PubMed Health⌕ Search

Biomedical subjects

S Trottier

Publications and source records attributed to S Trottier.

50 records · Page 3Linked to original sources
PubMed1982

[Is an alteration of noradrenergic afferents involved in focal epilepsies? (author's transl)].

Previous studies have indicated that noradrenergic system could be involved in various models of chemically, electrically or genetically induced epilepsy. The relationship between the development of a chronic cobalt focus in the rat and the alterations of the cortical noradrenergic system has been studied by means of biochemical analysis of the NA cortical content combined with the glyoxylic acid-induced fluorescence method and the micro-iontophoretic technique. It can be suggested that the noradrenergic system may influence the initiation, spread and disappearance of the epileptic syndrome: (1) The beginning of epileptic discharges coincides with a drop in the NA cortical content, with decrease in number of the NA-containing terminals and with a hypersensitivity of the cortical neurons to iontophoretically applied NA. (2) The termination of the epileptic syndrome coincides with an increase in density of the cortical noradrenergic innervation (sprouting) and consequently with an increase in NA cortical concentrations and a return to normal values of the NA threshold of the cortical neurons.

Animals↗
PubMed1982

Disturbed intrarenal distribution of gentamicin in experimental pyelonephritis due to Escherichia coli.

The intracortical, medullary, and papillary distribution of gentamicin was studied in normal and pyelonephritic rats. The animals were evaluated from 1 hr to 365 days after the end of therapy with either a single dose or two daily injections given every 12 hr for seven days. The serum levels of gentamicin at 1 hr were significantly (P less than 0.001) higher in the pyelonephritic rats than in the normal rats after one dose (26 vs. 12 microgram/ml) and 14 doses (25.7 vs. 8.8 microgram/ml). Peak concentrations or gentamicin in all parts of infected kidneys were significantly (P less than 0.001) higher than in normal kidneys. Gentamicin was still detectable at levels of 1.2 microgram/g in the cortex of one pyelonephritic animal one year after the end of therapy, when the levels of both serum creatinine (1.1 mg/100 ml) and blood urea nitrogen (30 mg/100 ml) were much higher than at seven days after the end of therapy (0.5 and 19 mg/100 ml, respectively).

Animals↗
PubMed1982

[Continuous partial epilepsy: syndrome and disease].

Twenty three patients are described with a Kojewnikow syndrome in order to identify possible etiological factors. According to their history, clinical and E.E.G. features, patients could be classified into two groups; 1) Eleven patients corresponded to the classical description of the Kojewnikow syndrome: variable age at onset of the disease, rare somatomotor seizures, delay of onset of myoclonic jerks often of long duration, myoclonus limited to a small region, normal neurological examination, stable hemiplegia, normal results of psychometric tests, localised E.E.G. alterations. In most of these patients the etiology of the disorder was known, and the symptoms could be related to a localised lesion of the central cortex; 2) the second group (11 patients) presented with completely different characteristics: early onset of fits (age: 2 to 10 years), presence of other seizure types, short delay of onset of myoclonic jerks, high frequency of seizures, localization of myoclonus over large parts of the body, progressive evolution of a motor syndrome, associated neurological signs and disorders of sleep and behavior, progressive mental deterioration, characteristic E.E.G. pattern with long subclinical paroxysms of slow spikes (sharp waves) with variable localization, diffuse cerebral lesions of unknown etiology were found. Only one patient could not be allocated to either group. Several circumstantial data suggest that patients of the second group may suffer from a slow virus infection. Should this hypothesis be confirmed, a reconsideration of the Kojewnikow syndrome from the etiological standpoint would be of great theoretical and practical interest.

Adolescent↗
PubMed1981

Intrarenal concentrations of ampicillin in acute pyelonephritis.

The intracortical, medullary, and papillary distribution of ampicillin was studied in normal and pyelonephritic rats. At 4 days after induction of pyelonephritis, the animals were given a single injection of 100 mg of ampicillin per kg or were treated for 1 week with two daily doses of 100 mg/kg. Major differences in the intrarenal distribution of ampicillin were noted between normal and pyelonephritic animals. At 2 hours after injection, the concentrations of ampicillin in all parts of the infected kidneys were significantly lower (P less than 0.05) than in normal kidneys. The area under the curve (micrograms.minute per milliliter) over a 4-h period after single injection was much lower in the medulla (6.3 +/- 0.9) and papilla (29.6 +/- 4.2) of infected kidneys than in the medulla (11.2 +/- 1.6) and papilla (44 +/- 10.1) of noninfected kidneys. Whereas the ratio of concentration in tissue to concentration in serum ranged to 11.1 in the papilla of normal animals, this ratio was reduced to 2.4 in the presence of pyelonephritis. The diminution of the concentration gradient was also striking in the urine, where there was a reduction of more than threefold in pyelonephritic animals. One week of therapy resulted in a noticeable reduction of the inflammatory process associated with a return to near-normal intrarenal distribution of ampicillin. In normal rats treated with multiple doses, there were decreases of the antibiotic concentrations in serum and kidneys and in the area under the curve for these tissues.

Acute Disease↗
PubMed1980

Intrarenal distribution of trimethoprim and sulfamethoxazole.

In the present study, rats were given trimethoprim (TMP, 10 mg/kg), sulfamethoxazole (SMZ, 50 mg/kg), or a combination of the respective doses of TMP and SMZ. Thirty-six rats received each of the drugs studied. Six recipients of a compound (or mixture) were evaluated hourly, from 1 to 6 h after intraperitoneal injection of the agent. At each timed interval, serum, urine, cortex, medulla, and papilla were analyzed for drug content. Peak serum values of 1.1 microgram of TMP and 131.1 microgram of active SMZ (nonacetylated sulfonamide) per ml were observed after injection of the combination TMP-SMZ. Although the cortical, medullary, and papillary TMP concentrations were severalfold higher than the respective serum values (P < 0.01), microbiologically active SMZ did not concentrate in the renal parenchyma and was found in lower concentration there than in the serum (P < 0.01). The levels of SMZ in all parts of the kidney of animals which received the mixture SMZ-TMP were lower than those detected in the animals which were given SMZ alone. The average ratio of active SMZ to TMP within the medulla and the papilla was less than 20 to 1 in the first 2 h. The intrarenal distribution of these drugs may have therapeutic implications.

Animals↗
PubMed1979

Influence of single or multiple doses of gentamicin and netilmicin on their cortical, medullary, and papillary distribution.

In this study, the comparative intrarenal distribution and accumulation of both gentamicin and netilmicin were investigated in normal rats. The animals received 1, 3, or 14 injections of 10 mg of gentamicin or netilmicin per kg. A total of 324 animals and 648 kidneys were analyzed. These animals were sacrificed at from 1 h to 25 days after the intraperitoneal injections. At each timed interval, the serum, urine, cortex, medulla, and papilla were analyzed for antimicrobial content. The peak serum values of gentamicin (8 to 12 mug/ml) and netilmicin (9 to 14 mug/ml) were close to those found in humans. There was a progressive increase in the cortical concentrations of both antibiotics from a low of 53 mug/g to a high of 719 mug/g when the animals were given increasing doses of the agents. At most timed intervals, the concentrations of gentamicin within the cortex were slightly lower than those of netilmicin. The accumulation of the drugs was also demonstrated in the medulla, where therapeutic levels could be detected for up to 25 days after the cessation of therapy. Even though gentamicin and netilmicin were transiently present in the papilla after 1 or 3 injections, both drugs could still be detected in the papilla on day 25 after 14 doses. The urinary concentration closely paralleled the papillary concentration. If applicable to humans, the persistence of high levels of both drugs within the medulla and papilla may have therapeutic implications.

Animals↗
PubMed1977

Penetration of cefamandole, cephalothin, and desacetylcephalothin into fibrin clots.

The conversion of cephalothin into a less active metabolite (desacetylcephalothin) might influence its distribution in tissues. An experimental rabbit model devised to determine concentrations of antibiotics in subcutaneous fibrin clots was used in this study. Groups of five to six animals received 100-mg/kg intravenous injections of either cefamandole or cephalothin. One hour after the injection, the concentration of cefamandole in serum was 20 times higher than that of cephalothin. Whereas cephalothin was undetectable at 4 h, cefamandole was still detectable at the end of the experiment. The half-lives of cephalothin and cefamandole in serum were 16 and 27 min, respectively. The concentration of cefamandole found in fibrin clots was severalfold higher than that of cephalothin. The half-life of cefamandole in clots (81 min) was superior to that of cephalothin (38 min). Although concentrations of both antibiotics were higher in serum than in clots at 1 h, the concentrations of these drugs in the clots persisted at higher levels throughout the next 5 h of the experiment. The extent of binding of cefamandole (87%) to rabbit serum was greater than that of cephalothin (50%). At least 55% of cephalothin was metabolized in vivo into its less active metabolite desacetylcephalothin. This metabolite was found in higher proportion in the serum (75%) than in the clots (55%). Whereas only 12% of the free (unbound) cephalothin reached the clots, 78% of the free cefamandole was found in the clots. This lower level of penetration of unbound cephalothin might be explained by the short half-life of this antibiotic, not permitting equilibrium to occur.

Animals↗
PubMed1977

[Late syringomyelic syndromes in paraplegics].

The authors have reviewed 35 cases in the literature and reported on 12 cases seen personally of late onset syringomyelia in paraplegics. Initial pain was found to be present in only slightly more than half the cases and an insidious onset particularly with sensory disturbance led sometimes to delayed recognition. In the fully developed case, it can closely simulate idiopathic syringomyelia with arthropathy but impairment of touch and proprioception sometimes occurs in addition. Neurosurgical treatment to the fluid-filled cavity, does not seem to modify obviously the spontaneous evolution of the condition. In 5 cases, the paraplegia was not of traumatic origin. Possible mechanisms are discussed.

Adolescent↗
PubMed1976

[Behavioral manifestations induced by electric stimulation of the anterior cingulate gyrus in man].

The electrical stimulation of a restricted part of area 24 in awake man elicits important behavioral changes. The present study is dealing with 83 epileptic patients whose brain activity was recorded in SEEG conditions, with a view to possible neurosurgery. In order to determine how seizures originate and propagate, 116 multileads electrodes (65 right, 51 left) were stereotaxically inserted in the anterior part of the cingular gyrus. 521 stimulations were performed. In 362 cases, this stimulation induced a particular behaviour which was characterized by an arousal, motor activities (involving fingers and hand, mouth, legs, eyes, associated movements of hand mouth, highly integrated movements), thymic modifications and hallucinatory manifestations. Topographical organization of the effective area in the cingular gyrus and the relation between the electrical responses and stimulation parameters are studied.

Adolescent↗
PubMed1975

[Neurophysiopathological hypothesis on startle epilepsy in man].

Clinical observation and S.E.E.G. recordings performed with a surgical purpose in a typical case of startle-epilepsy has led to a reassessment of the relationship of this form of epilepsy and "Startle reaction". It is confirmed that the critical discharges take origin in the primary motor cortex. The authors discuss, in the light of experimental data already published, the physiopathological hypotheses likely to lead to a better understanding of startle epilepsy. On the one hand it is suggested that the startle reaction may be responsible through a feed-back mechanism for triggering the epileptogenic focus. On the other hand it is assumed that afferent pathways, central organization and efferent systems involved in startle reaction and actual fits are different.

Adult↗