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1.
Clin Radiol ; 69(6): e247-52, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24594378

RESUMO

AIM: To evaluate the outcome of percutaneous cholecystostomy in critically ill patients with acute cholecystitis. MATERIALS AND METHODS: The study group included critically ill patients who underwent percutaneous cholecystostomy for acute cholecystitis at a tertiary medical centre in 2007-2011. Data on complications, morbidities, surgical outcome, and imaging findings were collected from the medical files and radiology information system. RESULTS: There were 48 women (59.3%) and 33 men (40.7%), with a median age of 82 years (range 47-99 years). Seventy-one (88%) had calculous cholecystitis and 10 (12%), acalculous cholecystitis. The drain was successfully inserted in all cases with no immediate major procedural complications. Fifteen patients (18.5%) died in-hospital within 30 days, mainly (93%) due to septic shock (14/15), another 20 patients (24.7%) died during the study period of unrelated co-morbidities. Of the remaining 46 patients, 36 (78.2%) had surgical cholecystectomies. In patients with acalculous cholecystitis, the drain was removed after cessation of symptoms. Transcystic cholangiography identified five patients with additional stones in the common bile duct. They were managed by pushing the stones into the duodenum via the cystostomy access, sparing them the need for surgical exploration. CONCLUSIONS: Early percutaneous gallbladder drainage is safe and effective in critically ill patients in the acute phase of cholecystitis, with a high technical success rate. Surgical results in survivors are better than reported in patients treated surgically without drainage. Bile duct stones can be eliminated without creating an additional access.


Assuntos
Colecistite Aguda/cirurgia , Colecistostomia/métodos , Idoso , Idoso de 80 Anos ou mais , Colecistite Aguda/diagnóstico por imagem , Colecistostomia/efeitos adversos , Estado Terminal , Drenagem/métodos , Feminino , Cálculos Biliares/cirurgia , Humanos , Tempo de Internação , Masculino , Pessoa de Meia-Idade , Radiografia , Estudos Retrospectivos , Sepse/cirurgia , Resultado do Tratamento
2.
Phlebology ; 29(1): 16-24, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23202139

RESUMO

OBJECTIVES: We tested a novel technique to treat great saphenous vein (GSV) incompetence in an animal model. METHODS: V-block (VVT Medical Ltd, Kfar Saba, Israel), an occlusion device composed of a nitinol frame and anchoring hooks, was percutaneously deployed at the saphenofemoral junction in 12 sheep. Four of the 12 sheep were treated with adjunctive liquid sclerotherapy. Animals underwent duplex ultrasound, venography and histopathological evaluation immediately postimplantation at 30, 60 and 90 days. RESULTS: V-block was successfully deployed in all animals without adverse events. There was no device migration at follow-up. Histopathological analysis demonstrated V-block to be lodged within the GSV and surrounded by fibrous tissue in all samples. Obliteration of the GSV lumen, widespread intimal loss and multifocal medial smooth muscle loss was noted. CONCLUSIONS: In this animal study V-block was deployed without complications, remained in stable position and led to GSV occlusion. This device has promise for future use in humans.


Assuntos
Ablação por Cateter/instrumentação , Veia Safena/cirurgia , Insuficiência Venosa/cirurgia , Animais , Ablação por Cateter/métodos , Modelos Animais de Doenças , Desenho de Equipamento , Veia Femoral/cirurgia , Flebografia , Projetos Piloto , Veia Safena/patologia , Soluções Esclerosantes/administração & dosagem , Ovinos , Seringas , Resultado do Tratamento , Ultrassonografia , Insuficiência Venosa/patologia
3.
Cardiovasc Intervent Radiol ; 30(2): 273-5, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17171307

RESUMO

PURPOSE: To report our experience with the Angioseal vascular closure device for hemostasis of distal brachial artery puncture. METHODS: Between September 2003 and August 2005, 64 Angioseal vascular closure devices were inserted in 64 patients (40 men, 24 women; mean age 65 years) immediately after diagnostic or therapeutic arterial angiographies performed through a 5 Fr to 7 Fr sheath via the distal brachial artery. Ultrasound examination of the brachial artery preceded the angiography in all cases and only arteries wider than 4 mm were closed by the Angioseal. In cases of a sonographically evident thin subcutaneous space of the cubital fossa, tissue tumescence, using 1% Lidocaine, was performed prior to the arterial closure. RESULTS: The deployment success rate was 100%. No major complications were encountered; only 2 patients developed puncture site hematoma, and these were followed conservatively. CONCLUSIONS: Closure of low brachial artery punctures with the Angioseal is simple and safe. No additional manual compression is required. We recommend its use after brachial artery access interventions, through appropriately wide arteries, to improve early patient ambulation and potentially reduce possible puncture site complications.


Assuntos
Artéria Braquial/cirurgia , Colágeno/uso terapêutico , Hemostasia Cirúrgica/métodos , Punções/instrumentação , Adulto , Idoso , Idoso de 80 Anos ou mais , Desenho de Equipamento , Segurança de Equipamentos , Feminino , Seguimentos , Hematoma/etiologia , Humanos , Masculino , Pessoa de Meia-Idade , Punções/efeitos adversos , Resultado do Tratamento , Doenças Vasculares/cirurgia , Procedimentos Cirúrgicos Vasculares
4.
Cardiovasc Intervent Radiol ; 27(4): 335-8, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15346208

RESUMO

We report our experience with percutaneous balloon dilatation (PBD) for the treatment of ureteral strictures in patients with renal allografts. Of the 422 consecutive patients after renal transplantation in our center 10 patients had ureteral strictures. An additional 11 patients were referred from other centers. The 21 patients included 15 men and 6 women aged 16 to 67 years. Strictures were confirmed by sonography and scintigraphy in all cases. Patients underwent 2 to 4 PBDs at 7-10-day intervals. Clinical success was defined as resolution of the stenosis and hydronephrosis on sequential ultrasound and normalization of creatinine levels. Patients were divided into two groups: those who underwent transplantation more than 3 months previously and those who underwent transplantation less than 3 months previously. PBD was successful in 13 of the 21 patients (62%). There was no statistically significant difference in success rate between the patients with early (n = 12) and those with late (n = 9) obstruction: 58.4% and 66%, respectively. No major complications were documented. PBD is a safe and simple tool for treating ureteral strictures and procedure-related morbidity is low. It can serve as an initial treatment in patients with early or late ureteral strictures after renal transplantation.


Assuntos
Cateterismo , Transplante de Rim/efeitos adversos , Obstrução Ureteral/terapia , Adolescente , Adulto , Idoso , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Tempo , Resultado do Tratamento , Obstrução Ureteral/etiologia
5.
Urology ; 62(4): 647-50, 2003 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-14550435

RESUMO

OBJECTIVES: To appraise detrusor blood flow by Doppler ultrasonography in men with suspected bladder outlet obstruction (BOO) to determine whether this imaging technique provides useful information for the assessment of BOO. Experimental studies have shown that BOO is associated with reduced blood flow to the detrusor. METHODS: Twenty-nine consecutive men with lower urinary tract symptoms were prospectively enrolled. A urodynamic pressure-flow study was performed by the urologist to determine BOO, and Doppler ultrasonography was subsequently performed by the radiologist. The physicians were unaware of the other's results. Scanning was performed on a filled and empty bladder. Arterial blood flow was measured at three distinct sites, the two lateral walls and the trigone, and the resistive index (RI) of each site was calculated (RI = (V(MAX) - V(MIN))/V(MAX)). For each patient, the arithmetic average of the three RIs was defined as the detrusor RI. The findings were compared between patients with and without evidence of BOO. A logistic regression model tested the predictive value of the RI. RESULTS: According to the pressure-flow study results, 22 (75%) and 7 (25%) of the 29 patients were diagnosed as having or not having BOO, respectively. A statistically significant difference was found between the detrusor RI in the obstructed versus nonobstructed patients in both full (P <0.001) and empty (P <0.03) bladder states (0.79 versus 0.68 and 0.74 versus 0.66, respectively). Our logistic regression model predicted BOO with an overall accuracy of 86%, positive predictive value of 95%, and negative predictive value of 57%. CONCLUSIONS: The RI of arterial blood flow in the detrusor measured by Doppler ultrasonography provides important predictive information for the presence of BOO. Additional studies are warranted to validate our results and explore the role of Doppler ultrasonography in the management paradigms of patients with suspected BOO.


Assuntos
Obstrução do Colo da Bexiga Urinária/diagnóstico por imagem , Idoso , Estudos de Coortes , Método Duplo-Cego , Humanos , Masculino , Pessoa de Meia-Idade , Músculo Liso/irrigação sanguínea , Projetos Piloto , Estudos Prospectivos , Fluxo Sanguíneo Regional , Ultrassonografia Doppler em Cores , Bexiga Urinária/diagnóstico por imagem , Urodinâmica
6.
Harefuah ; 141(2): 132-4, 224, 2002 Feb.
Artigo em Hebraico | MEDLINE | ID: mdl-11905080

RESUMO

The anomalous origin of the left coronary artery can lead to angina pectoris, acute myocardial infarction or even sudden death, especially during exercise. We present a patient in whom the anomalous origin of the left coronary artery is from the right sinus of Valsalva, crossing between the aorta and the pulmonary trunk and causing ischemic chest pain. The anomaly was verified by a Spiral CT, as the coronary angiographic findings were not conclusive, particularly regarding the left course in relation to the major arteries. We suggest that Spiral CT is useful for detecting this kind of anomaly, particularly in clarifying the relationship between the left main coronary artery and the major arteries.


Assuntos
Angina Pectoris/etiologia , Anomalias dos Vasos Coronários/diagnóstico por imagem , Adulto , Angina Pectoris/diagnóstico por imagem , Anomalias dos Vasos Coronários/complicações , Humanos , Masculino , Infarto do Miocárdio/diagnóstico por imagem , Infarto do Miocárdio/etiologia , Tomografia Computadorizada por Raios X
7.
Isr Med Assoc J ; 3(10): 719-21, 2001 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11692543

RESUMO

BACKGROUND: Leiomyoma is the common benign tumor of the female genital tract. The traditional treatment is hysterectomy, myomectomy or medical therapy by hormonal manipulation. Uterine arterial embolization, a recognized treatment for acute pelvic hemorrhage, has recently been applied to the management of non-acute uterine hemorrhage due to leiomyoma. OBJECTIVES: To describe our experience with uterine arterial embolization for the management of uterine fibroid. METHODS: Uterine arterial embolization was performed in nine patients with leiomyomas in whom medical therapy failed and who sought to avoid surgery. RESULTS: Follow-up ultrasound examination after 2 months revealed an average reduction in fibroid volume of 38%. There were no early or long-term complications. CONCLUSIONS: Uterine arterial embolization appears to be effective and safe in the management of symptomatic leiomyomas. It is a promising alternative to myomectomy or hysterectomy and warrants further investigation in this setting.


Assuntos
Embolização Terapêutica/métodos , Leiomioma/terapia , Neoplasias Uterinas/terapia , Adulto , Angiografia , Feminino , Humanos , Leiomioma/diagnóstico por imagem , Pessoa de Meia-Idade , Satisfação do Paciente , Resultado do Tratamento , Ultrassonografia , Neoplasias Uterinas/diagnóstico por imagem
8.
J Chromatogr A ; 921(1): 3-13, 2001 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-11461010

RESUMO

In the last 10 years mass spectrometry (MS) has become an important method for analysis of peptides, proteins and DNA. It was recently utilized for accurate high-throughput protein identification, sequencing and DNA genotyping. The presence of non-volatile buffers compromises sensitivity and accuracy of MS biopolymer analysis; it is essential to remove sample contaminants prior to analysis. We have developed a fast and efficient method for desalting of DNA oligonucleotides and peptides using 96-well solid-phase extraction plates packed with 5 mg of Waters Oasis HLB sorbent (Waters, Milford, MA, USA). This reversed-phase sorbent retains the biopolymer analytes, while non-retained inorganic ions are washed out with pure deionized water. DNA oligonucleotides or peptides are eluted using a small amount (20-100 microl) of acetonitrile-water (70:30, v/v) solution. The SPE desalting performance meets the requirements for MS applications such as protein digest analysis and DNA genotyping.


Assuntos
Biopolímeros/química , DNA/isolamento & purificação , Espectrometria de Massas por Ionização por Electrospray/métodos , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Cromatografia Líquida de Alta Pressão , Grupo dos Citocromos c/química , Mapeamento de Peptídeos , Sais , Sensibilidade e Especificidade
9.
J Clin Ultrasound ; 29(6): 339-43, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11424099

RESUMO

PURPOSE: We investigated the technique of ultrasound-guided testicular sperm aspiration (USTSA) and compared it with "blind" testicular sperm aspiration (TSA) in patients with nonobstructive azoospermia. METHODS: Thirty-nine consecutive azoospermic men underwent TSA, 16 under sonographic guidance (USTSA group) and 23 with no imaging guidance (TSA group). Clinical and hormonal evaluation and sonography of the scrotum and testes were performed 1-2 days before the procedure. The aspiration was done using short-term general anesthesia. Follow-up consisted of sonographic reexamination of the scrotum and testes immediately and 1 month after the procedure. RESULTS: Intraoperative sonography with power Doppler imaging enabled good visualization of the testicular parenchyma, easy sampling, and avoidance of prominent vessels. Sufficient material was retrieved in 15 USTSA patients (94%) and 19 TSA patients (83%). No patients needed more than 4 hours' ambulatory hospitalization after the procedure. In the remaining 5 patients, aspiration failed to yield sperm, so open biopsy was performed. In those patients, postaspiration surgical exploration revealed subtunical bleeding in 3 patients after TSA but none after USTSA. Late minor complications occurred in 2 patients (13%) in the USTSA group and 7 (30%) in the TSA group. No difference was found between the 2 groups in pregnancy rate in the patients' female partners. CONCLUSIONS: USTSA is a safe and accurate method for sperm retrieval in azoospermic patients.


Assuntos
Oligospermia/diagnóstico por imagem , Oligospermia/patologia , Espermatozoides , Testículo/diagnóstico por imagem , Ultrassonografia de Intervenção/métodos , Adulto , Biópsia , Humanos , Masculino , Escroto/diagnóstico por imagem , Manejo de Espécimes , Injeções de Esperma Intracitoplásmicas , Ultrassonografia Doppler
10.
AJR Am J Roentgenol ; 176(1): 113-5, 2001 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11133547

RESUMO

OBJECTIVE. We describe the sonographic features of focal intratesticular lesions seen in men who underwent sperm retrieval procedures. CONCLUSION. Although many urologists believe that solid intratesticular masses are malignant until proven otherwise, a growing number of benign focal testicular lesions have been described. Awareness of the cause and sonographic appearance of focal abnormalities in men who have undergone testicular aspiration or extraction should help radiologists suggest the correct diagnosis and advise a conservative approach on the basis of close surveillance by serial physical, laboratory, and imaging studies.


Assuntos
Espermatozoides , Neoplasias Testiculares/diagnóstico por imagem , Testículo/diagnóstico por imagem , Testículo/lesões , Coleta de Tecidos e Órgãos/efeitos adversos , Adulto , Diagnóstico Diferencial , Humanos , Masculino , Ultrassonografia
11.
Electrophoresis ; 21(14): 2999-3009, 2000 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11001316

RESUMO

The solutions of linear polymers traditionally used for DNA separation have been employed for the capillary electrophoresis (CE) of diastereomers of chemically modified DNA. The selectivity of diastereomeric separation of the phosphorothioate (PS) and 2'-O-methylated (2-OMe) PS oligonucleotides depends on the nature of the polymer additive in the CE background electrolyte. The selectivity of separation for different polymers increases in the line: linear polyacrylamide < polyethylene glycol < polyvinyl pyrrolidone. The separation of oligomer diastereomers was shown to be primarily based on the hydrophobic interaction with the polymer network that acts as a pseudostationary phase. While lowering the temperature resulted in improved separation, the addition of organic modifiers such as formamide, methanol or acetonitrile counteracts the solute adsorption on the polymer network, and decreases the selectivity of DNA diastereoseparation. The effect of molecular mass and concentration of the polymer on the separation selectivity was investigated.


Assuntos
Cromatografia/métodos , DNA/análise , Eletroforese Capilar/métodos , Animais , DNA/química , Polímeros
13.
Nucleic Acids Res ; 28(9): E43, 2000 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-10756210

RESUMO

As a trial practical application, we have applied optimized microfabricated electrophoresis devices, combined with enzymatic mutation detection methods, to the determination of single nucleotide polymorphism (SNP) sites in the p53 suppressor gene. Using clinical samples, we have achieved robust assays with quality factors as good as conventional electrophoresis in approximately 100 s. This is 10 and 50 times faster than capillary and slab gel electro-phoresis, respectively. The method was highly accurate with an average error of mutation site measurement of only +/-5 bp. No clean-up of the digestion mixtures was needed prior to injection. This greatly simplifies sample handling relative to capillary instruments, which is important for high-throughput screening applications. Following identification, absolute mutation determination of the screened samples was achieved in a second microdevice optimized for four-color DNA sequencing. Total run time was 25 min in this second device and sequencing data were in full agreement with ABI Prism 377 sequencing runs which required 3.5 h. The tandem application of microdevices for location then full characterization of SNPs appears to confirm many of the improvements claimed for future application of microdevices in practical scaled screening for mutational analysis.


Assuntos
Análise Mutacional de DNA/métodos , Eletroforese em Gel de Poliacrilamida/métodos , Análise de Sequência com Séries de Oligonucleotídeos , Polimorfismo de Nucleotídeo Único , DNA Complementar , Endodesoxirribonucleases/metabolismo , Genes p53 , Humanos , Técnicas In Vitro , Miniaturização , Reprodutibilidade dos Testes , Análise de Sequência de DNA/métodos
14.
Tumour Biol ; 20 Suppl 1: 86-93, 1999.
Artigo em Inglês | MEDLINE | ID: mdl-10628414

RESUMO

Epitope mapping analysis was performed on 53 antibodies submitted to the ISOBM TD-3 PSA Workshop. Western blotting and N-terminal amino acid sequencing, using both native and recombinant human prostate-specific antigen (rPSA), identified four different epitope groups for native PSA. Under reducing conditions native PSA was not recognized by 18/53 antibodies suggesting they reacted with conformation-dependent epitopes. Nine other antibodies reacted with a rPSA polypeptide doublet of 34-35 kD corresponding to different rPSA glycoforms. From sequence mapping studies 22/53 antibodies bound epitopes within amino acid residues 25-85, 3/53 antibodies bound to epitopes within residues 86-220, while 10/53 antibodies bound epitopes within residues 221-261. These results indicate that there are multiple immunogenic epitopes localized on the PSA molecule.


Assuntos
Anticorpos Monoclonais/imunologia , Antígeno Prostático Específico/imunologia , Reações Antígeno-Anticorpo , Baculoviridae/metabolismo , Western Blotting , Clonagem Molecular , DNA Complementar/imunologia , Eletroforese em Gel de Poliacrilamida , Mapeamento de Epitopos , Humanos , Masculino , Próstata/imunologia , Antígeno Prostático Específico/genética , Conformação Proteica , Proteínas Recombinantes/genética , Proteínas Recombinantes/imunologia , Sêmen/imunologia , Análise de Sequência de Proteína
15.
Tumour Biol ; 20 Suppl 1: 1-12, 1999.
Artigo em Inglês | MEDLINE | ID: mdl-10628402

RESUMO

Twelve research groups participated in the ISOBM TD-3 Workshop in which the reactivity and specificity of 83 antibodies against prostate-specific antigen (PSA) were investigated. Using a variety of techniques including cross-inhibition assays, Western blotting, BIAcore, immunoradiometric assays and immunohistochemistry, the antibodies were categorized into six major groups which formed the basis for mapping onto two- and three-dimensional (2-D and 3-D) models of PSA. The overall findings of the TD-3 Workshop are summarized in this report. In agreement with all participating groups, three main antigenic domains were identified: free PSA-specific epitopes located in or close to amino acids 86-91; discontinuous epitopes specific for PSA without human kallikrein (hK2) cross-reactivity located at or close to amino acids 158-163; and continuous or linear epitopes shared between PSA and hK2 located close to amino acids 3-11. In addition, several minor and partly overlapping domains were also identified. Clearly, the characterization of antibodies from this workshop and the location of their epitopes on the 3-D model of PSA illustrate the importance of selecting appropriate antibody pairs for use in immunoassays. It is hoped that these findings and the epitope nomenclature described in this TD-3 Workshop are used as a standard for future evaluation of anti-PSA antibodies.


Assuntos
Mapeamento de Epitopos , Antígeno Prostático Específico/imunologia , Anticorpos Monoclonais/química , Reações Cruzadas , Epitopos/imunologia , Humanos , Imuno-Histoquímica , Modelos Moleculares , Estrutura Terciária de Proteína , Terminologia como Assunto
16.
J Chromatogr B Biomed Sci Appl ; 714(1): 13-20, 1998 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-9746230

RESUMO

The effect of phosphorothioate (PS) internucleotide linkages on the stability of phosphodiester oligodeoxyribonucleotides (ODNs) was investigated using 25-mer ODNs containing single or multiple PS backbone modifications. The in vitro stability of the oligomers was measured both in 3'-exonuclease solution and in plasma. For the separation of ODNs, capillary electrophoresis with a replaceable polymer separation matrix was used. As expected, DNA fragments with PS linkages at the 3'-end were found to be more resistant to 3'-exonuclease hydrolysis. Also increasing exonuclease resistance was the non-specific adsorption of phosphorothioate ODNs to enzyme.


Assuntos
Exonucleases/química , Oligodesoxirribonucleotídeos/química , Oligonucleotídeos Antissenso/química , Organotiofosfatos/química , Eletroforese Capilar , Exonucleases/sangue , Produtos do Gene gag/química , HIV-1/química , Humanos , Oligodesoxirribonucleotídeos/sangue , Oligonucleotídeos Antissenso/sangue , Organotiofosfatos/sangue , RNA Viral/química , Espectrofotometria Ultravioleta
17.
J Clin Lab Anal ; 12(4): 242-9, 1998.
Artigo em Inglês | MEDLINE | ID: mdl-9671177

RESUMO

The Bayer Immuno 1 PSA Assay measures free and ACT-complexed PSA on an equimolar basis, although it uses a monoclonal antibody (MM1) for capture and polyclonal antibodies for detection. Competitive inhibition studies using antibodies directed at various epitopes on PSA and PSA-ACT demonstrated that the capture antibody, MM1, does not bind to free PSA simultaneously with antibodies against Epitope E which is exposed only in free PSA. Affinity studies showed that the affinity constants of MM1 for both free PSA and PSA-ACT are similar. One explanation for the properties of MM1 is that it precludes the binding of antibodies to Epitope E due to steric hindrance. Alternatively, the binding of MM1 causes a conformation change within the free PSA molecule, so that Epitope E is altered in a way that causes a loss of binding affinity. The unusual properties of MM1 are responsible for the equimolar response of this monoclonal-polyclonal sandwich assay for free and ACT-complexed PSA.


Assuntos
Anticorpos Monoclonais/imunologia , Anticorpos/imunologia , Antígeno Prostático Específico/análise , alfa 1-Antiquimotripsina/metabolismo , Fosfatase Alcalina/imunologia , Especificidade de Anticorpos , Epitopos , Fluoresceína-5-Isotiocianato , Humanos , Imunoensaio , Antígeno Prostático Específico/imunologia , Antígeno Prostático Específico/metabolismo , Ligação Proteica
18.
Antisense Nucleic Acid Drug Dev ; 8(1): 35-42, 1998 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-9512094

RESUMO

For the enzymatic digestion of a 25-mer phosphorothioate (PS) oligonucleotide, the reaction kinetics was previously determined to be the sum of two parallel processes: a fast and a very slow phase of digestion suggesting a two-exponential model. A characteristic metabolite profile was observed both in vitro and in vivo. This behavior is shown to be the result of the stereoselective cleavage of chiral R-configuration and S-configuration PS internucleotide linkages by 3'-exonucleases. The stereoselective nature of 3'-exonuclease action was analyzed by reverse-phase HPLC. The separation of eight diastereomers of the tetramer TTCT (5'-3') was used to follow the stereoselective course of exonuclease hydrolysis of PS internucleotide linkages. Degradation of the 25-mer parent compound having a 3' S-terminal internucleotide linkage was calculated to be more than 300 times slower than an analog with a 3'-terminal R-configuration. These results support an approach for protecting antisense oligonucleotides based on the chirality of only the 3'-end internucleotide linkage.


Assuntos
Exonucleases/metabolismo , Oligonucleotídeos/metabolismo , Tionucleotídeos/metabolismo , Hidrólise , Cinética , Estereoisomerismo , Especificidade por Substrato
19.
Nucleic Acids Res ; 25(21): 4219-23, 1997 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-9336449

RESUMO

The progress of antisense DNA therapy demands development of reliable and convenient methods for sequencing short single-stranded oligonucleotides. A method of phosphorothioate antisense DNA sequencing analysis using UV detection coupled to capillary electrophoresis (CE) has been developed based on a modified chain termination sequencing method. The proposed method reduces the sequencing cost since it uses affordable CE-UV instrumentation and requires no labeling with minimal sample processing before analysis. Cycle sequencing with ThermoSequenase generates quantities of sequencing products that are readily detectable by UV. Discrimination of undesired components from sequencing products in the reaction mixture, previously accomplished by fluorescent or radioactive labeling, is now achieved by bringing concentrations of undesired components below the UV detection range which yields a 'clean', well defined sequence. UV detection coupled with CE offers additional conveniences for sequencing since it can be accomplished with commercially available CE-UV equipment and is readily amenable to automation.


Assuntos
DNA Antissenso/química , Eletroforese Capilar/métodos , Análise de Sequência de DNA/métodos , Tionucleotídeos , Raios Ultravioleta , Primers do DNA , DNA Polimerase Dirigida por DNA , Oligodesoxirribonucleotídeos/química , Sensibilidade e Especificidade
20.
Nucleic Acids Res ; 25(18): 3615-20, 1997 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-9278481

RESUMO

The in vitro stability and metabolism of GEM[91, a 25mer phosphorothioate antisense oligonucleotide complementary to the gag mRNA region of HIV-1, was investigated using capillary electrophoresis (CE). The in vitro degradation of the parent compound at 37 degrees C was followed over the course of 120 h in human plasma. A CE method using laser-induced fluorescence detection was able to detect 5'-end intact metabolites including the parent compound extracted from biological fluids. Because the primary metabolic pathway is believed to be via 3'-exonuclease activity, the results of this study were compared with the stability of the compound in a solution containing 3'-exonuclease. The numerical solution of sequential first-order reactions was used to obtain kinetic parameters. Exonuclease digestion of the parent compound, as measured using an automated CE-UV instrument, yielded striking similarities between the two in vitro systems as well as between in vitro and in vivo systems.


Assuntos
Oligonucleotídeos/sangue , Animais , Líquidos Corporais/metabolismo , Produtos do Gene gag/genética , Humanos , Cinética , Oligonucleotídeos/genética
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