A program for automatic acquisition and processing of electroretinograms obtained in vivo in albino rats.

A program sequence has been developed on a microcomputer that affords automatic acquisition and processing of electroretinogram (ERG) obtained in vivo in dark-adapted albino rats. A 50-Hz digital filter and an averaging summation remove the background noise.

Association of N-acetyllactosamine with tumor progression in human breast cancer: a study using a 16 kDa chick embryo lectin.

This study documents modifications in the expression and the cellular distribution of binding sites for a 16 kDa chick embryo lectin (CL16-BS) in breast cancer. This lectin binds preferentially to terminal and penultimate N-acetyllactosamine residues (Galbeta1-4GlcNAc). BS density and distribution, studied by lectin binding followed by indirect immunofluorescence, were compared in normal breast tissues and 45 invasive carcinomas (lobular and ductal). Increased number of fluorescent epithelial cells (ETC+) were observed in normal ducts adjacent to lobular carcinomas and in tumors from both types when compared to normal glands. In ductal carcinomas, a significant diminution of ETC+ percentage was observed in the highest anatomopathological SBR grades: 32.7% in grade III, 80.8% in grade II and 66.5% in grade I (p<0.001). For both lobular and ductal carcinomas, ETC+ percentages were also positively correlated with low versus high MSBR grades (p<0.002). The subcellular distribution of CL16-BS varied according to the tumor type and/or the histological grades. It was mostly membrane-associated in low SBR and MSBR grades (p<0.001 and p<0.01, respectively) and cytoplasm-associated in high grades (p<0.02 and p<0.05). Some of these parameters were also correlated with certain other clinicopathological factors, such as tumor size (p<0.02), high S-phase cell fraction (p<0.04 and p<0.03) and low density estrogen receptors (p<0.05). Diminution in CL16-BS density and cytoplasmic versus membrane localization may be considered as indicators of tumor progression but not of metastasis.

[PS2 as a prognostic factor in 1065 cases of human breast cancer. A multicenter study]. / Rôle pronostique de la protéine pS2 dans 1065 cas de cancer du sein. Etude multicentrique.

pS2 protein assay was performed with Elsa-pS2 kit (CIS-Biointernational) on a group of 1,065 patients with operable breast cancer who underwent breast surgery in the years 1982 through 1990. The median follow-up was 57 months. This group included exclusively infiltrating ductal carcinoma with primary surgery. Age mean was 58 yr; T0-T1, 33.6%; T2-T4, 66.4%; Differentiation grade I, 29%; node negative, 53%; estrogen receptor (ER) positive, 62.4%; progesterone receptor (PR) positive, 55.2%; mean tumor size, 2.4 cm; local recurrence, 5.2%; metastasis, 17.5%. pS2 values varied from 0.1 to 707 ng/mg of cytosol protein (median, 5.6; mean 24.5; 95th percentile 112 ng/mg p). There was no significant relationship between the mean level of pS2 and age, tumor size, nodal status, whereas pS2 was related to histological grade (P < 10(-3)), ER (P < 10(-5)), and PR (P < 10(-5)). By using 2 ng/mg p as pS2 cutoff, 77/391 (19.7%) of ER+PR+ tumors were pS2-, and 122/345 (35.4%) of ER-PR-tumors were pS2+; with this cutoff, a strong relationship existed between pS2 and overall survival, but not between pS2 and relapse-free survival. With Cox multivariate analysis, pS2 protein was classified after lymph node status, histological size, ER, differentiation grade, age, clinical stage, PR. In patients with axillary lymph node involvement (N+), pS2 status could discriminate between good and bad prognosis, specially for patients with small tumors (< 2 cm) and with less than seven invaded nodes. This study showed that pS2 protein was a poor prognostic factor in comparison with classical factors.

Familial growth retardation with isolated thyroid-stimulating hormone deficiency.

Three brothers with isolated thyroid-stimulating hormone (TSH) deficiency were observed at ages 17, 15, and 10 years. They suffered from severely retarded growth, with a marked retardation in bone maturation. Their serum T4, T3, and TSH levels were low. Serum thyrotropin-releasing hormone (TRH) concentration was normal. No increases in TSH levels were elicited during the TRH test. The other pituitary hormones, adrenocorticotropic hormone, growth hormone, follicle-stimulating hormone, luteinizing hormone, and prolactin hormone, responded normally to stimulation. Thyroxin treatment triggered a growth acceleration. Genetic investigation revealed several instances of small stature on the father's side.

The hyperglycemic neuropeptide of the terrestrial isopod, Porcellio dilatatus. II. Immunocytochemical demonstration in neurosecretory structures of the nervous system.

By use of an rabbit antiserum raised against the crustacean hyperglycemic hormone (CHH) of the shore crab, Carcinus maenas, CHH-producing perikarya were detected in the brain of the isopod, Porcellio dilatatus, by the double-antibody immunofluorescence technique. The course of the secretory axons to the neurohemal organ, the sinus gland, could be traced. The sinus gland also exhibited strong fluorescence. The reaction was very specific, no other structures gave appreciable immunofluorescence. There are two CHH cells in each hemisphere of the brain, located in the medio-rostral part of the protocerebrum. This area appears to correspond to the medulla terminalis of decapods. The cells are aldehyde fuchsin-positive and have been previously described as beta 1 cells. The immunofluorescence could be inhibited by preabsorption of the antiserum with pure Carcinus-CHH.

[Neuroendocrine control of reproduction in Crustacea]. / Contrôle neuroendocrine de la reproduction chez les Crustacés.

The neuroendocrine factors synthetized by various regions of the nervous system and which have inhibiting or stimulating effects can control the male and female physiology of malacostraca via sexual hormones and moulting hormone. There are between decapods and peracarids functional homologies but some differences can be noticed as to the localization of these antagonistic neurosecretory systems. The functioning of these systems is regulated by external factors such as the photoperiod and the temperature. The interactions between these different neurohormones, the sexual hormones and the moulting hormone are discussed.

The mechanism of translational coupling in Escherichia coli. Higher order structure in the atpHA mRNA acts as a conformational switch regulating the access of de novo initiating ribosomes.

Bacterial genes are commonly transcribed to form polycistronic mRNAs bearing reading frames whose respective translational efficiencies are not independently determined. As in many bacterial operons, expression of the atp genes of Escherichia coli is strongly influenced by translational coupling. The gene pair atpHA is tightly coupled, whereby atpA is translated at least three times more efficiently than atpH. However, there is no fixed stoichiometry of coupling: mutations in atpH lead to increases in the translation ratio (atpA/atpH) of up to approximately 40-fold. We have demonstrated that secondary structure sequestering the atpA translational initiation region (TIR) is important to the coupling mechanism in that it inhibits de novo translational initiation at the atpA start codon. Genetic and structural analyses indicate that this inhibitory structure can be induced to refold into a less inhibitory conformation either by introducing two single-base substitutions or as a result of ribosomes translating atpH. We propose a model in which the secondary structure of the atpA TIR acts analogously to a "gating device" in that it restricts de novo ribosomal initiation until it is "switched" into a more open conformation. This contrasts with the function of a stem-loop structure located immediately downstream of atpA and upstream of the Shine-Dalgarno region of atpG, which was found to inhibit translation, but not to mediate tight coupling. Results obtained using the "specialized" ribosome system of Hui and de Boer ((1987) Proc. Natl. Acad. Sci. U.S.A. 84, 4762-4766) indicate that primarily ribosomes reinitiating after termination on atpH are responsible for inducing refolding of the atpA TIR. The principle of alternative mRNA conformations with different functional properties embodied in the model presented here can only be fulfilled by certain types of structure. It is likely to operate in several steps of prokaryotic gene expression, underlying a range of regulatory events including transcriptional attenuation and translational activation.

Effect of Gingko biloba extract (EGb 761) on chloroquine induced retinal alterations.

Electroretinography was used to investigate the preventive action of Ginkgo biloba extract (EGb 761) in experimental chloroquine-induced retinopathy in rats. EGb 761 contains flavones and anthocyanosides known for their oxygenated radical scavenging properties. Chronic administration of chloroquine (20 days) caused an overall lengthening of the duration of the ERG b-wave, together with delayed peaking. These anomalies became more marked with increased duration of treatment. In rats treated simultaneously with chloroquine and EGb 761 no such modification of the electroretinogram (ERG) was observed. These results suggest that retinal toxicity may be related to a localized inflammation releasing oxygenated free radicals and/or PAF. EGb 761 may thus afford a useful preventive treatment for chloroquine-induced retinopathy, and generally for xenobiotic retinotoxicities.

The hyperglycemic neuropeptide of the terrestrial isopod, Porcellio dilatatus. I. Isolation and characterization.

From isolated sinus glands of Porcellio dilatatus, a hyperglycemic neuropeptide (CHH) was purified by means of a single, two-step purification procedure which consisted of gel chromatography on Sephadex G-50, followed by high-performance liquid chromatography. The 5800- to 6100-Da peptide contains 50-52 amino acids residues. The amino acid composition is (Pro, Ile)1; His1-2; (Thr, Ser, Gly, Met, Tyr)2; (Val, Phe, Lys)3; (Ala, 1/2Cys, Leu, Arg)4; Glx5; Asx7; Trp, n.d. The amino acid composition differs from that of two decapod CHHs analyzed thus far. The N-terminus is blocked. The neuropeptide exhibits little or no interspecific hyperglycemic effect in the brachyuran, Uca pugilator, and its cross-reactivity and potency in the RIA for Carcinus-CHH is very low.

Fetal serum erythropoietin in twin pregnancies with discordant growth. A clue for the prenatal diagnosis of monochorionic twins with vascular communications.

Ten sets of diamniotic twins with discordant fetal growth (ultrasonographic estimated fetal weight difference > 25%) and abnormal amniotic fluid volume were assessed for fetal serum erythropoietin concentration (Epo). All 20 fetuses had a percutaneous umbilical blood sampling performed between 21 and 33 weeks gestation. Three sets of twins were dichorionic while 7 sets were monochorionic. In these 7 monochorionic sets a vascular communication between twins was demonstrated prenatally and postnatally. From 24 weeks gestation the smaller twin of the dichorionic group had a higher serum Epo than its larger cotwin; the larger cotwin's serum Epo was within normal limits for singleton controls. All fetuses with documented vascular communications had higher serum Epo concentration than singleton controls. These findings suggest that determination of fetal serum Epo in the large cotwin may be a clue to the diagnosis of vascular communications between twins with discordant growth.

[Transient hypothyroidism in 8 low birth weight newborns. Role of topical application of iodine chemicals]. / Hypothyroidie transitoire chez huit nouveau-nés de petit poids de naissance. Rôle de l'application cutanée de produits iòdés.

Very low plasma levels of thyroxine with a parallel decrease in the free thyroxine index were observed in 8 low birth weight infants. The tri-iodo-thyronine levels were slightly but significantly reduced and there was a concommitant increase in thyrotropin concentrations. The abnormalities, which were usually seen between the 10th--45th day, were transitory and resolved completely. The possible role of topical iodinated products is discussed.

Labeling of human lymphocytes with 99mTc by means of stannous pyrophosphate. Scintigraphic applications.

An original 99mTc-labeling method applied to human lymphocytes is described. This technique is based on the use of stannous pyrophosphate to reduce sodium pertechnetate. The proposed procedure has two main advantages: firstly, the labeling process takes place in a neutral and buffered medium which prevents any cellular aggregation; secondly, the labeling yield obtained is compatible with scintigraphic studies in man. The influence of each parameter on the labeling quality had been studied as well as the binding stability of the technetium fixed on cells. A systematic study of lymphocyte surface markers, before and after labeling, has led to the suggestion that the labeling process seems to affect cellular membranes, probably because of the technetium binding. Finally, scintigraphic results are presented, the study being performed on eight healthy volunteers. These results are compared with those published by other authors who used either a different radioisotope or a different labeling method.

Serum erythropoietin in small for gestational age fetuses.

Serum erythropoietin (Epo) concentration was compared prenatally in adequate (AGA) and small for gestational age (SGA) fetuses. Fifty-four percutaneous umbilical blood samplings were paired with maternal blood and assessed for Epo, hematocrit and reticulocyte count. Seventeen fetuses were growth-retarded (SGA) on the basis of ultrasonic biometry and birth weight. Controls (AGA; n = 37) underwent cordocentesis for risk of toxoplasmosis, maternal age or malformations (CNS, GI, heart). No cytogenetic abnormality or infections was found in the 54 fetuses. Linear and polynomial regressions were fitted to determine correlations between parameters. Nonparametric Mann-Whitney test was used for comparison between groups. Gestational age at sampling was similar in AGA and SGA. The SGA fetuses had a higher Epo concentration than controls (p < 0.001). Fetal AGA Epo increased significantly throughout pregnancy (p < 0.01) but did not correlate with maternal Epo (p > 0.05). An inverse correlation was found between fetal reticulocyte count and Epo concentration (p < 0.02). The mechanism of high Epo level in SGA fetuses may involve low pO2 and hemoconcentration.