RESUMEN
Differential cross sections and photon-beam asymmetries for the γ[over â]pâπ^{-}Δ^{++}(1232) reaction have been measured for 0.7
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The Ï-Λ(1520) interference effect in the γpâK^{+}K^{-}p reaction has been measured for the first time in the energy range from 1.673 to 2.173 GeV. The relative phases between Ï and Λ(1520) production amplitudes were obtained in the kinematic region where the two resonances overlap. The measurement results support strong constructive interference when K^{+}K^{-} pairs are observed at forward angles but destructive interference for proton emission at forward angles. Furthermore, the observed interference effect does not account for the sqrt[s]=2.1 GeV bump structure in forward differential cross sections for Ï photoproduction. This fact suggests possible exotic structures such as a hidden-strangeness pentaquark state, a new Pomeron exchange, or rescattering processes via other hyperon states.
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The exclusive reaction γpâK(+)π(-)Σ(+) was measured for the first time using linearly polarized photons at beam energies from 1.85 to 2.96 GeV. Angular distributions in the rest frame of the K(+)π(-) system were fitted to extract spin-density matrix elements of the K(*0) decay. The measured parity spin asymmetry shows that natural-parity exchange is dominant in this reaction. This result clearly indicates the need for t-channel exchange of the κ(800) scalar meson.
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Adjunctive balloon dilatation strategy has been shown to improve optimal stent deployment. As improvements in current stent designs evolve, less adjunctive balloon dilatation may be needed. However, few data currently exist to support this practice. We evaluated 88 native coronary lesions treated with single stent implantation (Nir, Tristar or S670). Serial intravascular ultrasound was performed after successful stent deployment and again after adjunctive balloon dilatation. To investigate further the precise expansion characteristics of the stents, serial volumetric intravascular ultrasound analyses were performed in 40 patients with automated pullback. After adjunctive balloon dilatation, minimal stent area increased significantly, from 6.4 +/- 2.1 to 7.4 +/- 2.2 mm(2) (p <0.001). Volumetric analysis showed a corresponding increase in stent volume index (6.6 +/- 1.8 to 7.5 +/- 2.0 mm(3)/mm, p <0.001). In the analysis of cross sections at 0.5-mm axial intervals, the percentage of cross sections, where stent area was > or =80% of the average reference lumen area, increased from 51% to 78% (p <0.001). Similarly, the percentage of cross sections, where stent area was > or =90% of the average reference lumen area, increased from 29% to 56% (p <0.001) with postdilatation. Postdeployment high- pressure balloon dilatation improved minimal stent area and volumetric expansion throughout the stented segment.
Asunto(s)
Angioplastia Coronaria con Balón , Enfermedad Coronaria/terapia , Stents , Enfermedad Coronaria/diagnóstico por imagen , Femenino , Humanos , Masculino , Persona de Mediana Edad , Resultado del Tratamiento , UltrasonografíaRESUMEN
With the advent of intravascular brachytherapy (IVBT), a striking reduction in the rate of restenosis has been observed. The use of intravascular ultrasound (IVUS) during IVBT trials has shown many aspects and relevant pathophysiologic mechanisms following this practical therapy. Specifically, IVUS quantitative assessments have demonstrated a drastic inhibition of both neointimal formation and negative remodeling to be the predominant vascular response to IVBT. Moreover, IVBT has shown promise for challenging high-risk restenosis cases, such as patients with diabetes mellitus and smaller caliber target vessels. However, unexpected radiation-induced complications have also been discovered, as more patients have been treated for a broad class of lesion subsets. Edge effect, induced by catheter-based radiation, was seen to be due to geographic miss of the radiation source, advocating a new concept known as "radiation edge". Furthermore, late thrombosis, which is known to be strongly associated with new stent implantation following IVBT, may be avoided with novel antiplatelet agents. Two additional complications, whose clinical significance remains unclear, are unhealed dissection and late stent malapposition featured by IVUS qualitative assessment. Unhealed dissection was observed in half of radiated dissections and late stent malapposition has been seen for all radiation sources in a small percentage of cases at 6-12 months follow-up. Radiation sources, dosimetry, and delivery methods continue to improve and should ultimately translate to more effective treatment for the patient with atherosclerotic coronary disease.
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Braquiterapia , Oclusión de Injerto Vascular/diagnóstico por imagen , Oclusión de Injerto Vascular/prevención & control , Oclusión de Injerto Vascular/radioterapia , Humanos , Ultrasonografía IntervencionalRESUMEN
OBJECTIVES: The study was done to elucidate the relationship between baseline arterial remodeling and clinical outcome following stenting. BACKGROUND: The impact of preintervention arterial remodeling on subsequent vessel response and clinical outcome has been reported following nonstent coronary interventions. However, in stented segments, the impact of preintervention remodeling on clinical outcome has not been clarified. METHODS: Preintervention remodeling was assessed in 108 native coronary lesions by using intravascular ultrasound (IVUS). Positive remodeling (PR) was defined as vessel area (VA) at the target lesion greater than that of average reference segments. Intermediate or negative remodeling (IR/NR) was defined as VA at the target lesion less than or equal to that of average reference segment. Remodeling index expressed as a continuous variable was defined as VA at the target lesion site divided by that of average reference segments. RESULTS: Positive remodeling was present in 59 (55%) and IR/NR in 49 (45%) lesions. Although final minimal stent areas were similar (7.76 +/- 1.80 vs. 8.09 +/- 1.90 mm2, p = 0.36), target vessel revascularization (TVR) rate at nine-month follow-up was significantly higher in the PR group (22.0% vs. 4.1%, p = 0.01). By multivariate logistic regression analysis, higher remodeling index was the only independent predictor of TVR (p = 0.02). CONCLUSIONS: Lesions with PR before intervention appear to have a worse clinical outcome following IVUS-guided stenting. Intravascular ultrasound imaging before stenting may be helpful to stratify lesions at high risk for accelerated intimal proliferation.
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Enfermedad Coronaria/terapia , Vasos Coronarios/fisiopatología , Stents , Ultrasonografía Intervencional , Arterias/diagnóstico por imagen , Arterias/fisiopatología , Angiografía Coronaria , Enfermedad Coronaria/diagnóstico por imagen , Enfermedad Coronaria/fisiopatología , Vasos Coronarios/diagnóstico por imagen , Femenino , Humanos , Masculino , Persona de Mediana Edad , RecurrenciaRESUMEN
BACKGROUND: Cilostazol is an antiplatelet agent that increases the intracellular concentration of cyclic adenosine monophosphate by inhibiting phosphodiesterase III; it has been shown to reduce neointimal hyperplasia in animal balloon injury models. METHODS: One hundred thirty patients who underwent elective stenting (Palmaz-Schatz stent) were randomly assigned to cilostazol treatment 200 mg/d (n = 65) or to ticlopidine treatment 200 mg/d (n = 65). Angiographic follow-up was performed at 6 months, and clinical follow-up was continued up to 1 year. RESULTS: One sudden death and one myocardial infarction resulting from subacute occlusion were observed in the ticlopidine group. Drug adverse effects were observed in 3 patients in the cilostazol group, as opposed to 6 patients in the ticlopidine group. In the intention-to-treat analysis, 56 patients (61 lesions) in the cilostazol group and 58 patients (58 lesions) in the ticlopidine group were assessed with quantitative coronary angiography. Late loss in the cilostazol group was smaller (0.58+/-0.52 mm vs. 1.09+/-0.65 mm, P<.0001) than in the ticlopidine group. The restenosis rate was lower in the cilostazol group than in the ticlopidine group (16% vs. 33%, P = .044). The target vessel revascularization rate at 1 year was 23% in the cilostazol group and 42% in the ticlopidine group (P =.03). CONCLUSIONS: The results of this study suggest that cilostazol may be a safe medication that is effective in preventing restenosis after stent implantation.
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Enfermedad Coronaria/terapia , Inhibidores de Agregación Plaquetaria/uso terapéutico , Stents , Tetrazoles/uso terapéutico , Ticlopidina/uso terapéutico , Cilostazol , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Análisis Multivariante , Estudios Prospectivos , Recurrencia , Análisis de Regresión , Factores de TiempoRESUMEN
A 78-year-old woman with renal cell carcinoma and pulmonary metastasis presented with reversible cardiomyopathy induced by gamma(gamma)-interferon. She was treated with gamma-interferon twice a week since November 1996. She presented with severe acute congestive heart failure and gamma-interferon was immediately discontinued in December 1997. Left ventricular fractional shortening was 38% before admission, 12% on admission, and improved to 31% by 40 days after discontinuation of interferon together with administration of diuretics and angiotensin converting enzyme inhibitor. We restarted the same gamma-interferon regimen because it was effective against renal cell carcinoma after 47 days. She has remained well with no significant changes of cardiac function or renal cell carcinoma for almost one year.
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Carcinoma de Células Renales/terapia , Cardiomiopatías/etiología , Interferón gamma/efectos adversos , Neoplasias Renales/terapia , Anciano , Carcinoma de Células Renales/patología , Carcinoma de Células Renales/secundario , Femenino , Humanos , Neoplasias Renales/patología , Neoplasias Pulmonares/secundario , Proteínas RecombinantesRESUMEN
The present study retrospectively investigated cerebral complications of coronary artery bypass grafting in 205 consecutive patients aged 70 years or older, who underwent elective cardiopulmonary bypass from 1990 to 1997. Computed tomography of the brain and chest was done before surgery. Ten patients had so-called 'aortic no-touch surgery' and suffered no cerebral complications; the other 195 patients had conventional surgery. Adverse cerebral events occurred in 8.7%, including cerebral infarction (4.1%), diffuse encephalopathy (1.0%), convulsions (1.0%), transient disturbance of consciousness (1.0%), and severe loss of volition (1.5%). Multivariate analysis showed that only the detection of calcification of the ascending aorta was significantly associated with cerebral complications (p = 0.029). Total clamping tended to be superior to partial clamping for prevention of cerebrovascular accidents. The mortality rate was 7.3%. In-hospital death was related to age (p = 0.0062), cerebral complications (p = 0.0032), and a low left-ventricular function (p = 0.018). Therefore, chest computed tomography to assess the ascending aorta should be performed preoperatively. Modified techniques like aortic no-touch surgery or other therapies combined with coronary intervention may be needed in elderly patients with severe calcification of the ascending aorta.
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Encéfalo/diagnóstico por imagen , Infarto Cerebral/diagnóstico por imagen , Puente de Arteria Coronaria/efectos adversos , Complicaciones Posoperatorias/diagnóstico por imagen , Tomografía Computarizada por Rayos X , Anciano , Calcinosis/diagnóstico por imagen , Infarto Cerebral/etiología , Femenino , Humanos , Masculino , Pronóstico , Estudios Retrospectivos , Factores de RiesgoRESUMEN
A 75-year-old man presented with palpitations due to atrial flutter. Transthoracic echocardiography revealed a mobile aortic valve mass (17 mm in diameter) attached to the non-coronary cusp of the aortic valve. There was no evidence of hypercoagulative state. Computed tomography showed old cerebral infarction in the territory supplied by the right middle cerebral artery. The mass was surgically resected. The aortic valve was preserved because there were no organic changes in the valve. Histological examination demonstrated an organized thrombus. Only three cases of thrombus attached to the normal native aortic valve have been reported. Native aortic valve thrombus may be important in the differential diagnosis of aortic valve mass.
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Válvula Aórtica , Ecocardiografía , Trombosis/diagnóstico por imagen , Anciano , Válvula Aórtica/cirugía , Ecocardiografía Transesofágica , Enfermedades de las Válvulas Cardíacas/diagnóstico por imagen , Enfermedades de las Válvulas Cardíacas/cirugía , Humanos , Masculino , Trombosis/cirugíaRESUMEN
An arbitrarily primed polymerase chain reaction (AP-PCR) DNA profile was applied to epidemiological analysis of Salmonella enterica subsp. enterica serovar Enteritidis. A total 21 strains of S. Enteritidis isolated from 21 cases (10 cases of healthy persons, 7 cases of food poisoning outbreaks and 4 sporadic diarrhea cases), during the period between December 1991 and August 1996 in Wakayama City, were used. A total of 60 arbitrary primers (DNA oligomer (12) set, Wako) were screened with 4 S. Enteritidis strains of different cases. A-11, B-32, C-42 and C-45 primers were chosen. Plasmid DNA profiles, antimicrobial susceptibility patterns and phage types were also examined. The combination of these three methods resolved the collection into five groups (A to E). And type C strains were found in 17 cases (81%) out of 21 cases. However, according to AP-PCR DNA profile, all 21 strains were classified into six groups (I to VI), and 17 type C strains were classified into three groups (III, IV and V). Type IV was predominant in Wakayama City, and type C.IV was found in 15 cases (71%). In conclusion, we considered that AP-PCR DNA profile using appropriate primers was an effective epidemiological marker.
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Intoxicación Alimentaria por Salmonella/microbiología , Salmonella enteritidis/aislamiento & purificación , Antibacterianos/farmacología , Tipificación de Bacteriófagos , Cartilla de ADN , Brotes de Enfermedades , Farmacorresistencia Microbiana , Humanos , Japón/epidemiología , Plásmidos , Reacción en Cadena de la Polimerasa , Intoxicación Alimentaria por Salmonella/epidemiología , Salmonella enteritidis/clasificación , Salmonella enteritidis/efectos de los fármacosRESUMEN
A case of hyperglycemia induced by the injection of interferon-alpha was experienced in our hospital. This patient showed a sustained high titer of anti-GAD antibody after the onset of diabetes, suggesting that the involvement of immunological disturbance by IFN induces the onset of the disease. However, the susceptibility and the response of the immune system differs from patient to patient, and only limited destruction of beta-cells in the islet of Langerhans and normalization of glucose tolerance by CSII was induced in this patient.
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Antivirales/efectos adversos , Diabetes Mellitus Tipo 1/etiología , Glutamato Descarboxilasa/inmunología , Hepatitis Crónica/tratamiento farmacológico , Interferón-alfa/efectos adversos , Antivirales/uso terapéutico , Glucemia/análisis , Glucemia/metabolismo , Femenino , Estudios de Seguimiento , Prueba de Tolerancia a la Glucosa , Glutamato Descarboxilasa/efectos de los fármacos , Hepatitis Crónica/sangre , Hepatitis Crónica/inmunología , Humanos , Hipoglucemiantes/administración & dosificación , Hipoglucemiantes/sangre , Hipoglucemiantes/uso terapéutico , Infusiones Parenterales , Insulina/administración & dosificación , Insulina/sangre , Insulina/uso terapéutico , Interferón-alfa/uso terapéutico , Persona de Mediana Edad , Proteínas Recombinantes/administración & dosificación , Proteínas Recombinantes/efectos adversosRESUMEN
Continuing a previous investigation (Kintanar, A., Metzler, C. M., Metzler, D. E., and Scott, R. D. (1991) J. Biol. Chem. 266, 17222-17229), we have recorded 1H NMR spectra at 500 MHz in the 10-18-ppm range for the 93-kDa porcine cytosolic aspartate aminotransferase and for four specific mutant forms of the enzyme in which histidine 68 has been replaced by lysine or histidine 143, 189, or 193 has been replaced by glutamine. We have correlated resonances for apoenzyme, pyridoxamine and pyridoxal phosphate forms, and dicarboxylate complexes and have assigned imidazole NH resonances of active site histidines. The chemical shifts of several resonances undergo pH-dependent changes around the pKa of the Schiff base proton at the active site. Other resonances shift upon binding of dicarboxylates or other ligands. Phosphate or carboxylate ions, which can also occupy the site of the substrate's alpha-carboxylate, cause rapid exchange of the Schiff base proton. Although most resonances in the 10-18-ppm range disappear rapidly in D2O, a few are retained for months in the presence of the dicarboxylate inhibitor glutarate. We demonstrate that changes in chemical shifts and in exchange rates are sensitive indicators of electronic interactions of the enzyme with ligands and of conformational change. Nuclear Overhauser effects from NH protons have allowed us to identify resonances of CH protons of the imidazole rings of histidines 143, 189, and 193. Observed and predicted chemical shifts have been compared. We conclude that the net charge on this histidine cluster is zero but that some negative charge from the aspartate 222 carboxylate is donated inductively into the histidine 143 ring. Studies of the related enzyme from Escherichia coli are provided in an accompanying paper (Metzler, D. E., Metzler, C. M., Scott, R. D., Mollova, E. T., Kagamiyama, H., Yano, T., Kuramitsu, S., Hayashi, H., Hirotsu, K., and Miyahara, I. (1994) J. Biol. Chem. 269, 28027-28033). Our approach should be applicable to the study of active sites of a broad range of relatively large proteins.
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Aspartato Aminotransferasas/química , Conformación Proteica , Secuencia de Aminoácidos , Animales , Aspartato Aminotransferasas/biosíntesis , Aspartato Aminotransferasas/aislamiento & purificación , Secuencia de Bases , Clonación Molecular , Citosol/enzimología , Cartilla de ADN , Glutamina , Histidina , Hidrógeno , Enlace de Hidrógeno , Lisina , Espectroscopía de Resonancia Magnética/métodos , Datos de Secuencia Molecular , Mutagénesis Sitio-Dirigida , Mutación Puntual , Fosfato de Piridoxal , Proteínas Recombinantes/biosíntesis , Proteínas Recombinantes/química , Proteínas Recombinantes/aislamiento & purificación , Sensibilidad y Especificidad , PorcinosRESUMEN
The functional roles of Val37 and Gly38 in porcine cytosolic aspartate aminotransferase have been studied in the site-directed mutants V37A, G38A, and G38S where the size and hydrophobic character of these residues has been altered. Previous x-ray studies have shown that Val37 and Gly38, which are part of a flexible loop, interact directly with bound substrate. From x-ray and solution experiments we find that the V37A, G38A, and G38S mutations do not cause significant perturbations to the unliganded enzyme. Replacing Val37 with a less bulky alanine residue does not affect the maximal catalytic rate (kcat), but it does increase significantly the Michaelis constants for substrates in the overall transamination reaction between aspartate and 2-oxoglutarate. On the other hand, replacing Gly38 with alanine or serine results in striking decreases in kcat to 5 and 0.6%, respectively, of the value observed for the wild-type enzyme, as well as in considerable increases in Km values. Consequently, the catalytic competence, kcat/Km, decreases by 3 orders of magnitude for G38A and by 4 orders of magnitude for G38S. Single turnover reactions of G38A and G38S with four individual substrates (aspartate, glutamate, oxalacetate, and 2-oxoglutarate) are characterized by kinetic parameters that are largely consistent with those of the overall reaction. In addition, the mutations at position 38 impair more seriously the catalytic competence of the enzyme toward C5-substrates than toward C4-substrates. We conclude that Gly38 is probably required for proper function of the enzyme because it permits a high level of flexibility for the 36-39 peptide, which in turn allows the essential substrate-induced movement of the small domain.
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Aspartato Aminotransferasas/metabolismo , Glicina/metabolismo , Valina/metabolismo , Aminas/química , Secuencia de Aminoácidos , Animales , Aspartato Aminotransferasas/química , Aspartato Aminotransferasas/aislamiento & purificación , Secuencia de Bases , Dicroismo Circular , Citosol/enzimología , Cartilla de ADN , Estabilidad de Enzimas , Calor , Datos de Secuencia Molecular , Especificidad por Sustrato , Porcinos , Difracción de Rayos XRESUMEN
A cytochrome P450 was purified from microsomes of Rhodotorula minuta. The optical spectrum of the purified cytochrome was characteristic of a low-spin ferric heme protein. Isovalerate caused a type I spectral change in it. The amino-terminal sequence of the cytochrome was different from those of other known microsomal cytochrome P450s. These results indicate that the cytochrome, which is tentatively named P450rm, is a novel species of cytochrome P450.
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Sistema Enzimático del Citocromo P-450/aislamiento & purificación , Rhodotorula/enzimología , Alquenos/metabolismo , Secuencia de Aminoácidos , Cromatografía en Gel , Cromatografía por Intercambio Iónico , Sistema Enzimático del Citocromo P-450/química , Sistema Enzimático del Citocromo P-450/metabolismo , Electroforesis en Gel de Poliacrilamida , Datos de Secuencia Molecular , Análisis EspectralRESUMEN
A single enzyme isolated from Pseudomonas syringae pv. phaseolicola PK2 simultaneously catalyzed two reactions, namely, the formation of ethylene and succinate from 2-oxoglutarate, at a molar ratio of 2:1. In the main reaction, 2-oxoglutarate was dioxygenated to produce one molecule of ethylene and three molecules of carbon dioxide. In the sub-reaction, both 2-oxoglutarate and L-arginine were mono-oxygenated to yield succinate plus carbon dioxide and L-hydroxyarginine, respectively, the latter being further transformed to guanidine and L-delta 1-pyrroline-5-carboxylate. We propose a dual-circuit mechanism for the entire reaction, in which the binding of L-arginine and 2-oxoglutarate in a Schiff-base structure generates a common intermediate for two reactions.
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Arginina/metabolismo , Etilenos/metabolismo , Ácidos Cetoglutáricos/metabolismo , Liasas/metabolismo , Pseudomonas/enzimología , Succinatos/metabolismo , Cinética , Liasas/aislamiento & purificación , Ácido SuccínicoRESUMEN
The gene for the ethylene-forming enzyme of Pseudomonas syringae pv. phaseolicola PK2 was found to be encoded by an indigenous plasmid, designated pPSP1. The gene for the ethylene-forming enzyme was cloned and expressed in Escherichia coli JM109. Nucleotide sequence analysis of the clone revealed an open reading frame that encodes 350 amino acids (mol. wt. 39,444). In a comparison with other proteins, the homology score for the entire amino-acid sequence of the ethylene-forming enzyme of Pseudomonas syringae versus ethylene-forming enzymes from plants and 2-oxoglutarate-dependent dioxygenases was low. However, functionally significant regions are conserved.
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Escherichia coli/genética , Genes Bacterianos , Liasas/genética , Pseudomonas/enzimología , Pseudomonas/genética , Secuencia de Aminoácidos , Secuencia de Bases , Clonación Molecular , Sondas de ADN , Expresión Génica , Liasas/aislamiento & purificación , Liasas/metabolismo , Datos de Secuencia Molecular , Sondas de Oligonucleótidos , Plásmidos , Proteínas Recombinantes/aislamiento & purificación , Proteínas Recombinantes/metabolismo , Mapeo RestrictivoRESUMEN
A cytosolic protein factor(s) is involved in the import of precursor proteins into mitochondria. PBF (presequence binding factor) is a protein factor which binds to the precursor form (pOTC) of rat ornithine carbamoyltransferase (OTC) but not to the mature OTC, and is required for the mitochondrial import of pOTC. The precursors for aspartate aminotransferase and malate dehydrogenase as well as pOTC synthesized in a reticulocyte lysate were efficiently imported into the mitochondria. However, the precursors synthesized in the lysate depleted for PBF by treatment with pOTC-Sepharose were not imported. Readdition of the purified PBF to the depleted lysate fully restored the import. pOTC synthesized in the untreated lysate sedimented as a complex with a broad peak of around 9 S, whereas pOTC synthesized in the PBF-depleted lysate sedimented at an expected position of monomer (2.5 S). When the purified PBF was readded to the depleted lysate, pOTC sedimented as a complex of about 7 S. In contrast to most mitochondrial proteins, rat 3-oxoacyl-CoA thiolase is synthesized with no cleavable presequence and an NH2-terminal portion of the mature protein functions as a mitochondrial import signal. The thiolase synthesized in the PBF-depleted lysate could be efficiently imported into the mitochondria, and readdition of PBF had little effect on the import. The thiolase synthesized in the untreated, the PBF-depleted, or the PBF-readded lysate sedimented at an expected position of monomer (2.5 S). These observations provide support for the existence of PBF-dependent and -independent pathways of mitochondrial protein import.