuli but had no effect on the motor correlates of ADs. These findings suggest that cortically induced ADs are not a good model of secondarily generalized seizures. The response to VPA and PB suggests that cortical ADs may represent a model of myoclonic seizures.

Animals↗