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1.
Int Orthop ; 45(10): 2507-2517, 2021 10.
Article in English | MEDLINE | ID: mdl-34148120

ABSTRACT

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.


Subject(s)
Arthroscopy , Femoracetabular Impingement , Adult , Athletes , Female , Femoracetabular Impingement/diagnosis , Femoracetabular Impingement/surgery , Hip Joint/surgery , Humans , Male , Return to Sport , Treatment Outcome
2.
Public Health ; 170: 10-16, 2019 May.
Article in English | MEDLINE | ID: mdl-30897384

ABSTRACT

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.


Subject(s)
Accidents/statistics & numerical data , Models, Statistical , Wounds and Injuries/epidemiology , Child , Child, Preschool , Emergency Service, Hospital/statistics & numerical data , Family , Female , Humans , Infant , Male , Recurrence , Retrospective Studies , Risk Assessment , Risk Factors
3.
Cytogenet Genome Res ; 143(1-3): 150-6, 2014.
Article in English | MEDLINE | ID: mdl-24642790

ABSTRACT

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.


Subject(s)
Centromere/genetics , Chromatin/genetics , Chromosomes, Plant/genetics , Histones/genetics , Histones/metabolism , Phosphorylation/genetics , Nucleosomes/genetics
4.
J Dent Res ; 88(7): 673-6, 2009 Jul.
Article in English | MEDLINE | ID: mdl-19641157

ABSTRACT

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.


Subject(s)
Computer-Aided Design , Dental Porcelain , Dental Prosthesis Design , Dental Prosthesis , Printing/instrumentation , Zirconium , Crowns , Humans
5.
Anaesthesist ; 57(7): 670-6, 2008 Jul.
Article in German | MEDLINE | ID: mdl-18463833

ABSTRACT

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.


Subject(s)
Brachial Plexus/diagnostic imaging , Nerve Block , Humans , Ultrasonography
6.
Phys Rev Lett ; 86(19): 4267-70, 2001 May 07.
Article in English | MEDLINE | ID: mdl-11328151

ABSTRACT

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.
Article in English | MEDLINE | ID: mdl-11775129

ABSTRACT

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.


Subject(s)
Hypertension, Renal/pathology , Insulin-Like Growth Factor I/genetics , Ischemia/pathology , Kidney/pathology , Animals , Atrophy , Chronic Disease , Hypertension, Renal/physiopathology , Hypertrophy , Insulin-Like Growth Factor Binding Protein 1/analysis , Insulin-Like Growth Factor Binding Protein 1/genetics , Insulin-Like Growth Factor I/analysis , Ischemia/physiopathology , Kidney/chemistry , Kidney/surgery , Male , Nephrectomy , RNA, Messenger/analysis , Rats , Rats, Sprague-Dawley , Receptor, IGF Type 1/genetics , Renal Circulation , Ribonucleases
8.
Surg Endosc ; 14(10): 955-9, 2000 Oct.
Article in English | MEDLINE | ID: mdl-11080411

ABSTRACT

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.


Subject(s)
Minimally Invasive Surgical Procedures/methods , Phantoms, Imaging
9.
J Mol Evol ; 51(4): 353-62, 2000 Oct.
Article in English | MEDLINE | ID: mdl-11040286

ABSTRACT

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.


Subject(s)
DNA, Intergenic , Genes, Bacterial , Rickettsia prowazekii/genetics , Models, Genetic , Point Mutation , Polymorphism, Single Nucleotide
10.
J Theor Biol ; 206(3): 379-86, 2000 Oct 07.
Article in English | MEDLINE | ID: mdl-10988023

ABSTRACT

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.


Subject(s)
Algorithms , Amino Acid Sequence , Information Theory , Animals , Models, Biological , Peptide Library , Sequence Analysis, DNA
11.
Bioinformatics ; 15(3): 187-93, 1999 Mar.
Article in English | MEDLINE | ID: mdl-10222405

ABSTRACT

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).


Subject(s)
DNA/chemistry , DNA/genetics , Genome , Nucleic Acid Conformation , Protein Conformation , Archaea/genetics , Bacteria/genetics , DNA, Archaeal/chemistry , DNA, Archaeal/genetics , DNA, Bacterial/chemistry , DNA, Bacterial/genetics , DNA, Fungal/chemistry , DNA, Fungal/genetics , DNA, Superhelical/chemistry , DNA, Superhelical/genetics , Databases, Factual , Fungal Proteins/chemistry , Fungal Proteins/genetics , Genome, Fungal , Nucleosomes/genetics , Repetitive Sequences, Nucleic Acid , Software , Yeasts/genetics
12.
Gut ; 44(5): 704-8, 1999 May.
Article in English | MEDLINE | ID: mdl-10205209

ABSTRACT

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.


Subject(s)
Adenocarcinoma/metabolism , Colonic Neoplasms/metabolism , Neoplasm Proteins/metabolism , Receptors, Somatomedin/metabolism , Somatomedins/metabolism , Aged , Aged, 80 and over , Female , Gene Expression , Humans , Insulin-Like Growth Factor I/metabolism , Insulin-Like Growth Factor II/metabolism , Male , Middle Aged , RNA, Messenger/genetics , RNA, Neoplasm/genetics , Receptors, Somatomedin/genetics , Somatomedins/genetics
13.
J Biomol Struct Dyn ; 16(2): 341-5, 1998 Oct.
Article in English | MEDLINE | ID: mdl-9833672

ABSTRACT

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.


Subject(s)
DNA, Archaeal/chemistry , DNA, Superhelical/chemistry , Nucleic Acid Conformation
14.
Metabolism ; 47(11): 1331-6, 1998 Nov.
Article in English | MEDLINE | ID: mdl-9826208

ABSTRACT

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.


Subject(s)
Gene Expression Regulation , Hypoxia/genetics , Insulin-Like Growth Factor Binding Proteins/genetics , Insulin-Like Growth Factor I/genetics , Receptors, Somatomedin/genetics , Retina/metabolism , Animals , Animals, Newborn , RNA, Messenger/genetics , RNA, Messenger/metabolism , Rats
15.
J Endocrinol ; 159(1): 133-40, 1998 Oct.
Article in English | MEDLINE | ID: mdl-9795351

ABSTRACT

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.


Subject(s)
Diabetes Mellitus, Experimental/drug therapy , Insulin-Like Growth Factor I/genetics , Kidney/drug effects , Octreotide/administration & dosage , Somatostatin/analogs & derivatives , Animals , Diabetes Mellitus, Experimental/metabolism , Drug Administration Schedule , Gene Expression/drug effects , Genetic Techniques , Hormones/therapeutic use , Insulin-Like Growth Factor Binding Protein 1/genetics , Kidney/metabolism , Male , Metabolic Clearance Rate/drug effects , Octreotide/therapeutic use , RNA, Messenger/analysis , Rats , Rats, Inbred Strains , Receptor, IGF Type 1/genetics
16.
J Theor Biol ; 190(4): 341-53, 1998 Feb 21.
Article in English | MEDLINE | ID: mdl-9533869

ABSTRACT

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.


Subject(s)
Amino Acids/metabolism , Proteins/chemistry , Animals , Models, Statistical , Monte Carlo Method , Peptide Mapping
17.
Diabetes ; 47(6): 924-30, 1998 Jun.
Article in English | MEDLINE | ID: mdl-9604870

ABSTRACT

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.


Subject(s)
Diabetes Mellitus, Experimental/metabolism , Insulin-Like Growth Factor Binding Protein 1/biosynthesis , Kidney/metabolism , Octreotide/pharmacology , Transcription, Genetic/drug effects , Animals , Blood Glucose/metabolism , Body Weight/drug effects , Diabetes Mellitus, Experimental/blood , Diabetes Mellitus, Experimental/physiopathology , Gene Expression Regulation/drug effects , Gene Expression Regulation/physiology , Growth Hormone/blood , Insulin/blood , Insulin-Like Growth Factor I/biosynthesis , Kidney/drug effects , Kinetics , Male , Octreotide/blood , Organ Size/drug effects , RNA, Messenger/biosynthesis , Rats , Rats, Inbred Strains , Reference Values , Time Factors
18.
Am J Physiol ; 274(3): F490-7, 1998 03.
Article in English | MEDLINE | ID: mdl-9530265

ABSTRACT

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.


Subject(s)
Acute Kidney Injury/metabolism , Contrast Media/toxicity , Insulin-Like Growth Factor I/metabolism , Iothalamic Acid/toxicity , Animals , Gene Expression/drug effects , Insulin-Like Growth Factor Binding Protein 1/metabolism , Insulin-Like Growth Factor Binding Protein 3/metabolism , Kidney Cortex/metabolism , Kidney Medulla/metabolism , Liver/metabolism , Male , Rats , Rats, Sprague-Dawley , Receptor, IGF Type 1/metabolism
19.
Evol Comput ; 5(4): 419-38, 1997.
Article in English | MEDLINE | ID: mdl-10021766

ABSTRACT

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.
Article in German | MEDLINE | ID: mdl-9574241

ABSTRACT

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.


Subject(s)
Education, Medical, Continuing , General Surgery/education , Laparoscopy , Minimally Invasive Surgical Procedures , Attitude of Health Personnel , Cholecystectomy, Laparoscopic , Clinical Competence , Curriculum , Germany , Humans
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