[Sensory ataxia caused by central axonopathy]. / Ataxie sensitive par axonopathie centrale.

Sensory ataxia with central axonopathy. A case of sensory ataxia of undefined origin is described and the differential diagnosis is discussed. The originality of the case lies in the fact that the nerve sensory potentials are preserved whereas the medullary and cortical somesthesic potentials no longer exist. This situates the pathological process in the central axon of the sensory ganglion, as in tabes or clioquinol poisoning.

Human thyroglobulin reference material (CRM 457). 2nd Part: Physicochemical characterization and certification.

This report describes the characterization of a purified human thyroglobulin (Tg) reference material, and details the procedures used in its certification. The purified Tg is intended to be used as a primary reference material to establish calibration of working serum based reference material for immunoassay procedures. The programme involved the participation of 15 European laboratories and one laboratory from the United States. The physicochemical characterization showed by polyacrylamide gel electrophoresis and immunoblotting that the purified Tg had for the major part the expected molecular size of 660 kDa with traces of lower molecular forms. The amino acid composition was close to that demonstrated for the cDNA and the content of iodine was in keeping with a moderately to highly iodinated Tg. The mass concentration in reference material RM 457 is certified to be (0.324 +/- 0.018) g/L on the basis of protein determined by the Lowry method and supported by nitrogen determination, absorbance measurement, and amino acid analysis. This reference material is considered the first step towards decreasing the interlaboratory variability between Tg methods of measurement.

Human thyroglobulin reference material (CRM 457). 1st Part: Assessment of homogeneity, stability and immunoreactivity.

This paper describes the assessment of the homogeneity and stability of a purified and lyophilized human thyroglobulin (Tg), and characterizes its immunoreactivity. The purified and lyophilized Tg is intended to be used as a primary reference material to establish calibration of working serum based reference material. The programme involved the participation of 15 European laboratories and one laboratory from the United States. The homogeneity of the content of the ampoules was considered acceptable (< 9%). The stability was tested by accelerated temperature degradation showing predicted annual relative losses of 0.01% at -70 degrees C and 1.04% at -20 degrees C. The immunoreactivity of the Tg material as measured in different laboratories varied mostly according to the method used rather than the laboratory. The interlaboratory variability showed that the two commercial methods used in several laboratories (kit 1 and 2) had an interlaboratory variation (CV) of 15.9% (N = 5) and 7.1% (N = 3), respectively, whereas the total interlaboratory CV was 64.3% (N = 18). The immunoreactive Tg had dilution curves parallel with other Tg calibrators (those of the methods). Dilution curves of the Tg material after storage at various temperatures and time were parallel in both RIA and IRMA. In conclusion, we have prepared a Tg reference material which in extensive studies in several participating laboratories has demonstrated a sufficient homogeneity and stability as well as dilution curves parallel to the calibrators of all the immunoassays tested in the study. This reference material is considered the first step towards decreasing the interlaboratory variability between Tg immunoassays.

Effect of methylergobasine maleate on serum gonadotrophin and prolactin in humans.

Intramuscular injection of 0.2 mg methylergobasine maleate3) (Methergin, Sandoz) in women on day 3 post-partum, in regularly menstruating women and in adult men, is followed within 30 to 75 min by a 50% decrease in serum prolactin concentration: the levels remain low until 180 min and increase between 180 and 240 min. The amplitude of the decrease is the same when prolactin is measured in terms of the same serum prolactin standard by a homologous ovine assay and by a homologous human assay. However, in the case of regularly menstruating women and of men serum prolactin concentration is some three times higher when estimated by the ovine assay than when estimated by the human assay. This difference between assay results obtained by the two radioimmunoassay methods could be due to heterogeneity of serum prolactin. However, non-specific effects of serum are not excluded. In regularly menstruating women and in men, intramuscular injection of 0.2 mg methylergobasine maleate is followed within 45 to 75 min by a 50% decrease in immunoreactive serum LH concentration without concomtant change in immunoreactive FSH. The depression of LH secretion lasts for 1 to 2 h. The circulating levels of HCG in post-partum women are not modified after intramuscular injection of Methergin. In humans as in animals and in in vitro studies, inhibition of prolactin and LH release induced by ergot drugs are likely due to both an indirect effect via the hypothalamus and to a direct effect on the pituitary cells.

Acute endocrine profile of sulpiride in the human.

Normal men and normally menstruating women received i.m. injections of 0.1 to 4.0 mg/kg sulpiride. This psychotropic drug induced a very rapid (already significant after 5 minutes) and sustained (still significant after 7 hours) elevation of prolactin (PRL) concentrations in all subjects with no consistent modification of LH and FSH. After injection of 4.0 mg/kg, there was similarly no modification of mean TSH concentrations in the women tested in the luteal phase, as well as of mean GH levels in men. Sulpiride prevented the inhibitory effect on PRL levels of 500 mg levodopa, administered orally simultaneously; levodopa administered 2 hours prior to sulpiride failed to counteract the PRL-stimulatory effect of sulpiride. Under chronic sulpiride-induced hyperprolactinaemia, levodopa exhibited however a very slight inhibitory effect on PRL concentrations. These data are in agreement with the hypothesis that sulpiride acts mainly at the pituitary level by blocking dopamine receptors of the lactotropes and support the concept that the menstrual cycle perturbations observed under chronic sulpiride administration result from hyperprolactinaemia itself or from a mechanism quite similar to that by which sulpiride induces hyperprolactinaemia.