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J Lopez

Publications and source records attributed to J Lopez.

At least 19 recordsLinked to original sources
PubMed1995

GAL4/GAL80-dependent nucleosome disruption/deposition on the upstream regions of the yeast GAL1-10 and GAL80 genes.

Metabolic reactivation (incubating spheroplasts with galactose and casamino acids) causes disruption of nucleosomes from the upstream regions of the yeast GAL1, GAL10, and GAL80 genes. The disruption is specific. It depends on the transcription activator Gal4; it only occurs in galactose-reactivated chromatin from galactose-grown cells; it only affects upstream region, gene-proximal nucleosomes. Due to this specificity and because some of the same regions have shown induction-dependent changes by in vivo analyses, we suggest that the nucleosome-disrupted structure produced by reactivation is the authentic chromatin structure for these regions under conditions of galactose-induced GAL1-10 and GAL80 expression. It is necessary to carry out a spheroplast reactivation treatment in order to observe this disrupted structure in nuclear chromatin because nucleosomes are redeposited onto these regions during the preliminary steps of nuclear isolation (cell harvest/spheroplast preparation) probably in response to the nonphysiological conditions associated with these steps. However, during the same isolation procedures in cells lacking Gal80 protein, there is no nucleosome deposition on these regions, and the in vivo disrupted structure remains present in the nuclear chromatin. Therefore, the nucleosome deposition process that operates in wild-type cells is dependent on Gal80 protein, defining another activity of this negative regulator.

Chromatin↗
PubMed1995

Retroviral-mediated gene transfer corrects very-long-chain fatty acid metabolism in adrenoleukodystrophy fibroblasts.

Adrenoleukodystrophy (ALD), a lethal demyelinating disease of the brain, is caused by mutations of a gene encoding an ATP-binding transporter, called ALDP, localized in the peroxisomal membrane. It is associated with a defective oxidation of very-long-chain fatty acids, leading to their accumulation in many tissues. This study reports that the retroviral-mediated transfer of the ALD cDNA restored very-long-chain fatty acid oxidation in ALD fibroblasts in vitro following abundant expression and appropriate targeting of the vector-encoded ALDP in peroxisomes. The same method may be used in hematopoietic cells as a further step of a gene therapy approach of ALD.

Adrenoleukodystrophy↗
PubMed1994

Purification and characterization of recombinant human apolipoprotein A-II expressed in Escherichia coli.

We have expressed recombinant human apolipoprotein A-II (apoA-II) in Escherichia coli, as a fusion protein with Schistosoma japonicum glutathione-S-transferase (GST). The GST-AII fusion protein was recovered by affinity chromatography using glutathione as a ligand. After thrombin cleavage and removal of the GST carrier, recombinant apoA-II was obtained in a highly purified form and was exclusively composed of dimeric apoA-II. Kinetics of association to dimyristoylglycerophosphocholine (Myr2GroPCho) vesicles showed that recombinant apoA-II exhibited the same pattern of association as human plasma apoA-II. Electron microscopic analysis of the complexes showed a typical pattern of rouleaux, characteristic of stacked discs, with a diameter similar to that determined by gradient-gel electrophoresis. Circular dichroism measurements showed that the alpha-helical content of both plasma and recombinant apoA-II increased similarly when the proteins associated with Myr2GroPCho vesicles, at the expense of a random-coil structure. Lipid-bound apoA-II consisted of 70-72% alpha helices, suggesting the presence of three 18-residue alpha helices/apoA-II monomer. Cross-linking experiments indicated that Myr2GroPCho complexes contained two molecules dimeric apoA-II/vesicle. Recombinant apoA-II was as efficient as plasma apoA-II in associating with HDL subclasses, and in displacing apoA-I from dipalmitoylglycerophosphocholine/cholesterol/apoA-I complexes, most likely due to its highly ordered secondary structure when associated with Myr2GroPCho vesicles. These findings demonstrate that recombinant apoA-II exhibits the same structural and functional properties as human plasma apoA-II. Thus, the expression system utilized is appropriate to produce mutagenized forms to further structure/function analysis.

Amino Acid Sequence↗
PubMed1994

Intracellular early and late modifications of human apolipoprotein A-II. Effect of glutamine- +1 to leucine substitution.

It has been shown previously that apoA-II undergoes several intracellular modifications in HepG2 cells (Hussain & Zannis, 1990). In the present study, we have generated permanent cell lines in mouse C127 cells which express the normal apoA-II gene and a mutated form in which Gln+1 was substituted with Leu (Leu+1). This modification was designed to prevent cyclization of the N-terminal glutamine of apoA-II and thus identify the isoproteins which are precursors and products of the N-terminal cyclization reaction. The C127-expression cells were also utilized to study the cellular compartments where the apoA-II modifications occur as well as the importance of the modifications for apoA-II trafficking and secretion. We have found that apoA-II (Gln+1) synthesized by C127 and HepG2 cells had similar isoproteins. In both cell types, unmodified pro-apoA-II, designated isoprotein 3, had a similar isoelectric point as the cell-free translation product of apoA-II mRNA, suggesting that isoprotein 3 results from cleavage of the signal peptide. Isoprotein 3 represents an unmodified apoA-II isoprotein and undergoes an early modification into a more acidic isoprotein 1, which differs from isoprotein 3 by two negative charges. Brefeldin A treatment of the cells did not prevent the formation of isoprotein 1, suggesting that this modification occurs in a pre-Golgi compartment. Neuraminidase treatment of secreted apoA-II isoproteins did not affect isoprotein 1, indicating that it is not sialylated isoprotein. Isoprotein 1 undergoes further modifications which are consistent with cleavage of the propeptide, N-terminal cyclization and sialylation most likely resulting from O-glycosylation.(ABSTRACT TRUNCATED AT 250 WORDS)

Apolipoprotein A-II↗
PubMed1994

X-linked adrenoleukodystrophy gene: identification of a candidate gene by positional cloning.

Adrenoleukodystrophy (ALD) is an X-linked peroxisomal disorder characterized by a progressive demyelination of the central nervous system, adrenal insufficiency and impaired capacity to o-oxidase very long chain fatty acids, a metabolic process that normally takes place in peroxisomes. The ALD locus has been mapped to Xq28 and we have recently identified a patient with ALD who has a complex rearrangement in the 5' end of the red/green color pigment genes in Xq28. This rearrangement comprises two deletions separated by a large inversion. The second deletion of this key ALD patient extends 19 kb into the 3' region of an expressed gene which was found partially deleted in six of 85 independent patients with ALD. This segment thus constitutes a candidate region for the ALD gene.

Adolescent↗
PubMed1994

The gene responsible for adrenoleukodystrophy encodes a peroxisomal membrane protein.

Adrenoleukodystrophy is a severe genetic demyelinating disease associated with an impairment of beta-oxidation of very long chain fatty acids (VLCFA) in peroxisomes. Earlier studies had suggested that a deficiency in VLCFA CoA synthetase was the primary defect. A candidate adrenoleukodystrophy gene has recently been cloned and was found unexpectedly to encode a putative ATP-binding cassette transporter. We have raised monoclonal antibodies against this protein, that detect a 75kDa band. This protein was absent in several patients with adrenoleukodystrophy. Immunofluorescence and immunoelectron microscopy showed that the adrenoleukodystrophy protein (ALDP) is associated with the peroxisomal membrane. Distinct immunofluorescence patterns were observed in cell lines from patients with Zellweger syndrome (a peroxisomal biogenesis disorder) belonging to different complementation groups.

ATP Binding Cassette Transporter, Subfamily D, Mem↗
PubMed1994

Cross-sectional study of the susceptibility of Candida isolates to antifungal drugs and in vitro-in vivo correlation in HIV-infected patients.

OBJECTIVES: To investigate (1) the frequency of clinical resistance to oral polyenes or azole treatment for oral candidiasis, (2) the frequency of resistant in vitro Candida strains, (3) the relationship between the susceptibilities of in vitro Candida species and in vivo status in HIV patients. DESIGN: Prospective cross-sectional study. SETTING: Tertiary care clinic at Bocage Hospital, Dijon, France. PATIENTS: HIV-infected patients with and without oral candidiasis. INTERVENTIONS: Clinical examination, oral swab for mycologic investigations. MAIN OUTCOME MEASURES: Clinical diagnosis of oral candidiasis, identification of the antifungal treatment given within the previous month, identification of Candida species, antimycogramm and determination of the minimal inhibitory concentration (MIC) for fluconazole, and measurement of T-helper cell count. RESULTS: Within a 2-month period, 154 HIV-infected patients were studied: 46 heterosexuals, 51 intravenous drug users (IVDU), 52 homosexuals and five blood transfusion recipients. The percentages of patients with oral candidiasis were: 41, 80, 44 and 20%, respectively (P < 0.05); the mean T-helper cell counts were 200, 135, 210 and 238 x 10(6)/l cells, respectively (P < 0.05). Twenty-two patients (14.3%) had received recent azole treatment and 29 (18.8%) recent oral polyene treatment. Among the 84 patients with and the 70 patients without oral candidiasis, 78 and 28 Candida strains were isolated, respectively. Although Candida albicans represented the majority of Candida species (88 strains, 83%), the non-albicans strains were isolated more frequently in patients who had received recent antifungal treatment. No strains were resistant to ketoconazole, miconazole or econazole; however, six (5.6%), 16 (15%) and 10 (9.5%) were intermediately susceptible to the three drugs, respectively. Twelve (13.6%) of the 88 C. albicans, five of the six C. (Torulopsis) glabrata, one of the five C. tropicalis and all three C. krusei strains were resistant to fluconazole. These resistant strains were separated as follows: 41.1% of C. albicans strains resistant to fluconazole were isolated from patients who had received recent azole therapy, 17.6% from patients who received recent oral polyene, and 3.7% from patients who had not received any recent antifungal treatment (P = 0.004). The mean MIC of these three categories of isolates were 3.6, 1.6 and 0.6 mg/l, respectively (P = 0.06). CONCLUSIONS: Oral candidiasis and fluconazole-resistant Candida isolates are more frequently found in IVDU. Treatments using azoles select non-albicans strains and are associated with decreased susceptibilities of C. albicans strains to fluconazole in particular. These findings show that prolonged azole treatment in severely immunocompromised patients should be avoided.

AIDS-Related Opportunistic Infections↗
PubMed1994

Circulating stem cell collection in lymphoma and myeloma after mobilization with cyclophosphamide and granulocyte colony-stimulating factor for autologous transplantation.

We report the results of 72 leukapheresis procedures performed for autologous peripheral blood stem cell collection in 18 patients with lymphoma and myeloma, after combined mobilization with cyclophosphamide and granulocyte colony-stimulating factor (G-CSF). The numbers of mononuclear cells (MNCs), CD34+ cells and granulocyte-macrophage colony-forming units (CFU-GM) either in the peripheral circulation (preleukapheresis sample) or in the product obtained from leukapheresis (leukapheresis sample) were evaluated. A highly superior proportion of CD34+ cells (14-fold) and CFU-GM (5-fold) resulted from the mobilization therapy. CFU-GM and CD34+ cells were highly enriched with respect to all MNCs (relative recoveries: 2.13, range 0.3-41, and 1.08, range 0.2-8.5, respectively) due to an additional mobilization effect by the leukapheresis procedure. Also, a relatively strong linear correlation between the three different parameters was found in the leukapheresis product (CD34+:CFU-GM, r = 0.81; MNCs:CD34, r = 0.69; MNCs:CFU-GM, r = 0.75; CFU-GM:CD34+, and MNCs, r = 0.85). Our data suggest that the number of MNCs and CD34+ cells obtained after combined mobilization with cyclophosphamide and G-CSF can be used as predictor of the number of granulomonocytic progenitors.

Antigens, CD↗
PubMed1994

Rheumatoid factors from the peripheral blood of two patients with rheumatoid arthritis are genetically heterogeneous and somatically mutated.

We report the DNA sequences of the heavy and light chain immunoglobulin genes of 11 monoclonal rheumatoid factor (RF)-secreting lines derived from the peripheral blood of two patients with rheumatoid arthritis (RA). It is evident from immunogenetic analysis of these lines that RA-associated RF activity can arise from a wide variety of heavy and light chain genes and gene combinations. Although the RF response from our two patients shows a bias in gene usage toward those genes used to encode monoclonal RF, particularly VkIII, relatively few of these RFs are reactive with the monoclonal antiidiotypes 6B6.6 and 17.109 that define VkIII germline-encoded light chains and the loss of this idiotypic reactivity is clearly related to somatic mutation. Finally, RFs derived from peripheral blood of RA patients show a similar heterogeneity of epitope binding to Fc as that seen for synovium-derived RF and some are clearly different in binding specificity from the restricted RF population found in patients with B cell malignancies. Somatic mutations as well as different VH/VL combinations contribute to the heterogeneity in the binding patterns of these RA-derived RF.

Amino Acid Sequence↗
PubMed1994

Time series analysis of physiological response during ICU visitation.

Time series analysis (TSA) is an important statistical procedure for clinical nursing research. The current paucity of nursing research reports using TSA may be due to unfamiliarity with this technique. In this article, TSA is compared with the ordinary least squares regression model; validity concerns of time series designs are discussed; and concomitant and interrupted TSA of data collected on the effects of family visitation on intracranial pressure (ICP), heart rate, and blood pressure of patients in ICUs are presented. The concomitant TSA of the effect of family on ICP suggested that family presence tended to be associated with decreased ICP. Interrupted TSA indicated the effect of family on heart rate and blood pressure was not as consistent: The overall effect on blood pressure appeared to be negligible, and heart rate may increase overall. Restrictive visiting policies, once typical of intensive care units, should be reconsidered.

Blood Pressure↗
PubMed1994

Grandmother dishonored: violence against women by male partners in American Indian communities.

Extensive and scrupulously conducted research during the past decade has established the issue of violence against women by male partners as both an international human rights issue and a public health problem of national concern. This research has rarely been extended into communities of color, and, in particular, to American Indian women. This article presents conceptual and methodological factors involved in conducting research with American Indian women, a comprehensive literature review of available data, assertions regarding abuse of women by male partners in American Indian communities, and directions for future research.

Adult↗
PubMed1993

Amylase-producing Bence Jones multiple myeloma with pancreatitis-like symptoms.

Amylase-producing tumors are mainly adenocarcinomas and, in rare instances, multiple myelomas. We describe here a first case of amylase-producing Bence Jones type myeloma with pancreatitis-like symptoms and the second in a Caucasian patient. The finding of salivary-type hyperamylasemia in a 72-year-old female with a possible pancreatitis made us suspect the diagnosis. Amylase production was observed in bone marrow cultures in which 96% of cellularity was composed of plasmablasts. Serum amylase level decreased when chemotherapy was given.

Aged↗
PubMed1993

Perioperative care management for the patient undergoing gynecologic laparoscopy.

Patients undergoing abdominal laparoscopy require a process that is systematic and thorough and that at the same time has the flexibility to adapt to each individual's needs. The use of standards of care will facilitate the delivery of care by all staff, providing important links to standardized perioperative documentation, orientation, and meeting of quality performance indicators. Two examples of standards of care are provided in this article.

Female↗
PubMed1993

Inhibition of visceral protein synthesis by certain amino acid supplements.

This study was focused on the effects produced by diets with different amino acid proportions on visceral protein synthesis (liver and jejunal mucosa). Eight groups of rats received an enteral modular diet supplemented with different amino acids (Group 1: Ile, Leu, Val; Group 2: Phe, Met, Gly; Group 3: Glu, Arg, Gly; Group 4: Gly, Group 5: Orn-Asp, Cys, Pro; Group 6: Lys, Ser, Thr; Group 7: Tyr, His, Ala). Group 8 was the control group. Rats were fed for four days. At the end of this period a flooding dose of 14C-Leu was injected and animals were killed. Liver and jejunal mucosa were removed and protein synthesis rate was determined. Results show a decreased liver protein synthesis in group fed with aromatic amino acids (53.8 +/- 8.4 vs. 88.6 +/- 12.1) and Glu-Arg (68.6 +/- 10.9). In jejunal mucosa there was a decrease of protein synthesis in groups fed with aromatic amino acids (98.7 +/- 16 vs 160.5 +/- 49). These changes seem to be related to the intracellular amino acid pool size and its influence on protein metabolism.

Amino Acids↗
PubMed1992

p65 fragments, homologous to the C2 region of protein kinase C, bind to the intracellular receptors for protein kinase C.

Receptors for activated protein kinase C (RACKs) have been isolated from the particulate cell fraction of heart and brain. We previously demonstrated that binding of protein kinase C (PKC) to RACKs requires PKC activators and is via a site on PKC that is distinct from the substrate binding site. Here, we examine the possibility that the C2 region in the regulatory domain of PKC is involved in binding of PKC to RACKs. The synaptic vesicle-specific p65 protein contains two regions homologous to the C2 region of PKC. We found that three p65 fragments, containing either one or two of these PKC C2 homologous regions, bound to highly purified RACKs. Binding of the p65 fragments and PKC to RACKs was mutually exclusive; preincubation of RACKs with the p65 fragments inhibited PKC binding, and preincubation of RACKs with PKC inhibited binding of the p65 fragments. Preincubation of the p65 fragments with a peptide resembling the PKC binding site on RACKs also inhibited p65 binding to RACKs, suggesting that PKC and p65 bind to the same or nearby regions on RACKs. Since the only homologous region between PKC and the p65 fragments is the C2 region, these results suggest that the C2 region on PKC contains at least part of the RACK binding site.

Amino Acid Sequence↗