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Biomedical subjects

M Pierson

Publications and source records attributed to M Pierson.

At least 19 recordsLinked to original sources
PubMed1992

Noise exposure-induced audiogenic seizure susceptibility in Sprague-Dawley rats.

Parameters were evaluated for the optimum induction of audiogenic seizure susceptibility in Sprague-Dawley (SD) rats by noise exposure. The effect of maturation on this susceptibility was also examined. It was found that SD rats are most inducible between neonatal days 13 and 15 and that susceptibility requires a minimum of 2 days to develop. Noise exposure on day 14 results in universal susceptibility by day 20, but seizure severity is not maximal until days 32-36. Although susceptibility persists at high levels into adulthood, seizures in older rats revert to the wild-running-only type. Seizure latency (from stimulus onset to onset of wild running) becomes increasingly shorter during the prepubescent period (days 16-24) but is stable at older ages. The mean shortness of latency in adult seizures depends somewhat on the age when initial noise exposure occurred; day-14 noise exposures result in seizures with shortest latencies. Ontogenetic comparisons were made of susceptibility in these noise exposure-induced rats, genetically epilepsy prone rats (GEPRs, which are SD substrains)29 and noise exposure-induced Wistar (WI) rats28. It appears that epileptogenesis begins at virtually the same age in all four groups of rats but that considerable differences characterize the absolute severity of seizures and the age dependence of maximum seizure severity among the strains.

Acoustic Stimulation↗
PubMed1992

Audiogenic seizures in unilaterally sensitized and monaurally stimulated Wistar rats.

Results of previous studies (Pierson, M. and Swann, J., Epilepsia, 32 (1991) 1-9) have demonstrated that exposure of Wistar rats to noise on day 14 results in audiogenic seizure susceptibility. Experiments reported here examined whether unilateral susceptibility could be induced in rats by monaural restriction of this noise exposure. Behavioral attributes of seizures on day 28 were compared in groups that were: binaurally noise-exposed/binaurally tested, binaurally noise-exposed/monaurally tested, monaurally noise-exposed/binaurally tested and monaurally noise-exposed/monaurally tested. Effects of left- and right-ear exposures and tests were assessed separately. Unilateral susceptibility was evident since seizures could be elicited later only by stimulation of the originally noise-exposed ear. Seizures were behaviorally different in monaurally noise-exposed and binaurally noise-exposed animals. Convulsions, directional reversals during running episodes, and relatively short latencies occur only in binaurally noise-exposed rats. These behaviors occur with either monaural or binaural stimulation. Initial, running direction was random in binaurally stimulated/binaurally noise-exposed rats, but was fixed in all other groups depending on which ear was exposed in either sensitization (day 14) or testing (day 28). Right- and left-ear sensitizations or tests resulted in left-directed and right-directed running onsets respectively. Previous studies of the effect of selective CNS lesions in instances of unilateral or bilateral susceptibility have led to the understanding that seizure initiation in unilaterally susceptible animals is mediated by the crossed ascending auditory pathway.(ABSTRACT TRUNCATED AT 250 WORDS)

Acoustic Stimulation↗
PubMed1992

[LH-RH agonist in subjects treated with growth hormone for somatotropin deficiency. Development of growth velocity and prediction of body height].

The final adult height in patients with growth deficiency treated with growth hormone has been shown to depend upon pubertal development. This is mainly related to the shortening of puberty duration and accelerated bone maturation. A long acting analogue of gonadoliberin, Trp-6-GnRH, has been given to 17 patients with isolated growth hormone deficiency in order to delay pubertal progression. In seven of these patients, GH treatment and the analogue of Gn-RH were initiated simultaneously. The other 10 patients had been treated for more than one year with hGH at the onset of the analogue. Mean duration of treatment was 17 months. Annual growth rate was low in all cases. Statural progression was parallel to the delayed bone maturation without change in the ratio of statural maturation to bone maturation. No significant change in height prediction was observed after the combined treatment. Combination of the long-acting analogue of gonadoliberin, Trp-6-Gn-RH, with growth hormone in GH-deficient patients does not seem to be an appropriate way to improve final height after the onset of spontaneous puberty.

Adolescent↗
PubMed1991

Sensitization to noise-mediated induction of seizure susceptibility by MK-801 and phencyclidine.

The effect of single administrations of MK-801 (5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine) or PCP (phencyclidine) on the induction of audiogenic seizure susceptibility by noise in immature rats was examined. Treatments with these non-competitive N-methyl-D-aspartate (NMDA) receptor antagonists resulted in increases in noise exposure-dependent susceptibility. In neonatally drug-treated rats, seizures during adulthood were found to occur with significantly higher incidence and severity. Furthermore, drug treatments were found to lengthen what is normally a restricted developmental period within which susceptibility can be induced by noise exposure. The drugs, however, had no inherent ability to induce audiogenic seizure susceptibility if given alone. Moreover, in already-susceptible rats, MK-801 exhibited predictable anticonvulsant effects. These data suggest acute PCP or MK-801 exposures may transiently exacerbate risks inherent in certain forms of trauma. The mechanism underlying these effects is unknown although certain inferences are possible and may reveal much about epileptogenesis in this model.

Acoustic Stimulation↗
PubMed1991

Growth hormone response following growth hormone releasing hormone injection in thalassemia major: influence of pubertal development.

Thirty-five patients with thalassemia major, aged 7 to 21 years, were studied to define the relationship between the pubertal development and the growth-hormone (GH) secretion during sleep, after administration of GH-releasing factor (hpGRF 1-44), and betaxolol-glucagon or arginin-insulin. Pubertal development was classified as being appropriate or delayed for chronological age. GH response to pharmacological stimuli and during sleep was not linked to the pubertal development according to the chronological age. The peak of GH secretion after GHRH injection was significantly delayed in thalassemic patients with retarded puberty. The integrated secretion of GH during the 120-min test was slightly but not significantly reduced in these patients. The prepubertal pattern of GHRH response was restored in the patients receiving substitutive therapy by HCG or testosterone. The alteration of GH response to GHRH in thalassemic patients is likely to be only due to delayed puberty and decreased endogeneous GHRH secretion since it is corrected by androgen or gonadotropin replacement.

Adolescent↗
PubMed1991

Comparative study of biosynthetic human growth hormone immunogenicity in growth hormone deficient children.

The immunogenicities of six recombinant human growth hormone (rhGH) preparations, from KABI (A rhGH191 and B rhGH192), Eli Lilly (C), Nordisk (D), Sanofi (E) and Serono (F), used to treat 260 GH-deficient children, have been compared using a common specific and sensitive procedure for antibody determination. For this purpose we developed two immunoassays: a competitive liquid radioimmunoassay using 125I-rhGH, and an immunometric solid enzymoimmunoassay in which the rhGHs were immobilized. Blood samples were collected from the GH-deficient children before treatment and after 3, 6, 9, 12, 18 and 24 months of therapy. Human GH antibodies were detected in children treated with 3 of the 6 rhGH preparations. Seven percent of the patients treated with hormone A, 14% with hormone B and 22% with hormone C formed antibodies against the respective rhGH. Differences in capacity and affinity of the hGH antibodies were observed between these anti-GH-positive groups. They could be divided into 2 groups according to their immunopotency. One group (7, 14 and 6% of the patients treated with hormones A, B and C, respectively) developed anti-hGH antibodies with very low binding capacities (30-100 fmol/ml). The other group (16% of the patients treated with hormone C) developed IgG-type antibodies to hGH with higher binding capacities (200-1,200 fmol/ml) and a measurable binding affinity (Ka = 10(8) M-1). These hGH antibodies partially inhibited the binding of labeled GH to its specific liver membrane receptor. However, because of their low titer, they did not inhibit growth in the treated children.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

Peripheral nerve function in children with end-stage renal failure.

Information on clinical and subclinical peripheral neuropathy in children with end-stage renal failure (ESRF) is scarce. We have studied the presence of clinical and subclinical peripheral neuropathy in children with ESRF comparing recently developed non-invasive methods with the measurement of nerve conduction velocities. Twelve children (7 boys, 5 girls; age range: 5-17 years; duration of haemodialysis: 0.5-60 months) participated. Thermal discrimination threshold (TDT) and vibration perception threshold (VPT) were determined twice before and after haemodialysis in each patient. Peroneal nerve conduction velocity was determined once before haemodialysis. No clinical or subclinical peripheral neuropathy was observed in any of the children. Except for two slightly increased TDT values after haemodialysis all results were within the normal range. No correlation was found with age or duration of haemodialysis and no association was found between the three methods. VPT values showed a significant improvement after haemodialysis treatment, although all VPT values were in the normal range. This suggests that haemodialysis has an influence on cutaneous sensation, but further study is needed to confirm this observation. Longitudinal investigations will be necessary to evaluate whether TDT and VPT determinations can be used for early screening of clinical and subclinical neuropathy in children with ESRF.

Blood Chemical Analysis↗
PubMed1989

[Value of anthropometric techniques in pediatric otology].

The recurrent and severe infections of the ENT region during childhood are frequently related to cranio-facial malformations or/and deficiency of the immune system. The cranio-facial abnormalities are at risk to be complicated by transmission deafness either primary or secondary through recurrent middle ear infections. In our pediatric out-patient clinic, most of the patients suffering severe recurrent ENT problems show variable malformations: abnormal implantation or shape of the external ear, a microretrognathism, cervical or facial branchial fistulae, high or ogival palate with anomalies of the dental occlusion or a bifid uvula. All these abnormalities share their origins in a pathological development of the first branchial arch. These developmental anomalies may directly lead to deafness (especially due to an abnormal middle car ossicular development since they are derived in part from the first arch). They may also favor secondary pathologies (middle ear otitis, abnormal soft palate). Moreover the development of the immune system is also dependent of a normal function of the endoblastic epithelium of the pharyngeal pouches which is a part of the branchial system. Immune dysfunctions may therefore accentuate the severity of the ENT Infections.

Anthropometry↗
PubMed1989

[Adynamia episodica hereditaria: Gamstorp's disease or Eulenburg's paramyotonia?].

Over seven generations owing 71 identified and studied persons, 18 (12 males and 6 females) suffered paroxystically adynamic paralysis or myotonic accesses. A such association is rare and according to the proeminent symptoms is denominated as hyperkaliemic periodic paralysis or as congenital paramyotonia. In the both forms of the diseases: cold injury, fasting, long time resting, or efforts are able to provoke crisis and so does an oral potassium loading. Studies on Ka+Na membrane permeability suggest the responsibility of Na+ K+ pump and may explain the physiopathology of the alternative manifestations at the muscle cellular level but may be are rather a marker than a cause of permeability disturbances. In the present family, some clinical, biological and electrophysiological arguments suggest the unicity of the disease. A better way to confirm that would be the localisation of a unique gene in the patient. DNA samples of several members are in study for molecular biology in the hope to precise a identical location. Some informations from molecular biologists suggest a probable location near the myotonic dystrophy (M.D.) in the 19 q12 but not identical with it.

Genes, Dominant↗
PubMed1989

[Stature after 18 months of treatment with synthetic growth hormone in 12 patients with Turner's syndrome].

The increased availability of recombined human growth hormone (rhGH) allows its possible use in clinical situations not classically recognized as regular indications. Among these, the Turner's short stature is presently under experimental evaluation for its responsiveness to rhGH. Twelve patients, 10 with a 45, X karyotype, 1 46 XXiq, and 1 mosaicism, have been given rhGH at a dosage of 0.15 U/kg per injection six times a week. Mean age at onset of treatment was 12.8, mean growth retardation was 4.1 SDS according to Sempé. After 18 months of treatment mean growth catch-up was 0.9 SDS. Maximal velocity was reach during the first trimester of treatment and decreased thereafter but was above normal for bone age in all but 2 after 18 months. The bone age increased less than structural age. No side effects were reported. At the present time the efficacy of rhGH in increasing final height in Turner's patients is likely but not demonstrated by any studies. The exact place of ovarian substitution, even during the prepubertal period, is still matter of discussion. Since the velocity response to rhGH was maximal among the youngest patients an early diagnosis of the syndrome will likely be necessary to improve final stature.

Adolescent↗
PubMed1989

A case of Alagille's syndrome with translocation (4;14) (q21;q21).

This paper reports a case of Alagille's syndrome, in association with a translocation 46,XY,t(4;14)(q21;21). The possible relationship between this autosomal dominant syndrome and the apparently balanced chromosomal rearrangement is discussed.

Bile Ducts, Intrahepatic↗