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1.
Orthopade ; 49(2): 88-97, 2020 Feb.
Artigo em Alemão | MEDLINE | ID: mdl-32025742

RESUMO

Biopsy followed by histopathological assessment is the key procedure to establish the correct diagnosis of unclear bone or soft tissue tumors. There are several possibilities to obtain a biopsy specimen. The indication for biopsy should be established in a specialized center, as should the type of biopsy (fine needle, incisional, excisional, percutaneous CT-guided/navigated biopsy), which must be performed according to established guidelines. The tumor biopsy must be representative and adequate in terms of quantity, to enable a conclusive histopathological diagnosis and planning of appropriate treatment. For the correct biopsy tract, the surgical approach for definitive resection must be considered; thus, biopsy should be conducted in the center where the subsequent resection will be performed. Of note, patients whose biopsy is performed at a specialized musculoskeletal tumor center benefit in terms of improved local tumor control.


Assuntos
Neoplasias Ósseas/diagnóstico , Biópsia , Humanos , Neoplasias de Tecidos Moles , Tomografia Computadorizada por Raios X
2.
Orthopade ; 49(2): 123-132, 2020 Feb.
Artigo em Alemão | MEDLINE | ID: mdl-32006053

RESUMO

BACKGROUND: Tumourous destruction of the periacetabular region and the proximal femur is a typical consequence of either primary malignant bone tumour manifestation or skeletal metastatic diseases. Pathological fractures of the proximal femur and periacetabular regions due to primary manifestation or metastatic disorders are frequent. OBJECTIVES: Presentation of the most common complications of tumour endoprostheses at the hip and a description of management strategies, including therapeutic recommendations and concepts for complication avoidance. MATERIALS AND METHODS: The current knowledge and our own experience of complication management with the use of megaprostheses around the hip are presented. RESULTS: Compared to elective/primary total hip arthroplasty, megaprosthetic reconstructions following tumour resections have an increased rate of postoperative deep infections, dislocations, incidence of pathological and periprosthetic fractures and of deep vein thrombosis. The postoperative mortality and local tumour recurrence along with deep infections represent the most serious complications. CONCLUSIONS: In comparison to primary arthroplasty, the risk of failure and complications following tumour-endoprosthetic replacement is increased. Precise surgical planning and careful selection and preoperative preparation of suitable patients should be performed in close interdisciplinary cooperation with final decision-making on an interdisciplinary tumour board. Wide resection and advanced reconstruction, as well as complicated palliative stabilization due to malignant bone tumour growth around the hip joint should be performed in musculoskeletal tumour centres with profound expertise in osteosynthetic and endoprosthetic reconstruction and consecutive complication management of the pelvis and the proximal femur.


Assuntos
Artroplastia de Quadril , Neoplasias Ósseas , Fraturas Periprotéticas , Fêmur , Articulação do Quadril , Humanos , Reoperação , Estudos Retrospectivos , Resultado do Tratamento
3.
Orthopade ; 48(7): 588-597, 2019 Jul.
Artigo em Alemão | MEDLINE | ID: mdl-31127332

RESUMO

BACKGROUND: Tumor endoprostheses are available as modular systems with which bone defects can be partially reconstructed, usually close to the joints, or as a total replacement of long tubular bones. As a result of continuously improved survival times, they are used with bone tumors, skeletal metastases and, increasingly, in revision arthroplasty. OBJECTIVES: Presentation of the most common complications of tumor endoprostheses and a description of their management, including treatment recommendations. MATERIALS AND METHODS: The current knowledge and our own experience of complication management with the use of megaprostheses are presented. RESULTS: The number of tumor endoprostheses procedures is limited, so that a limited number of studies and classifications are available. Periprosthetic infections involving the soft tissues represent the most serious failure after perioperative dying and local recurrence of the tumor. Two-stage revision remains the gold standard in periprosthetic infection, even if one-stage revision is justifiable in selective indications. Periprosthetic infection and local recurrence is associated with the risk of secondary amputations. Mechanical failure can be treated more easily. Specific socket systems for proximal femoral replacement and attachment tubing allow for adequate soft tissue reconstruction, restoration of joint function, and minimize the risk of dislocation. CONCLUSIONS: In comparison to primary arthroplasty, the risk of failure following tumor endoprosthetic replacement is increased but is basically controllable by revision surgery.


Assuntos
Neoplasias Ósseas , Recidiva Local de Neoplasia , Neoplasias Ósseas/complicações , Fêmur , Humanos , Recidiva Local de Neoplasia/complicações , Falha de Prótese , Reoperação/instrumentação , Reoperação/métodos , Resultado do Tratamento
4.
Orthopade ; 46(6): 484-497, 2017 Jun.
Artigo em Alemão | MEDLINE | ID: mdl-28451704

RESUMO

BACKGROUND: Benign bone lesions are much more common than malignant lesions. Some benign bone tumors have a characteristic and typical radiographic appearance, while others are more challenging. Therapy of benign bone tumors differs greatly. While the majority of benign bone tumors do not require surgical therapy, other specific lesions, e. g. aneurysmal bone cysts or giant cell tumors (GCT) of the bone require surgery due to their locally aggressive behavior. DIAGNOSTICS: The major challenge for the radiologist and/or pathologist is the differentiation between a benign and low-grade malignant lesion (e. g. enchondroma versus low-grade chondrosarcoma) for which all available clinical and radiographic information is mandatory. Therefore, surgical therapy is rather more often performed than necessary due to uncertainty in many cases. THERAPY: Novel systemic therapies are available for fibrous dysplasia and GCT of the bone: Fibrous dysplasia can be treated with bisphosphonates, and GCT responds to denosumab. In fact, denosumab has been approved for the treatment of irresectable GCT. Osteoid osteoma is fairly easy to recognize and also to treat given the characteristic clinical presentation and rapid and effective response to local therapy (possible as percutaneous thermo-/laser ablation). In summary, several therapeutic options exist for benign bone tumors, and the choice depends upon the tendency/risk of local recurrence, the rate of surgical complications, options for defect reconstruction, postoperative functional deficits, and specific patient characteristics.


Assuntos
Doenças Ósseas/diagnóstico , Neoplasias Ósseas/diagnóstico , Cistos Ósseos Aneurismáticos/diagnóstico , Cistos Ósseos Aneurismáticos/patologia , Cistos Ósseos Aneurismáticos/cirurgia , Doenças Ósseas/classificação , Doenças Ósseas/patologia , Doenças Ósseas/cirurgia , Neoplasias Ósseas/classificação , Neoplasias Ósseas/patologia , Neoplasias Ósseas/cirurgia , Osso e Ossos/patologia , Osso e Ossos/cirurgia , Condroma/classificação , Condroma/diagnóstico , Condroma/patologia , Condroma/cirurgia , Condrossarcoma/classificação , Condrossarcoma/diagnóstico , Condrossarcoma/patologia , Condrossarcoma/cirurgia , Diagnóstico Diferencial , Displasia Fibrosa Óssea/diagnóstico , Displasia Fibrosa Óssea/patologia , Displasia Fibrosa Óssea/cirurgia , Tumor de Células Gigantes do Osso/diagnóstico , Tumor de Células Gigantes do Osso/patologia , Tumor de Células Gigantes do Osso/cirurgia , Humanos , Prognóstico , Resultado do Tratamento
5.
Orthopade ; 42(8): 651-3, 2013 Aug.
Artigo em Alemão | MEDLINE | ID: mdl-23695194

RESUMO

Nerve injury after total hip replacement is a rare but severe complication. If the nerve lesion becomes evident in the early postoperative phase the lesion is often due to an incorrect implant position, direct nerve injury or vascular injury with manifestation of a hematoma which results in nerve compression. Secondary nerve lesions are more often due to a chronic hematoma with nerve compression. Secondary nerve lesions in particular are often a diagnostic challenge and should lead to an early revision after comprehensive imaging diagnostics.


Assuntos
Artroplastia de Quadril/efeitos adversos , Parafusos Ósseos/efeitos adversos , Neuropatia Femoral/diagnóstico , Neuropatia Femoral/etiologia , Hematoma/etiologia , Paralisia/diagnóstico , Paralisia/etiologia , Idoso de 80 Anos ou mais , Feminino , Humanos , Implantação de Prótese/efeitos adversos , Falha de Tratamento
6.
Phys Rev Lett ; 100(5): 057204, 2008 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-18352420

RESUMO

We used polarized neutron reflectometry to determine the temperature dependence of the magnetization of thin AuFe films with 3% Fe concentration. We performed the measurements in a large magnetic field of 6 T in a temperature range from 295 to 2 K. For the films in the thickness range from 500 to 20 nm we observed a Brillouin-type behavior from 295 K down to 50 K and a constant magnetization of about 0.9 micro(B) per Fe atom below 30 K. However, for the 10 nm thick film we observed a Brillouin-type behavior down to 20 K and a constant magnetization of about 1.3 micro(B) per Fe atom below 20 K. These experiments are the first to show a finite-size effect in the magnetization of single spin-glass films in large magnetic fields. Furthermore, the ability to measure the deviation from the paramagnetic behavior enables us to prove the existence of the spin-glass state where other methods relying on a cusp-type behavior fail.

7.
Chirurg ; 74(7): 657-64, 2003 Jul.
Artigo em Alemão | MEDLINE | ID: mdl-12883794

RESUMO

INTRODUCTION: In view of its predictive potential, axillary nodal status plays a particularly important role in breast cancer. The concept of sentinel node biopsy (SNB) revealed an accurate method with low postoperative morbidity for staging the axilla in patients with lymph node-negative breast cancer. The aim of this study was to show that SNB alone must have a place in routine clinical work and is reliable after preoperative chemotherapy (PC) and also in patients with multicentric tumors (MC). PATIENTS AND METHOD: Between April 1997 and March 2002, a total of 300 SNBs were performed in patients with uni- or bilateral breast cancer. Of them, 45 who had completed PC and 13 with multicentric lesions underwent SNB followed by axillary dissection. The sentinel nodes (SN) were labelled with a blue dye and radioactive colloids. Median follow-up was 33.6 months (range 8.2-67.0) (StAw 1.4). RESULTS: The detection rate in the learning phase was 81.8% and later 93.5%, independently of the size of the primary tumor. Overall accuracy and negative predictive value of the first 55 patients, after PC and in those with MC came to 97.8% and 96.7%, 97.6%, 95.8% and 100%, respectively. Through focused pathologic examination, staging was improved in 11.3% of patients. A year after the procedure, one patient developed recurrence. Morbidity after SNB alone was significantly lower than after axillary dissection. CONCLUSION: Our experience shows SNB to be reliable and accurate for axillary staging in breast cancer patients. Morbidity after SNB alone was low. Conclusive data on the local recurrence rate are not yet available. Under certain conditions, SNB appears to have future clinical potential, even in patients with PC and MC, which must be confirmed in further multicentric studies. In the meantime, this method has attained definite value in the surgical therapy of breast cancer patients.


Assuntos
Neoplasias da Mama/patologia , Carcinoma Ductal/patologia , Carcinoma Lobular/patologia , Neoplasias Primárias Múltiplas/patologia , Biópsia de Linfonodo Sentinela , Adulto , Idoso , Idoso de 80 Anos ou mais , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Axila , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/cirurgia , Carcinoma Ductal/tratamento farmacológico , Carcinoma Ductal/cirurgia , Carcinoma Lobular/tratamento farmacológico , Carcinoma Lobular/cirurgia , Terapia Combinada , Feminino , Seguimentos , Humanos , Excisão de Linfonodo , Mastectomia Radical Modificada , Mastectomia Segmentar , Pessoa de Meia-Idade , Terapia Neoadjuvante , Estadiamento de Neoplasias , Neoplasias Primárias Múltiplas/tratamento farmacológico , Neoplasias Primárias Múltiplas/cirurgia
8.
Mol Biol (Mosk) ; 36(5): 901-11, 2002.
Artigo em Russo | MEDLINE | ID: mdl-12391855

RESUMO

The interaction of short nucleotide duplexes with bis-netropsins, in which netropsin fragments are linked in the tail-to-tail orientation via cis-diammineplatinum group (<--Nt-Pt(NH3)-Nt-->) or aliphatic pentamethylene chain (<--Nt-(CH2)5-Nt-->), has been studied. Both the bis-netropsins have been shown to bind to DNA oligomer 5'-CCTATATCC-3' (I) as a hairpin with parallel orientation of netropsin fragments in 1:1 stoichiometry. Monodentate binding has been detected upon binding of bis-netropsins to other duplexes of sequences 5'-CCXCC-3'--where X = TTATT (II), TTAAT (III), TTTTT (IV), and AATTT (V)--along with the binding of bis-netropsins as a hairpin. The formation of dimeric antiparallel motif between the halves of two bound bis-netropsin molecules has been observed in the complexes of <--Nt-(CH2)5-Nt--> with DNA oligomers IV and V. The ratio of binding constant of bis-netropsin as a hairpin (K2) to monodentate binding constant (K1) has been shown to correlate with the width and/or conformational lability of DNA in the binding site. The share of bis-netropsin bound as a hairpin decreases in the order: TATAT > TTATT > TTAAT > TTTTT > AATTT, whereas the contribution of monodentate binding rises. The minimal strong binding site for <--Nt-Pt(NH3)-Nt--> and <--Nt-(CH2)5-Nt--> binding as a hairpin has been found to be DNA duplex 5'-CGTATACG-3'.


Assuntos
Antibacterianos/metabolismo , DNA/química , DNA/metabolismo , Netropsina/metabolismo , Antibacterianos/química , Sítios de Ligação , Análise Heteroduplex , Netropsina/química , Conformação de Ácido Nucleico , TATA Box
9.
Cancer ; 92(5): 1080-4, 2001 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-11571718

RESUMO

BACKGROUND: Many studies support the concept and accuracy of sentinel lymph node biopsy (SNB) for staging patients with breast carcinoma, which can be performed with low morbidity in lymph node negative patients. Preoperative chemotherapy (PC) plays an important role in the treatment of patients with operable breast carcinoma and is another approach with which to reduce radical surgery in patients with more advanced disease. It is of interest whether the sentinel lymph node accurately represents the axillary status after PC and, thus, whether the sentinel node concept can be applied to both groups. METHODS: Thirty-three patients underwent SNB after chemotherapy and prior to axillary lymph node dissection. RESULTS: The average greatest tumor dimension before chemotherapy (33 mm +/- 2 mm) was significantly larger (P = 0.000) than after therapy (20 mm +/- 3 mm). Histopathologic complete remission was seen in only three patients. One or two sentinel lymph nodes (average, 1.7 lymph nodes) were identified with certainty in 29 of 33 procedures and accurately predicted axillary lymph node status in all of these patients. Breast-conserving surgery was possible in 21 patients (64%), and axillary lymph nodes were involved in 22 patients (67%). CONCLUSIONS: Even after patients undergo PC, SNB seems to be a reliable method for accurate staging of the axilla in those more advanced breast carcinoma. Thus, axillary dissection may be avoided in certain patients. Lymph node involvement seems to be likely in women with suspicious axillary findings before chemotherapy who have no visible sentinel lymph nodes on preoperative lymphosintigraphy and in patients without recurrent tumors. Further investigation of the SNB concept in this patient group should be evaluated in larger studies.


Assuntos
Neoplasias da Mama/patologia , Biópsia de Linfonodo Sentinela , Adulto , Idoso , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/cirurgia , Terapia Combinada , Feminino , Humanos , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Indução de Remissão , Reprodutibilidade dos Testes
10.
J Biomol Struct Dyn ; 19(1): 159-74, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11565847

RESUMO

The DNA duplex d-(CATGGGCCCATG)2 has been studied in solution by FTIR, NMR and CD. The experimental approaches have been complemented by series of large-scale unrestrained molecular dynamics simulation with explicit inclusion of solvent and counterions. Typical proton-proton distances extracted from the NMR spectra and the CD spectra are completely in agreement with slightly modified B-DNA. By molecular dynamics simulation, starting from A-type sugar pucker, a spontaneous repuckering to B-type sugar pucker was observed. Both experimental and theoretical approaches suggest for the dodecamer d-(CATGGGCCCATG)2 under solution conditions puckering of all 2'-deoxyribose residues in the south conformation (mostly C2'-endo) and can exclude significant population of sugars in the north conformation (C3'-endo). NMR, FTIR and CD data are in agreement with a B-form of the dodecamer in solution. Furthermore, the duplex shows a cooperative B-A transition in solution induced by addition of trifluorethanol. This contrasts a recently published crystal structure of the same oligonucleotide found as an intermediate between B- and A-DNA where 23 out of 24 sugar residues were reported to adopt the north (N-type) conformation (C3'-endo) like in A-DNA (Ng, H. L., Kopka, M. L. and Dickerson, R. E., Proc. Natl. Acad. Sci. U S A 97, 2035-2039 (2000)). The simulated structures resemble standard B-DNA. They nevertheless show a moderate shift towards A-type stacking similar to that seen in the crystal, despite the striking difference in sugar puckers between the MD and X-ray structures. This is in agreement with preceding MD reports noticing special stacking features of G-tracts exhibiting a tendency towards the A-type stacking supported by the CD spectra also reflecting the G-tract stacking. MD simulations reveal several noticeable local conformational variations, such as redistribution of helical twist and base pair roll between the central GpC steps and the adjacent G-tract segments, as well as a substantial helical twist variability in the CpA(TpG) steps combined with a large positive base pair roll. These local variations are rather different from those seen in the crystal.


Assuntos
DNA/química , Oligodesoxirribonucleotídeos/química , Sequência de Bases , Dicroísmo Circular , Espectroscopia de Ressonância Magnética , Conformação de Ácido Nucleico , Soluções , Espectroscopia de Infravermelho com Transformada de Fourier , Termodinâmica
11.
Nucl Med Commun ; 22(8): 867-73, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11473205

RESUMO

Single photon emission computed tomography (SPECT) and positron emission tomography (PET) are examination procedures that have shown that repetitive transcranial magnetic stimulation (rTMS) is biologically active. The aim of the present study was to investigate the patterns of regional cerebral 18F-fluorodeoxyglucose (18F-FDG) uptake and regional 99mTc-hexamethylpropyleneamine oxime (99mTc-HMPAO) uptake simultaneously during a series of therapeutic rTMS at low frequency. Four drug-resistant depressed patients underwent 10 rTMS as an add-on measure over 14 days. One day before and one day after TMS, simultaneous measurements of 18F-FDG, representing regional cerebral metabolic rate (rCMR), and 99mTc-HMPAO, representing regional cerebral blood flow (rCBF), were carried out. A conventional double head SPECT camera with 511 keV collimators was used. Statistically significant simultaneous overall changes of rCBF and rCMR were found in the upper prefrontal regions bilaterally in terms of increased uptake rates and in the left gyrus frontalis inferior in terms of decreased uptake rates of both isotopes compared to controls. Although this method improves our understanding of rTMS mechanism, there are limitations due to the lower resolution provided. Therapeutic rTMS seems to influence distinct, cortical regions affecting rCBF and rCMR.


Assuntos
Antidepressivos/uso terapêutico , Mapeamento Encefálico/métodos , Encéfalo/diagnóstico por imagem , Encéfalo/metabolismo , Transtorno Depressivo/diagnóstico por imagem , Transtorno Depressivo/metabolismo , Fluordesoxiglucose F18/farmacocinética , Magnetismo , Tecnécio Tc 99m Exametazima/farmacocinética , Tomografia Computadorizada de Emissão de Fóton Único/métodos , Adulto , Citalopram/uso terapêutico , Transtorno Depressivo/tratamento farmacológico , Feminino , Lateralidade Funcional , Humanos , Masculino , Maprotilina/uso terapêutico , Projetos Piloto , Compostos Radiofarmacêuticos/farmacocinética , Valores de Referência , Distribuição Tecidual , Trazodona/uso terapêutico
12.
J Biomol Struct Dyn ; 18(5): 689-701, 2001 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11334106

RESUMO

Cis-diammine Pt(II)- bridged bis-netropsin and oligomethylene-bridged bis-netropsin in which two monomers are linked in a tail-to-tail manner bind to the DNA oligomer with the sequence 5'-CCTATATCC-3' in a parallel-stranded hairpin form with a stoichiometry 1:1. The difference circular dichroism (CD) spectra characteristic of binding of these ligands in the hairpin form are similar. They differ from CD patterns obtained for binding to the same duplex of another bis-netropsin in which two netropsin moieties were linked in a head-to-tail manner. This reflects the fact that tail-to-tail and head-to-tail bis-netropsins use parallel and antiparallel side-by-side motifs, respectively, for binding to DNA in the hairpin forms. The binding affinity of cis-diammine Pt(II)-bridged bis-netropsin in the hairpin form to DNA oligomers with nucleotide sequences 5'-CCTATATCC-3' (I), 5'-CCTTAATCC-3' (II), 5'-CCTTATTCC-3' (III), 5'-CCTTTTTCC-3' (IV) and 5'-CCAATTTCC-3' (V) decreases in the order I = II > III > IV > V . The binding of oligomethylene-bridged bis-netropsin in the hairpin form follows a similar hierarchy. An opposite order of sequence preferences is observed for partially bonded monodentate binding mode of the synthetic ligand.


Assuntos
DNA/química , Netropsina/análogos & derivados , Netropsina/química , Sítios de Ligação , Modelos Moleculares , Estrutura Molecular , Conformação de Ácido Nucleico , Oligodesoxirribonucleotídeos/química , Poli dA-dT/química
14.
Psychiatry Res ; 98(1): 43-54, 2000 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-10708925

RESUMO

The assumption of a dynamic coupling between regional cerebral blood flow (rCBF) and cerebral glucose metabolic rates (rCMRGlu) has been challenged by simultaneous measurements of both. Through the use of a dual-headed gamma camera with a 511-keV collimator applying the double isotope 18F-FDG and 99mTc-HMPAO SPECT technique, the uptake rates of these isotopes can be semi-quantitatively evaluated. Sixteen depressed patients, diagnosed by ICD-10 criteria and assessed with the 17-item Hamilton Rating Scale for Depression (HRSD), were studied. Based on the severity of HRSD-rated anxiety (item 10: low=1-21; high=3-4), two eight-patient subgroups were formed and compared with 12 age- and handedness-matched healthy control subjects. As regions of interest, we selected areas implicated in the neuroanatomy of anxiety and depression: hippocampus (hippo), basal ganglia (BG) and gyri temporales superiores (G.t.s.). In the control subjects, a significant statistical coupling between rCBF and rCMRGlu was revealed by the Spearman correlation coefficient only in left hippo and left BG. Patients in the low-anxiety subgroup demonstrated a marked dynamic coupling bilaterally for the G.t.s., while patients in the high-anxiety subgroup showed a significant statistical correlation of rCBF and rCMRGlu only in the left G.t.s. These findings indicate that a dynamic coupling between blood flow and glucose metabolism exists only in distinct brain regions, and that the depressive illness has an uncoupling effect on this correlation in the left BG. Furthermore, our results suggest that the HRSD anxiety score might interact with the underlying depressive illness to influence the relationship of rCBF and rCMRGlu.


Assuntos
Ansiedade/diagnóstico por imagem , Encéfalo/diagnóstico por imagem , Circulação Cerebrovascular , Transtorno Depressivo/diagnóstico por imagem , Fluordesoxiglucose F18 , Glucose/metabolismo , Compostos Radiofarmacêuticos , Tecnécio Tc 99m Exametazima , Tomografia Computadorizada de Emissão de Fóton Único/métodos , Adulto , Ansiedade/metabolismo , Ansiedade/fisiopatologia , Gânglios da Base/diagnóstico por imagem , Encéfalo/metabolismo , Encéfalo/fisiopatologia , Estudos de Casos e Controles , Transtorno Depressivo/metabolismo , Transtorno Depressivo/fisiopatologia , Feminino , Hipocampo/diagnóstico por imagem , Humanos , Masculino , Pessoa de Meia-Idade , Estatísticas não Paramétricas , Lobo Temporal/diagnóstico por imagem
15.
Biochemistry ; 38(39): 12860-8, 1999 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-10504256

RESUMO

The three-dimensional solution structure of a DNA molecule of the sequence 5'-d(GCATCGAAAAAGCTACG)-3' paired with 5'-d(CGTAGCCGATGC)-3' containing a five-adenine bulge loop (dA(5)-bulge) between two double helical stems was determined by 2D (1)H and (31)P NMR, infrared, and Raman spectroscopy. The DNA in both stems adopt a classical B-form double helical structure with Watson-Crick base pairing and C2'-endo sugar conformation. In addition, the two dG/dC base pairs framing the dA(5)-bulge loop are formed and are stable at least up to 30 degrees C. The five adenine bases of the bulge loop are localized at intrahelical positions within the double helical stems. Stacking on the double helical stem is continued for the first four 5'-adenines in the bulge loop. The total rise (the height) of these four stacked adenines roughly equals the diameter of the double helical stem. The stacking interactions are broken between the last of these four 5'-adenines and the fifth loop adenine at the 3'-end. This 3'-adenine partially stacks on the other stem. The angle between the base planes of the two nonstacking adenines (A10 and A11) in the bulge loop reflects the kinking angle of the global DNA structure. The neighboring cytosines opposite the dA(5)-bulge (being parts of the bulge flanking base pairs) do not stack on one another. This disruption of stacking is characterized by a partial shearing of these bases, such that certain sequential NOEs for this base step are preserved. In the base step opposite the loop, an extraordinary hydrogen bond is observed between the phosphate backbone of the 5'-dC and the amino proton of the 3'-dC in about two-thirds of the conformers. This hydrogen bond probably contributes to stabilizing the global DNA structure. The dA(5)-bulge induces a local kink into the DNA molecule of about 73 degrees (+/-11 degrees ). This kinking angle and the mutual orientation of the two double helical stems agree well with results from fluorescence resonance energy transfer measurements of single- and double-bulge DNA molecules.


Assuntos
Adenina/química , DNA/química , Conformação de Ácido Nucleico , Sequência de Bases , Transferência de Energia , Fluorescência , Espectroscopia de Ressonância Magnética , Modelos Moleculares , Soluções
16.
Wien Klin Wochenschr ; 111(16): 636-42, 1999 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-10510841

RESUMO

The symptoms and prognosis of patients after myocardial infarction are essentially influenced by left ventricular function. About 50% of infarct related segments contain partly viable myocardium. The aim of this study was to test the hypothesis that regional and global left ventricular function can be improved by revascularization of infarct related segments with residual myocardial viability. In 15 of 30 consecutive patients, residual viable myocardium was found in the affected segment within 2.2 +/- 1.6 months after AMI. Myocardial viability was estimated by exercise-redistribution-reinjection thallium scintigraphy (SPECT imaging). Rest and exercise radionuclide ventriculography was performed to measure regional and global left ventricular ejection fraction before and after revascularization of the infarct related artery. 10 +/- 3 months after revascularization we observed a significant increase in the regional left ventricular ejection fraction at rest (from 32 +/- 16% to 41 +/- 19%; p = 0.03), global left ventricular ejection fraction at rest (from 38 +/- 12% to 46 +/- 11%; p = 0.01), regional LV ejection fraction during exercise (from 34 +/- 16% to 46 +/- 20%; p = 0.01), and global left ventricular ejection fraction during exercise (from 38 +/- 14% to 49 +/- 14%; p = 0.02). The results show that after revascularization of infarct related segments with residual myocardial viability, the regional and global left ventricular ejection fraction may be significantly improved, both at rest and during exercise. Thus infarct related segments should be tested for residual viability. In its presence revascularization is recommended, as the left ventricular function may be markedly improved.


Assuntos
Infarto do Miocárdio/diagnóstico por imagem , Revascularização Miocárdica/métodos , Disfunção Ventricular Esquerda/diagnóstico por imagem , Idoso , Feminino , Coração/diagnóstico por imagem , Humanos , Masculino , Pessoa de Meia-Idade , Miocárdio/metabolismo , Tomografia Computadorizada de Emissão de Fóton Único , Disfunção Ventricular Esquerda/etiologia
17.
Wien Klin Wochenschr ; 111(6): 219-25, 1999 Mar 26.
Artigo em Alemão | MEDLINE | ID: mdl-10234775

RESUMO

Clinical examinations and imaging methods are not sufficiently reliable for an exact staging of axillary nodes in breast cancer. The sentinel node biopsy concept is a minimally invasive procedure to locate and remove the first and important nodes responsible for draining a tumor. Histologic examinations using immunohistochemical methods permit more accurate staging than hematoxylin and eosin staining alone. Between 4/1997 and 9/1998 a total of 62 patients with 65 breast cancers underwent surgery. The sentinel node procedure with radio tracers and/or blue dye was performed in patients with clinically negative or unclear positive findings in the axilla, with a primary tumor size less than 5 cm; 11 patients had received preoperative chemotherapy. The sentinel node biopsy was followed by axillary dissection in 44 cases. In 58 (89%) cases we found one or more (on an average 1.4) sentinel nodes with radio tracers (in 73%) and/or the blue dye method (in 85%). Axillary nodal status was correctly predicted in 43 of 44 (97.7%) cases; only in one patient was the sentinel node false negative. After preoperative chemotherapy sentinel nodes were found in 9 cases; all of these were predictive. Micrometastases were found in two patients only after cytokeratine staining. Our results concur with the experience of other study groups in regard of sentinel node biopsy. The sentinel node concept is a fascinating method; its importance in breast cancer treatment appears to be comparable with introduction of breast saving surgery in the 1980's.


Assuntos
Neoplasias da Mama/patologia , Neoplasias da Mama/cirurgia , Linfonodos/patologia , Linfonodos/cirurgia , Adulto , Idoso , Idoso de 80 Anos ou mais , Axila/patologia , Axila/efeitos da radiação , Axila/cirurgia , Biópsia/métodos , Feminino , Humanos , Imuno-Histoquímica , Queratinas , Linfonodos/efeitos da radiação , Metástase Linfática/diagnóstico , Metástase Linfática/patologia , Pessoa de Meia-Idade , Procedimentos Cirúrgicos Minimamente Invasivos/métodos , Estadiamento de Neoplasias , Compostos Radiofarmacêuticos
19.
J Biol Chem ; 274(11): 6957-62, 1999 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-10066749

RESUMO

Sequence-dependent structural features of the DNA double helix have a strong influence on the base pair opening dynamics. Here we report a detailed study of the kinetics of base pair breathing in tracts of GC base pairs in DNA duplexes derived from 1H NMR measurements of the imino proton exchange rates upon titration with the exchange catalyst ammonia. In the limit of infinite exchange catalyst concentration, the exchange times of the guanine imino protons of the GC tracts extrapolate to much shorter base pair lifetimes than commonly observed for isolated GC base pairs. The base pair lifetimes in the GC tracts are below 5 ms for almost all of the base pairs. The unusually rapid base pair opening dynamics of GC tracts are in striking contrast to the behavior of AT tracts, where very long base pair lifetimes are observed. The implication of these findings for the structural principles governing spontaneous helix opening as well as the DNA-binding specificity of the cytosine-5-methyltransferases, where flipping of the cytosine base has been observed, are discussed.


Assuntos
Pareamento de Bases , Sequência de Bases , DNA , Espectroscopia de Ressonância Magnética , Prótons , Espectrofotometria Infravermelho
20.
Wien Klin Wochenschr ; 110(13-14): 479-84, 1998 Jul 31.
Artigo em Alemão | MEDLINE | ID: mdl-9746961

RESUMO

BACKGROUND: Malignant hemangioendothelioma of the thyroid is a rare tumor predominantly described in areas with endemic goiter like the Alpine regions. The estimated incidence of the disease is between 0.15 and 0.25 per 100,000 inhabitants per year for Western Austria. The prognosis is reported to be dismal. MATERIALS AND METHODS: Between 1982 and 1995, 10 cases with immunohistochemically confirmed malignant hemangioendotheliomas of the thyroid were referred to our department for postoperative or palliative treatment. Two patients with clear margins at surgery received no adjuvant radiotherapy and were only observed. By surgery, clear margins (R-0 resection) were achieved in 5, microscopic residuals (R-1) were left in 3, and gross residual disease in 1 patient. One patient had an inoperable primary tumor. Postoperative radiotherapy was administered in 6 cases, 4 of them additionally received the radiosensitizer razoxane. Total tumor doses ranged between 58 and 65 Gy. RESULTS: Local tumor control was achieved in 9 of 10 patients; 4 of 10 lived longer than 4 years. The median survival time has not yet been reached and is presently between 7.5 and 21+ months.--Noteworthy is a complete regression of 2 lung metastases in a 72-year-old man by a combination of vindesine, razoxane and radiotherapy. The patient is still in complete remission under a maintenance therapy with vindesine and razoxane since 14 months.--It may also be of interest that 4 of the 10 patients were strongly exposed to vinyl chloride and other polymeric materials during their occupational life. CONCLUSIONS: This small series may indicate that the outcome of this disease may not be uniformly deleterious, and that the resistance to radiotherapy reported in the literature may be questioned.--The data offer new evidence of the occurrence of vinyl chloride-induced angiosarcomas outside the liver, and support observations which have already been published in case reports.


Assuntos
Hemangioendotelioma/cirurgia , Neoplasias da Glândula Tireoide/cirurgia , Idoso , Terapia Combinada , Feminino , Seguimentos , Hemangioendotelioma/mortalidade , Hemangioendotelioma/patologia , Hemangioendotelioma/radioterapia , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Radioterapia Adjuvante , Taxa de Sobrevida , Glândula Tireoide/patologia , Neoplasias da Glândula Tireoide/mortalidade , Neoplasias da Glândula Tireoide/patologia , Neoplasias da Glândula Tireoide/radioterapia
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