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Biomedical subjects

J Guijarro

Publications and source records attributed to J Guijarro.

15 recordsLinked to original sources
PubMed2000

Sonographic diagnosis of a pseudoaneurysm in an intravenous drug abuser.

We report a case of a traumatic pseudoaneurysm and arteriovenous fistula in the groin of a drug abuser. Gray-scale and Doppler sonography were used to establish the diagnosis. Gray-scale sonography revealed an anechoic, ovoid, 7 x 4 cm mass posterior to the right superficial femoral artery, which was displaced anteriorly, with limited visualization of the deep femoral artery. Power Doppler sonography showed complete color filling of the mass, and turbulence was seen on conventional color Doppler sonography. The turbulence was confirmed with pulsed Doppler sonography of the mass. Pulsed Doppler imaging of the right external iliac vein also showed an arterialized spectral flow pattern.

Adult↗
PubMed1998

Segmental arrangement of multiple, partly congenital and partly acquired melanocytic nevi.

A 15 year-old girl presented with numerous congenital melanocytic nevi, occasionally hairy, with a segmental distribution at the left pre-auricular region. On the left side of the back of the neck there were multiple melanocytic nevi with a warty appearance, which had started to appear when she was 5 and which had remained stable from the time she was 10. These lesions had a distribution reminiscent of an epidermal nevus with a pattern similar to Blaschko's lines. On general physical examination there was a moderate degree of idiopathic scoliosis, with a left lumbar curvature. Biopsies were taken from both types of nevus which were diagnosed as congenital compound melanocytic nevus and acquired compound melanocytic nevus respectively. We consider that the segmental distribution of the melanocytic nevi of this patient supports the theory that a genetic defect determined the appearance of both these congenital and acquired lesions.

Adolescent↗
PubMed1993

Specific in vitro guanylylation of a 43-kilodalton membrane-associated protein of Streptomyces coelicolor.

Incubation of [alpha-32P]GTP with cellular extracts or membranes of Streptomyces coelicolor labels a protein of 43 kDa, which was also labeled with [8,5'-3H]GTP but not with [alpha-32P]ATP or [gamma-32P]GTP. Radioactivity remained associated with this protein after boiling in 0.1 N NaOH, but it was dissociated after incubation in 0.1 N HCl or hydroxylamine. Chromatographic analysis of the HCl-dissociated compound showed that GMP was the covalently bound nucleotide. Furthermore, guanylylation appeared to be reversible and to take place by a pyrophosphorylytic mechanism. Guanylylation was more efficient at low temperatures. Several Streptomyces species showed a guanylylated protein with a similar molecular mass.

Bacterial Proteins↗
PubMed1991

Extracellular complementation of a developmental mutation implicates a small sporulation protein in aerial mycelium formation by S. coelicolor.

The filamentous bacterium S. coelicolor differentiates by forming aerial hyphae, which protrude into the air and metamorphose into chains of spores. Aerial hyphae formation is associated with the production of a small, abundant protein, SapB, which is present in a zone around colonies of differentiating bacteria. Production of SapB is impaired in bld mutants, which are blocked in aerial hyphae formation, but not in whi mutants in which spore formation is prevented. We report that aerial hyphae formation by a newly identified bld mutant is restored by juxtaposition of the mutant near colonies of SapB-producing bacteria or by the application of the purified protein near mutant colonies. These observations implicate SapB in aerial mycelium formation and suggest that SapB is a morphogenetic protein that enables hyphae on the surface of colonies to grow into the air.

Bacterial Proteins↗
PubMed1988

Visualizing gene expression in time and space in the filamentous bacterium Streptomyces coelicolor.

Streptomycetes are prokaryotic microorganisms that exhibit a complex, mycelial fungus-like cycle of morphological differentiation. Development involves at least two spatially separated types of cells: the branching hyphae of the substrate mycelium, which penetrate the stratum upon which the colony feeds, and the upwardly protruding hyphae of the aerial mycelium, which undergo metamorphosis into spores. The luciferase-encoding luxA and luxB operon of the luminescent marine bacterium Vibrio harveyi was used as a promoter probe to visualize gene expression in differentiating colonies of Streptomyces coelicolor. Promoters for developmental genes of several kinds gave distinctive temporal and spatial patterns of light emission.

DNA, Bacterial↗
PubMed1988

Promoter determining the timing and spatial localization of transcription of a cloned Streptomyces coelicolor gene encoding a spore-associated polypeptide.

Streptomyces coelicolor is a filamentous, gram-positive bacterium that exhibits a complex cycle of morphological differentiation involving the formation of an aerial mycelium of multinucleoid hyphae which undergo septation to form long chains of spores. We report the identification of two proteins of 13 and 3 kilodaltons, designated SapA and SapB, respectively, that are produced during formation of the aerial mycelium and are found in assocation with purified, mature spores. We cloned the structural gene (sapA) for one of these spore-associated proteins. Nucleotide sequence analysis suggests that the 13-kilodalton polypeptide is derived from a larger pre- or preproprotein containing a leader sequence of 37 amino acids. Nuclease protection-hybridization analysis and experiments using the Vibrio harveyi, luciferase-encoding luxAB operon as a gene tag demonstrated that expression of sapA is controlled from a promoter contained within a region of less than 110 base pairs in length, whose transcription start site is located approximately 50 base pairs upstream from the initiation codon for the sapA open reading frame. Transcription of sapA was induced at the time of appearance of the aerial mycelium, and the level of sapA transcripts was significantly reduced in certain mutants blocked in aerial mycelium (bld) and or spore (whi) formation. As further evidence of the association of sapA transcription with morphological differentiation, experiments in which we monitored sapA transcription topographically by use of a sapA-luxAB operon fusion demonstrated a close spatial correlation between colony regions undergoing aerial mycelium formation and zones of sapA-promoted light emission.

Amino Acid Sequence↗
PubMedDate not supplied

Bronchogenic cyst presenting as a nodular lesion.

We report a subcutaneous bronchogenic cyst in a 7-year-old girl with unusual presentation as a nodular lesion. The cyst was excised and no connection with deeper structures was found. Histologic examination showed the typical features of a bronchogenic cyst. The characteristic clinical and histologic features of bronchogenic cysts are reviewed. The problems of differential diagnosis are also discussed.

Bronchogenic Cyst↗
PubMedDate not supplied

[Iatrogenic bilateral hydrothorax following the placement of a central catheter].

We present a case of bilateral hydrothorax after internal jugular vein catheterization. 60 hours after placing the catheter, the patient showed an abrupt picture of jugular ingurgitation, abolished vesicular breath sounds, and displaced cardiac tones. It was necessary to immediately drain one hemithorax to guarantee ventilation of the patient. The present article examines iatrogenicity derived from the placement of central catheters, and special attention is given to the need for post-insertion x-ray control.

Adult↗