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Biomedical subjects

V Vidal

Publications and source records attributed to V Vidal.

At least 37 records · Page 2Linked to original sources
PubMed2000

Direct evidence for involvement of NF-kappaB in transcriptional activation of tumor necrosis factor by a spirochetal lipoprotein.

Variable major lipoprotein (Vmp) is a major tumor necrosis factor (TNF)-inducing component of Borrelia recurrentis, the agent of louse-borne relapsing fever. B. recurrentis Vmp rapidly stimulates nuclear translocation of NF-kappaB and proinflammatory cytokine gene expression in the human monocyte-like cell line MonoMac 6. By overexpressing disabled mutant IkappaBalpha in MonoMac 6 cells cotransfected with a reporter gene, we provide evidence that NF-kappaB is essential for the transcriptional activation of TNF in this system.

Bacterial Proteins↗
PubMed2000

Requirement of WT1 for gonad and adrenal development: insights from transgenic animals.

Development of the gonad and adrenal gland occurs in close proximity and it has been proposed that they share a common primordium. Recent knockout and transgenic studies in mice have demonstrated that besides the orphan nuclear receptor SF1, the Wilms' tumor suppressor gene WT1 is important for gonad and adrenal gland development. WT1 is a complex gene with at least 24 isoforms produced from its locus. Although the role of each isoform is not yet understood, biochemical studies and analyses of human patients suggest that they do serve different functions in the cell. Here we present our current view of the part WT1 may play in the development of the gonad and discuss its possible role in the formation of the adrenal primordium.

Adrenal Glands↗
PubMed2000

[Atypical sonographic findings of bacterial colitis].

We report three pediatric cases of infectious colitis that were misinterpreted on US examination as Crohn's disease. These colitis were limited to the left colon and presented with transmural hypoechoic thickening of the wall and homogenous hyperechoic appearance of the surrounding fat.

Abdominal Pain↗
PubMed2000

[Primitive neuroectodermal tumor of the kidney manifested as a spontaneous hematoma].

Ultrasound and CT in a young man, admitted for violent left flank pain, revelead a large heterogeneous left renal mass, with hypodense collection along the psoas. The diagnosis was spontaneous renal hematoma. A check CT 3 weeks later found a large tumor of the inferior pole. After radical nephrectomy, histopathology diagnosed a primitive neuroectodermal tumor. The patient died one year later despite neoadjuvant chemotherapy. This article reports the clinical, radiological and histopathological aspect of a primitive neuroectodermal tumor of the kidney, compared with the other cases in literature.

Adult↗
PubMed1999

Use of ipsilateral greater saphenous vein as a valved transplant in management of post-thrombotic deep venous insufficiency: long-term results.

Incompetence of the deep venous valve is a common feature of post-thrombotic deep venous insufficiency. Various surgical techniques have been proposed to treat reflux. In this study we describe long-term results of a novel transposition technique using the ipsilateral greater saphenous vein. From 1984 to 1994 we used this procedure to treat 16 patients including 10 men and 6 women with a mean age of 56 years (range: 25 to 76 years). In all 16 cases the indication for surgery was incapacitating pain associated with recurring ulceration in 9 patients. From the results of using this technique we conclude that transposition using the ipsilateral greater saphenous vein is safe and effective with good mid-term results, especially for pain. For ulcers the primary success rate was 55% but this increased to 84% with proper surveillance and treatment of secondary insufficiency of the superficial venous system.

Female↗
PubMed1999

[Retroperitoneal non-secreting paraganglioma].

Paraganglioma is a rare tumor arising from indifferentiated cells of the primitive neural crest. These tumors are most commonly found in the adrenal gland but other localisations are possible. We described a 60-year-old men with a right retro-peritoneal mass discovered on ultrasound examination. This tumor had an heterogeneous appearance on i.v. contrast injected CT (computed tomography) and MR (magnetic resonance) images. Plasma and urinary catecholamines were normal. This tumor was surgically removed. Immunohistochemical analyses revealed that the tumor cells were strongly positive for neurone specific enolase and chromogranin A. Histopathologic examination diagnosed a non secreting paraganglioma in the right retroperitoneum. After surgery, the patient remained asymptomatic without treatment.

Chromogranin A↗
PubMed1999

[Prostatic ultrasonography in routine radiological practice: a survey of 122 radiologists].

OBJECTIVE: To evaluate the indications and practical modalities of prostatic ultrasonography in routine radiological practice. METHODS: An anonymous questionnaire composed of 18 multiple choice questions was sent to 122 radiologists. RESULTS: Among the 76 responses, 90% were men, 90% were in private practice and 94% regularly performed prostatic ultrasonography without clinical information (81%). The prostatic examination was performed by transrectal ultrasonography (60%) combined with vesical and renal ultrasonography. The indications were: urinary functional disorders (56%) and abnormal PSA (40%). Prostatic ultrasonography was considered to be useful to calculate prostatic volumes by 59% of radiologists and in the staging of prostatic cancer (81%). 80% of radiologists did not start by performing digital rectal examination. 59% of patients were informed. CONCLUSION: The observed indications did not correspond to urological consensus recommendations, but ultrasonography was performed according to classical recommendations. This study could justify a more precise definition of the role of ultrasonography in prostatic disease.

Adult↗
PubMed1999

[Renal malakoplakia: prognostic aspects].

We report the changes in imaging findings over a 5 year period of a patient with unilateral malakoplakia involving renal parenchyma and pelvis. The imaging findings of malakoplakia will be reviewed.

Adult↗
PubMed1998

Complex NF-kappaB interactions at the distal tumor necrosis factor promoter region in human monocytes.

We describe a dense cluster of DNA-protein interactions located 600 nucleotides upstream of the transcriptional start site of the human tumor necrosis factor (TNF) gene. This area was identified as being of potential importance for lipopolysaccharide-inducible TNF expression in the human monocyte cell line Mono Mac 6, based on reporter gene analysis of point mutations at a number of nuclear factor kappaB (NF-kappaB)-like motifs within the human TNF promoter region. The area contains two NF-kappaB sites, which are here shown by DNase I and methylation interference footprinting to flank a novel binding site. UV cross-linking studies reveal that the novel site can also bind NF-kappaB as well as an unknown protein(s) of approximately 40 kDa. We show that these three adjacent kappaB-binding sites differ markedly in their relative affinities for p50/p50, p65/p65, and p65/p50, yet this 39-nucleotide segment of DNA appears capable of binding up to three NF-kappaB heterodimers simultaneously. Reporter gene studies indicate that each element of the cluster contributes to lipopolysaccharide-induced transcriptional activation in Mono Mac 6 cells. These findings suggest that NF-kappaB acts in a complex manner to activate TNF transcription in human monocytes.

Base Sequence↗
PubMed1998

Identification of recurrent and novel mutations in the LDL receptor gene in Spanish patients with familial hypercholesterolemia. Mutations in brief no. 135. Online.

We used the single strand conformation polymorphism (SSCP) method to investigate 13 apparently unrelated Spanish patients with familial hypercholesterolemia (FH) for mutations in the promoter region and the 18 exons and their flanking intron sequences of the low density lipoprotein (LDL) receptor gene. We found 16 aberrant SSCP patterns, and the underlying mutations were characterized by DNA sequencing. Five novel missense mutations, Q71E, C74G, C95R, C281Y and D679E, and one nonsense mutation, Q133X, were identified. We also found six missense mutations, S156L, D200Y, D200G, E256K, T413K and C646Y, and one stop codon mutation, W(-18)X, that were previously described in patients from other populations. A new frameshift mutation, 2085del19, was found in one patient. We also identified three splicing mutations; two of them are novel mutations, 1706-10G->A and 2390-1G->A, and the other one has been reported recently, 313+1G->C. Four patients were found to carry two different mutations in the same allele: Q71E and 313+1G->C; C95R and D679E; W(-18)X and E256K, and C281Y and 1706-10G->A. Our results demonstrate that there is a broad spectrum of mutations in the LDL receptor gene in the Spanish population.

DNA Mutational Analysis↗
PubMed1998

Variable major lipoprotein is a principal TNF-inducing factor of louse-borne relapsing fever.

Massive release of tumor necrosis factor is responsible for the potentially fatal larisch-Herxheimer reaction that follows antibiotic treatment of relapsing fever due to Borrelia recurrentis. We have undertaken the quantitative purification of the components of B. recurrentis that stimulate human monocytes to produce tumor necrosis factor. We show that the predominant factor inducing tumor necrosis factor is a variable lipoprotein homologous to the variable major protein of B. hermsii. We found antibodies to different forms of variable major protein in two patients with louse-borne relapsing fever. The three purified variable major proteins studied here differ in their ability to induce tumor necrosis factor production, which may partly explain the variable clinical severity of borrelial infection. These results may be of considerable relevance for the pathogenesis of Lyme disease and other forms of human borreliosis.

Amino Acid Sequence↗
PubMed1998

1,25-Dihydroxyvitamin D3 induces nitric oxide synthase and suppresses growth of Mycobacterium tuberculosis in a human macrophage-like cell line.

Inducible synthesis of nitric oxide (NO) by macrophages is an important mechanism of the host defense against intracellular infection in mice, but the evidence for significant levels of inducible NO production by human macrophages is controversial. Here we report that the human promyelocytic cell line HL-60, when differentiated to a macrophage-like phenotype, acquires the ability to produce substantial amounts of NO on stimulation with LPS or 1, 25-dihydroxyvitamin D3 (1,25-D3) in the absence of activating factors such as gamma interferon. Expression of the inducible nitric oxide synthase (NOS2) was confirmed by sequencing of the reverse transcription-PCR product from stimulated HL-60 cells. Kinetic studies after lipopolysaccharide stimulation show that NOS2 mRNA levels rise within 3 to 6 h, that conversion of [14C]arginine to [14C]citrulline is maximal at 5 to 6 days, and that levels of reactive nitrogen intermediates stabilize at around 20 microM at 7 to 8 days. We find that 1,25-D3 acts to suppress the growth of Mycobacterium tuberculosis in these cells and that this effect is inhibited by NG-monomethyl-L-arginine, suggesting that vitamin D-induced NO production may play a role in the host defense against human tuberculosis.

Calcitriol↗
PubMed1998

Pathology of sporadic breast tumors with LOH at the BRCA1 locus: correlation with histopathological features specific to familial BRCA1 tumors and absence of microsatellite instability.

To investigate the coordinated occurrence of loss of heterozygosity (LOH) at the BRCA1 locus and microsatellite instability (MI) in sporadic breast carcinomas, 56 tumors were analysed for both genetic alterations. The comparison of clinicopathological features with the obtained data revealed that LOH at the BRCA1 locus was significantly correlated with features specific for familial BRCA1 tumors and with absence of hormone receptors. No correlation was found between LOH and MI. These results suggest that sporadic and familial breast tumors, where BRCA1 is altered, could display similar clinicopathological features and that LOH and MI are distinct genetic events in sporadic breast carcinogenesis.

Adult↗
PubMed1997

[Epidemiology and genetics of cancers of the ovary].

5% of ovarian cancers occur in a hereditary predisposition context. Clinical syndromes are defined by 3 or more cases of breast or ovarian cancers, or cancers from the Lynch-type II spectrum (colon, endometrium...) in one family branch. When the diagnosis is established, genetic counselling is provided to the kindred, a molecular diagnosis is undertaken for BRCA1 and BRCA2 genes, screening for ovarian and other at risk cancers is proposed, or prophylactic oophorectomy is proposed for at least 35 years old women without children conception projects.

Causality↗
PubMed1997

Metathesis of Alkanes Catalyzed by Silica-Supported Transition Metal Hydrides

The silica-supported transition metal hydrides (=Si-O-Si=)(=Si-O-)2Ta-H and (=Si-O-)xM-H (M, chromium or tungsten) catalyze the metathesis reaction of linear or branched alkanes into the next higher and lower alkanes at moderate temperature (25degrees to 200degreesC). With (=Si-O-Si=)(=Si-O-)2Ta-H, ethane was transformed at room temperature into an equimolar mixture of propane and methane. Higher and lower homologs were obtained from propane, butane, and pentane as well as from branched alkanes such as isobutane and isopentane. The mechanism of the step leading to carbon-carbon bond cleavage and formation likely involves a four-centered transition state between a tantalum-alkyl intermediate and a carbon-carbon final sigma-bond of a second molecule of alkane.

Journal Article↗
PubMed1996

ATP hydrolysis is not required for the dissociation of a substance P.BiP complex.

BiP is a member of the hsp70 family of proteins that is present in the endoplasmic reticulum where it functions as a molecular chaperone. Rapid quantitative assays have been used to study the effect of mutating BiP residue 229, located in the ATP binding site, from threonine to glycine. Although binding of ATP to the mutant BiP was not affected, the mutant protein possessed 10-20% of the wild-type BiP ATPase activity. Binding to a model peptide substrate, substance P (Brot et al. (1994) Proc. Natl. Acad. Sci. USA 91, 12120-12124), was twofold higher with mutant BiP at 4 degrees C than with wild-type BiP, and was ATP dependent. Under these conditions the substance P that was bound to mutant BiP, but not the wild-type, could be released by higher levels of ATP (5-10 microM), and the ratio of substance P released to ATP hydrolyzed was greater than 10. These results suggest that stoichiometric ATP hydrolysis is not required for release of a chaperone from its substrate.

Adenosine Triphosphate↗