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Biomedical subjects

M A Fernandez

Publications and source records attributed to M A Fernandez.

At least 37 records · Page 2Linked to original sources
PubMed1997

Morel-Lavallée effusions in the thigh.

OBJECTIVE: To assess the radiological features of Morel-Lavallée effusion in the thigh. DESIGN AND PATIENTS: A retrospective study of clinical records and radiological studies was carried out on three patients with Morel-Lavallée effusion. RESULTS AND CONCLUSIONS: Ultrasound and computed tomography (CT) were able to locate the effusion in the three patients. CT demonstrated a capsule around the lesion. A fluid-fluid level was visible with both techniques. Ultrasound and CT are good methods for assessing patients with Morel-Lavallée effusion of the thigh. CT can be used to distinguish patients requiring surgical treatment from those who could be treated by conservative measures.

Adult↗
PubMed1996

GNAI3, GNAT2, AMPD2, GSTM are clustered in 120 kb of Chinese hamster chromosome 1q.

We studied a polygenic region located on Chromosome (Chr) 1q in Chinese hamster cells that is coamplified along with the AMPD2 gene. Previous sequence analysis identified both members of the GSTM family and the GNAI3 gene within a cloned 120-kb region surrounding the AMPD2 locus. We show here that the GNAT2 gene, which is inactive in the fibroblastic cells, lies within the 20 kb separating the transcriptionally active GNAI3 and AMPD2 genes. We map most gene ends by sequence comparison with human homologs; one is inferred from the presence of an unmethylated CpG island. This Chinese hamster locus corresponds to a region of conserved linkage between human Chr 1 (locus 1p13) and mouse Chr 3 (position 52.5 cM), where Gnai-3 and Gnat-2 have been mapped. The AMPD2 gene is presently unlocalized in human genome; its proposed position on mouse Chr 3 is at 53.4 cM. Our results, obtained by physical mapping, strongly suggest that the order and possibly the tight linkage of these genes are conserved on all three genomes.

Animals↗
PubMed1995

Molecular characterization of an 18 kb segment of DNA puff C4 of Bradysia hygida (Diptera, sciaridae).

The data presented here are an extension of the molecular characterization of DNA puff C4 of Bradysia hygida. A cDNA related to a gene amplified in this puff and expressed when puff C4 expands was cloned and sequenced. Analysis of the amino acid sequence deduced from the open reading frame present in the cDNA indicate that the encoded protein is secreted and comprises mostly alpha-helical coiled-coil. An 18 kb genomic segment containing the transcription unit of this gene was also cloned and the structure and expression of the 1.4 kb mRNA was determined. Quantitative slot blot hybridization of DNA complementary to the transcription unit shows that this gene is amplified about 21 times in the salivary gland, confirming data previously obtained. Fragments upstream of the 5' end, and beyond the 3' end, of the gene transcription unit were also analysed and shown to be amplified at least eight and five times, respectively. Based on these data we discuss how amplification could occur at DNA puffs.

Amino Acid Sequence↗
PubMed1995

3-D reconstruction of hepatic neoplasms: a preoperative planning procedure.

Three-dimensional display of intrahepatic vascular structures, tumour(s) and liver surface offers the possibility of perceiving the complex individual anatomy in a coherent fashion. Since this presentation of anatomical structures can be varied at will, the resulting interactive dynamic display of the 3-D data sets can be considered an example of Virtual Reality; the surgeon experiences the interactive 3-D display as a realistic presentation of the patient's surgical anatomy. Three-dimensional display offers the possibility of planning a specific resection in detail, tailored to the individual anatomy. The benefits and problems of various surgical approaches can be worked out in detail, and potential hazardous phases in the operation can be anticipated, thus minimizing unexpected complications. However, because the generation of detailed 3-D renderings takes considerable time investment by an experienced operator it is important to select patients, in whom such an effort is warranted. In our experience, 3-D display of the liver is most likely to be of benefit in the presence of central tumours, or if segmental resections are considered.

Diagnostic Imaging↗
PubMed1994

The highly conserved Chinese hamster GNAI3 gene maps less than 60 kb from the AMPD2 gene and lacks the intronic U6 snRNA present in its human counterpart.

The identity of a gene coamplified with the adenylate deaminase 2 gene (AMPD2) in coformycin-resistant cells was determined by analysis of its genomic sequence. Sequence comparisons reveal a significant homology with the 3' terminal part of the gene encoding the alpha i3 subunit of Gi proteins from several species (GNAI3). Identification of the gene was confirmed by Western blot analysis of its products. A precise sequence comparison was performed with the human genomic sequence. It showed that conservation remains important in noncoding exons as well as in introns. However, sequences corresponding to combined U6 snRNA and E protein pseudogene, previously identified inside intron 7 of the human gene, were not found in the Chinese hamster gene. GNAI3 is mapped to a region of conserved linkage between human chromosome 1 (locus 1p13) and mouse chromosome 3 (at 48.4 cM). The Chinese hamster GNAI3 gene maps to chromosome 1 within a 120-kb fragment that also comprises the AMPD2 and GSTM genes.

AMP Deaminase↗
PubMed1994

Variations in venous and segmental anatomy of the liver: two- and three-dimensional MR imaging in healthy volunteers.

OBJECTIVE: The purpose of this study was to use two- and three-dimensional analysis of thin-slice MR imaging data to study the anatomic variations in the segmental anatomy of the liver. It is important to recognize these anatomic variations in order to ensure accurate localization of hepatic lesions and preoperative delineation of resection planes. SUBJECTS AND METHODS: T1-weighted MR images of contiguous 4-mm sections were obtained in 10 healthy subjects. We measured the orientations of external and internal hepatic landmarks that indicated segmental boundaries and created three-dimensional renderings of hepatic veins, intrahepatic portal branches, liver surface, and gallbladder. RESULTS: Variations in the portal branching pattern were seen in eight of 10 subjects. Most variations occurred in the right hemiliver and consisted of the absence of a right portal trunk or the presence of accessory portal branches. The division between right anterior and right posterior segments was inclined posteriorly (average, 31.2 degrees) relative to the right hepatic vein. The landmarks indicating the position of the umbilical fissure showed marked variability. Only two of 10 subjects had three hepatic veins, with the left and middle veins sharing a common trunk. In the remaining eight subjects, nine accessory veins were present: three left, one middle, and five right. CONCLUSION: Planes of resection in liver surgery are largely determined by the precise position of tumor relative to the individual segmental anatomy. Consequently, localization of liver lesions and preoperative delineation of resection planes requires consideration of the significant anatomic variations in the segmental anatomy of the liver. These anatomic variations can be depicted on two- and three-dimensional displays of T1-weighted MR images of contiguous 4-mm sections.

Adult↗
PubMed1994

Portal venous and segmental anatomy of the right hemiliver: observations based on three-dimensional spiral CT renderings.

OBJECTIVE: The purpose of this study was to evaluate the segmental anatomy of the right hemiliver and to assess whether the right hepatic vein and right portal trunk are accurate indicators of the position of the right and transverse scissurae, respectively. SUBJECTS AND METHODS: We examined 26 patients with spiral CT using 5-mm slices, reconstructed at 2-mm intervals. Three-dimensional renderings of the portal and hepatic venous structures were created. The portal ramification pattern and relationship between the hepatic veins and portal system were evaluated. RESULTS: In the right hemiliver, an anterosuperior sector and a posteroinferior sector were present in all patients. In addition, in nine patients, a total of 15 accessory portal sectors were present, each arising directly from the portal bifurcation or the right portal trunk. Further subdivision of the portal sectors showed marked individual variability, with no prevailing branching pattern. The scissura between the anterosuperior and posteroinferior sectors showed an angled orientation--its cranial part was tilted posteriorly (average, 58.4 degrees) and its caudal part was tilted anteriorly (average, 2.8 degrees)--relative to the coronal plane. In 24 patients, portal branches crossed the plane of the right hepatic vein. No transverse scissura could be seen in the anterosuperior or posteroinferior sector. CONCLUSION: The right hemiliver could be divided into anterosuperior and posteroinferior sectors in all patients studied. Many patients have accessory sectors. Further subdivision into portal segments can be described only after the individual portal branching pattern has been studied. The right hepatic vein is an inaccurate indicator of the position of the right scissura. No clear transverse scissura can be seen in the right hemiliver.

Adult↗
PubMed1993

CT angiography: application to the evaluation of carotid artery stenosis.

PURPOSE: To determine whether computed tomographic (CT) angiography can be used to accurately quantify carotid stenoses and differentiate severe stenoses from occlusions. MATERIALS AND METHODS: CT angiography was used to evaluate 50 carotid arteries in 27 patients who were referred for surgical evaluation after diagnosis of carotid stenosis and who had undergone standard angiography. Four observers read each study separately in a blinded fashion, then all four observers together reviewed those studies in which the individual readings differed to reach a consensus reading. RESULTS: The consensus readings for the two modalities were in agreement on stenosis category in 41 (82%) of the 50 carotid arteries (kappa W = 0.852 +/- 0.114). The consensus readings in the other nine arteries differed by only one category; seven had less severe stenosis at CT angiography and two had more severe stenosis. The CT angiograms also depicted a variety of additional abnormalities, including loops (n = 6), aneurysms (n = 2), and ulcers (n = 4). CONCLUSION: These results indicate that CT angiography can non-invasively provide most of the information needed before carotid endarterectomy.

Adult↗
PubMed1993

Spiral CT angiography.

Spiral CT angiography is a new, minimally invasive technique for vascular imaging that is made possible by combining two recently developed techniques: slip-ring CT scanning and computerized three-dimensional (3D) reconstruction. The purpose of this essay is to illustrate the appearances of various normal and diseased vessels using this technique.

Angiography↗
PubMed1992

Transposon Tn5-259 mutagenesis of Pseudomonas cepacia to isolate mutants deficient in antifungal activity.

Transposon Tn5-259 was inserted into the chromosome of Pseudomonas cepacia by mating with an Escherichia coli strain harboring a self-mobilizable, temperature-sensitive plasmid, pME12. Data from Southern blots and auxotroph analyses indicated that a single copy of the transposon was inserted in several places into the chromosome of P. cepacia. Among 1500 Tn5-259 transconjugants, only one mutant was found to be defective in the production of an antifungal compound, pyrrolnitrin. In addition, this mutant lost its ability to antagonize fungal phytopathogens. Using flanking DNA of the mutated gene as a probe, we have isolated four overlapping cosmid clones from a genomic library of P. cepacia. However, we were unable to complement the mutant because of difficulty in mobilizing the cosmids from E. coli to P. cepacia.

Antifungal Agents↗
PubMed1992

[Changes in the physiologic pattern of mitral prosthesis regurgitation in the presence of a prosthetic dysfunction].

AIM OF STUDY: Evaluation by transesophageal echocardiography of the effect on the characteristics of physiological regurgitant jets (JF) resulting from prosthetic disfunction due to pathologic regurgitation (JF). PATIENTS AND METHODS: We studied 69 consecutive patients with the diagnosis of prosthesis in mitral position using transesophageal echocardiography and color doppler codification. The patients were divided in two groups (N and D groups) according to the presence of prosthesis disfunction by pathologic regurgitation. In each patient we determined planimetric areas and atrial peak depth of each JF and also the sum of JF planimetric areas of each mitral prosthesis. When pathological regurgitation was present we calculated the highest planimetric area, severity degree and atrial peak depth in each JP. RESULTS: The planimetric area in each JF of group N was 330 +/- 167 mm2 and in group D 117 +/- 116 mm2 (p less than 0.001). The sum of the areas of JF in group N was 474 +/- 204 mm2 and in group D 254 +/- 176 mm2 (p less than 0.01). The atrial depth of JF in group was 32 +/- 15 mm and in group D 26 +/- 18 mm (p less than 0.01). In group D 29% of the patients had mild pathological regurgitation, 10% moderate and 61% severe. The maximum planimetric area of JP in group D was 1078 +/- 1007 mm2 with atrial depth of 37 +/- 28 mm. CONCLUSION: The pathological regurgitation in disfunction prosthesis in mitral position has a significant reduction effect in the dimension of prosthesis physiologic regurgitation jets. This transesophageal echocardiographic observation makes it possible to characterize and clarify more precisely the different types of mitral prosthesis jets.

Adult↗
PubMed1990

Isolation and characterization of a pseudomonas strain that restricts growth of various phytopathogenic fungi.

The characterization of a novel Pseudomonas strain exhibiting antagonism towards many important corn fungal pathogens is presented. This strain was isolated from the caryopses of the grass Tripsacum dactyloides and was identified as Pseudomonas cepacia. The antagonistic activity is due to the production of an antifungal compound. The chromatographic properties of this partially purified compound isolated from growth medium differ from those reported previously for other pseudomonads. The suppression of the growth of economically important phytopathogens by this strain and by the partially purified compound indicates a potential biocontrol agent.

Journal Article↗
PubMed1988

Treatment of experimental lens-induced uveitis by dimethyl thiourea.

Dimethyl thiourea is a highly specific hydroxyl radical scavenger. The antiinflammatory potential of this hydroxyl radical scavenger was studied in Lewis rats sensitized with soluble lens protein. Intraperitoneal injection of dimethyl thiourea into the experimental animals at the onset of the disease resulted in marked reduction of intraocular inflammation, hemorrhage and edema, and eliminated the retinal and choroidal necrotizing vasculitis that was characteristic in untreated animals. These findings indicate that dimethyl thiourea may act as a potent antiphlogistic agent in the treatment of experimental lens-induced uveitis.

Animals↗
PubMed1988

Anti-inflammatory effect of glutathione peroxidase on experimental lens-induced uveitis.

An acute lens-induced necrotizing intraocular inflammation was produced in Lewis rats. Treatment of these animals by intraperitoneal injection of glutathione peroxidase resulted in marked decrease in uveal inflammation, retinal edema, hemorrhage and vasculitis. Intraperitoneal injection of glutathione peroxidase resulted in increased levels of this enzyme in ocular tissue. These findings suggest that glutathione peroxidase can modulate acute lens-induced ocular inflammation by serving as a potent anti-inflammatory agent.

Animals↗
PubMed1987

Treatment of experimental granulomatous uveitis by lipoxygenase and cyclo-oxygenase inhibitors.

Lens-induced granulomatous uveitis was produced in brown Norway rats. To determine the role of the lipoxygenase and cyclo-oxygenase products of arachidonic acid in the modulation of granulomatous uveitis, one group of experimental animals was treated with nafazatrom, while another group was treated with nordihydroguaiaretic acid (lipoxygenase inhibitors). Both resulted in significant attenuation of granulomatous inflammation, with reduced giant-cell infiltration into the choroid. In contrast, indomethacin (a cyclo-oxygenase inhibitor) therapy resulted in increased giant-cell formation. These findings suggest that the lipoxygenase and cyclo-oxygenase products of arachidonic acid play a role in the development of granulomatous uveitis and that such inflammation can be selectively suppressed by lipoxygenase inhibitors.

Animals↗