Impacto de la salud bucal sobre la calidad de vida de los niños de 11 a 14 años de tres escuelas nacionales de Asunción / Impact of oral health on the quality of life of children from 11 to 14 years of taking three National Schools from Asunción

INTRODUCCIÓN: La cavidad bucal no es solo una parte importante de nuestro sistema digestivo, es un lugar cargado de emociones desde el inicio de la vida. Todas las personas deberían contar con una salud bucal que permita cumplir con sus funciones físicas y emocionales. La calidad de vida y la salud bucal están estrechamente relacionadas. OBJETIVO: Conocer el impacto de la salud bucal de los niños de 11 a 14 años de tres Escuelas Nacionales de Asunción en su calidad de vida. MATERIAL Y MÉTODOS: Estudio observacional, descriptivo y de corte transverso. Realizado en niños (n=133) de tres escuelas nacionales de Asunción en el año 2016, donde se utilizó el cuestionario de autopercepción (CPQ 11-14) del impacto de las condiciones bucales en su versión corta en español. Los datos fueron procesados en el programa Excel. RESULTADOS: El 63% de los encuestados tiene una autopercepción de Regular en cuanto a la salud de sus dientes. El 37% respondió haber tenido problemas en sus actividades diarias por causa de sus dientes. El 43% manifestó tener Sintomatología oral (empaquetamiento dentario 67,2%, dolor dentario (50,4%), sangrado en las encías (48,6%) y problemas para dormir por dolor (28%), el 26% reportó una Limitación funcional. La hipersensibilidad fue la limitación con mayor frecuencia (53%), seguido por problemas para comer cosas duras (28%). El 18% presentó afección en el Bienestar emocional y el 10% en el ámbito Bienestar social. En la evaluación de necesidad de salud bucal percibida se concluyó que los encuestados necesitan asistir al dentista para una evaluación, pues existe impacto físico y emocional en la calidad de vida de los encuestados.

INTRODUCTION: The oral cavity is not only an important part of our digestive system, is a place full of emotions from the beginning of life. Every ones hould have an oral health that can effectively meet their physical and emotional functions. Quality of life and oral health are closely related. OBJECTIVE: Tok now the impact of oral health of children from 11 to 14 years of three national schools of Asuncion in their quality of life. METHODS: Observational, descriptive and transverse sectional study. Involving children (n = 133) of three National Schools of Asunción in 2016, where the self-perception questionnaire (CPQ 11-14) the impact of oral conditions in its short version in spanish was used. The data were processed in the Excel program. RESULTS: 63% of respondent shave a self-perception Regular regarding the health of your teeth. 37% of respondent shave had problems in their daily activities because of their teeth. 43% reported Oral symptoms (67.2%), packaging tooth toothache (50.4%), bleeding gums (48.6%) and pain trouble sleeping (28%), 26% reported a Functional limitation. The hypersensitivity was limited more often (53%), followed by trouble eating hard (28%) things. the 18% presented condition in the emotional well being and 10% in the field Social welfare in assessing perceived need for oral health was concluded that respondents need to attend to the dentist for an evaluation, as there is physical and emotional impact on the quality of life of respondents.

Medicación preanestésica con dexmedetomidina intranasal y midazolam oral como ansiolítico. Un ensayo clínico / Pre-anesthetic medication with intranasal dexmedetomidine and oral midazolam as an anxiolytic. A clinical trial

INTRODUCCIÓN: La dexmedetomidina es una opción farmacológica en la sedación del paciente pediátrico. En este estudio, se compara la eficacia de la dexmedetomidina intranasal versus midazolam por vía oral para disminuir la ansiedad preoperatoria en pacientes pediátricos. MATERIAL Y MÉTODOS: Se realizó un ensayo clínico, doble ciego, en niños de 2 a 12 años de edad, asignados aleatoriamente a uno de los siguientes dos grupos: a) recibió medicación preanestésica con midazolam por vía oral y placebo intranasal; b) recibió dexmedetomidina intranasal y placebo por vía oral. Se evaluó la ansiedad con la escala de Yale modificada y realizamos el análisis de reducción de riesgo y un número necesario a tratar. RESULTADOS: Se estudió a 108 pacientes, 52 (48,1%) tratados con dexmedetomidina y 56 (51,9%) con midazolam. La ansiedad fue menos frecuente en el grupo de dexmedetomidina a los 60 min (p = 0,001), en la inducción (p = 0,04) y en la recuperación (p = 0,0001). El análisis de riesgo mostró que la dexmedetomidina redujo el riesgo de ansiedad en un 28% (RAR=0,28, IC del 95%, 0,12 a 0,43) y que para prevenir un caso de ansiedad es necesario tratar con dexmedetomidina intranasal a 4 pacientes (NNT=4, IC del 95%, 3 a 9). En el grupo de dexmedetomidina se registraron cambios estadísticamente significativos en la frecuencia cardiaca, la presión arterial media y la saturación de oxígeno, sin repercusión clínica; no se registraron casos de bradicardia, hipotensión ni desaturación de oxígeno. CONCLUSIONES: La premedicación con dexmedetomidina intranasal es más eficaz que el midazolam por vía oral para disminuir la ansiedad preoperatoria en pacientes pediátricos

INTRODUCTION: Dexmedetomidine is a pharmacological option for sedation in children. In this study, the efficacy of intranasal dexmedetomidine to reduce preoperative anxiety in pediatric patients is compared with that of oral midazolam. MATERIAL AND METHODS: A prospective, randomized, double-blind, controlled trial was conducted on children 2-12 years of age, randomly assigned to one of the following two groups: group A received premedication with oral midazolam and intranasal placebo, group B received intranasal dexmedetomidine and oral placebo. Anxiety was assessed with the modified Yale scale, and a risk analysis and number needed to treat was performed. RESULTS: A total of 108 patients were included, 52 (48.1%) treated with dexmedetomidine, and 56 (51.9%) with midazolam. Anxiety was less frequent in the dexmedetomidine group at 60minutes (P=0.001), induction (p = 0.04), and recovery (P=0.0001). Risk analysis showed that dexmedetomidine reduced the risk of anxiety by 28% (RAR=0.28, 95% CI; 0.12 to 0.43) and to prevent one case of anxiety, four patients need to be treated with intranasal dexmedetomidine (NNT=4, 95% CI: 3-9).Changes in heart rate, mean arterial pressure, and oxygen saturation, were statistically significant in the dexmedetomidine group, with no clinical consequences. There were no cases of bradycardia, hypotension or oxygen desaturation. CONCLUSIONS: Intranasal dexmedetomidine premedication is more effective than oral midazolam to reduce preoperative anxiety in pediatric patients

[Pre-anesthetic medication with intranasal dexmedetomidine and oral midazolam as an anxiolytic. A clinical trial]. / Medicación preanestésica con dexmedetomidina intranasal y midazolam oral como ansiolítico. Un ensayo clínico.

INTRODUCTION: Dexmedetomidine is a pharmacological option for sedation in children. In this study, the efficacy of intranasal dexmedetomidine to reduce preoperative anxiety in pediatric patients is compared with that of oral midazolam. MATERIAL AND METHODS: A prospective, randomized, double-blind, controlled trial was conducted on children 2-12 years of age, randomly assigned to one of the following two groups: group A received premedication with oral midazolam and intranasal placebo, group B received intranasal dexmedetomidine and oral placebo. Anxiety was assessed with the modified Yale scale, and a risk analysis and number needed to treat was performed. RESULTS: A total of 108 patients were included, 52 (48.1%) treated with dexmedetomidine, and 56 (51.9%) with midazolam. Anxiety was less frequent in the dexmedetomidine group at 60minutes (P=.001), induction (p=.04), and recovery (P=.0001). Risk analysis showed that dexmedetomidine reduced the risk of anxiety by 28% (RAR=0.28, 95% CI; 0.12 to 0.43) and to prevent one case of anxiety, four patients need to be treated with intranasal dexmedetomidine (NNT=4, 95% CI: 3-9).Changes in heart rate, mean arterial pressure, and oxygen saturation, were statistically significant in the dexmedetomidine group, with no clinical consequences. There were no cases of bradycardia, hypotension or oxygen desaturation. CONCLUSIONS: Intranasal dexmedetomidine premedication is more effective than oral midazolam to reduce preoperative anxiety in pediatric patients.

Early steroid treatment improves the recovery of renal function in patients with drug-induced acute interstitial nephritis.

The role of steroid treatment in drug-induced acute interstitial nephritis (DI-AIN) is controversial. We performed a multicenter retrospective study to determine the influence of steroids in 61 patients with biopsy-proven DI-AIN, 52 of whom were treated with steroids. The responsible drugs were antibiotics (56%), non-steroidal anti-inflammatory drugs (37%) or other drugs. The final serum creatinine was significantly lower in treated patients while almost half of untreated patients remained on chronic dialysis. Among treated patients, over half showed a complete recovery of baseline renal function, whereas the rest remained in renal failure. There were no significant initial differences between these two subgroups in terms of duration or dosage of steroids. After withdrawal of the presumed causative drug, we found that when steroid treatment was delayed (by an average of 34 days) renal function did not return to baseline levels compared to those who received steroid treatment within the first 2 weeks after withdrawal of the offending agent. We found a significant correlation between the delay in steroid treatment and the final serum creatinine. Renal biopsies, including three patients who underwent a second biopsy, showed a progression of interstitial fibrosis related to the delay in steroid treatment. Our study shows that steroids should be started promptly after diagnosis of DI-AIN to avoid subsequent interstitial fibrosis and an incomplete recovery of renal function.

The IGFBP-3 mRNA and protein levels are IGF-I-dependent and GH-independent in MG-63 human osteosarcoma cells.

Growth Hormone (GH), Insulin-like Growth Factors (IGFs) and IGF-Binding Proteins which modulate the IGFs' bioavailability (e.g. IGFBP-3, -4, -5), are essential regulators of bone remodeling. In this study, MG-63 human osteosarcoma cells were used as a model system to investigate the mechanism(s) whereby IGF-I and GH control IGFBP-3 gene expression. Physiological concentrations of IGF-I (1-20 nM) induced a dose-dependent increase in the steady-state amount of IGFBP-3 mRNA (maximal stimulation: approximately 9-10-fold). This increase was detectable 3 h after the onset of IGF-I treatment, was enhanced over a 24 h period, then plateaued until at least 30 h. Consistently, a dose-dependent increase in IGFBP-3 secretion ( approximately 40-50-fold at IGF-I concentrations>/=16 nM) was observed by western ligand- and immuno-blot analysis of MG-63 cells conditioned medium, and its time course was similar to that observed for IGFBP-3 transcripts. IGFBP-3 mRNA stability (t(1/2) approximately 20 h) was identical in the presence or absence of IGF-I treatment. By contrast, human (h) GH treatment (24-72 h) of MG-63 cells did not increase IGFBP-3 secretion in the conditioned medium. Ectopic expression of recombinant rat GH-R resulted in hGH-enhanced expression of GH-responsive reporter gene constructs, but did not increase endogenous IGFBP-3 gene expression, suggesting that the GH unresponsiveness was not only due to the very low level of GH binding sites at the plasma membrane level. Altogether, these results support the conclusions that in MG-63 cells (i) transcriptional rather post-transcriptional mechanisms are involved in the IGF-I-induced increase of IGFBP-3; (ii) the abundance of GH-R is very low at the plasma membrane level; (iii) the dowstream GH-signaling cascade is fully functional in this human osteosarcoma cell line; and (iv) the endogenous IGFBP-3 gene is not responsive to hGH in human MG-63 osteosarcoma cells.

Trauma abdominal: estudio de lesiones viscerales

Se estudiaron 575 pacientes con trauma cerrado y penetrante de abdomen operados en el Servicio de Emergencia del Hospital Luis Vernaza de 1997 a 1998. Del total de pacientes operados encontramos que el 15.4 por ciento de los pacientes tuvieron traumas cerrados y 84.5 por ciento tuvieron trauma penetrante de abdomen. Los órganos más afectados fueron intestino con el 36.1 por ciento (ileon 24 por ciento y yeyuno 12.1 por ciento), hígado 26.6 por ciento, colon 24.3 por ciento, estómago 13.5 por ciento. Los traumas encontrados fueron en 4 casos de tipo especial, en 219 casos producidos por arma cortopunzante y en 263 por arma de fuego.

Proteolytic fragments of insulin-like growth factor binding protein-3: N-terminal sequences and relationships between structure and biological activity.

Insulin-like growth factors (IGF-I and IGF-II) in biological fluids bind to high-affinity binding proteins (IGFBP-1 to -6), which transport them and regulate their activities. Limited proteolysis of certain IGFBPs plays a major role in this regulation. IGFBP-3 is proteolysed in vivo and in several cell lines by serine proteases, including plasmin. In earlier studies we reproduced this proteolysis in vitro using recombinant human non-glycosylated IGFBP-3. Two major fragments were obtained, the larger retaining weak affinity for IGF-I and weakly inhibiting IGF I mitogenic effects. The smaller fragment, though lacking affinity for IGFs, is a potent growth inhibitor. These proteolytic fragments were isolated by HPLC and their N-terminal amino acids sequenced. Both major fragments contain the N-terminal region of the intact protein, the larger form corresponding to residues 1-160, and the smaller form, to residues 1-95. Kinetics experiments using the MG-63 osteoblast-like cell line showed that the larger peptide is generated before the smaller peptide, the latter probably being a product of secondary proteolysis of the former. Our data suggest that proteolysis of IGFBP-3 is intimately linked to its biological function. We propose a model for its action at cellular level.

Growth retardation in constitutionally short children is related both to low serum levels of insulin-like growth factor-I and to its reduced bioavailability.

Measurements of serum levels of insulin-like growth factor (IGF)-I, IGF-II and IGF binding protein (IGFBP)-1 have been carried out in conjunction with Western ligand blot analysis of serum IGFBPs in 39 constitutionally short children and adolescents and compared with those of 27 age-matched normal subjects (and also with 23 hypopituitary patients). Estimated amounts of the two forms of IGFBP-3 (42 and 39 kDa) and of IGFBP-2 (34 kDa) were obtained by laser densitometry scanning. Mean serum levels of IGF-I were decreased by 46% +/- 5% in short, compared to normal, prepubertal children (P < 0.01) and reduced slightly, but not significantly, in short pubertal children. IGFBP-1 levels decreased with age in short children, as they did in normals, but average values were significantly higher in short children (P < 0.001). There was also a tendency for higher IGFBP-2 levels in short prepubertal and pubertal children. IGFBP-3 bands were of equal intensity in short and normal subjects. Physiologically, IGFBP-3 undergoes limited proteolysis which results in facilitated dissociation of the IGFs, particularly IGF-I, and an increase in their turnover. Western immunoblotting detects proteolytic fragments of IGFBP-3 (the major one being of 30 kDa) that are not detected by ligand blotting. The ratio of proteolysed to total IGFBP-3 in short prepubertal children (36.8% +/- 2.6%) was significantly lower (P < 0.01) than in normal prepubertal subjects (60.6% +/- 8.9%). This lesser proteolysis of IGFBP-3 would explain the excessive levels of IGFBP-3 (detected by ligand blotting) relative to IGF levels in short children. These results suggest that growth retardation in short children involves IGF-I deficiency resulting from both decreased IGF-I synthesis and lesser bioavailability of the circulating IGF-I bound to IGFBP-3. High IGFBP-1 levels may also contribute towards limiting the availability of IGF-I to its target cells.

Interactions between insulin-like growth factor-I (IGF-I) and the system of plasminogen activators and their inhibitors in the control of IGF-binding protein-3 production and proteolysis in human osteosarcoma cells.

Limited proteolysis in vivo of insulin-like growth factor-binding protein-3 (IGFBP-3) by as yet unidentified serine proteases plays a key role in controlling the bioavailability of IGFBP-3-associated insulin-like growth factors (IGFs). Both the IGF system and the system of plasminogen activators (PAs) and their inhibitors (PAIs) are involved in bone remodeling, and plasmin has been shown to provoke dissociation of IGFBP-IGF complexes in cultured MG-63 human osteoblasts. The aim of this work was to investigate interactions between IGF-I and the PA/PAI system and their influence on IGFBP-3 production and proteolysis in this cell model. At confluency, MG-63 cells maintained for 3 days in serum-free medium constitutively secreted IGFBP-2 and small amounts of IGFBP-3 and IGFBP-4. As shown by Western ligand and immunoblot analyses of the culture medium and Northern blot analysis of IGFBP-3 messenger RNA, production of these IGFBPs, and of IGFBP-3 in particular, was dose dependently stimulated by the addition of 12.5-100 ng/ml recombinant human (rh) IGF-I. Increasing concentrations of plasminogen (0.05-3.5 micrograms/ml) added during the final 12 h of culture reduced the amounts of IGFBP detectable by Western ligand blotting, especially IGFBP-3. This reduction reflected proteolysis, as shown by immunoblotting, which revealed 30-, 20-, and 16-kilodalton fragments of IGFBP-3. In the presence of 25 ng/ml IGF-I, which stimulated IGFBP-3 production, proteolysis was reduced by approximately half. Incubation of glycosylated [125I]rh-IGFBP-3 as substrate in cell-free conditioned medium gave the same results. Addition of 50 ng/ml rhIGF-I to conditioned medium (to promote IGFBP-3-rhIGF-I complex formation) failed to diminish plasmin-induced proteolysis of IGFBP-3. Urokinase PA activity in the conditioned medium decreased significantly when the cells were cultured with rhIGF-I, indicating a direct action of IGF-I on urokinase PA and/or PAI production. Our results support the notion of a regulation loop whereby IGF-I controls its own bioavailability via its action on both IGFBP-3 production and the PA/PAI system, which regulates IGFBP-3 proteolysis. The proteolytic cleavages of IGFBP-3 caused by plasmin were the same as those caused in vivo by serine protease acting on this IGFBP.

[Interactions of insulin-like growth factors (IGF) and their binding proteins with the plasminogen/plasmin activator system in cultured osteoblasts]. / Interactions des insulin-like growth factors (IGF) et de leurs protéines de liaison avec le système activateur du plasminogène/plasmine dans les cellules ostéoblastiques en culture.

In biological media, insulin-like growth factors (IGFs) are bound to specific high-affinity binding proteins (IGFBPs). Limited proteolysis of these IGFBPs by serine proteases facilitates dissociation of the IGFs and their access to receptors. Osteoblasts produce IGFs and IGFBPs as well as plasminogen activators and inhibitors, and it has been shown that plasmin may be involved in proteolysis of the IGFBPs. The IGFBPs secreted by the human osteoblast cell line, MG63, were analysed by Western ligand- and immuno-blotting. IGFBP-2, -3 and -4 were found in the conditioned media in the absence of stimulatory factors. When the cells were incubated with IGF-I, IGFBP-3 and -4 concentrations increased, but IGFBP-2 production was much less stimulated. When increasing amounts of plasminogen were added during the final hours of culture, proteolysis of IGFBP-3 and -4 was detected. If the cells had been treated with IGF-I, this was minimal or absent and urokinase activity measured in the conditioned media was decreased. This study reveals a feed-back mechanism by which IGF-I regulates its own bioavailability, acting simultaneously on IGFBP secretion and the proteolytic balance.

Expression of insulin-like growth factor binding protein-1 and -2 genes through the perinatal period in the rat.

Insulin-like growth factor binding proteins (IGFBPs) are essential mediators of the bioavailability and biological effects of the IGFs. Liver expression of the rat (r) IGFBP-1 and rIGFBP-2 genes has been characterized between day 16 in utero (16 diu) and 16 days postnatally (+16 dpn). Run-on experiments showed transcriptional activity of the rIGFBP-1 and rIGFBP-2 genes at birth (B) to be 25 and 5 times that at 16 diu, respectively. After B, transcriptional activity of the rIGFBP-1 gene remained high (140% B at +6 dpn), but that of the rIGFBP-2 gene dropped to 70% B by +6 dpn. Northern blot analysis done simultaneously showed rIGFBP-1 messenger RNA (mRNA) levels to increase approximately 50-fold between 16 diu and B, whereas rIGFBP-2 mRNA increased only 5- to 10-fold. rIGFBP-1 mRNA levels decreased after birth, reaching about 20% B by +6 dpn; rIGFBP-2 mRNA, however, remained stable (about 80% B) at least up to +6 dpn. Parallel Western ligand blot and immunoblot analyses of serum rIGFBPs revealed rIGFBP-1 and rIGFBP-2 concentrations to be increased 3- and 2-fold, respectively between 20 diu and B. Maximal expression of rIGFBP-1 was at +1 dpn (220% B), and of rIGFBP-2, at B. Both rIGFBPs then decreased, reaching about 5% B at adulthood. All these data indicate that increased transcriptional activity of the rIGFBP-1 and rIGFBP-2 genes at birth would determine the increased synthesis in the liver and circulating levels of these proteins. In addition, it would seem that post-transcriptional events (reduced half-life of the rIGFBP-1 messenger after birth, translation efficiency of the rIGFBP-2 messenger) modulate transcriptional regulation.

Purification from human cerebrospinal fluid of insulin-like growth factor binding proteins (IGFBPs). Isolation of IGFBP-2, an altered form of IGFBP-3 and a new IGFBP species.

Cerebrospinal fluid insulin-like growth factor binding proteins (CSF IGFBPs) characteristically have a preferential affinity for IGF-II, which is largely accounted for by a 32-30 kDa IGFBP(Ka = 10(11) M-1) previously purified from human CSF, with an N-terminal sequence unlike any other IGFBP identified at the time. We have now used procedure (including ammonium sulphate precipitation, acidic gel filtration, affinity chromatography and reverse phase chromatography) and purified three further IGFBPs to homogeneity from child CSF. Apart from the 32-30-kDa form, the predominant IGFBP in CSF is a 34-kDa form (non-reduced in SDS-polyacrylamide gel electrophoresis). Like the 32-30-kDa IGFBP, it has a preferential affinity for IGF-II (Ka = 2 x 10(10) M-1). Its N-terminus, Phe-Arg-(/)-Pro-Pro-(/)-Thr-Pro-Glu-Arg-Arg-(/)-Gly-Pro-Pro-Pro-Val, corresponds to that deduced for IGFBP-2, except for the first three residues which were not found in the CSF IGFBP. Another form, of 30 kDa, has an N-terminus identical to IGFBP-3's over the first 18 residues determined and seems to be an altered form of IGFBP-3. A third minor species, of 22 kDa, with a preferential affinity for IGF-II similar to that of the 34-kDa IGFBP, has an N-terminal sequence, (/)-(/)-Asp-Ser-Phe-Val-Pro-(/)-Glu-Pro-Ser-Asp-Glu-Lys-Ala-Leu-Ser-(/)- (/)-Pro, which bears some analogy with those of other known human IGFBPs, particularly IGFBP-3 (7 homologous residues), and appears to be related to, but distinct from, other IGFBP species.

Evidence of enzymatic degradation of insulin-like growth factor-binding proteins in the 150K complex during pregnancy.

Western ligand blot analysis of the different molecular forms of insulin-like growth factor-binding protein IGF-BP) in serum and plasma samples from 89 pregnant women has revealed a marked decrease, after the second month of pregnancy, in the 41.5 and 38.5K species (which are the binding units of the 150K complex) as well as in the 24K form. There was also a slight decrease in the 34K form, the 30K form was unaffected, and additional 21.5 and 20K bands appeared. Cross-linking experiments demonstrated the disapperance of a 49K band which is characteristic of the 150K complex. The alterations of the electrophoretic profile of the BPs were accompanied by a decrease in binding activity of up to 90%. Gel filtration at pH 7.4 confirmed that the decrease was essentially attributable to changes in the 150K complex BPs: 1) material eluting in the 150K zone contained only one third of the binding activity, as opposed to three quarters in reference material; 2) radiocompetition experiments illustrated the loss of affinity for IGF-I and IGF-II of the BPs extracted from the 150K complex; 3) ligand blot analysis revealed, in contrast with the virtual disappearance of the 41.5 and 38.5K forms, the appearance of a broad indistinct band at 30K and additional bands at 21.5 and 20K. With immunoblotting, the anti-IGF-BP-3 antibody, which specifically recognizes the 41.5 and 38.5K species, cross-reacted with this 30K material. The alterations of the BPs appeared to be enzymatic. When pregnancy serum was mixed with reference serum, the 41.5, 38.5, and 24K forms contributed by the reference serum were markedly reduced after 30 min of incubation at 37 C. However, these alterations could be prevented by incubation at either 0 or at 37 C in the presence of EDTA or aprotinin and could be curbed in the presence of high concentrations of phenylmethylsulfonylfluoride. Unmixed reference serum incubated at 37 C yielded an unchanged BP profile. Incubation of pregnancy serum with hypopituitary serum, which has elevated levels of the 34 and 30K BPs, resulted in a marked decrease in the 41.5 and 38.5K forms, a slight alteration of the 34K form, and no change in the 30K form. These findings suggest that during pregnancy, enzymatic (probably protease) activity either appears or is significantly increased in the circulation, which specifically degrades some of the IGF-BPs.(ABSTRACT TRUNCATED AT 400 WORDS)

Heterogeneity of insulin-like growth factor binding proteins and relationships between structure and affinity. 1. Circulating forms in man.

Circulating insulin-like growth factors (IGFs) are bound to specific, high-affinity binding proteins (BPs), and form complexes with relative molecular masses of about 150,000 ('large' complex) and 40,000 ('small' complex). The large complex appears to be under growth-hormone control and its proportions vary with those of the IGFs. Molecular heterogeneity among the binding proteins was revealed by polyacrylamide gel electrophoresis (SDS-PAGE) of serum in which they were cross-linked to 125I-labelled IGF I or II. Out of the six specific bands observed, of 150,000, 120,000, 49,000, 40,000 and 37,000 Mr, the last three appeared in both complexes, whereas the first three were visible only in the large complex. Some or all of the 49,000-37,000-Mr species may constitute the subunits of 150,000-Mr and/or 120,000-Mr IGF-BP complexes. With electrophoresis followed by transfer onto nitrocellulose and incubation with either 125I-labelled IGF I or II (western blot), the different binding proteins were identified per se. There were five molecular forms with Mr of 41,500, 38,500, 34,000, 30,000 and 24,000. In normal serum the 41,500 and 38,500-Mr forms were the major binding proteins. They appeared in both complexes, but were predominant in the large complex where they constitute the elementary binding units. These two proteins therefore bind to IGFs to form both 'monomeric' IGF-BP and 'oligomeric' (IGF-BP)n complexes. The 34,000, 30,000 and 24,000-Mr forms, by contrast, were visible only in the small complex. Different mechanisms appear to regulate the different binding proteins: in acromegalic serum the 41,500 and 38,500-Mr forms were augmented and the 34,000-Mr form diminished, whereas in hypopituitary serum the reverse was true and, in addition, the 30,000-Mr form was augmented. With chromatofocusing, the 34,000, 30,000 and 24,000-Mr forms eluted in three peaks between pH 6.0 and 4.0, whereas the 41,500 and 38,500-Mr forms eluted throughout the gradient, principally at pH 7.5 and 7.0. Competitive binding studies, done on binding proteins separated either by chromatofocusing or by SDS-PAGE and transfer onto nitrocellulose, revealed different affinities for the IGFs among the different molecular forms. The 41,500 and 24,000-Mr binding proteins preferentially bound IGF I and the 38,500, 34,000 and 30,000-Mr proteins preferentially bound IGF II. Our findings demonstrate the molecular heterogeneity of the binding proteins and the existence of a relationship between their structure and their affinities for the IGFs.(ABSTRACT TRUNCATED AT 400 WORDS)

Heterogeneity of insulin-like growth factor binding proteins between structure and affinity. 2. Forms released by human and rat liver in culture.

Since the liver is considered to be the major source both of circulating insulin-like growth factors (IGFs) and of their specific binding proteins (BPs), human and rat liver explants were cultured in serum-free medium with a view to characterizing the binding proteins released into the medium and to comparing them with serum binding proteins. In the culture media, as in the serum, IGFs are associated with their binding proteins in the form of complexes. In gel filtration experiments the liver IGF-BP complexes eluted as a single, homogeneous peak with a relative molecular mass of about 40,000, which is similar to that of the 'small' complex of serum. Their sedimentation coefficient, estimated from sucrose gradient centrifugation, was 2.9 S. Polyacrylamide gel electrophoresis (SDS-PAGE) of human liver culture media, in which the binding proteins were cross-linked to 125I-labelled IGF I revealed molecular heterogeneity. Three specific bands corresponding to Mr 46,000, 40,000 and 37,000 were observed, which resemble those of the serum small complex, but none of the higher-Mr bands seen in serum. SDS-PAGE followed by transfer onto nitrocellulose and incubation with 125I-labelled IGF I (western blot) led to the identification in human liver culture media of five molecular forms of binding protein with Mr of 41,500, 38,500, 34,000, 30,000 and 24,000, identical to those seen in serum. The relative concentrations of the 41,500 and 38,500-Mr forms varied from one medium to another, but the 34,000 and 30,000-Mr forms were regularly more abundant in the liver culture media than in normal serum. The binding proteins produced by the liver therefore represent the native forms in the circulation (although this does not exclude other sources). The absence of high-Mr IGF-BP complexes in the liver culture media, and yet the presence of the 41,500 and 38,500-Mr forms, which are the only binding units of the serum 'large' complex (150,000 Mr), indicates that these two binding proteins are capable of binding IGFs to form 'monomeric' IGF-BP complexes. Western-blot analysis of rat binding proteins revealed a certain analogy with the human proteins, three forms having their Mr between 43,000 and 39,000 and three between 32,000 and 24,000. Liver binding proteins in human adults and foetuses were found to be identical, whereas in the case of serum the 41,500 and 38,500-Mr forms were more abundant in the adult and the 34,000 and 30,000-Mr forms more abundant in the foetus.(ABSTRACT TRUNCATED AT 400 WORDS)