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Biomedical subjects

S Moreno

Publications and source records attributed to S Moreno.

At least 91 records · Page 5Linked to original sources
PubMed2000

Therapy of visceral leishmaniasis in renal transplant recipients intolerant to pentavalent antimonials.

Visceral leishmaniasis should be suspected in renal transplant recipients in whom a fever develops of unknown origin. A 53-year-old renal transplant recipient developed pyrexia, hepatosplenomegaly, and pancytopenia 4 years after transplantation. Antileishmaniasis serology was negative, and the diagnosis was confirmed through bone marrow examination. Treatment with glucantine (N-methylglucamine antimoniate) led to acute pancreatitis, and treatment with ketoconazole plus allopurinol for 21 days was effective to eradicate Leishmania donovani.

Antimony↗
PubMed2000

Mechanism of activation of cAMP-dependent protein kinase: in Mucor rouxii the apparent specific activity of the cAMP-activated holoenzyme is different than that of its free catalytic subunit.

Kinetic constants for peptide phosphorylation by the catalytic subunit of the dimorphic fungus Mucor rouxii protein kinase A were determined using 13 peptides derived from the peptide containing the basic consensus sequence RRASVA, plus kemptide, S6 peptide, and protamine. As a whole, although with a greater Km, the order of preference of the peptides by the M. rouxii catalytic subunit was similar to the one displayed by mammalian protein kinase A. Particularly significant is the replacement of serine by threonine in the basic peptide RRATVA, which impaired its role as a substrate of M. rouxii catalytic subunit. Mucor rouxii protein kinase A is a good model in which to study the mechanism of activation since cAMP alone is not enough to promote activation and dissociation. Four peptides were selected for the study of holoenzyme activation under conditions in which the enzymatic activity was not proportional to the holoenzyme concentration: RRASVA, RRRRASVA, KRRRLSSRA (S6 peptide), and LRRASLG (kemptide); protamine was used as reference. Differential activation degree was observed depending on the peptide used and on cAMP concentration. Ratios of activity between different substrates displayed by the holoenzyme under the above conditions did not reflect the one expected for the free catalytic subunit. The degree of inhibition of the holoenzyme activity by an active peptide derived from the thermostable protein kinase inhibitor was dependent on the substrate used and on the holoenzyme concentration, while it was found to be independent of these two parameters for free catalytic subunit. Polycation modulation of holoenzyme activation by cAMP was also dependent on the polycation itself and on the peptide used as substrate. The observed kinetic differences between holoenzyme and free catalytic subunit were decreased or almost abolished when working at low enzyme or at high cAMP concentrations. Two hypotheses compatible with the results are discussed: substrate participation in the dissociation process and/or holoenzyme activation without dissociation.

Amino Acid Sequence↗
PubMed2000

APC(ste9/srw1) promotes degradation of mitotic cyclins in G(1) and is inhibited by cdc2 phosphorylation.

Fission yeast ste9/srw1 is a WD-repeat protein highly homologous to budding yeast Hct1/Cdh1 and Drosophila Fizzy-related that are involved in activating APC/C (anaphase-promoting complex/cyclosome). We show that APC(ste9/srw1) specifically promotes the degradation of mitotic cyclins cdc13 and cig1 but not the S-phase cyclin cig2. APC(ste9/srw1) is not necessary for the proteolysis of cdc13 and cig1 that occurs at the metaphase-anaphase transition but it is absolutely required for their degradation in G(1). Therefore, we propose that the main role of APC(ste9/srw1) is to promote degradation of mitotic cyclins when cells need to delay or arrest the cell cycle in G(1). We also show that ste9/srw1 is negatively regulated by cdc2-dependent protein phosphorylation. In G(1), when cdc2-cyclin kinase activity is low, unphosphorylated ste9/srw1 interacts with APC/C. In the rest of the cell cycle, phosphorylation of ste9/srw1 by cdc2-cyclin complexes both triggers proteolysis of ste9/srw1 and causes its dissociation from the APC/C. This mechanism provides a molecular switch to prevent inactivation of cdc2 in G(2) and early mitosis and to allow its inactivation in G(1).

Amino Acid Sequence↗
PubMed2000

Phenotypic testing predicts virological response in successive protease inhibitor-based regimens.

OBJECTIVE: To evaluate the importance of the number of active drugs, as determined by phenotypic resistance testing, in achieving virological response in successive salvage regimens. DESIGN: Phenotypic study of 57 plasma samples corresponding to 24 patients who had sequentially received three protease inhibitor-containing regimens. Phenotypic susceptibility to a drug (active drug) was defined as less than a four-fold-increase in the IC50 in comparison with the wild type. MAIN OUTCOME MEASURE: Virological response according to the number of active drugs (three versus two or fewer), HIV load, length of antiretroviral exposure, and line of protease inhibitor-based therapy (first, second and third regimen). RESULTS: Before the first protease inhibitor-based therapy, the median time on antiretroviral treatment was 42 months, and before the second and third protease inhibitor-salvage regimens it was 10 and 8 months, respectively. The number of patients receiving three active drugs simultaneously was 24, 35 and 31% in each line of therapy. At week 12, a close correlation was found between the presence of three active drugs in the antiretroviral regimen and the rate of virological response, in comparison with those patients receiving two or fewer active drugs [76 versus 45%, relative risk (RR), 1.7; 95% confidence interval (CI) 1.1-2.6; P = 0.028]. In a multivariate analysis, the use of two or fewer active drugs was an independent predictor of lack of response, regardless of HIV load, length of previous antiretroviral exposure and line of salvage therapy (RR, 4.5; 95%CI, 1.1-18.3; P = 0.03). Of note, a higher rate of response was observed in patients receiving the first protease inhibitor-containing regimen in comparison with those in subsequent protease inhibitor-based salvage regimens (83 versus 50 versus 28%, P < 0.01), even when only those patients receiving three active drugs were included (100 versus 71 versus 60%). CONCLUSIONS: This data confirm the usefulness of phenotypic testing in guiding antiretroviral therapy in heavily pretreated patients. The number of active drugs and the line of salvage therapy are independent predictors of virological response, regardless of HIV load and the length of antiretroviral exposure.

Anti-HIV Agents↗
PubMed2000

Early alterations in gene expression and cell morphology in a mouse model of Huntington's disease.

Several mouse models for Huntington's disease (HD) have been produced to date. Based on differences in strain, promoter, construct, and number of glutamines, these models have provided a broad spectrum of neurological symptoms, ranging from simple increases in aggressiveness with no signs of neuropathology, to tremors and seizures in absence of degeneration, to neurological symptoms in the presence of gliosis and TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling) positivity, and finally to selective striatal damage associated with electrophysiological and behavioral abnormalities. We decided to analyze the morphology of striatum and hippocampus from a mouse transgenic line obtained by microinjection of exon 1 from the HD gene after introduction of a very high number of CAG repeat units. We found a massive darkening and compacting of striatal and hippocampal neurons in affected mice, associated with a lower degree of more classical apoptotic cell condensation. We then explored whether this morphology could be explained with alterations in gene expression by hybridizing normal and affected total brain RNA to a panel of 588 known mouse cDNAs. We show that some genes are significantly and consistently up-regulated and that others are down-regulated in the affected brains. Here we discuss the possible significance of these alterations in neuronal morphology and gene expression.

Animals↗
PubMed2000

Postprandial apolipoprotein B48-and B100-containing lipoproteins in type 2 diabetes: do statins have a specific effect on triglyceride metabolism?

There is little information about the effect of an alteration of low-density lipoprotein (LDL) turnover on chylomicron and very-low-density lipoprotein (VLDL) metabolism, yet chylomicron remnant particles are thought to be particularly atherogenic. This study examined the effect of inhibition of cholesterol synthesis on postprandial lipoproteins. Eight type 2 diabetic patients were examined before treatment with the 3-hydroxy-3-methyl glutaryl coenzyme A (HMGCoA) reductase inhibitor cerivastatin, after 4 weeks on active treatment, and 4 weeks after stopping treatment. On each occasion, blood was collected fasting and at 2-hour intervals for up to 8 hours after a high-fat meal. Chylomicrons and VLDLs were isolated by sequential ultracentrifugation. Compositional analysis was performed including the measurement of apolipoprotein B48 (apo B48) and apo B100 using polyacrylamide gradient gel electrophoresis. During statin treatment, there was a significant reduction in the postprandial chylomicron apo B48 area under the curve (AUC) from 23 +/- 16 to 17 +/- 10 (P < .01) and apo B100 in the chylomicron fraction from 166 +/- 148 to 70 +/- 70 (P < .05). Postprandial cholesterol (362 +/- 193 to 74 +/- 39, P < .005), triglyceride (2,222 +/- 1,440 to 746 +/- 329), and phospholipid (518 +/- 267 to 205 +/- 94) also decreased (P < .005). In the VLDL fraction, the postprandial cholesterol and triglyceride AUC were significantly reduced by statin (316 +/- 228 to 171 +/- 78, P < .05, and 1,733 +/- 833 to 857 +/- 468, P < .02, respectively). Four weeks after cessation of treatment, the chylomicron fraction triglyceride AUC had returned to the pretreatment level, but postprandial chylomicron cholesterol and VLDL cholesterol, triglyceride, and phospholipid were significantly lower than baseline (P < .05). Plasma total cholesterol and LDL cholesterol were significantly reduced with treatment (6.2 +/- 0.5 to 4.3 +/- 1.0 mmol/L, P < .001, and 4.5 +/- 0.4 to 2.8 +/- 1.0 mmol/L, P < .01, respectively) and returned to baseline following cessation of treatment. Fasting plasma triglycerides decreased significantly on treatment (2.4 +/- 1.0 to 1.7 +/- 0.2 mmol/L, P < .05) but remained significantly lower than baseline 4 weeks later (1.8 +/- 0.3 mmol/L, P < .05). This study suggests major postprandial lipoprotein changes on statin therapy which may account, in part, for the beneficial effects of statins in the prevention of myocardial infarction.

Adult↗
PubMed2000

The puc1 cyclin regulates the G1 phase of the fission yeast cell cycle in response to cell size.

Eukaryotic cells coordinate cell size with cell division by regulating the length of the G1 and G2 phases of the cell cycle. In fission yeast, the length of the G1 phase depends on a precise balance between levels of positive (cig1, cig2, puc1, and cdc13 cyclins) and negative (rum1 and ste9-APC) regulators of cdc2. Early in G1, cyclin proteolysis and rum1 inhibition keep the cdc2/cyclin complexes inactive. At the end of G1, the balance is reversed and cdc2/cyclin activity down-regulates both rum1 and the cyclin-degrading activity of the APC. Here we present data showing that the puc1 cyclin, a close relative of the Cln cyclins in budding yeast, plays an important role in regulating the length of G1. Fission yeast cells lacking cig1 and cig2 have a cell cycle distribution similar to that of wild-type cells, with a short G1 and a long G2. However, when the puc1(+) gene is deleted in this genetic background, the length of G1 is extended and these cells undergo S phase with a greater cell size than wild-type cells. This G1 delay is completely abolished in cells lacking rum1. Cdc2/puc1 function may be important to down-regulate the rum1 Cdk inhibitor at the end of G1.

CDC2 Protein Kinase↗
PubMed2000

Inactivation of the ampDE operon increases transcription of algD and affects morphology and encystment of Azotobacter vinelandii.

Transcription of algD, encoding GDP-mannose dehydrogenase, the key enzyme in the alginate biosynthetic pathway, is highly regulated in Azotobacter vinelandii. We describe here the characterization of a Tn5 insertion mutant (AC28) which shows a higher level of expression of an algD::lacZ fusion. AC28 cells were morphologically abnormal and unable to encyst. The cloning and nucleotide sequencing of the Tn5-disrupted locus in AC28 revealed an operon homologous to the Escherichia coli ampDE operon. Tn5 was located within the ampD gene, encoding a cytosolic N-acetyl-anhydromuramyl-L-alanine amidase that participates in the intracellular recycling of peptidoglycan fragments. The ampE gene encodes a transmembrane protein, but the function of the protein is not known. We constructed strains carrying ampD or ampE mutations and one with an ampDE deletion. The strain with a deletion of the ampDE operon showed a phenotype similar to that of mutant AC28. The present work demonstrates that both alginate production and bacterial encystment are greatly influenced by the bacterial ability to recycle its cell wall.

Alginates↗
PubMed2000

The GacS sensor kinase regulates alginate and poly-beta-hydroxybutyrate production in Azotobacter vinelandii.

Azotobacter vinelandii produces two polymers: the extracellular polysaccharide alginate and the intracellular polyester poly-beta-hydroxybutyrate (PHB). A cosmid clone (pSMU588) from an A. vinelandii gene library diminished alginate production by A. vinelandii mucoid strain ATCC 9046. The nucleotide sequence and predicted amino acid sequence of the locus responsible for the mucoidy suppression revealed 65% identity to Pseudomonas GacS, a transmembrane sensor kinase of the two-component regulators, whose cognate response regulator, GacA, is a global activator regulating several products and virulence factors. Plasmid pMC15, harboring gacS, and a strain carrying a gacS nonpolar mutation were constructed. Either pMC15 or the gacS mutation significantly reduced alginate production and transcription of algD, the gene coding for the key enzyme GDP-mannose dehydrogenase of the alginate biosynthetic pathway. We found that the gacS mutation also reduced PHB accumulation and impaired encystment. Taken together, these data indicate that in A. vinelandii the gacSA global system regulates polymer synthesis.

Alginates↗
PubMed2000

Contribution of artificial intelligence to the knowledge of prognostic factors in laryngeal carcinoma.

Many studies have investigated prognostic factors in laryngeal carcinoma, with sometimes conflicting results. Apart from the importance of environmental factors, the different statistical methods employed may have influenced such discrepancies. A program based on artificial intelligence techniques is designed to determine the prognostic factors in a series of 122 laryngeal carcinomas. The results obtained are compared with those derived from two classical statistical methods (Cox regression and mortality tables). Tumor location was found to be the most important prognostic factor by all methods. The proposed intelligent system is found to be a sound method capable of detecting exceptional cases.

Aged↗
PubMed2000

Effectiveness and pitfalls of initial highly active antiretroviral therapy in HIV-infected patients in routine clinical practice.

OBJECTIVE: To assess the long-term effectiveness of and factors associated with response to protease inhibitors (PIs) in a cohort of treatment-naive HIV-infected patients. DESIGN AND SETTING: Prospective study in a tertiary care centre. SUBJECTS: A total of 207 treatment-naive patients starting PIs from March 1996 to May 1998. MAIN OUTCOME MEASURES: Clinical, virological and immunological outcomes, and adherence to therapy after 12 months. RESULTS: Baseline median CD4 cell count and viral load were 160 cells/mm3 and 5 log10 copies/ml, respectively. After 48 weeks, 168 patients (81%) reached plasma HIV-RNA levels below 400 copies/ml, and the mean increase in CD4 cell count was 196 cells/mm3. Clinical events were observed in 29 patients (14%) after a median time of 100 days on therapy, yet mortality was extremely low (0.9%). By multivariate analysis, adherence over 90% [relative risk (RR), 16.66; 95% confidence interval (CI), 5.26-50; P=0.00001] and AIDS diagnosis at baseline (RR 0.35; 95% CI, 0.14-0.90; P=0.02) were the strongest predictors for virological suppression. An immunological recovery over 100 cells/mm3 was significantly associated with an initial virological response (RR 2.94; 95% CI, 1.31-6.66; P=0.009) and adherence over 90% (RR 3.44; 95% CI, 1.61-7.69; P=0.005). There were high rates of change with the first PI (40%), mostly due to adverse events (51%), but it did not compromise long-term effectiveness. CONCLUSIONS: Initial PI treatment in the clinical setting is able to reach equally good outcomes as those found in controlled trials. Changes in therapy due to toxicity do not compromise a successful outcome, which clearly depends on an adequate adherence to therapy.

Adolescent↗
PubMed2000

[Recommendations of GESIDA (Grupo de Estudio de SIDA)/National Plan on AIDS with respect to the anti-retroviral treatment in adult patients infected with the human immunodeficiency virus in the year 2000 (II)].

OBJECTIVE: To update the recommendations for antiretroviral therapy (ART) in adult HIV-infected persons according to the new scientific advances and the existence of new antiretroviral drugs in the last two years. METHODS: The ART recommendations have been condensed by a panel of experts from the Spanish AIDS Study Group (Grupo de Estudio de Sida-GESIDA) of the Spanish Infectious Diseases and Clinical Microbiology Society (SEIMC) and from the Clinical Advisory Panel (CAP) of the Secretariat of the Spanish National Plan on AIDS (SPNS) of the Ministry of Health. Three levels of evidence have been established depending if the data came from randomized and controlled studies, from cohort or case-control studies or from descriptive studies and expert opinions, for that purpose we have reviewed the advanced in HIV pathophysiology and results of efficacy (clinical, virologic and immunologic) and security (toxicity) from clinical trials involving ART lasting at least 12 months, from cohort studies and pharmacokinetic and security data of antoiretrovírico drugs, presented in international conferences or published in biomedical journals in the last two years. In each situation we have established either to recommend or to consider or not recommend ART. RESULTS: Nowadays, ART consistent of at least three drugs constitutes the election therapy for chronic HIV infection, since it delays clinical progression, increases significantly the survival and diminishes hospital admissions and associated costs. The decision to start ART must be based upon three elements: presence or absence of symptoms, plasma vírica load and CD4+ cells counts. Thus, in asymptomatic cases with a high CD4+ cells count (> 500/microliter) and low vírica load (< 10,000 copies/ml by branched DNA bDNA or < 20,000 copies/ml by reverse-transcription polymerase chain reaction [RT-PCR] or nucleic acid sequence based amplification [NASBA]) we recommend to delay ART. In symptomatic patients we recommend to start it, and in asymptomatic patients, we could recommend or consider ART initiation depending on the risk of progression, established by the vírica load and the CD4+ cells count. In any case, if therapy is started, the objective must be to reach an indetectable vírica load (< 50 copies/ml). The adherence to ART plays a key role for its initial moment and for the duration of the antiviral response. ART can achieve a restoration of cellular immunity inb the advanced patients. There are few therapeutic options in failing patients due to cross-resistance. Resistance studies can be useful in this setting. The toxicity (lypodistrophy) is a new and limiting factor of ART which requires to look for new therapeutic options. ART criteria for acute infection, pregnancy, post-exposure prophylaxis and when to use resistance testing are discussed. CONCLUSIONS: In this moment, there is a more conservative attitude towards starting ART than in previous recommendations in which a virus eradication was considered. On the other hand, the high number of disposable drugs, the more sensitive monitorization methods (plasma vírica load) and the possibility of performing resistance studies make therapeutic strategies more dynamic and individualized for each patient and situation. In any case, it is mandatory to ensure a perfect adherence to ART from the patients.

Acquired Immunodeficiency Syndrome↗
PubMed2000

Neuropsychological profile of a large kindred with familial Alzheimer's disease caused by the E280A single presenilin-1 mutation.

It was hypothesized that subjective memory complaints represent the earliest sign of dementia in carriers of the presenilin-1 (PS1) mutation. A total of 122 subjects (44 males, 78 females) were included in this study. Forty of them were positive for the mutation in the PS1 gene (mutation positive, MP) whereas 82 showed negative results (mutation negative, MN). Subjects were active, functionally normal, even though some of them complained of memory difficulties. Two groups of neuropsychological instruments were administered: (a) The Consortium to Establish a Registry for Alzheimer's Disease (CERAD) neuropsychological test battery (Morris et al., 1989), and (b) some additional neuropsychological tests (Raven Test, Wechsler Memory Scale, Rey-Osterrieth Complex Figure, Boston Naming Test, Naming of Categories, Boston Diagnostic Aphasia Examination, Memory of Three Phrases, Knopman Test, Digit Symbol, and Visual "A" Cancellation Test). Performance in both groups was quite similar. In a secondary analysis, the MP group was subdivided into two subgroups: without and with memory complaints. When comparing both subgroups, a better performance in the first subgroup was found throughout the different subtests. Statistically significant differences were observed in the following test scores: Mini-Mental State Examination, Naming Test (Low Frequency), Memory of Words Test, Recall of Drawings, Wechsler Memory Scale (Logical Memory, Associative Learning, and Total Score), Rey-Osterrieth Complex Figure (Immediate Recall Condition), Boston Diagnostic Aphasia Examination (Complex Ideational Material Subtest), Memory of Three Phrases Test, Serial Verbal Learning (maximum score and Delayed Recall), Knopman Test (First Trial, Second Trial, and Recall after 5 Minutes), Digit Symbol, and Visual "A" Cancellation Test (Additions). Results supported the hypothesis that memory complaints represent the earliest symptom of familial Alzheimer's disease. In addition to the memory difficulties, other minor cognitive impairments were also found, particularly, mild anomia, concentration difficulties and defects in the understanding of complex verbal material.

Journal Article↗
PubMed1999

Structural and functional characterization of the mouse p8 gene: promotion of transcription by the CAAT-enhancer binding protein alpha (C/EBPalpha) and C/EBPbeta trans-acting factors involves a C/EBP cis-acting element and other regions of the promoter.

Rat p8 mRNA was discovered because of its strong activation in pancreas during the acute phase of pancreatitis. We report here structural and functional data on the mouse p8 gene. The mouse p8 polypeptide is 80 amino acids long and shows 91% and 75% identity with its rat and human counterparts respectively. The p8 gene is organized into three exons interrupted by two introns. Promoter regions involved in the regulation of p8 gene expression in NIH 3T3 cells were analysed. Chloramphenicol acetyltransferase (CAT) reporter assays with progressive deletions of the 5' flanking region of the mouse p8 gene revealed four silencer elements located from nucleotides -5000 to -1472, -1471 to -671, -670 to -473, and -239 to -117 respectively. One positive element was identified between nucleotides -117 and -72. We identified a CAAT-enhancer binding protein (C/EBP) cis-acting element at position -111. Site-directed mutagenesis of this consensus site decreased promoter activity to 5% of that of the wild-type. An electrophoretic mobility-shift assay, using an oligonucleotide probe corresponding to the C/EBP consensus and nuclear extracts of NIH 3T3 cells transfected with C/EBPalpha or C/EBPbeta expression vectors, generated specific DNA-protein complexes that were supershifted with specific antibodies against C/EBPalpha and C/EBPbeta. Co-transfection with C/EBPalpha or C/EBPbeta expression vectors and the p-116/+36p8-CAT construct increased the reporter gene activity in a dose-dependent fashion. Surprisingly, overexpression of C/EBPalpha or C/EBPbeta still increased the promoter activity of both pC/EBPmut-116/+36p8-CAT (which contains the C/EBP mutated site) and the p-71/+36-CAT construct (which does not contain the C/EBP site). Collectively, these results show that C/EBPalpha and C/EBPbeta trans-acting factors can promote transcription of the mouse p8 gene (i) by direct binding to the C/EBP consensus site, and (ii) by enhancing the activity of other trans-acting factors interacting with the p8 promoter.

3T3 Cells↗