Value of basal luteinizing hormone level combined with uterine volume measurement in the early diagnosis of central precocious puberty in girls with different Tanner stages / 中国当代儿科杂志

OBJECTIVES@#To study the value of basal luteinizing hormone (LH) level combined with uterine volume measurement in the early diagnosis of central precocious puberty (CPP) in girls with different Tanner stages.@*METHODS@#A retrospective analysis was performed on the girls who presented with breast development before the age of 8 years and attended the Third Affiliated Hospital of Zhengzhou University from January 2017 to September 2022. According to the results of gonadotropin-releasing hormone (GnRH) agonist test, the girls with peak LH ≥5.0 IU/L and peak LH/follicle stimulating hormone ≥0.6 were enrolled as the positive group, and the other girls were enrolled as the negative group. The two groups were compared in terms of the basal LH level and uterine volume. The receiver operating characteristic (ROC) curve was used to analyze their value in the early diagnosis of CPP.@*RESULTS@#For the girls with Tanner B2 and B3 stages, the positive group had significantly higher basal LH level and uterine volume than the negative group (P<0.05). The basal LH level had an optimal cut-off value of 0.325 IU/L and 0.505 IU/L respectively in the diagnosis of Tanner stage B2/B3 CPP, while uterine volume had an optimal cut-off value of 1.639 mL and 2.158 mL respectively. Basal LH level combined with uterine volume measurement had a significantly larger area under the ROC curve than uterine volume measurement alone (P<0.001), but with no significant difference compared with that of basal LH level measurement alone (P>0.05).@*CONCLUSIONS@#Basal LH level combined with uterine volume measurement is valuable in the early diagnosis of CPP in girls with different Tanner stages, which provides a basis and guiding significance for clinical diagnosis of CPP.

Significance of charge on lysine residue of ovine luteinizing hormone on immunological and biological properties of the hormone.

In order to understand the significance of positive charge of lysine residues of ovine luteinizing hormone (oLH) on immunological and biological activity, the epsilon-NH2 group(s) of ovine LH were sequentially modified with 2-iminothiolane (2IT) that preserves the positive charge of the lysine while the overall charge of the hormone remains unchanged. These studies have also been compared with the oLH modified by N-succinimidyl 3-(2 pyridyldithio) propionate (SPDP) and succinimidyl 6-[3-(2-pyridyldithio)propionamido]hexanoate (LC-SPDP) that abolish positive charge of lysine residues. The modification primarily occurs in the alpha-subunit. Sequential modification led to progressive reduction in receptor binding and immunological activities. However, the steroidogenic activity was substantially retained. The immunoreactivity and receptor binding properties of 2IT modified oLH (oLH-2IT) were less affected when compared to SPDP (oLH-SPDP) or LC-SPDP (oLH-LC-SPDP) modified derivatives suggesting that increase in hydrophobic carbon chain in oLH-LC-SPDP molecule resulted in drastic inhibition in immunological and biological properties. But the steroidogenic potential of oLH-2IT, oLH-LC-SPDP or oLH-SPDP was relatively comparable. This suggests that a single -NH2 group modification with 2IT would generate the site in the hormone for conjugation to the toxin/carrier proteins that may retain better immunological and biological activity compared to that of SPDP or LC-SPDP modified oLH.

Modification of ovine luteinizing hormone subunits with SMPT and its effect on subunit recombination, immunological activity, receptor binding and steroidogenic activity.

The increasing use of heterobifunctional cross-linking agents in the design of defined conjugates for selective targeting and inducing immune response has prompted us to study the role of epsilon-NH2 group modification of oLH subunits, their recombination and effect on immunoreactivity, receptor binding and biological activity. The epsilon-NH2 groups of alpha oLH and beta oLH subunits were separately modified by using SMPT. The alpha oLH-SMPT modified derivatives hybridize to beta oLH. Similarly, the beta oLH-SMPT derivatives recombined with alpha oLH. The recombination was judged by gel filtration chromatography and RP-HPLC analysis. The sequential modification of subunits led to progressive reduction in immunoreactivity and receptor binding activity. The modification of six or more epsilon-NH2 groups in alpha oLH although recombine fully with native beta oLH but failed to react to anti-oLH antibody. Moreover, the steroidogenic activity was also abolished. Introduction upto four SMPT groups in alpha oLH compromised immunological and biological activities but further addition of two or more SMPT groups completely abolished antibody reactivity, receptor binding and steroidogenic activity indicating the importance of later two amino groups in the receptor binding and steroidogenic activity. The present investigation clearly demonstrate that only 1:2-3 molar ratio of oLH subunits:SMPT could generate the site(s) in the subunits of the oLH that retained reasonable immunological, receptor binding and biological activity of the hormone. Therefore, this molar ratio may be used in future for the design and synthesis of bioeffective hormonotoxins.

Obtención y caracterización de un anticuerpo específico contra la hormona luteinizante humana / Obtention and characterization of a specific antibody against human luteinizing hormone

En el presente trabajo se describe la obtención del anticuerpo policlonal específico contra la hormona luteinizante humana (HL). la Hormona fue purificada a partir de una fracción rica en glicoproteínas, obtenida de hipófisis humanas, siguiendo el método desarrollado previamente en el proyecto basado en diferencias de solubilidad y constante dieléctrica entre las diferentes proteínas. El antisuero específico se obtuvo por inoculación del antígeno en conejos raza Nueva Zelanda y su producción controlada valorando el título por RIA. La caracterización parcial del antisuero se realizó mediante la determinación del título óptimo, afinidad, especificidad y su aplicabilidad para la cuantificación en términos de curva estándar y control de calidad, en comparación con un antisuero de referencia internacional. Los resultados indicaron que el anticuerpo obtenido puede emplearse en la cuantificación del HL por RIA

Fucosylated glycoconjugates of the human spermatozoon. Comparison of the domains of these glycoconjugates with the alpha-fucosyl binding sites, and with lactosaminic glycoconjugates and beta-D-galactosyl binding site domains

Fucosylated glycoconjugates play an important role in fertilization as the recognition signal of the zona pellucida. In this work, using "critical" concentrations of either, FITC Lotus tetragonolobus lectin or FITC alpha-L-fucosyl-BSA neoglycoprotein as molecular probes, population densities of fucosylated glycoconjugates and of their "complementary" molecules (carrying fucosyl receptors), were found all over the sperm surface with higher population densities in post acrosomal sheath, neck and midpiece. These results were compared with previously reported data on the population densities of lactosaminic compounds and their "complementary" molecules, obtained on same samples of spermatozoa. Statistical data demonstrate that fucosylated glycoconjugates share the same domains with biantennary N-acetyllactosaminic oligosaccharides carrying outer galactose and bisected N-acetylglucosamine residues. These domains highly differ with those of the lactosaminic glycoproteins carrying tri and tetraantennary N-acetyllactosaminic oligosaccharides. These studies also show that the domains of fucosylated glycoconjugates and their "complementary" molecules (carrying fucosyl receptors) locate in different zones of the spermatozoon than those of the compounds carrying beta-galactosyl receptors. Besides, the results suggest structural differences between fucosylated glycoconjugates of the acrosome, equatorial zone and post acrosomal sheath. This may be relevant to the different biological behavior of these compounds and zones, in fertilization.

Effect of lysine residue modification of ovine luteinizing hormone by heterobifunctional crosslinking reagent SPDP on subunit-subunit association, receptor binding and biological activity.

The increasing use of heterobifunctional crosslinking agent in the design of hormone-carrier conjugates for selective targeting or inducing immune response against the hormone has prompted us to study the effect of epsilon-NH2 group modification of oLH-subunit, their recombination, immunoreactivity, receptor binding and biological activity. The epsilon-NH2 groups of oLH alpha and oLH beta subunits were modified by using SPDP. The SPDP modified oLH alpha derivatives hybridize to native OLH beta as judged by RP-HPLC analysis. The sequential modification of alpha and beta subunits led to progressive reduction in immunoreactivity and receptor binding activities. The steroidogenic potential of oLH beta.SPDP.alpha oLH recombinant was relatively comparable. The modification of six or more epsilon-NH2 groups in oLH alpha although recombine fully with native oLH beta but failed to react to anti-oLH antibody. Moreover, steroidogenic activity was also abolished. Introduction up to four SPDP groups in oLH alpha compromised immunological and biological activities but further addition of two more SPDP groups completely abolished antibody reactivity, receptor binding and steroidogenic activity indicating the importance of later two -NH2 groups in the receptor recognition and steroidogenic potential.

Heterogeneity in buffalo lutropin.

Lutropin (LH-1) from water buffaloes has been shown to exhibit microheterogeneity in the N-terminal amino-acid sequence of its alpha-subunit. The beta-subunit did not exhibit such microheterogeneity. Another protocol of purification yielded a preparation of buffalo LH (bu LH-2) different from the buffalo LH-1 in certain physico-chemical properties like ease of dissociation into subunits, sugar composition, isoelectric point, and elution profile on S-200. Data appear to indicate the presence of more than one form of buffalo lutropin.