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1.
Int Orthop ; 45(10): 2507-2517, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34148120

RESUMO

BACKGROUND: The tremendous physical demands of elite performance increase the risk of elite athletes sustaining various orthopaedic injuries. Hip pain is common in high-level athletes representing up to 6% of all athletic injuries. Expedient diagnosis and effective treatment are paramount for their future sporting careers and to prevent subsequent joint degeneration. PURPOSE: This systematic review aimed to evaluate the outcome and the rate of return to play (RTP) following arthroscopic procedures in the hip (osteoplasty, chondroplasty, labral repair and/or debridement, capsulotomy, capsulorrhaphy or any soft tissue procedure) in elite athletes. Elite athletes were defined as those who represented their country in international contests or were competing professionally for the purpose of this study. METHODS: A computer-based systematic search, following the PRISMA Guidelines, was performed on CENTRAL, PUBMED, EMBASE, SCOPUS, EBSCO, Google Scholar and Web of Science from inception until January 1, 2020, identifying studies that looked at return to sports post-hip arthroscopy in elite athletes. Weighted means were calculated for the RTP rate and duration and for patient-reported outcome measures (PROMs). RESULTS: After eligibility screening, 22 articles were included with a total of 999 male and seven female patients, 1146 hips and a mean age of 28.4 ± 3.2 years. The mean follow-up period was 35.8 ± 13.4 months and 15.9 ± 9.6% of athletes had undergone bilateral procedures. Overall, 93.9% (95% CI: 90.5, 96.6, P < 0.0001) of patients demonstrated RTP after 6.8 ± 2.1 months post-surgery and all PROMs improved post-operatively. During follow-up, 9.6% (95% CI: 5.2, 15.2, P = 0.025) patients needed further intervention. CONCLUSION: A high percentage of elite athletes return to the same level of competition after hip arthroscopy, with a low rate of further interventions. Hip arthroscopy appears to be an efficacious treatment for hip and/or groin pain, caused by pathologies such as FAI or labral tears, in elite athletes in the shorter term. Long term outcomes need further evaluation.


Assuntos
Artroscopia , Impacto Femoroacetabular , Adulto , Atletas , Feminino , Impacto Femoroacetabular/diagnóstico , Impacto Femoroacetabular/cirurgia , Articulação do Quadril/cirurgia , Humanos , Masculino , Volta ao Esporte , Resultado do Tratamento
2.
Public Health ; 170: 10-16, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30897384

RESUMO

OBJECTIVE: Existing research on recurrent unintentional injury (UI) focuses on the individual child rather than family risks. This study developed a statistical model for identifying families at highest risk, for potential use in targeting public health interventions. STUDY DESIGN: A retrospective birth cohort study of hospital and emergency room (ER) medical records of children born in Ziv hospital between 2005 and 2012, attending ER for UI between 2005 and 2015, was conducted. METHODS: Using national IDs, we assigned children to mothers and created the family entity. Data were divided into two time periods. Negative binomial regression was used to examine predictive factors in the first period for recurrent child UI in the second period. Sensitivity analyses were conducted to examine the model's robustness. RESULTS: Eight predictive factors for child injury (P < 0.05) were found: male gender, the number of UI visits, the number of illness visits, age 36-59 months, birth weight <1500 g, maternal ER visits, siblings' UI visits, and the number of younger siblings. Some predictive factors are documented in the literature; others are novel. Five were significant in all sensitivity analyses. CONCLUSIONS: These factors can assist in predicting risk for a child's repeat UI and family's cumulative UI risk. The model may offer a valuable and novel approach to targeting interventions for families at highest risk.


Assuntos
Acidentes/estatística & dados numéricos , Modelos Estatísticos , Ferimentos e Lesões/epidemiologia , Criança , Pré-Escolar , Serviço Hospitalar de Emergência/estatística & dados numéricos , Família , Feminino , Humanos , Lactente , Masculino , Recidiva , Estudos Retrospectivos , Medição de Risco , Fatores de Risco
3.
Cytogenet Genome Res ; 143(1-3): 150-6, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24642790

RESUMO

Based on the analysis of 20 different monocot and eudicot species, we propose that the centromeric distribution of the phosphorylated histone H2AThr120 is evolutionary highly conserved across species with mono- and holocentric chromosomes. Therefore, antibodies recognizing the phosphorylated threonine 120 of the histone H2A can serve as a universal marker for the cytological detection of centromeres of mono- and holokinetic plant species. In addition, super resolution microscopy of signals specific to the centromere-specific histone H3 variant CENH3 and to H2AThr120ph revealed that these histone variants are incorporated into different nucleosomes, which form distinct, partly intermingled chromatin domains. This specific arrangement of both histone variants suggests different centromeric functions during the cell cycle.


Assuntos
Centrômero/genética , Cromatina/genética , Cromossomos de Plantas/genética , Histonas/genética , Histonas/metabolismo , Fosforilação/genética , Nucleossomos/genética
4.
J Dent Res ; 88(7): 673-6, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-19641157

RESUMO

CAD/CAM milling systems provide a rapid and individual method for the manufacturing of zirconia dental restorations. However, the disadvantages of these systems include limited accuracy, possible introduction of microscopic cracks, and a waste of material due to the principle of the 'subtractive process'. The hypothesis of this study was that these issues can be overcome by a novel generative manufacturing technique, direct inkjet printing. A tailored zirconia-based ceramic suspension with 27 vol% solid content was synthesized. The suspension was printed on a conventional, but modified, drop-on-demand inkjet printer. A cleaning unit and a drying device allowed for the build-up of dense components of the size of a posterior crown. A characteristic strength of 763 MPa and a mean fracture toughness of 6.7 MPam(0.5) were determined on 3D-printed and subsequently sintered specimens. The novel technique has great potential to produce, cost-efficiently, all-ceramic dental restorations at high accuracy and with a minimum of materials consumption.


Assuntos
Desenho Assistido por Computador , Porcelana Dentária , Planejamento de Prótese Dentária , Prótese Dentária , Impressão/instrumentação , Zircônio , Coroas , Humanos
5.
Anaesthesist ; 57(7): 670-6, 2008 Jul.
Artigo em Alemão | MEDLINE | ID: mdl-18463833

RESUMO

BACKGROUND: The perivascular axillary plexus block is an easily applicable procedure with a low risk of complications but with a high failure rate. To improve this, the standard procedure was combined with transpectoral sonography to benefit from the advantages of ultrasound, while using a nearly unchanged puncture technique. METHOD: The technique developed by the authors is described in this article and the success rate and the time factor were determined in a sample of 86 patients. The success rates were compared to previous rates without ultrasound and to those in the literature. RESULTS AND CONCLUSIONS: The rate of complete blocks without the use of transpectoral sonography in our clinic and in the literature was approximately 72%, whereas using transpectoral ultrasound it was 96.5%. None of the 86 patients with transpectoral sonography required general anaesthesia. The onset time using transpectoral sonography was approximately 6 min. The perivascular axillary plexus block, combined with transpectoral sonography, is an effective and efficient procedure.


Assuntos
Plexo Braquial/diagnóstico por imagem , Bloqueio Nervoso , Humanos , Ultrassonografia
6.
Phys Rev Lett ; 86(19): 4267-70, 2001 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-11328151

RESUMO

We report on the generation of a continuous variable Einstein-Podolsky-Rosen (EPR) entanglement using an optical fiber interferometer. The Kerr nonlinearity in the fiber is exploited for the generation of two independent squeezed beams. These interfere at a beam splitter and EPR entanglement is obtained between the output beams. The correlation of the amplitude (phase) quadratures is measured to be 4.0+/-0.2 (4.0+/-0.4) dB below the quantum noise limit. The sum criterion for these squeezing variances 0.80+/-0.03<2 verifies the nonseparability of the state. The product of the inferred uncertainties for one beam (0.64+/-0.08) is well below the EPR limit of unity.

7.
Am J Hypertens ; 14(12): 1211-8, 2001 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11775129

RESUMO

To examine the role of insulin-like growth factor-1 (IGF-1) in renal atrophy of rats with two-kidney, one-clip (2K1C), in which the clipped kidney atrophies, and in the one-kidney, one-clip (IK1C) model of renovascular hypertension, in which it hypertrophies, we studied levels of IGF-I, mRNA, and protein in 2K1C, IK1C, and unilateral nephrectomy (NPX) in rats by solution-hybridization RNase protection, and radioimmunoassay, respectively, both cross-reactively and longitudinally at 3, 10, and 30 days after clipping. Three days after clipping, there were no differences in blood pressure or kidney size; however, 10 and 30 days postoperation, the clipped kidney shrank in the 2K1C model. The nonclipped 2K1C and the clipped lK1C and unilateral nephrectomy kidneys increased in weight (P < .05. At day 3 the IGF-I levels were lower (557 +/- 54, 335 +/- 61 ng/g in control and clipped 2K1C, P < .05, v 1,074 +/- 186, 1,109 +/- 54, and 1,154 +/- 200 ng/g kidney, nonclipped 2K1C, 1K1C, and NPX, respectively). At 30 days the IGF-I levels were 300 +/- 24 ng/g in control (P < .05) v clipped 2K1C, 160 +/- 19, 218 +/- 20 ng/g in nonclipped 2K1C and 406 +/- 33 and 470 +/- 34 ng/g in 1K1C and NPX, respectively (P < .05) v control and clipped 2K1C. Kidney mRNA was increased in the clipped 2K1C. In conclusion, the kidney that had higher IGF-I levels early in nonclipped 2K1C, 1K1C, and nephrectomy hypertrophied, and the kidney (clipped 2K1C) that failed to increase IGF-I atrophied. IGF-I levels are dissociated from the local mRNA message.


Assuntos
Hipertensão Renal/patologia , Fator de Crescimento Insulin-Like I/genética , Isquemia/patologia , Rim/patologia , Animais , Atrofia , Doença Crônica , Hipertensão Renal/fisiopatologia , Hipertrofia , Proteína 1 de Ligação a Fator de Crescimento Semelhante à Insulina/análise , Proteína 1 de Ligação a Fator de Crescimento Semelhante à Insulina/genética , Fator de Crescimento Insulin-Like I/análise , Isquemia/fisiopatologia , Rim/química , Rim/cirurgia , Masculino , Nefrectomia , RNA Mensageiro/análise , Ratos , Ratos Sprague-Dawley , Receptor IGF Tipo 1/genética , Circulação Renal , Ribonucleases
8.
Surg Endosc ; 14(10): 955-9, 2000 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11080411

RESUMO

BACKGROUND: Robotic aid in minimally invasive surgery (MIS) is becoming more and more common. We designed an experimental trial in a phantom model to verify the feasibility of solo surgery for MIS. By performing laparoscopic cholecystectomy on a phantom model, we compared combinations of different systems available in terms of safety, comfort, and time requirements. METHODS: Two surgeons skilled in endoscopic procedures tested the following systems as endoscope holders: the robotic system (AESOP), foot-controlled (AESOP 1000), and voice-controlled (AESOP 2000); the remote controlled FIPS Endoarm, electrically driven and controlled by a finger-ring joystic; the passive system TISKA Endoarm, a mechanical arm moved by hand and fixed by electromagnetical brakes. All of these systems combined with a second TISKA Endoarm as an instrument holder. A combination of two mechanical Martin arms, c, also was tested. The results were compared with those from a control group involving an assistant surgeon. A total of 70 experiments were performed. RESULTS: The shortest dissection time was registered by the combination of two TISKA Endoarms, with a statistically significant difference as compared with the control group (p < 0.05) and experiments using AESOP 1000 (p < 0.05). The TISKA Endoarm also proved to be more comfortable when used as an instrument holder (p < 0.001 vs Martin arm), and rated second only to AESOP 2000 as an endoscope holder. The rating of AESOP 2000 as endoscope holder was significantly higher than that of all other groups (p < 0.001). The study proved the feasibility of solo surgery. The time needed for dissection was shortest when two TISKA Endoarms were used, demonstrating the possible advantages of solo surgery. The TISKA Endoarm received a subjective positive rating when used as both endoscope holder and instrument holder. The voice control of AESOP 2000 seemed to be a major improvement in the development of an optimal man-machine interface. Nevertheless, the system presents considerable space requirements and does not supply control of 30 degrees optics. The principle of the finger-ring joystick adopted by the FIPS Endoarm seemed very intuitive but lacking in ergonomy. CONCLUSION: Laparoscopic solo surgery can be considered a safe procedure, although further technologic developments should lead to improved ergonomy, intuitiveness of handling, and architecture of the systems, offering the surgeon better control, increased precision of action, and reduction in operation time.


Assuntos
Procedimentos Cirúrgicos Minimamente Invasivos/métodos , Imagens de Fantasmas
9.
J Mol Evol ; 51(4): 353-62, 2000 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11040286

RESUMO

It has been hypothesized that a large fraction of 24% noncoding DNA in R. prowazekii consists of degraded genes. This hypothesis has been based on the relatively high G+C content of noncoding DNA. However, a comparison with other genomes also having a low overall G+C content shows that this argument would also apply to other bacteria. To test this hypothesis, we study the coding potential in sets of genes, pseudogenes, and intergenic regions. We find that the correlation function and the chi(2)-measure are clearly indicative of the coding function of genes and pseudogenes. However, both coding potentials make almost no indication of a preexisting reading frame in the remaining 23% of noncoding DNA. We simulate the degradation of genes due to single-nucleotide substitutions and insertions/deletions and quantify the number of mutations required to remove indications of the reading frame. We discuss a reduced selection pressure as another possible origin of this comparatively large fraction of noncoding sequences.


Assuntos
DNA Intergênico , Genes Bacterianos , Rickettsia prowazekii/genética , Modelos Genéticos , Mutação Puntual , Polimorfismo de Nucleotídeo Único
10.
J Theor Biol ; 206(3): 379-86, 2000 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-10988023

RESUMO

The complexity of large sets of non-redundant protein sequences is measured. This is done by estimating the Shannon entropy as well as applying compression algorithms to estimate the algorithmic complexity. The estimators are also applied to randomly generated surrogates of the protein data. Our results show that proteins are fairly close to random sequences. The entropy reduction due to correlations is only about 1%. However, precise estimations of the entropy of the source are not possible due to finite sample effects. Compression algorithms also indicate that the redundancy is in the order of 1%. These results confirm the idea that protein sequences can be regarded as slightly edited random strings. We discuss secondary structure and low-complexity regions as causes of the redundancy observed. The findings are related to numerical and biochemical experiments with random polypeptides.


Assuntos
Algoritmos , Sequência de Aminoácidos , Teoria da Informação , Animais , Modelos Biológicos , Biblioteca de Peptídeos , Análise de Sequência de DNA
11.
Bioinformatics ; 15(3): 187-93, 1999 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-10222405

RESUMO

MOTIVATION: Completely sequenced genomes allow for detection and analysis of the relatively weak periodicities of 10-11 basepairs (bp). Two sources contribute to such signals: correlations in the corresponding protein sequences due to the amphipatic character of alpha-helices and the folding of DNA (nucleosomal patterns, DNA supercoiling). Since the topological state of genomic DNA is of importance for its replication, recombination and transcription, there is an immediate interest to obtain information about the supercoiled state from sequence periodicities. RESULTS: We show that correlations within proteins affect mainly the oscillations at distances below 35 bp. The long-ranging correlations up to 100 bp reflect primarily DNA folding. For the yeast genome these oscillations are consistent in detail with the chromatin structure. For eubacteria and archaea the periods deviate significantly from the 10.55 bp value for free DNA. These deviations suggest that while a period of 11 bp in bacteria reflects negative supercoiling, the significantly different period of thermophilic archaea close to 10 bp corresponds to positive supercoiling of thermophilic archaeal genomes. AVAILABILITY: Protein sets and C programs for the calculation of correlation functions are available on request from the authors (see http://itb.biologie.hu-berlin.de).


Assuntos
DNA/química , DNA/genética , Genoma , Conformação de Ácido Nucleico , Conformação Proteica , Archaea/genética , Bactérias/genética , DNA Arqueal/química , DNA Arqueal/genética , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Fúngico/química , DNA Fúngico/genética , DNA Super-Helicoidal/química , DNA Super-Helicoidal/genética , Bases de Dados Factuais , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Genoma Fúngico , Nucleossomos/genética , Sequências Repetitivas de Ácido Nucleico , Software , Leveduras/genética
12.
Gut ; 44(5): 704-8, 1999 May.
Artigo em Inglês | MEDLINE | ID: mdl-10205209

RESUMO

AIMS: To study changes in the expression of insulin-like growth factors (IGFs) and their receptors, as well as production of the IGF-I and IGF-II polypeptides, in adenocarcinoma of the colon. METHODS: Malignant tissue obtained at operation was used. Total RNA was extracted and specific IGF-I and IGF-II and their receptor mRNAs were measured by a solution hybridisation RNase protection assay. IGF-I and IGF-II polypeptides were measured by specific immunoassays. RESULTS: All normal tissues expressed IGF-II, IGF-I receptor, and IGF-II/mannose-6-phosphate (Man-6-P) receptor. IGF-I mRNA could not be detected but the polypeptide was present in small but equal amounts in normal and malignant tissue. IGF-II was expressed 40 times more abundantly in colonic tumours than in adjacent normal tissue and the concentration of the corresponding polypeptide was twice as high in the malignant tissue. IGF-I receptor expression was increased by a factor of 2.5 and IGF-II/Man-6-P receptor by a factor of 4. CONCLUSIONS: This study confirms that in adenocarcinoma of the human colon there is increased expression of IGF-I receptor and IGF-II. Furthermore, IGF-II/Man-6-P receptor message is increased and the increase in IGF-II message is accompanied by a doubling of the IGF-II protein in the tumour tissue compared with the adjacent normal tissue. These findings suggest that the IGF-II/Man-6-P receptor may also be involved in development of adenocarcinoma of the colon. There is rapidly accumulating evidence implicating the IGF system in the development of malignancy of the large bowel.


Assuntos
Adenocarcinoma/metabolismo , Neoplasias do Colo/metabolismo , Proteínas de Neoplasias/metabolismo , Receptores de Somatomedina/metabolismo , Somatomedinas/metabolismo , Idoso , Idoso de 80 Anos ou mais , Feminino , Expressão Gênica , Humanos , Fator de Crescimento Insulin-Like I/metabolismo , Fator de Crescimento Insulin-Like II/metabolismo , Masculino , Pessoa de Meia-Idade , RNA Mensageiro/genética , RNA Neoplásico/genética , Receptores de Somatomedina/genética , Somatomedinas/genética
13.
J Biomol Struct Dyn ; 16(2): 341-5, 1998 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-9833672

RESUMO

The topological state of genomic DNA is of importance for its replication, recombination and transcription. The wrapping of the DNA around nucleosomes is associated with sequence periodicities (Trifonov and Sussman, Proc. Natl. Acad. Sci. USA, 77, pp. 3816-20). Recently, also the negative supercoiling of eubacterial DNA was related to 11 base pair (bp) periodicity (Herzel et al. Physica A, 249, pp. 449-59). Archaeal plasmids and a virus-like particle from Sulfolobus are positively supercoiled, but the superhelical conformation of archaeal genomic DNA is still uncertain. The problem of superhelicity can now be addressed via a comparative statistical analysis of the available complete genomes. For this purpose one has to look for periodicities which are in phase with the helical repeat of 10-11 bp. Similar periodicities are induced, however, by the amphipatic character of alpha-helices of encoded proteins (Zhurkin, Nucl. Acids Res., 9, pp. 1963-71). We show that these protein-induced periodicities are extended over a few periods only. The periods of additional long-ranging oscillations deviate significantly from the value for free DNA. A period of 11 bp in Eubacteria reflects negative supercoiling, whereas the significantly different period of thermophilic Archaea close to 10 bp suggests positive supercoiling of archaeal genomes.


Assuntos
DNA Arqueal/química , DNA Super-Helicoidal/química , Conformação de Ácido Nucleico
14.
Metabolism ; 47(11): 1331-6, 1998 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-9826208

RESUMO

Hypoxia is the main stimulus for neovascularization in the retina. Insulin-like growth factor-I (IGF-I) is thought to be one of the mediators of this process. Severe persistent hypoxia, as occurs in central retinal artery occlusion, is associated with less retinal neovascularization than relative hypoxia. To study the influence of different types of hypoxia on the IGF system, we used a model of neonatal rat retina that responds with neovascularization to a relative hypoxic stimulus produced by alternating oxygen concentrations in the respired air. We studied the influence of 24-hour hypoxia (10% oxygen), 48-hour hyperoxia (75% oxygen), and relative hypoxia (shifting from 48 hours in 75% oxygen to 24 hours in room air) on the gene expression of IGF-I, IGF-I receptor (IGF-IR), and IGF binding protein-1 (IGFBP-1), IGFBP-2, and IGFBP-3 in retina using a solution hybridization RNase protection assay. Hypoxia induced a significant increase in retinal IGF-IR (178%), IGFBP-2 (227%), and IGFBP-3 (317%) mRNA; however, retinal IGF-I mRNA was reduced, as well as serum growth hormone (GH). Relative hypoxia caused a similar but less pronounced trend in the gene expression of IGF-IR and the binding proteins, whereas retinal IGF-I mRNA was unchanged and serum GH was elevated. Both hypoxia and relative hypoxia may cause IGF system stimulation in the retina through upregulation of IGF-IR and IGFBPs. This stimulation may result in neovascularization. However, during hypoxia, low levels of tissue oxygenation and reduced local production of IGF-I may impede the neovascularization process.


Assuntos
Regulação da Expressão Gênica , Hipóxia/genética , Proteínas de Ligação a Fator de Crescimento Semelhante a Insulina/genética , Fator de Crescimento Insulin-Like I/genética , Receptores de Somatomedina/genética , Retina/metabolismo , Animais , Animais Recém-Nascidos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ratos
15.
J Endocrinol ; 159(1): 133-40, 1998 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-9795351

RESUMO

The present study was undertaken to assess the chronic effects of low dose octreotide (Oc) administration in rats with experimental diabetes mellitus (DM). Metabolic and clearance studies were performed in control normal rats, in rats with streptozotocin-induced DM of 1 week duration and in similar DM rats treated with Oc, 10-20 microg/day. Gene expression of IGF-I, IGF-I receptor (IGF-I R) and IGF-binding protein-1 (IGFBP-1) was examined in renal tissue from normal DM animals and DM animals treated with Oc 10, 20 and 100 microg/day. Seven days of Oc administration, 10 microg/day, in rats with experimental DM, was associated with enhanced hyperglycemia, increased glomerular filtration rate and urinary sodium excretion as compared with untreated DM animals. After a higher Oc dose, 20 microg/day, however, there were no significant changes in renal function and in glycemic control. Significant increases in kidney weight and kidney weight/body weight ratio were seen in DM rats as compared with control intact animals. These changes were not affected by Oc therapy in various doses. Induction of DM was associated with a marked increase in renal IGFBP-1 mRNA expression. There were no significant changes in the expression of IGF-I or IGF-I R mRNA. Oc therapy in a low or high dose did not affect gene expression of IGF-I, IGF-I R or IGFBP-1. Thus, the response to chronic low dose Oc administration of DM rats may vary from enhanced hyperglycemia and hyperfiltration to a lack of change in renal function or in glycemic control. Low dose Oc therapy was not associated with significant variations in renal mass or in the gene expression of IGF-I axis components. These findings are at variance with previously published studies which show a suppressive effect of Oc on renal function and growth in experimental diabetes. This apparent discrepancy may be related to the duration of treatment or to a biphasic physiological effect of Oc when used in different doses.


Assuntos
Diabetes Mellitus Experimental/tratamento farmacológico , Fator de Crescimento Insulin-Like I/genética , Rim/efeitos dos fármacos , Octreotida/administração & dosagem , Somatostatina/análogos & derivados , Animais , Diabetes Mellitus Experimental/metabolismo , Esquema de Medicação , Expressão Gênica/efeitos dos fármacos , Técnicas Genéticas , Hormônios/uso terapêutico , Proteína 1 de Ligação a Fator de Crescimento Semelhante à Insulina/genética , Rim/metabolismo , Masculino , Taxa de Depuração Metabólica/efeitos dos fármacos , Octreotida/uso terapêutico , RNA Mensageiro/análise , Ratos , Ratos Endogâmicos , Receptor IGF Tipo 1/genética
16.
J Theor Biol ; 190(4): 341-53, 1998 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-9533869

RESUMO

Correlation functions in large sets of non-homologous protein sequences are analysed. Finite size corrections are applied and fluctuations are estimated. As symbol sequences have to be mapped to sequences of numbers to calculate correlation functions, several property codes are tested as such mappings. We found hydrophobicity autocorrelation functions to be strongly oscillating. Another strong signal is the monotonously decaying alpha-helix propensity autocorrelation function. Furthermore, we detected signals corresponding to an alteration of positively and negatively charged residues at a distance of 3-4 amino acids. To look beyond the property codes gained by the methods of physical chemistry, mappings yielding a strong correlation signal are sought for using a Monte Carlo simulation. The mappings leading to strong signals are found to be related to hydrophobicity of alpha-helix propensity. A cluster analysis of the top scoring mappings leads to two novel property codes. These two property codes are gained from sequence data only. They turn out to be similar to known property codes for hydrophobicity or polarity.


Assuntos
Aminoácidos/metabolismo , Proteínas/química , Animais , Modelos Estatísticos , Método de Monte Carlo , Mapeamento de Peptídeos
17.
Diabetes ; 47(6): 924-30, 1998 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-9604870

RESUMO

The early renal growth in streptozotocin (STZ)-induced diabetic rats is preceded by a transient rise in renal tissue insulin-like growth factor (IGF)-I concentration. Administration of the long-acting somatostatin analog octreotide to STZ diabetic rats inhibits the early increase in kidney IGF-I and the increase in kidney size without affecting metabolic control. We studied the effects of octreotide treatment on the intrarenal IGF axis at 2 and at 7 days after the induction of STZ diabetes. Two days after induction of diabetes, kidney IGF-I was increased from 850 +/- 43 ng/g tissue in controls to 1,648 +/- 165 ng/g tissue (P < 0.001) in diabetic animals. The diabetes-associated increase in renal IGF-I 48 h after STZ injection was totally prevented by octreotide (IGF = 780 +/- 57 ng/g tissue). However, 7 days after the induction of diabetes, kidney IGF-I was similar to that of control and was not affected by octreotide. No difference in serum IGF-I was observed between controls and diabetic rats after 2 days of diabetes; however, octreotide treatment resulted in a significant decrease of serum IGF-I after 2 days when compared with control rats (P < 0.05). Renal IGF-I mRNA was significantly decreased to the same extent in both diabetic groups 2 and 7 days after the induction of diabetes, while renal IGF-I receptor (IGF-IR) mRNA was unchanged in rats from either group. Two days after induction of diabetes, renal insulin-like growth factor binding protein (IGFBP)-1 mRNA and 30-kDa IGFBPs (containing IGFBP-1) increased by 186 and 192%, respectively, in untreated diabetic animals compared with controls. Octreotide treatment prevented the diabetes-associated rise in renal IGFBP-1 mRNA and protein. However, 7 days after the induction of diabetes, renal IGFBP-1 mRNA and protein were similarly increased in both octreotide-treated or untreated diabetic rats. Renal IGFBP-3 gene expression and protein and IGFPB-5 mRNA remained unchanged after 2 and 7 days of diabetes when treated or untreated with octreotide. We conclude that the well-known inhibitory effect of octreotide on the early increase in renal IGF-I concentration and renal size in diabetes may be mediated through a direct effect on renal IGFBP-1 levels.


Assuntos
Diabetes Mellitus Experimental/metabolismo , Proteína 1 de Ligação a Fator de Crescimento Semelhante à Insulina/biossíntese , Rim/metabolismo , Octreotida/farmacologia , Transcrição Gênica/efeitos dos fármacos , Animais , Glicemia/metabolismo , Peso Corporal/efeitos dos fármacos , Diabetes Mellitus Experimental/sangue , Diabetes Mellitus Experimental/fisiopatologia , Regulação da Expressão Gênica/efeitos dos fármacos , Regulação da Expressão Gênica/fisiologia , Hormônio do Crescimento/sangue , Insulina/sangue , Fator de Crescimento Insulin-Like I/biossíntese , Rim/efeitos dos fármacos , Cinética , Masculino , Octreotida/sangue , Tamanho do Órgão/efeitos dos fármacos , RNA Mensageiro/biossíntese , Ratos , Ratos Endogâmicos , Valores de Referência , Fatores de Tempo
18.
Am J Physiol ; 274(3): F490-7, 1998 03.
Artigo em Inglês | MEDLINE | ID: mdl-9530265

RESUMO

The response of insulin-like growth factor (IGF) I in acute renal failure was evaluated in a model of radiocontrast nephropathy associated with selective necrosis of medullary thick ascending limbs. In brief, rats were administered radiocontrast medium or vehicle injections for controls after combined inhibition of prostanoids and nitric oxide. Twenty-four hours after the insult, tissue mRNAs for IGF-I, the IGF-I receptor, and IGF-binding proteins (IGFBP) 1 and 3 were assayed in cortex, medulla, and liver by solution hybridization-RNase protection assay, and IGFBPs were measured in serum and tissue by Western ligand blotting. Cortical IGF-1 increased, whereas medullary IGF-I mRNA decreased. Renal IGFBPs decreased, whereas IGFBP-1 mRNA increased. The IGF system in the liver was unchanged. We conclude that general changes in renal IGFBPs in this experimental model of acute renal failure might increase the level of cortical IGF-I in a way that could modulate medullary recovery.


Assuntos
Injúria Renal Aguda/metabolismo , Meios de Contraste/toxicidade , Fator de Crescimento Insulin-Like I/metabolismo , Ácido Iotalâmico/toxicidade , Animais , Expressão Gênica/efeitos dos fármacos , Proteína 1 de Ligação a Fator de Crescimento Semelhante à Insulina/metabolismo , Proteína 3 de Ligação a Fator de Crescimento Semelhante à Insulina/metabolismo , Córtex Renal/metabolismo , Medula Renal/metabolismo , Fígado/metabolismo , Masculino , Ratos , Ratos Sprague-Dawley , Receptor IGF Tipo 1/metabolismo
19.
Evol Comput ; 5(4): 419-38, 1997.
Artigo em Inglês | MEDLINE | ID: mdl-10021766

RESUMO

A road network usually has to fulfill two requirements: (i) it should as far as possible provide direct connections between nodes to avoid large detours; and (ii) the costs for road construction and maintenance, which are assumed proportional to the total length of the roads, should be low. The optimal solution is a compromise between these contradictory demands, which in our model can be weighted by a parameter. The road optimization problem belongs to the class of frustrated optimization problems. In this paper, a special class of evolutionary strategies, such as the Boltzmann and Darwin and mixed strategies, are applied to find differently optimized solutions (graphs of varying density) for the road network, depending on the degree of frustration. We show that the optimization process occurs on two different time scales. In the asymptotic limit, a fixed relation between the mean connection distance (detour) and the total length (costs) of the network exists that defines a range of possible compromises. Furthermore, we investigate the density of states, which describes the number of solutions with a certain fitness value in the stationary regime. We find that the network problem belongs to a class of optimization problems in which more effort in optimization certainly yields better solutions. An analytical approximation for the relation between effort and improvement is derived.

20.
Artigo em Alemão | MEDLINE | ID: mdl-9574241

RESUMO

The actual situation regarding the education für MIS requires the optimisation and standardisation of the training system. This paper presents the results of an inquiry about the evaluation of the course of operative laparoscopy. 80-90% of those interviewed made the comments "very good" and "good", with regard to the imparting of the theoretic foundation of the technique of endoscopic operations, for sufficient possibility of manual training and for the realistic setting of the animal organ model compared with the clinical operation. Because of our experience, we recommend attending such training courses before starting laparoscopic operations.


Assuntos
Educação Médica Continuada , Cirurgia Geral/educação , Laparoscopia , Procedimentos Cirúrgicos Minimamente Invasivos , Atitude do Pessoal de Saúde , Colecistectomia Laparoscópica , Competência Clínica , Currículo , Alemanha , Humanos
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