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Biomedical subjects

P Fernandez

Publications and source records attributed to P Fernandez.

At least 55 records · Page 3Linked to original sources
PubMed1998

Identification and characterization of human cDNAs specific to BCS1, PET112, SCO1, COX15, and COX11, five genes involved in the formation and function of the mitochondrial respiratory chain.

We have successfully applied a strategy based on the "cyberscreening" of the expressed sequence tags database using yeast protein sequences as "probes" to identify the human gene orthologs to BCS1, COX15, PET112, COX11, and SCO1, five yeast genes involved in the biogenesis of the mitochondrial respiratory chain complexes. In yeast, BCS1 is involved mainly in the assembly of complex III, while the other genes appear to control the structure/function of cytochrome-c oxidase. Significant amino acid identity and similarity were demonstrated by comparison of the human with the corresponding yeast polypeptides. Sequence alignment revealed numerous colinear identical regions and the conservation of functional domains. Mitochondrial targeting of the human gene products, suggested by computer analysis of the protein sequences, was confirmed by an in vitro import and protease-protection assay. These data strongly suggest that the human gene products share similar or identical functions with their yeast homologues. Genes controlling the structure/function of the respiratory chain complexes are attractive candidates for human mitochondrial disorders such as Leigh disease. However, both sequence analysis and functional complementation assays on an index patient do not support an etiological role for any of these genes.

Alkyl and Aryl Transferases↗
PubMed1998

The major 36 kDa Neospora caninum tachyzoite surface protein is closely related to the major Toxoplasma gondii surface antigen.

The tachyzoites and the tissue cysts containing bradyzoites of Neospora caninum and Toxoplasma gondii, respectively, are difficult to distinguish morphologically. Specific antigens have been identified in T. gondii tachyzoites and bradyzoites, some of which are stage-specifically expressed, and different functions have been attributed to some of them. A tachyzoite stage-specifically expressed surface protein is the major surface antigen 1 (SAG1) which has been shown to be involved in host cell attachment and invasion. Previously we have identified a cell surface-associated glycoprotein (p36) in N. caninum tachyzoites. The full length coding sequence of the cDNA coding for p36 was determined, and analysis of the deduced amino acid sequence demonstrated that p36 is closely related to SAG1. p36 is encoded by a single copy gene which produces a transcript of 1.4 kb. Immunogold labeling of resin-embedded parasites using polyclonal antibodies affinity-purified on a recombinant p36 fusion protein expressed in Escherichia coli showed that this protein is located exclusively on the tachyzoite cell surface. As SAG1 in T. gondii, p36 is expressed in the tachyzoite stage, but is absent from bradyzoites. p36 is recognized by antibodies present in sera of cows experimentally infected with N. caninum tachyzoites.

Amino Acid Sequence↗
PubMed1998

Enhanced sensitivity in the analysis of trace organochlorine compounds by negative-ion mass spectrometry with ammonia as reagent gas.

A comparison of the performances of ammonia and methane as reagent gases for the analysis of trace organochlorine compounds by gas chromatography coupled to negative-ion chemical ionization mass spectrometry is performed in the present study. Examples of standard mixtures and human blood samples analyzed with both reagents in scan and selected-ion monitoring mode are shown. Important advantages are observed as a consequence of the use of ammonia. These concern detection and quantitation limits and the lower dependence of sensitivity on the degree of chlorine substitution of the compounds.

Ammonia↗
PubMed1998

Prognostic value of bone sialoprotein expression in clinically localized human prostate cancer.

BACKGROUND: Bone sialoprotein (BSP), a bone matrix protein, was recently found to be expressed ectopically in breast cancer and to have a statistically significant association with poor prognosis and the development of bone metastases in that disease. These data prompted us to investigate whether BSP might also be expressed in human prostate cancer, which often metastasizes to bone, and be predictive for progression risk. METHODS: Tissue sections from 180 patients who had undergone a radical prostatectomy for localized prostate cancer were analyzed immunohistochemically for BSP expression. Biochemical progression was defined as an increasing serum prostate-specific antigen level of 0.5 ng/mL or more. Statistical analysis was used to assess associations between pathologic findings and level of BSP expression, and a Cox proportional hazards model was used to determine which clinical and histologic parameters, including stage, Gleason score, and BSP expression (immunostaining intensity and extent), were independently associated with biochemical progression. All P values were two-sided. RESULTS: Most of the prostate cancer lesions examined (78.9%) expressed detectable levels of BSP, compared with no or low expression in the adjacent normal glandular tissue. A statistically significant association was found between BSP expression and biochemical progression in both univariate and multivariate analyses. After a follow-up interval of 3 years, the biochemical relapse rate was 36.7% (95% confidence interval [CI] = 23.4%-47.7%) in patients whose tumors expressed high levels of BSP compared with 12.1% (95% CI = 2.3%-20.8%) in patients whose tumors expressed no or a low detectable level of the protein (logrank test, P = .0014). BSP expression status could identify those patients at higher risk of biochemical progression (logrank test, P<.05) among patients with moderately differentiated tumors or with pathologically confined tumors. CONCLUSIONS: To our knowledge, this study is the first to demonstrate BSP expression in human prostate cancer and to highlight the protein's statistically significant prognostic value in patients with clinically confined prostate adenocarcinomas.

Adenocarcinoma↗
PubMed1998

Spastic paraplegia and OXPHOS impairment caused by mutations in paraplegin, a nuclear-encoded mitochondrial metalloprotease.

Hereditary spastic paraplegia (HSP) is characterized by progressive weakness and spasticity of the lower limbs due to degeneration of corticospinal axons. We found that patients from a chromosome 16q24.3-linked HSP family are homozygous for a 9.5 kb deletion involving a gene encoding a novel protein, named Paraplegin. Two additional Paraplegin mutations, both resulting in a frameshift, were found in a complicated and in a pure form of HSP. Paraplegin is highly homologous to the yeast mitochondrial ATPases, AFG3, RCA1, and YME1, which have both proteolytic and chaperon-like activities at the inner mitochondrial membrane. Immunofluorescence analysis and import experiments showed that Paraplegin localizes to mitochondria. Analysis of muscle biopsies from two patients carrying Paraplegin mutations showed typical signs of mitochondrial OXPHOS defects, thus suggesting a mechanism for neurodegeneration in HSP-type disorders.

ATPases Associated with Diverse Cellular Activitie↗
PubMed1998

Altered phenotypic characteristics of T47d human breast cancer cells after prolonged growth in estrogen-deficient medium.

T47D human breast cancer cells were cultured in estrogen-deficient media for up to 32 months and the resulting cell line (L(hE(-))) exhibited unique phenotypic and genotypic characteristics. Compared to low passage (L) cells, the L(hE(-)) cells exhibited a significantly higher rate of proliferation, unique morphological features, advanced ploidy status and 5- to 10-fold higher levels of the estrogen receptor (ER) as determined by ligand binding and Western blot analysis. Sequence analysis of the DNA binding domain of the ER revealed a C-->A transversion which resulted in a H513N amino acid change. Treatment of L cells with 10 n m 17beta-estradiol (E2) resulted in a greater than two-fold increase in cell proliferation which was inhibited by tamoxifen, 4'-hydroxytamoxifen, ICI 164,384 and ICI 182,780. In contrast, 10 n m E2 caused a 70% decrease in growth of L(hE(-)) cells and this antimitogenic activity was blocked by ICI 164,384 and ICI 182,780 but not by tamoxifen or 4'-hydroxytamoxifen. L(hE(-)) cells were E2-responsive in transient transfection studies using a plasmid containing an estrogen-responsive element derived from the vitellogenin A2 gene promoter. These data show that the phenotypic and genotypic characteristics of L(hE(-)) T47D cells resemble those described for ER-negative cell lines stably transfected with the ER.

Breast Neoplasms↗
PubMed1998

Odor reduction potential of a chlorine dioxide mouthrinse.

The efficacy of a chlorine dioxide-containing mouthrinse in reducing oral malodor was compared to that of a water control in randomized, double-blind crossover study in 12 male and female subjects. Entrance criteria required a score of < or = 1 (slightly unpleasant/stale) on a 7-point ordinal odor pleasantness scale at both screening and baseline. On the test mornings, subjects refrained from oral hygiene and rinsed with 15 mL of either mouthrinse or water (one occasion each), under supervision for a timed 30-second interval. Three trained, previously calibrated sensory judges independently evaluated mouth odor pleasantness and intensity. Odor pleasantness scores (7-point scale) and odor intensity scores (5-point scale) from the three sensory judges were analyzed using an Analysis of Variance. The average score of all the judges was analyzed for each time point. The mean (+/- SD) mouth odor pleasantness in the chlorine dioxide group improved from -1.25 +/- 0.29 at baseline to -0.72 +/- 0.31 at 0.5 hour, -0.81 +/- 0.26 at 1 hour, -0.61 +/- 0.45 at 2 hours, and -0.61 +/- 0.55 at 4 hours post-rinsing (delta = 0.53, 0.44, 0.64, and 0.64, respectively). In the control group, the mean (+/- SD) mouth odor pleasantness improved from -1.06 +/- 0.40 at baseline to -0.94 +/- 0.58 at 0.5 hour, and to -0.97 +/- 0.46 at 1 hour, then deteriorated from -1.06 +/- 0.40 at baseline to -1.11 +/- 0.38 at 2 hours, and -1.08 +/- 0.61 at 4 hours post-rinsing (delta = 0.11, 0.08, -0.06, and -0.03, respectively). The mean (+/- SD) mouth odor intensity in the chlorine dioxide group improved from 1.14 +/- 0.17 at baseline to 0.92 +/- 0.35 at 0.5 hour, 1.06 +/- 0.24 at 1 hour, 0.83 +/- 0.44 at 2 hours, and 0.81 +/- 0.44 at 4 hours post-rinsing (delta = -0.22, -0.08, -0.31, and -0.33, respectively). In the control group, the mean (+/- SD) mouth odor intensity improved from 1.11 +/- 0.26 at baseline to 0.97 +/- 0.44 at 0.5 hour and 1.03 +/- 0.33 at 1 hour, then deteriorated from 1.11 +/- 0.26 at baseline to 1.17 +/- 0.39 at 2 hours, and 1.19 +/- 0.52 at 4 hours post-rinsing (delta = -0.14, -0.08, 0.06, and 0.08, respectively). Analyses of Variance showed that improvement in mouth odor pleasantness compared to baseline for the chlorine dioxide-containing mouthrinse versus the water control was statistically significant (p < 0.05) at all post-rinsing evaluations. For the reduction in mouth odor intensity, there was a statistically significant difference favoring the oral rinse at 2 and 4 hours post-rinsing. Thus, this study demonstrates that a one-time use of a chlorine dioxide-containing mouthrinse significantly improves mouth odor pleasantness and reduces mouth odor intensity for at least 4 hours.

Adult↗
PubMed1997

Parasite-mediated nuclear factor kappaB regulation in lymphoproliferation caused by Theileria parva infection.

Infection of cattle with the protozoan Theileria parva results in uncontrolled T lymphocyte proliferation resulting in lesions resembling multicentric lymphoma. Parasitized cells exhibit autocrine growth characterized by persistent translocation of the transcriptional regulatory factor nuclear factor kappaB (NFkappaB) to the nucleus and consequent enhanced expression of interleukin 2 and the interleukin 2 receptor. How T. parva induces persistent NFkappaB activation, required for T cell activation and proliferation, is unknown. We hypothesized that the parasite induces degradation of the IkappaB molecules which normally sequester NFkappaB in the cytoplasm and that continuous degradation requires viable parasites. Using T. parva-infected T cells, we showed that the parasite mediates continuous phosphorylation and proteolysis of IkappaBalpha. However, IkappaBalpha reaccumulated to high levels in parasitized cells, which indicated that T. parva did not alter the normal NFkappaB-mediated positive feedback loop which restores cytoplasmic IkappaBalpha. In contrast, T. parva mediated continuous degradation of IkappaBbeta resulting in persistently low cytoplasmic IkappaBbeta levels. Normal IkappaBbeta levels were only restored following T. parva killing, indicating that viable parasites are required for IkappaBbeta degradation. Treatment of T. parva-infected cells with pyrrolidine dithiocarbamate, a metal chelator, blocked both IkappaB degradation and consequent enhanced expression of NFkappaB dependent genes. However treatment using the antioxidant N-acetylcysteine had no effect on either IkappaB levels or NFkappaB activation, indicating that the parasite subverts the normal IkappaB regulatory pathway downstream of the requirement for reactive oxygen intermediates. Identification of the critical points regulated by T. parva may provide new approaches for disease control as well as increase our understanding of normal T cell function.

Animals↗
PubMed1997

Cranioplasty: cosmetic or therapeutic?

Cranioplasty is among the oldest surgical procedures. Trauma, infections, tumors and compression caused by brain edema are some of the reasons for the removal of bone. The indications for cranioplasty after resolution of the primary process that led to the bone defect were never well defined, and many were the "cosmetic" indications for cranioplasty. However, there are many theories suggesting that an underlying physiological alteration may occur which may require the correction of the bone defect; many patients improve after surgery. We discuss the physiopathological basis of the "syndrome of the trephined" and try to achieve a better understanding of the present status of cranioplasty and its possible therapeutic role.

Brain Injuries↗
PubMed1997

Parathyroid hormone prevents 1,25 (OH)2D3 induced down-regulation of the vitamin D receptor in growth plate chondrocytes in vitro.

1,25(OH)2D3 has an antiproliferative effect on growth plate chondrocytes when given in high doses, whereas low doses stimulate chondrocyte proliferation. In the present in vitro study we investigated the effects of parathyroid hormone (PTH) when given concomitantly with 1,25(OH)2D3 on cell proliferation and vitamin D receptor (VDR) regulation. Freshly isolated rat tibial chondrocytes were grown in monolayer cultures or in agarose stabilized suspension cultures (10% charcoal-treated FCS). VDR expression was determined by RT-PCR generating a 297 bp fragment and by binding assays (Scatchard analysis) with [3H]-1,25(OH)2D3. Cell proliferation was measured by [3H]-thymidine incorporation, growth curves in monolayer cultures and by colony formation in agarose-stabilized suspension cultures. Optimal concentration of 1,25(OH)2D3 (10(-12) M) and of PTH fragments [bPTH(1-34) or hPTH(28-48), 10(-10)M] showed additive effects on DNA synthesis of and colony formation by growth plate chondrocytes. This may be explained in part by an up-regulation of VDR by PTH: PTH increased both mRNA expression of VDR and binding capacity. 1,25(OH)2D3 (10(-12) M) induced an up-regulation of the VDR within 24 hours followed by a down-regulation after incubation for more than 24 hours. PTH fragments added concomitantly prevented the down-regulation seen with 1,25(OH)2D3. These findings provide evidence that PTH is a growth promoting hormone that also modulates the effects of 1,25(OH)2D3 by regulating the VDR status of 1,25(OH)2D3 target cells.

Animals↗
PubMed1997

Post-cranioplasty cerebrospinal fluid hydrodynamic changes: magnetic resonance imaging quantitative analysis.

The syndrome of the trephined has been described in many patients with cranial defects as an indication for cranioplasty. Cerebral blood flow changes, the effect of the atmospheric pressure on the brain, as well as cerebrospinal fluid hydrodynamic changes have been postulated as the possible reasons for this syndrome. Using dynamic phase-contrast magnetic resonance imaging we measured arterial, venous, and cerebrospinal fluid flow into and out of the skull, before and after cranioplasty in one patient whose bone flap was removed because of osteomyelitis. We report significant changes in the oscillatory CSF flow after cranioplasty. A moderate increase in venous outflow as well as a two-fold increase in craniocaudal cerebrospinal fluid systolic flow velocity was measured after the skull closure. The changes in the cerebrospinal fluid oscillatory flow at the level of the craniovertebral junction could reflect changes in the compliance of the craniospinal system produced by closure of the cranial defect.

Adult↗
PubMed1997

Characteristics of low-and high-fat beef patties: effect of high hydrostatic pressure.

The purpose of this study was to analyze the consequences of applying high pressures (100 and 300 MPa for 5 or 20 min) on characteristics such as water- and fat-binding properties, texture, color, microstructure, and microbiology of low-fat (9.2%) and high-fat (20.3%) beef patties. In nonpressurized patties, the low-fat product exhibited significantly poorer (P < 0.05) binding properties and higher (P < 0.05) Kramer shear force and Kramer energy than did high-fat patties. Although high pressure did not clearly influence the binding properties of low- and high-fat beef patties, it did produce a rise in the Kramer shear force and energy which were more pronounced at 300 MPa. High pressures altered patty color, the extent of alteration depending on fat content, pressure, and pressurizing time. Pressurizing high- and low-fat beef patties at 300 MPa not only produced a lethal effect (P < 0.05) on microorganisms, but caused sublethal damage as well.

Animals↗
PubMed1996

Homozygous expression of a missense mutation at nucleotide 385 in the FUT2 gene associates with the Le(a+b+) partial-secretor phenotype in an Indonesian family.

A new point mutation was found in the coding sequence of the secretor FUT2 gene. This missense mutation with an A-->T substitution at nucleotide 385 resulted in an amino acid change of Ile129 to Phe129. This mutation showed a clear genetic trait in an Indonesian pedigree and, when appearing in a homozygous form, it was associated with the red cell Le(a+b+) and salivary partial-secretor phenotype. This result suggests that the molecular basis for the Le(a+b+) and associated partial-secretor phenotype is caused by a partially inactivating amino acid change in the alpha(1,2)fucosyltransferase coded for by this new FUT2 allele.

Base Sequence↗
PubMed1996

Molecular basis for erythrocyte Le(a+ b+) and salivary ABH partial-secretor phenotypes: expression of a FUT2 secretor allele with an A-->T mutation at nucleotide 385 correlates with reduced alpha(1,2) fucosyltransferase activity.

The SewA385T mutation of the FUT2 gene was found to correlate with both the erthrocyte Le(a + b+) and/or salivary ABH partial-secretor phenotypes of Polynesians. Constructs with FUT1 and FUT2 wild type genes, and the FUT2 SewA385T, seG428A and seC571T mutated alleles, were cloned into pcDNAI, and expressed in COS-7 cells. COS-7 cells transfected with the SewA385T allele had weak, but detectable, alpha(1,2)fucosyltransferase activity, with an acceptor substrate pattern similar to the wild type FUT2 gene. Comparative kinetic studies from cell extracts with mutated SewA385T and wild type FUT2 alleles gave similar Km values, but less enzyme activity was present in cells transfected with SewA385T (Vmax 230 pmol h-1 mg-1), as compared to those transfected with FUT2 (Vmax 1030 pmol h-1 mg-1), suggesting that the mutated enzyme is more unstable. These results confirm that the molecular basis for the erythrocyte Le(a + b+), and the associated ABH salivary partial-secretor phenotype, is an amino acid change of Ile129-->Phe in the secretor alpha(1,2)fucosyltransferase.

ABO Blood-Group System↗
PubMed1996

Utility of C-erbB-2 in tissue and in serum in the early diagnosis of recurrence in breast cancer patients: comparison with carcinoembryonic antigen and CA 15.3.

To evaluate the utility of c-erbB-2, carcinoembryonic antigen (CEA) and CA 15.3 in the early diagnosis of recurrence, serial serum determinations of these antigens were performed in 200 patients (follow-up 1-4 years, mean 2.2 years) with primary breast cancer and no evidence of residual disease (NED) after radical treatment (radical mastectomy or simple mastectomy and radiotherapy). Eighty-nine patients developed metastases during follow-up. C-erbB-2, CEA and CA 15.3 were elevated (> 20 U ml-1, > 10 ng ml-1 or > 60 U ml-1 respectively) before diagnosis in 28%, 30% and 47% of the 89 patients with recurrence, with a lead time of 4.5 +/- 2.4, 4.9 +/- 2.4 and 4.8 +/- 2.4 months respectively. Tumour marker sensitivity was clearly related to the site of recurrence, with the lowest sensitivity found in locoregional relapse and the highest in patients with liver metastases. When patients with locoregional recurrences were excluded, sensitivity improved: 31% (c-erbB-2), 33% (CEA) and 56% (CA 15.3), with 76% having at least one of the three tumour markers. C-erbB-2 sensitivity in early diagnosis was significantly higher in patients with c-erbB-2 overexpression in tissue (8/10, 80%) than in those without overexpression (1/30, 3.3%) (P = 0.0001). Likewise, higher levels of both, c-erbB-2 and CA 15.3 at diagnosis of recurrence, higher sensitivity in early diagnosis of relapse and a higher lead time were found in PR+ patients (CA 15.3, P < 0.0001) or in PR- patients (c-erbB-2, P = 0.009). Specificity of the tumour markers was 100% for all three markers (111 NED patients). In conclusion, c-erbB-2 is a useful tool for early diagnosis of metastases, mainly in those patients with c-erbB-2 overexpression in tissue. Using all three markers simultaneously it is possible to increase the sensitivity in the early diagnosis of recurrence by 11.2%.

Bone Neoplasms↗