HMGB proteins involved in TOR signaling as general regulators of cell growth by controlling ribosome biogenesis.

The number of ribosomes and their activity need to be highly regulated because their function is crucial for the cell. Ribosome biogenesis is necessary for cell growth and proliferation in accordance with nutrient availability and other external and intracellular signals. High-mobility group B (HMGB) proteins are conserved from yeasts to human and are decisive in cellular fate. These proteins play critical functions, from the maintenance of chromatin structure, DNA repair, or transcriptional regulation, to facilitation of ribosome biogenesis. They are also involved in cancer and other pathologies. In this review, we summarize evidence of how HMGB proteins contribute to ribosome-biogenesis control, with special emphasis on a common nexus to the target of rapamycin (TOR) pathway, a signaling cascade essential for cell growth and proliferation from yeast to human. Perspectives in this field are also discussed.

Dual function of Ixr1 in transcriptional regulation and recognition of cisplatin-DNA adducts is caused by differential binding through its two HMG-boxes.

Ixr1 is a transcriptional factor involved in the response to hypoxia, which is also related to DNA repair. It binds to DNA through its two in-tandem high mobility group box (HMG-box) domains. Each function depends on recognition of different DNA structures, B-form DNA at specific consensus sequences for transcriptional regulation, or distorted DNA, like cisplatin-DNA adducts, for DNA repair. However, the contribution of the HMG-box domains in the Ixr1 protein to the formation of different protein-DNA complexes is poorly understood. We have biophysically and biochemically characterized these interactions with specific DNA sequences from the promoters regulated by Ixr1, or with cisplatin-DNA adducts. Both HMG-boxes are necessary for transcriptional regulation, and they are not functionally interchangeable. The in-tandem arrangement of their HMG-boxes is necessary for functional folding and causes sequential cooperative binding to specific DNA sequences, with HMG-box A showing a higher contribution to DNA binding and bending than the HMG-box B. Binding of Ixr1 HMG boxes to specific DNA sequences is entropy driven, whereas binding to platinated DNA is enthalpy driven for HMG-box A and entropy driven for HMG-box B. This is the first proof that HMG-box binding to different DNA structures is associated with predictable thermodynamic differences. Based on our study, we present a model to explain the dual function of Ixr1 in the regulation of gene expression and recognition of distorted DNA structures caused by cisplatin treatment.

Comparative transcriptome analysis of yeast strains carrying slt2, rlm1, and pop2 deletions.

The function of the genes SLT2 (encoding the Mpk1 protein), RLM1, and POP2 have previously been related to several stress responses in yeasts. DNA arrays have been used to identify differences among the transcriptomes of a Saccharomyces cerevisiae wild type strain and its derivative Δslt2, Δrlm1, and Δpop2 mutants. Correspondence analyses indicate that the vast majority of genes that show lower expression in Δrlm1 also show lower expression in Δslt2. In contrast, there is little overlap between the results of the transcriptome analyses of the Δpop2 strain and the Δslt2 or Δrlm1 strains. The DNA array data were validated by reverse Northern blotting and chromatin immunoprecipitation (ChIp). ChIp assays demonstrate Rlm1p binding to specific regions of the promoters of two genes that show expression differences between the Δrlm1 mutant and wild type strains. Interestingly, RLM1 deletion decreases the transcription of SLT2, encoding the Mpk1p kinase that phosphorylates Rlm1p, suggesting a feedback control in the signal transduction pathway. Also, deletion of RLM1 causes a decrease in the mRNA level of KDX1, which is paralogous to SLT2. In contrast, deletion of POP2 is accompanied by an increase of both SLT2 and KDX1 levels. We show that SLT2 mRNA increase in the Δpop2 strain is due to a decrease in RNA turnover, consistent with the expected loss of RNA-deadenylase activity in this strain.

Carcinoma diferenciado de tiroides (CDT) en niños y adolescentes: Evolución clínica y factores pronósticos / Differentiated thyroid carcinoma in children and adolescents: Clinial outcome and prognostic factors

Si bien la forma de presentación del CDT es más agresiva en la edad pediátrica que en los adultos, la tasa de sobrevida es superior al 90%.Objetivo: analizar retrospectivamente las características clínico-patológicas,la evolución y los factores pronósticos en pacientes prepuberales (PP) y puberales (P) con diagnostico de CDT controlados en nuestro servicio. Resultados se incluyeron 43 pacientes seguidos por un tiempo X (±DS) de 5.99 años(a) (3.57) a, rango 1 -14 a. El tratamiento consistió en tiroidectomía con vaciamiento ganglionar, Iodo131 y levotiroxina en dosis inhibitoria de TSH. Al diagnóstico: edad cronológica (EC) X (±DS)10.9 (3.84) a, rango: 4.7 -17a, relación femenino /masculino 2.9. Diecinueve PP y 24 P. El 53.5% (n:23) presentó nódulos confinados a la glándula con o sin extensión ganglionar y el 46.5% (n:20) tenia un estadío tumoral más avanzado con invasión local y metástasis (MTS) pulmonar. Treinta y ocho pacientes (88.4%) tenían MTS ganglionar cervical y 16(37.2%) MTS pulmonar. El grupo PP comparado con el P tenía EC significativamente menor X (±DS) 7.25 (2.03) a vs 13.83a (p <0.001), estadío tumoral más avanzado 84.2 vs16.8% (p<0.001) y mayor ocurrencia de MTS pulmonar 68.4 vs 12.5% (p<0.003). La sobrevida global fue de 92% y libre de enfermedad 78%.Las variables predictoras de persistencia de enfermedad más significativas fueron presencia de MTS pulmonar al diagnóstico y niveles séricos de tiroglobulina superiores a 8.5 ng/ml posterior al tratamiento inicial. Conclusión: el CDT pediátrico tiene una presentación agresiva especialmente en los pacientes prepuberales. El pediatra debería incorporar el examen clínico del cuello para realizar un diagnóstico y tratamiento precoz (AU)

Children-DTC has been found to behave differently than in adults. At diagnosis, children present in a more aggressive way. However the overall survival rates is greater than 90%. The aim of this study was to perform a retrospective analysis of clinicopathologycal features at diagnosis, evolution and prognostic factors for DTC in pre-pubertal (PP)and pubertal (P)children treated at our centre. Results: 43 CDT patients were included. Mean follow up was X (±DS) 5.99 (3.57) years (y) range: 1 -14 y. Treatment consisted on total thyroidectomy with lymph node dissection, radioiodine therapy, and TSH suppressive therapy with L-thyroxine. At diagnosis: chronological age (CA) was (±DS) :10.9 (3.84) y, range: 4.7 - 17y,sex: female/male ratio: 32/11,nineteen were PP and 24 P. Twentythree ( 53.5%) presented intrathyroidal nodes with or without lymph node MTS, Twenty patients (46.5%) had advanced disease, with adjacent tissue invasion and lung MTS. Thirty-eight patients (88.4%) had cervical lymph node MTS, 16 (37.2%) lung MTS.PP group had significant less CA X (±DS) 7.25 (2.03) y vs 13.83 (1.95)y (p <0.001),advanced tumor stage 84.2 vs16.8% (p<0.001) and more lung MTS occurrence 68.4 vs 12.5% (p<0.003). Global survival rate was 92% and disease free survival rate was 78%.Lung metastases (MTS) and serum thyroglobuline levels greater than 8.5 ng\ml post initial treatment were the most significant prognostic factor related to persistent disease. Conclusion: CDT had a more aggressive presentation in children; especially in PP children. Pediatricians should be aware of this in order to realize a precocious diagnosis and treatment (AU)

Evaluación de sensibilidad-especificidad de valores de 170H progesterona sérica, basales y post estímulo con ACTH, en función del análisis molecular del gen CYP21A2 en la deficiencia de 21-hidroxilasa no clásica / Evaluation of sensitivity and specificity of serum 170H progesterone values at baseline and post ACTH stimulation in the function of molecular analysis of the CYP21A2 gene in non-classic 21-hydroxilase deficiency

La forma no clásica, post natal, de la hiperplasia suprarrenal congénita tiene una incidencia de 1 en 1000 en la población general y afecta al 6% de las mujeres hirsutas. En este estudio se estableció la sensibilidad y la especificidad de la respuesta de los niveles séricos de 17-hidroxiprogesterona (17OHP4) al estímulo agudo con ACTH en 203 pacientes de ambos sexos, pre y post puberales, con hiperandrogenismo, en los cuales se analizó si tenían una alteración molecular del gen CYP21A2. Posteriormente al estudio molecular, los pacientes fueron clasificados en tres grupos de acuerdo al genotipo: Gr0, n=61: ningún alelo mutado (no portadores de mutación); Gr1, n=55: un alelo mutado (portadores) y Gr2, n=87: dos alelos mutados (afectados). Por análisis de regresión logística (curvas ROC) se compararon los valores basales del Gr2 vs Gr0 y se obtuvo un valor de 17OHP4 de 7,2 ng/ml con una sensibilidad del 83% y una especificidad del 85%. Se sugiere entonces que en los pacientes con este nivel basal no se debería realizar el test de ACTH, y habría que confirmar el diagnóstico con el estudio molecular. Los niveles 17OHP4 a los 60 minutos post estímulo con ACTH mayores a 20 ng/ml son confirmatorios del diagnóstico con 84% de sensibilidad y 88% de especificidad. No sería necesario entonces realizar estudios moleculares. Un valor de 15,6 ng/ml diferencia Gr2 de Gr0 con una sensibilidad del 89% y una especificidad del 95%. Este es un buen valor predictivo, pero el análisis molecular no debería obviarse en aquellos casos en los que exista una fuerte sospecha clínica. (AU)

The incidence of non classic congenital adrenal hyperplasia is 1:1000 in the general population and it is present in 6% of hirsute women. In this study, the sensitivity and specificity of serum 17-hydroxyprogesterone (17OHP4) response to acute ACTH stimulation was evaluated in 203 prepubertal and pubertal patients of the two sexes with hyperandrogenism, in whom the CYP21A2 gene was analyzed. After molecular analysis patients were divided in 3 groups according to genotype: Gr0, n=61, no mutated allele (no mutation carrier); Gr1, n=55, one mutated allele (carrier); and Gr2, n=81, two mutated alleles (affected patient). Using logistic regression analysis (ROC curves), basal values in Gr2 vs. Gr0 were compared and a cutoff value of 7.2 ng/ml was defined to separate groups, with 83% sensitivity and 85% specificity. It is suggested then that in patients with levels higher than 7,2 no ACTH test is necessary and molecular analysis is required to confirm diagnosis. Serum 17OHP4 values above 20 ng/ml 60 minutes after ACTH are confirmatory of diagnosis, with 84% sensitivity and 88% specificity. No molecular studies should be necessary. A 15.6 ng/ml cutoff value is able to differentiate Gr2 from Gr0, with 89% sensitivity and 95% specificity. It is a good predictive value, but carrying out molecular analysis is only advisable if clinical evidence is strong (AU)

Displasia septo-optica. Evaluación clínica, endocrinológica y neuro-radiológica. Seguimiento de 46 pacientes pediátricos / Septo-optic dysplasia. Clinical, endocrinological, and neuroradiological evaluation. Follow-up of 46 pediatric patients

La displasia septo-óptica (DSO) es una condición rara y altamente heterogénea, definida por la combinación de hipoplasia del nervio óptico (HNO), malformaciones cerebrales de la línea media, tales como aplasia/hipoplasia de septum pellucidum y cuerpo calloso, e insuficiencia hipotálamo-hipofisaria de grado variable. Se realizó un trabajo que tuvo como objetivo caracterizar la población de pacientes con diagnóstico de DSO seguidos en nuestro Hospital durante 7 años. Se incluyeron 46 pacientes (18 mujeres) que fueron divididos en 2 grupos, según tuviesen o no insuficiencia hipotálamo-hipofisaria (IHH). El 58.7% (n=27) presentó IHH de algún tipo, mientras que el 41.3% (n=19) no la presentó. En aquellos 19 pacientes con IHH se diagnosticaron deficiencia de GH y TSH (85.1%) y de ACTH (48.1%). La longitud corporal (mediana) del grupo con IHH fue más baja (p = 0,01) que la del grupo sin IHH, a pesar de que la edad fue menor a 2 años en todos los casos. Los pacientes fueron seguidos 1,3-8,3 años. Se observaron incidencias similares de agenesia del cuerpo calloso, del septum pellucidum, y ventriculomegalia, pero las alteraciones del desarrollo cortical se observaron con mayor frecuencia en los pacientes sin IHH. La ictericia neonatal, convulsiones y/o hipoglucemia, y micropene en neonatos y lactantes con DSO se presentaron en el subgrupo con IHH. El 58,7% de los pacientes con DSO presentaron algún grado de insuficiencia hipotálamo-hipofisaria. En la mayoría de los casos el diagnóstico de IHH no se realizó en el momento de aparición de los síntomas, sino más tardíamente en su seguimiento. En el 45% de los pacientes se evaluaron alteraciones radiológicas del SNC, específicamente en la región hipofisaria. Una fracción importante de las deficiencias de TSH/T4 (36,4%), GH (50%) y ACTH (23%) aparecieron mas tardíamente en el curso de la evolución. En 10 niños con déficit de hormona de crecimiento (2 tests farmacológicos sin respuesta) se realizó el tratamiento sustitutivo con rhGH (durante un periodo de 4±3 años), observándose una mejoría promedio de + 1,5 SDS en la talla de estos pacientes. En conclusión, la hipoplasia neonatal de nervios ópticos, asociada o no a ictericia e hipoglucemia, debe ser un signo de alarma para el diagnóstico de DSO, con riesgo de insuficiencia suprarrenal, shock y muerte, y puede requerir, por lo tanto, urgente tratamiento. Las deficiencias pueden aparecer en el curso de la evolución, a pesar del carácter congénito de la anomalía. Finalmente, se deben sustituir las deficiencias hormonales y tener presente que el tratamiento con rhGH puede mejorar la talla final en estos pacientes (AU)

Septo-optic dysplasia (SOD) is a rare and highly heterogeneous condition consisting of a combination of optic nerve hypoplasia (ONH), midline brain abnormalities, such as aplasia/hypoplasia of the septum pellucidum (ASP) and corpus callosum; and variable degree of hypoyalamo-pituitary insufficiency. The aim of this study was to characterize a population of SOD patients diagnosed and followed at the Garrahan Pediatric Hospital, from 1989 to 2006. We included 46 patients (18 females), that were divided into two groups according to the presence or absence of hypothalamic-pituitary insufficiency (IHH). Fifty nine% of SOD patients presented with IHH. GH and TSH deficiencies were diagnosed in 85.1% of IHH patients, while ACTH deficiency was found in 48.1%. Height (median) for the IHH group was shorter (p = 0,01) than for the group without IHH. Patients were followed for 1.3-8.3 years. Similar incidence of corpus callosum and/or septum pellucidum agenesis and ventriculomegaly were found in the two groups, but we observed more association with cortical developmental disorders in patients without IHH. In newborns, the association of ophthalmologic disorders and jaundice, seizures and/or hypoglycemia and micropene should frequently lead to the diagnosis of SOD and IHH. While 58,7% of DSO patients presented with hypothalamic-pituitary deficiency, only 45% of them showed sellar radiological abnormalities. Although SOD is a congenital disease, hormonal deficiencies may appear during follow-up. In 10 children with SOD and GH deficiency, rhGh treatment (for 4±3 years) improved height in 1.5 SDSs. In conclusion: in newborns with nerve optic hypoplasia, associated or not with jaundice, seizures and hypoglycaemia, the diagnosis of SOD and IHH should be considered. Treatment could be an emergency need because of risk of adrenal insufficiency and hypoglycemia (AU)

Tumores del sistema nervioso central de localización selar y supraselar. Alteraciones neuro-oftalmológicas y de la función endocrina al diagnóstico / Sellar and suprasellar central nervous system tumors. Neuro-ophthalmological and endocrine function impairment at diagnosis

Los tumores (Tu) del SNC constituyen la segunda enfermedad oncológica en edad pediátrica, con una incidencia referida aproximada que oscila entre el 10 y 15%. En 309 pacientes con tumores selares y supraselares, seguidos durante 15 años, se evaluó en función de los distintos oncotipos tumorales, síntomas iniciales y alteraciones endocrinológicas previas al inicio del tratamiento. De ellos, 227 pacientes presentaron el tumor a edad prepuberal. Los oncotipos tumorales más frecuentes fueron craneofaringioma (CRA), glioma (GLIA) y tumor de células germinales (GERM). También, se encontró una mayor incidencia de presentación en varones. En edad puberal (n:92), el oncotipo tumoral más frecuente fue adenoma hipofisario (ADENO), seguido de GLIA y CRA. En este ultimo oncotipo tumoral, y, a diferencia del grupo prepuberal, su incidencia fue significativamente mayor en niñas. Aproximadamente 90% de los pacientes tuvieron anormalidades neuro-oftalmológicas (hipertensión craneal, dolores de cabeza, vómitos y pérdida progresiva de la visión) como uno de los signos y/o síntomas iniciales. Alteraciones clínicas endocrinológicas como baja talla, velocidad de crecimiento anormal, diabetes insípida y alteraciones del tempo puberal son frecuentes en estos pacientes y están habitualmente asociadas con las alteraciones clínico-neuro-oftalmológicas como las ya mencionadas. No obstante, la mayoría de los tumores del SNC localizados en la línea media suelen ser diagnosticados por manifestaciones neuro-oftalmológicas. Los resultados del estudio muestran alteración de la función endócrina al diagnóstico del Tu. Se concluye que en todo paciente con crecimiento lento o baja talla, así como también signos clínicos que orienten a un diagnóstico de pubertad precoz y/o retardada, el pediatra debe incluir dentro de los diagnósticos diferenciales, el diagnóstico del tumor selar o supraselar. La morbilidad aumenta frecuentemente luego de la cirugía (AU)

During the last 15 years, 309 patients with tumors of the sellar and suprasellar areas of CNS were followed in our Hospital (Endocrine Service). Tumor oncotype, initial symptoms and endocrine disturbances before any treatment was started are presented. In 227 patients, the tumor was diagnosed at prepubertal age. In this group, the most frequent tumoral oncotypes were craniopharyngioma (CRA), glial tumors (GLIA) and germ cells tumors (GERM). The incidence was higher in boys. At pubertal age (n:92), the most frequent tumoral oncotype was pituitary adenoma (ADENO), followed by GLIA and CRA. In the latter, and different from the prepubertal group, the incidence was significantly higher in girls. Approximately 90% of patients had neuro-ophtalmological abnormalities (cranial hypertension, headaches, vomits, and progressive loss of vision) as one of the initial signs and/or symptoms. Clinical endocrine disorders, such as short stature, low growth velocity, diabetes insipidus, and alterations in pubertal "tempo" are frequent in these patients and are often associated with the neuro-ophtalmological abnormalities mentioned above. This clinical symptomatology has to alert the medical team to discard the presence of a CNS tumor at the sellar and/or suprasellar level. We conclude that tumors of the SNC localized in the midline, have potential capacity to provoke abnormalities in endocrine function. Morbidity is often increased after surgery (AU)

Serum IGF-I and IGFBP-3 reference values from a chemiluminescent assay in normal children and adolescents of hispanic and italian origin: presence of sexual dimorphism in IGF-I values.

Serum IGF-I and IGFBP-3 assays are used to monitor rhGH treatment. Some discrepancies in results obtained by means of different assays have been reported. The aim of this study was to establish normal ranges for circulating IGF-I and IGFBP-3 in children and adolescents of Hispanic and Italian origin. Circulating levels of IGF-I and IGFBP-3 were measured in 169 Hispanic and Italian prepubertal children and 66 adolescents of both sexes, using a chemiluminescent assay. Serum levels of IGF-I and IGFBP-3 increased from early childhood into adolescence. After pubertal peaks of IGF-I and IGFBP-3, slight decreases were observed with increasing age. Furthermore, serum IGF-I levels were significantly higher in girls than in boys, suggesting a sexual dimorphism in serum IGF-I values in late prepuberty and early puberty. Differences in IGF-I and IGFBP-3 absolute values between our study and previous studies suggest the need to establish reference ranges for each ethnic group.

Differences in serum GH cut-off values for pharmacological tests of GH secretion depend on the serum GH method. Clinical validation from the growth velocity score during the first year of treatment.

BACKGROUND: The serum GH cut-off value for pharmacological tests of GH secretion (PhT GH) depends on the type of test and also on the method used for determining serum GH. Cut-off serum GH values as different as 5-10 ng/ml, have been reported, and have been validated biochemically. We have used the growth velocity (GV)-standard deviation score (SDS) during the first year of treatment with rhGH to validate these cut-offs on a biological basis. METHODS: Fifty pre-pubertal patients with short stature (height < or =-2 SDS and GV < or =-1.2 SDS) were studied. GH deficiency (GHD) was diagnosed in 39 patients, on the basis of clinical and auxological parameters and on the serum concentration of IGF-1, and non-GHD in the other 11 patients. Two PhT GH (arginine and clonidine) were carried out in the 50 patients. Serum GH was determined by two different methods: one detecting most of serum GH isoforms, named Total GH (HGH Bio-Tech, MAIA Clone), and another one, only detecting the 22 kDa GH, named 22K GH (GH-22K IFMA, Wallac). RESULTS: Basal data: all patients with GHD and with non-GHD had maximal serum GH response (MaxR) values below and above the cut-off, respectively, for the serum Total GH and 22K GH. The mean 22K GH/Total GH ratio was similar to previous publications. Post-rhGH treatment data: the two groups improved their height SDS during the first year of treatment, particularly patients with GHD. A receiver-operator curve was used to define the best threshold for post-treatment GV-SDS that separates GHD from non-GHD patients. This value was 1.91 GV-SDS. A negative correlation between first year treatment GV-SDS and pre-treatment serum GH MaxR was found for the two assays (p < 0.001). Then, the best cut-off GV-SDS, previously calculated with the receiver-operator curve (1.91 SDS) was used to interpolate the corresponding serum GH values, as determined by the two methods. For Total GH, the value was 10.8 ng/ml, and for 22K GH, it was 5.4 ng/ml. CONCLUSION: The cut-off values calculated by biological means to separate GHD from non-GHD were remarkably similar to those calculated biochemically (10.0 and 4.8 ng/ml, respectively) for Total and 22K GH. This is a biological validation for using different cut-off values, appropriate for each assay, to diagnose GHD.

Dose dependency of the serum bio/immuno GH ratio in children during pharmacological secretion tests.

Dissociation between GH bioactivity (bio-GH) and GH immunoactivity (immuno-GH) is due to the heterogeneity of the molecule: the measurements do not always provide reliable information on the bio-GH. We studied the ratio of bio-GH and immuno-GH during pharmacological secretion tests in 211 sera to study the concentration-response curve of the assay (C1), 16 samples of normally growing subjects with idiopathic short stature (C2), 13 samples from patients with GH deficiency (GHD1) and 6 samples of 3 patients with GHD and normal provocative tests (GHD2). GH bioactivity was determined by the Nb2 cell proliferation assay (bio-GH) and immuno-GH by a time-resolved immunofluorometric assay (IFMA) (immuno-GH). A non-linear negative relationship between the serum bio-GH/immuno-GH ratio and serum immuno-GH was observed in C1. In log-log plotting representation, two cut-off lines were drawn: a vertical cut-off line separating above-below cut-off serum peak immuno-GH values in provocative tests, and a diagonal cut-off line separating normal-abnormal serum bio-GH/immunoGH ratio; four areas were defined. GHD1 had normal ratios, but below cut-off peak immuno-GH responses. P2 and P3 of Group GHD2 had abnormal ratios in samples with low serum immuno-GH but only P2 had autosomal dominant mutation. P1 had the same autosomal dominant isolated GHD as P2 but a low normal ratio. Our data underline the importance of relatively low serum GH concentrations in mediating GH biological actions. An abnormal serum bio-GH/immuno-GH ratio might explain certain cases of GHD and might be useful in detecting abnormal circulating isoforms of GH in patients with growth failure.

Characterization of a gene similar to BIK1 in the yeast Kluyveromyces lactis.

In Saccharomyces cerevisiae, Bik1p is a microtubule plus-end-tracking protein that plays several roles in mitosis and ploidy. KlBik1p (from Kluyveromyces lactis) maintains the same structural-domain organization as does S. cerevisiae Bik1p. As part of its characterization, we constructed a stable klbik1 mutant which is sensitive to benomyl only at 14 degrees C and has a higher frequency of crescent-shaped nuclei than S. cerevisiae bik1 mutants. This phenotype is partially rescued by S. cerevisiae BIK1. Other phenotypes associated with bik1 are not present in the K. lactis mutant. By fusion to GFP we were able to show the functionality of the KlBik1p CAP-Gly domain and found that the fusion protein changes its cellular location during the cell cycle.

Kluyveromyces lactis HIS4 transcriptional regulation: similarities and differences to Saccharomyces cerevisiae HIS4 gene.

Sequence analysis of the Kluyveromyces lactis HIS4 (KlHIS4) gene promoter reveals relevant differences in comparison to the Saccharomyces cerevisiae HIS4 homologous gene. Among them are the absence of a Rap1 binding site and the presence of only three putative Gcn4 binding consensus sites instead of the five described in the S. cerevisiae promoter. Since these factors are implicated in the general control, we investigated the transcriptional regulation of the KlHIS4 gene under conditions of amino acid starvation and discovered that the mechanisms previously described for S. cerevisiae HIS4 regulation and related to general control are not functional in K. lactis. The expression analysis of the KlHIS4 gene under phosphate starvation or high adenine supply shows that factors, such as Bas1 or Bas2, involved in the basal control may also operate in a different way in K. lactis. Interestingly, and also in contrast to the HIS4 regulation in S. cerevisiae, we found domains for Nit2-like and yeast-Ap1-like binding sequences. Northern analyses showed transcriptional activation under ammonia starvation and oxidative stress.

Thyroid function and serum thyroid binding proteins in prepubertal and pubertal children with chronic renal insufficiency receiving conservative treatment, undergoing hemodialysis, or receiving care after renal transplantation.

OBJECTIVE: The abnormalities reported in some thyroid function tests in children with renal disease could be adaptive phenomena, shared by a variety of other nonthyroidal illnesses, or could reflect hypothyroidism. STUDY DESIGN: To answer this question, we studied thyroid function and serum thyroid binding proteins in 36 prepubertal and 23 pubertal patients with renal disease receiving three different therapies: conservative treatment, hemodialysis, and care after renal transplantation. RESULTS: During prepuberty, the serum concentration thyroxine binding globulin (mean +/- SE) in the three groups of patients (294 +/- 18, 303 +/- 18, and 323 +/- 16 nmol/L, respectively) was significantly lower than in prepubertal control subjects (451 +/- 71 nmol/L). Only in prepubertal patients after renal transplantation (3583 +/- 573 nmol/L) were serum thyroxine binding prealbumin values lower than in respective control subjects (5999 +/- 908 nmol/L). The serum total thyroxine concentration in the three groups of patients (108 +/- 41.9, 121 +/- 5.7, and 123 +/- 5.5 nmol/L, respectively) was significantly lower than in prepubertal control subjects (149 +/- 10 nmol/L), whereas serum free thyroxine and serum albumin-bound thyroxine concentrations were similar to those in control subjects. The serum total triiodothyronine level in the three groups of patients (2.29 +/- 0.82, 2.13 +/- 0.13, and 2.01 +/- 0.20 nmol/L respectively) was significantly lower than in prepubertal control subjects (3.04 +/- 0.24 nmol/L), whereas serum levels of free triiodothyronine and serum albumin-bound triiodothyronine were similar to those in prepubertal control subjects. During puberty, serum thyroxine binding globulin and serum thyroxine binding prealbumin levels in the three groups of patients were not statistically different from those in pubertal control subjects (309 +/- 47 and 4950 +/- 1230 nmol/L, respectively). Serum levels of total thyroxine, free thyroxine, albumin-bound thyroxine, total triiodothyronine, free triiodothyronine, and albumin-bound triiodothyronine were similar to those in pubertal control subjects except for pubertal patients undergoing hemodialysis. In all clinical groups the basal serum thyrotropin concentration was similar to those in respective control subjects. The frequency of goiter was increased in patients undergoing hemodialysis, probably as a result of iodide washout with dialysis. CONCLUSION: Children and adolescents with chronic renal insufficiency or endstage renal disease or after renal transplantation do not have a primary abnormality of thyroid function and therefore are not candidates for thyroid hormone treatment.

Serum concentrations of follicle stimulating hormone and luteinizing hormone in normal girls and boys during prepuberty and at early puberty.

Serum luteinizing hormone (LH) and follicle stimulating hormone (FSH) morning levels were determined in 327 normal prepubertal and early pubertal children of both sexes, utilizing a highly sensitive and specific microparticle enzyme immunoassay. Female (F) and male (M) prepubertal (Tanner's stage I) subjects were divided into 4 age groups: less than 3 months (F1, M1), 3 to 12 months (F2, M2) 12 to 24 months (F3, M3) and older than 24 months (F4 and M4). F pubertal subjects were classified in Tanner's stage breast II (F5) and III F6), while M pubertal subjects belonged to Tanner's stage genitalia II (M5). Serum LH levels were relatively low in prepubertal girls and showed a significant increment in group F6. By contrast, serum LH levels were relatively high in M1 and M2, decreased to levels similar to F in M3 and M4, and increased again at puberty in M5. Serum FSH levels were relatively high in girls of all prepubertal groups, even though they decrease significantly in M4. An increase was detected in pubertal group M6. All M prepubertal groups had significantly lower FSH levels than F prepubertal groups. The high serum LH of boys during the first year of life is probably a consequence of an activation of the hypothalamic GnRH pulse generator that is not apparent in girls. On the other hand, the high serum FSH of prepubertal girls is probably a consequence of a weak restraint influence of the prepubertal ovary on pituitary FSH secretion. This sexual dimorphism in gonadotropin secretion regulates, in a sex-specific fashion, prepubertal gonadal function in the two sexes.

Endocrine disorders in 66 suprasellar and pineal tumors of patients with prepubertal and pubertal ages.

Tumor oncotypes, initial symptoms and endocrine disturbances before and/or 1 month after surgery were studied in 66 patients with prepubertal and pubertal ages having suprasellar or pineal intracranial tumors. Neoplasms found in patients of prepubertal age were: 15 craniopharyngiomas (CRA), 24 neuroepithelial-cell-derived tumors (NEC), 5 germ cell tumors (GERM) and 4 other lesions (OTHER). In patients of pubertal age, there were 7 CRA, 7 pituitary tumors (PIT), 2 NEC, 1 GERM and 1 OTHER. Approximately 90% of patients had visual abnormalities as one of the initial signs and symptoms, while 59% had increased intracranial pressure. Short stature was observed in only 10% of patients. Before surgery, somatotropic function was found to be deficient (by 2 pharmacological tests) in 90-100% of patients with CRA, PIT or GERM and in 40% of patients with NEC. Overt hypothyroidism was found in 5-25% of CRA, NEC or GERM but in 40% of PIT. Abnormal TSH responses to TRH were observed in 64% of CRA and in 29% of NEC. Low basal serum cortisol was found in 21 or 6% of patients with CRA or NEC, but in 100 or 60% of patients with PIT or GERM, respectively. Diabetes insipidus was diagnosed in 13.6% of all patients. Surgery produced few additional disturbances in endocrine function, except for the incidence of diabetes insipidus which was doubled. Gonadotropic deficiency was found in most patients of pubertal age with CRA and PIT. They were readily differentiated by the high prolactin or growth hormone (GH) levels of the latter.(ABSTRACT TRUNCATED AT 250 WORDS)