RESUMO
Multidrug-resistant pathogens often lead to treatment failure of antimicrobial regimens. After a period of imbalance between the occurrence/spread of resistance mechanisms and the development of new substances, some new substances have meanwhile been approved and many more are currently undergoing clinical testing. They are particularly effective against specific resistance mechanisms/pathogens and should be preserved for definitive treatment of an isolated pathogen. In the absence of alternatives reserve antibiotics, such as aztreonam and colistin have experienced a renaissance. They are again used in special infection scenarios and clinically tested in combination with new substances. Despite the introduction and development of new substances the building of resistance will at some time also render these (at least partially) ineffective. Therefore, their implementation must be carried out according to the antibiotic or infectious diseases stewardship.
Assuntos
Antibacterianos/uso terapêutico , Infecções Bacterianas/tratamento farmacológico , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Aztreonam/uso terapêutico , Colistina/uso terapêutico , Humanos , Testes de Sensibilidade MicrobianaRESUMO
The increase in resistant pathogens has long been a global problem. Complicated life-threatening infections due to multidrug-resistant pathogens (MRD) meanwhile occur regularly in intensive care medicine. An important and also potentially modifiable factor of the rapid spread of resistance is the irrational use of broad spectrum antibiotics in human medicine. In addition to many other resistance mechanisms, beta-lactamases play an important role in Gram-negative pathogens. They are not uncommonly the leading reason of difficult to treat infections and the failure of known routinely used broad spectrum antibiotics, such as cephalosporins, (acylamino)penicillins and carbapenems. Strategies for containment of MRDs primaríly target the rational use of antibiotics. In this respect interdisciplinary treatment teams, e.g. antibiotic stewardship (ABS) and infectious diseases stewardship (IDS) play a major role.
Assuntos
Antibacterianos/uso terapêutico , Farmacorresistência Bacteriana/efeitos dos fármacos , Carbapenêmicos/uso terapêutico , Cefalosporinas/uso terapêutico , Humanos , Penicilinas/uso terapêuticoRESUMO
The mortality of patients with sepsis and septic shock is still unacceptably high. An effective calculated antibiotic treatment within 1 h of recognition of sepsis is an important target of sepsis treatment. Delays lead to an increase in mortality; therefore, structured treatment concepts form a rational foundation, taking relevant diagnostic and treatment steps into consideration. In addition to the assumed infection and individual risks of each patient, local resistance patterns and specific problem pathogens must be taken into account during the selection of anti-infective treatment. Many pathophysiologic alterations influence the pharmacokinetics (PK) of antibiotics during sepsis. The principle of standard dosing should be abandoned and replaced by an individual treatment approach with stronger weighting of the pharmacokinetics/pharmacodynamics (PK/PD) index of the substance groups. Although this is not yet the clinical standard, prolonged (or continuous) infusion of ßlactam antibiotics and therapeutic drug monitoring (TDM) can help to achieve defined PK targets. Prolonged infusion is sufficient without TDM, but for continuous infusion, TDM is generally necessary. A further argument for individual PK/PD-oriented antibiotic approaches is the increasing number of infections due to multidrug-resistant (MDR) pathogens in the intensive care unit. For effective treatment, antibiotic stewardship teams (ABS teams) are becoming more established. Interdisciplinary cooperation of the ABS team with infectious disease (ID) specialists, microbiologists, and clinical pharmacists leads not only to rational administration of antibiotics, but also has a positive influence on treatment outcome. The gold standards for pathogen identification are still culture-based detection and microbiologic resistance testing for the various antibiotic groups. Despite the rapid investigation time, novel polymerase chain reaction(PCR)-based procedures for pathogen identification and resistance determination are currently only an adjunct to routine sepsis diagnostics, due to the limited number of studies, high costs, and limited availability. In complicated septic courses with multiple anti-infective therapies or recurrent sepsis, PCR-based procedures can be used in addition to treatment monitoring and diagnostics. Novel antibiotics represent potent alternatives in the treatment of MDR infections. Due to the often defined spectrum of pathogens and the practically (still) absent resistance, they are suitable for targeted treatment of severe MDR infections (therapy escalation). (Contribution available free of charge by "Free Access" [ https://link.springer.com/article/10.1007/s00101-017-0396-z ].).
Assuntos
Antibacterianos/uso terapêutico , Bacteriemia/diagnóstico , Bacteriemia/tratamento farmacológico , Gestão de Antimicrobianos , Biomarcadores , Monitoramento de Medicamentos , Humanos , Unidades de Terapia Intensiva , Choque Séptico/tratamento farmacológico , beta-Lactamas/farmacocinética , beta-Lactamas/uso terapêuticoRESUMO
The manufacture and preliminary testing of a drag-reducing riblet texture with fouling-control properties is presented. The commercial fouling-release product Intersleek® 1100SR was modified to manufacture riblet-textured coatings with an embossing technology. Hydrodynamic drag measurements in a Taylor-Couette set-up showed that the modified Intersleek® riblets reduced drag by up to 6% compared to a smooth surface. Barnacle settlement assays demonstrated that the riblets did not substantially reduce the ability of Intersleek® 1100SR to prevent fouling by cyprids of Balanus amphitrite. Diatom adhesion tests revealed significantly higher diatom attachment on the riblet surface compared to smooth Intersleek® 1100SR. However, after exposure to flow, the final cell density was similar to the smooth surface. Statically immersed panels in natural seawater showed an increase of biofilm cover due to the riblets. However, the release of semi-natural biofilms grown in a multi-species biofilm culturing reactor was largely unaffected by the presence of a riblet texture.
Assuntos
Biofilmes/crescimento & desenvolvimento , Incrustação Biológica/prevenção & controle , Diatomáceas/crescimento & desenvolvimento , Thoracica/crescimento & desenvolvimento , Animais , Hidrodinâmica , Água do Mar/microbiologia , Propriedades de SuperfícieRESUMO
In January 2018 the recent revision of the S2k guidelines on calculated parenteral initial treatment of bacterial diseases in adults-update 2018 (Editor: Paul Ehrlich Society for Chemotherapy, PEG) was realized. It is a helpful tool for the complex infectious disease setting in an intensive care unit. The present summary of the guidelines focuses on the topics of anti-infective agents, including new substances, pharmacokinetics and pharmacodynamics as well as on microbiology, resistance development and recommendations for calculated drug therapy in septic patients. As in past revisions the recent resistance situation and results of new clinical studies are considered and anti-infective agents are summarized in a table.
Assuntos
Antibacterianos/administração & dosagem , Infecções Bacterianas/tratamento farmacológico , Choque Séptico/tratamento farmacológico , Guias como Assunto , Humanos , Infusões ParenteraisRESUMO
Sepsis-induced changes in pharmacokinetic parameters are a well-known problem in intensive care medicine. Dosing of antibiotics in this setting is therefore challenging. Alterations to the substance-specific kinetics of anti-infective substances have an effect on the distribution and excretion processes in the body. Increased clearance and an increased distribution volume (Vd) and particularly compromized organ function with reduced antibiotic elimination are often encountered in patients with sepsis. Renal replacement treatment, which is frequently used in intensive care medicine, represents a substantial intervention in this system. Current international guidelines recommend individualized dosing strategies and adaptation of doses according to measured serum levels and pharmacokinetic/pharmacodynamic (PK/PD) parameters as concepts to optimize anti-infective therapy in the critically ill. Likewise, the recommendation to adjust the administration form of beta-lactam antibiotics to prolonged or continuous infusion can be found increasingly more often in the literature. This article reviews the background of the individual dosing in intensive care patients and their applicability to the clinical routine.
Assuntos
Antibacterianos/administração & dosagem , Antibacterianos/uso terapêutico , Antibacterianos/farmacocinética , Cuidados Críticos , Monitoramento de Medicamentos , Humanos , Medicina de Precisão , Sepse/tratamento farmacológico , Sepse/metabolismo , Choque Séptico/tratamento farmacológicoRESUMO
The mortality of patients with sepsis and septic shock is still unacceptably high. An effective antibiotic treatment within 1 h of recognition of sepsis is an important target of sepsis treatment. Delays lead to an increase in mortality; therefore, structured treatment concepts form a rational foundation, taking relevant diagnostic and treatment steps into consideration. In addition to the assumed focus and individual risks of each patient, local resistance patterns and specific problem pathogens must be taken into account for selection of anti-infection treatment. Many pathophysiological alterations influence the pharmacokinetics of antibiotics during sepsis. The principle of standard dosing should be abandoned and replaced by an individual treatment approach with stronger weighting of the pharmacokinetics/pharmacodynamics (PK/PD) index of the substance groups. Although this is not yet the clinical standard, prolonged (or continuous) infusion of beta-lactam antibiotics and therapeutic drug monitoring (TDM) can help to achieve defined PK targets. Prolonged infusion is sufficient without TDM but for continuous infusion TDM is basically necessary. A further argument for individual PK/PD-oriented antibiotic approaches is the increasing number of infections due to multidrug resistant pathogens (MDR) in the intensive care unit. For effective treatment antibiotic stewardship teams (ABS team) are becoming more established. Interdisciplinary cooperation of the ABS team with infectiologists, microbiologists and clinical pharmacists leads not only to a rational administration of antibiotics but also has a positive influence on the outcome. The gold standards for pathogen detection are still culture-based detection and microbiological resistance testing for the various antibiotic groups. Despite the rapid investigation time, novel polymerase chain reaction (PCR)-based procedures for pathogen identification and resistance determination, are currently only an adjunct to routine sepsis diagnostics due to the limited number of studies, high costs and limited availability. In complicated septic courses with multiple anti-infective treatment or recurrent sepsis, PCR-based procedures can be used in addition to therapy monitoring and diagnostics. Novel antibiotics represent potent alternatives in the treatment of MDR infections. Due to the often defined spectrum of pathogens and the practically absent resistance, they are suitable for targeted treatment of severe MDR infections (therapy escalation).
Assuntos
Antibacterianos/uso terapêutico , Infecções Bacterianas/diagnóstico , Infecções Bacterianas/tratamento farmacológico , Sepse/diagnóstico , Sepse/tratamento farmacológico , Infecções Bacterianas/microbiologia , Infecções Bacterianas/mortalidade , Farmacorresistência Bacteriana , Humanos , Unidades de Terapia Intensiva , Sepse/microbiologia , Sepse/mortalidade , Choque Séptico/diagnóstico , Choque Séptico/tratamento farmacológicoRESUMO
CONTEXT: Mutations in the androgen receptor (AR) gene can cause the androgen insensitivity syndrome (AIS). For complete and severe partial AIS, well-characterized in vitro functional assays can be used for genotype-phenotype correlation; however, for mild forms of AIS, as associated with male infertility, experimental evidence is scarce or lacking. In particular, optimal in vitro functional tests informative about the genotype-phenotype relation have not been described. OBJECTIVE: The objective of this study was to investigate the association among genotype and phenotype for AR mutations found in infertile males by conventional functional assays and additional in-depth studies performed with several gene reporters. DESIGN: To this aim, we selected four AR missense mutations associated with isolated male infertility (L547F and two novel mutations A474V and S650G) or partial AIS (Y571H). After introduction of the specific mutations in AR expression plasmid, we performed classical in vitro studies (Western immunoblotting, electrophoretic mobility shift assay, hormone-response curves) and transactivation assays with different reporter constructs (MMTV, Sc-ARU-TK, TAT-GRE- 2X, Slp-ARU-TK and PEM). RESULTS AND CONCLUSIONS: Our results showed that standard functional tests provide sufficient information only for severe AR mutations, whereas for AR mutations found in mild AIS patients with male infertility, only an extensive analysis with different in vitro systems, and in particular with PEM promoter, can give information on the functionality of the AR and therefore on the pathogenicity of the mutations and on genotype-phenotype correlation.
Assuntos
Síndrome de Resistência a Andrógenos/genética , Infertilidade Masculina/genética , Mutação de Sentido Incorreto , Receptores Androgênicos/genética , Adulto , Genótipo , Humanos , Técnicas In Vitro , Masculino , Fenótipo , Plasmídeos , Receptores Androgênicos/metabolismo , Índice de Gravidade de DoençaRESUMO
Considering the growing use of immunotherapeutic strategies in paediatric stem cell transplantation associated with risk of graft-versus-host disease, an accurate method for the enumeration of residual T cells/kg recipient's body weight is of paramount importance. Therefore, we propose a multi colour-flow cytometric strategy for correct absolute vital T cell enumeration in manipulated cell preparations for clinical use. The gating strategy is based on the ISHAGE single-platform stem cell enumeration method in combination with experiences from lymphocyte subtyping, using low scatter, high expression of CD3 and CD45 antigens and 7-AAD staining in a no-wash-preparation with counting beads. In spiking experiments, the detection limit was determined to be at 0.7 +/- 0.5 CD3(+) cells/microl with a minimum of 50 T cell events acquired. The cell preparations analysed contained a median absolute CD3(+) T cell number of 221 x 10(3) (0.09%, CD34 selected grafts, n = 187), 900 x 10(3) (0.004%, CD3/CD19 depleted grafts, n = 15) and 283 x 10(3) (0.012%, CD3 depleted/CD56 enriched NK-cells, n = 14), respectively. The results differed of those from conventional T cell measurement in cell products after extensive manipulation. Our method provides reliable residual T cell enumeration even at extremely low concentrations.
Assuntos
Citometria de Fluxo/métodos , Células Matadoras Naturais , Contagem de Linfócitos/métodos , Subpopulações de Linfócitos T , Antígeno AC133 , Antígenos CD/isolamento & purificação , Antígenos CD34/isolamento & purificação , Criopreservação , Glicoproteínas/isolamento & purificação , Humanos , Imunoterapia Adotiva , Transfusão de Linfócitos , Peptídeos/isolamento & purificaçãoRESUMO
Pharmacokinetic variability of anti-infective drugs due to pathophysiological changes by severe sepsis and septic shock is a well-known problem for critically ill patients resulting in suboptimal serum and most likely tissue concentrations of these agents.To cover a wide range of potential pathogens, high concentrations of broad spectrum anti-infectives have to reach the site of infection. Microbiological susceptibility testing (susceptible, intermediate, resistant) don't take the pharmacokinetic variability into account and are based on data generated by non-critically ill patients. But inter-patient variability in distribution and elimination of anti-infective drugs in ICU patients is extremely high and also highly unpredictable. Drug clearance of mainly renally eliminated drugs and thus the required dose can differ up to 10-fold due to the variability in renal function in patients with severe infections. To assure a timely and adequate anti-infective regime, individual dosing and therapeutic drug monitoring (TDM) seem to be appropriate tools in the setting of pathophysiological changes in pharmacokinetics (PK) and pharmakodynamics (PD) due to severe sepsis. In the case of known minimal inhibitory concentration, PK/PD indices (time or peak concentration dependent activity) and measured serum level can provide an optimal target concentration for the individual drug and patient.Modern anti-infective management for ICU patients includes more than the choice of drug and prompt application. Individual dosing, optimized prolonged infusion time and TDM give way to new and promising opportunities in infection control.
Assuntos
Antibacterianos , Monitoramento de Medicamentos , Sepse , Choque Séptico , Antibacterianos/uso terapêutico , Humanos , Testes de Sensibilidade Microbiana , Sepse/tratamento farmacológico , Choque Séptico/tratamento farmacológicoRESUMO
OBJECTIVE: The present study was designed to develop and assess a questionnaire measuring all relevant quality dimensions of general practice care from the patients' perspective. Furthermore, the study aimed to evaluate the implementation of a patient survey in outpatient care. METHODS: Based on the Kölner Patientenfragebogen (KPF) and by developing some additional new items, we created the new questionnaire KPF-A (Kölner Patientenfragebogen-ambulant) which covers all relevant aspects of outpatient care. The questionnaire was distributed to the patients of 41 GP's and specialists in ambulatory care from different regions of Germany. N=3188 patients were included in the sample. We used these data to assess some selected psychometric characteristics of the KPF-A. Factor analysis was used to examine the underlying factor structure. A qualitative study was conducted to evaluate the implementation of the patient survey. Therefore, all N=41 doctors involved were asked to complete five open questions concerning their experience. RESULTS: Most scales of the KPF-A showed good psychometric characteristics in the present study. Factor analysis revealed a two-factors solution for the new items representing the dimensions "professional competence" and "medical equipment". We have not yet been able to find a sound factor solution for those items representing the dimension "Staff and Organisation". The results of the qualitative study revealed a satisfying implementation of the patient survey in daily routine from the doctors' perspective. The length of the questionnaire was criticised by some participants. In the design of the study patients were supposed to fill in the questionnaires after consultation. This turned out to be difficult. We therefore modified the KPF-A so that patients can fill it in either before or after consultation.
Assuntos
Assistência Ambulatorial/normas , Inquéritos e Questionários , Gestão da Qualidade Total/organização & administração , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Competência Clínica/normas , Medicina de Família e Comunidade/normas , Feminino , Alemanha , Inquéritos Epidemiológicos , Humanos , Masculino , Medicina/normas , Pessoa de Meia-Idade , Projetos Piloto , Avaliação de Programas e Projetos de Saúde , Psicometria/estatística & dados numéricos , Sensibilidade e Especificidade , EspecializaçãoRESUMO
BACKGROUND: The transition from androgen-dependent to androgen-independent prostate cancer is not fully understood but appears to involve multiple genetic changes. We have identified a gene, GC79, that is more highly expressed in androgen-dependent LNCaP-FGC human prostate cancer cells than in androgen-independent LNCaP-LNO human prostate cancer cells. Physiologic levels (0.1 nM:) of androgens repress expression of GC79 messenger RNA (mRNA) in LNCaP-FGC cells. To determine the role of GC79, we cloned its complementary DNA (cDNA) and functionally characterized its product. METHODS: The differentially expressed GC79 gene was cloned from human prostate cDNA libraries, sequenced, and transfected into mammalian cells to study its function. Expression of GC79 was analyzed in various adult and fetal human tissues and in prostate glands of castrated rats. The association of GC79 expression and apoptosis was investigated in COS-1 and LNCaP cells transfected with GC79 cDNA. All statistical tests are two-sided. RESULTS: Sequence analysis indicates that GC79 encodes a large, complex, multitype zinc-finger protein, containing nine C(2)H(2)-type zinc-finger domains, a cysteine-rich region, and a GATA C(4)-type zinc-finger domain. Castration-induced androgen withdrawal increased the expression of GC79 mRNA in the regressing rat ventral prostate, suggesting that the expression of GC79 mRNA is associated with the process of apoptotic cell death in the rat ventral prostate. Transfection and induction of GC79 cDNA in both COS-1 and LNCaP prostate cancer cells led to an apoptotic index that was eightfold higher (P:<.001, two-sided Student's t test) than that observed in uninduced transfected cells. CONCLUSIONS: We have cloned an androgen-repressible gene, GC79, that is potentially involved in apoptosis. This finding may have implications for the development of androgen-independent prostate cancer and, ultimately, for the treatment of prostate cancer.
Assuntos
Androgênios/metabolismo , Proteínas de Ligação a DNA , Proteínas de Neoplasias/genética , Neoplasias da Próstata/genética , Neoplasias da Próstata/patologia , Dedos de Zinco/genética , Sequência de Aminoácidos , Animais , Apoptose , Sequência de Bases , Northern Blotting , Clonagem Molecular , Regulação Neoplásica da Expressão Gênica , Humanos , Masculino , Dados de Sequência Molecular , Neoplasias da Próstata/metabolismo , RNA Mensageiro/análise , RNA Neoplásico/análise , Proteínas Repressoras , Fatores de Transcrição , Células Tumorais CultivadasRESUMO
Differential gene expression between androgen-dependent (LNCaP-FGC) and androgen-independent (LNCaP-LNO) prostate cancer cells has been investigated using RNA arbitrarily primed and differential display PCR of mRNA. Four differentially expressed cDNA transcripts were identified, of which differential expression was confirmed by Northern blot analysis. Sequence analysis revealed two unknown (JC19 and GC79) and two known genes [B-cell translocation gene 1 and UDP-glucuronosyltransferase 2B15 (UGT2B15)]. JC19, GC79, and B-cell translocation gene 1 were more highly expressed in LNCaP-FGC cells compared with LNCaP-LNO cells, whereas UGT2B15 was only expressed in LNCaP-LNO cells. Androgens and 1,25-dihydroxyvitamin D3 were able to down-regulate UGT2B15 mRNA in LNCaP-LNO cells. For GC79 mRNA, down-regulation was only observed with androgens in LNCaP-FGC cells. Expression of JC19 mRNA was studied using a panel of human prostate cancer xenografts. In androgen-dependent xenografts, expression of JC19 mRNA was much higher compared with androgen-independent xenografts, in which significant expression was hardly detectable. The mRNA expression pattern in the xenografts is in good agreement with that observed in the cell culture system. In conclusion, the differential display technique used in the present study allows analysis of gene expression in vitro and in vivo and can be used for the identification of important genes involved in androgen-independent prostate cancer development.
Assuntos
Androgênios/fisiologia , Proteínas de Ligação a DNA , Glucuronosiltransferase/genética , Proteínas de Neoplasias/genética , Neoplasias da Próstata/genética , Animais , Sequência de Bases , Calcitriol/farmacologia , Ciclo Celular , Divisão Celular/efeitos dos fármacos , Clonagem Molecular , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Masculino , Metribolona/farmacologia , Camundongos , Camundongos Nus , Dados de Sequência Molecular , Transplante de Neoplasias , RNA Mensageiro/genética , RNA Neoplásico/genética , Proteínas Repressoras , Fatores de Transcrição , Transplante Heterólogo , Células Tumorais CultivadasRESUMO
Glucocorticoids play an important role in the treatment of a number of hematological malignancies, such as multiple myeloma. The effects of glucocorticoids are mediated through the glucocorticoid receptor alpha, the abundance of which can be modulated by alternative splicing of the glucocorticoid receptor mRNA. Two splice variants of the glucocorticoid receptor mRNA have been described: glucocorticoid receptor beta, which reportedly has a dominant negative effect on the actions of the glucocorticoid receptor alpha, and glucocorticoid receptor P, of which the effects are unknown. In this study, we have investigated the expression levels of these two splice variants at the mRNA level in multiple myeloma cells and in a number of other hematological tumors. Although the glucocorticoid receptor beta mRNA was, if at all, expressed at very low levels, considerable amounts (up to 50% of the total glucocorticoid receptor mRNA) glucocorticoid receptor P mRNA was present in most hematological malignancies. In transient transfection studies in several cell types and in multiple myeloma cell lines, the glucocorticoid receptor P increased the activity of the glucocorticoid receptor alpha. These results suggest that the relative levels of the glucocorticoid receptor alpha and the glucocorticoid receptor P may play a role in the occurrence of glucocorticoid resistance in tumor cells during the treatment of hematological malignancies with glucocorticoids.
Assuntos
Processamento Alternativo , Neoplasias Hematológicas/metabolismo , Receptores de Glucocorticoides/biossíntese , Animais , Medula Óssea/metabolismo , Células CHO , Células COS , Cricetinae , Células HeLa , Neoplasias Hematológicas/genética , Humanos , Mieloma Múltiplo/genética , Mieloma Múltiplo/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Receptores de Glucocorticoides/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transfecção , Células Tumorais CultivadasRESUMO
Calf uterine cytosol contains an androgen receptor with a relative molecular mass of approx. 90,000. In this study we have analysed the structure and aggregation properties of the androgen receptor, using sucrose density gradient centrifugation on a vertical rotor (VTi65). In the presence of 10 mM NaCl the androgen receptor in whole cytosol sedimented at 8 S irrespective of the presence of molybdate. In 400 mM NaCl the receptor dissociated to a 4.3 S entity. In whole cytosol molybdate promoted a partial shift of the 4.3 S receptor into the aggregated 8 S state. The time of exposure of the receptor to molybdate and NaCl determined the proportion of receptor sedimentating at 8 S and 4.3 S. The DNA-binding form of the uterine androgen receptor when analysed under the conditions of the DNA-cellulose binding assay, sedimented at 6.5 S. Increasing concentrations of molybdate shifted its sedimentation coefficient gradually from 6.5 S to 4.5 S and in parallel reduced the DNA-binding capacity. Molybdate added to a partially purified, DNA-binding form of the androgen receptor did not promote receptor aggregation to faster sedimentating forms. This suggests that such preparations are devoid of an androgen receptor-aggregation factor. Indirect evidence for such a factor was obtained from reconstitution experiments with whole cytosol. Our results indicate that the DNA-binding form of the androgen receptor interacts with a cytosol factor to form the 8 S receptor complex. Molybdate has diverse effects: in the presence of the cytosol factor it stabilizes the 8S complex; in its absence molybdate prevents in a concentration-dependent way DNA-binding as well as reaggregation of the monomeric 4.3 S form.
Assuntos
DNA/metabolismo , Molibdênio/farmacologia , Receptores Androgênicos/metabolismo , Útero/metabolismo , Animais , Bovinos , Celulose/análogos & derivados , Celulose/metabolismo , Centrifugação com Gradiente de Concentração , Citosol/metabolismo , DNA/análogos & derivados , Feminino , Concentração Osmolar , Cloreto de Sódio/farmacologiaRESUMO
In the present study, calf uterine tissue has been used for isolation of androgen receptors. This tissue appeared to be a favourable source for large-scale purification of androgen receptors, because of the relatively high level of androgen receptors and the low concentration of proteolytic enzymes. The purification involved differential phosphocellulose and DNA affinity chromatography as first steps. The non-transformed receptor was passed through these matrices in order to remove contaminating DNA-binding proteins. After a transformation step to the DNA-binding state, the receptor was bound to DNA cellulose and subsequently eluted with MgCl2. A 0.5% pure androgen receptor preparation was obtained. Photoaffinity labelling with [3H]R1881 (methyltrienolone) was used to determine the size of the receptor at this stage of purification and during the following steps. Subsequently, isoelectric focussing of the partially purified androgen receptor preparation in an aqueous glycerol gradient was performed. In this step, the progesterone receptor, which is copurified with the androgen receptor protein during the first part of the purification procedure, focussed at pH 5.5 while the androgen receptor could be isolated at pH 5.8. The isoelectric focussing procedure could be applied in a preparative way for further purification of androgen receptors. After this step an approx. 8% pure preparation was obtained. Polyacrylamide gel electrophoresis of S-carboxymethylated androgen receptor was used as the final purification step. The [3H]methyltrienolone labelled androgen receptor from calf uterus was purified to homogeneity and consisted of one polypeptide with a molecular mass of 110 kDa.
Assuntos
Receptores Androgênicos/isolamento & purificação , Útero/análise , Marcadores de Afinidade/metabolismo , Animais , Bovinos , Citosol/análise , Eletroforese em Gel de Poliacrilamida , Feminino , Focalização Isoelétrica , Peso Molecular , FotoquímicaRESUMO
Androgen receptors were partially purified from prostates of mature (non-castrated) rats by chromatography on 2',5'-ADP-Sepharose and labelled by exchange with 5 alpha-[3H]dihydrotestosterone. The partially purified receptor preparation was free of DNAase activity and sedimented at approx. 3 S. The specificity of the interaction of this androgen receptor with nucleotides was investigated in a competitive binding assay using inhibition of binding of the steroid receptor complex to ADP-Sepharose. Certain polyribonucleotides were strongly bound (e.g., poly(UG), poly(AU), poly(G) and poly(U] and competed more effectively for the receptor binding sites than prostate RNA. Restriction fragments of genomic clones from the genes which code for prostatic binding protein showed only moderate affinity for the 3 S receptor form. These data suggest that the 3 S form of the androgen receptor lacks the specific domain or conformation necessary for specific interaction with DNA, but retains a high affinity for certain forms of RNA. Some potent inhibitors of proteolysis (diisopropylfluorophosphate, leupeptin) did not have any effect on the form of the receptor isolated from mature intact animals. A possible function of the 3 S form in post-transcriptional processing is discussed.