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A Serrano

Publications and source records attributed to A Serrano.

At least 91 records · Page 5Linked to original sources
PubMed1998

Glyceraldehyde-3-phosphate dehydrogenase from Tetrahymena pyriformis: enzyme purification and characterization of a gapC gene with primitive eukaryotic features.

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH, EC.1.2.1.12) was purified to electrophoretic homogeneity from an amicronucleated strain of the ciliate Tetrahymena pyriformis using a three-step procedure. The native enzyme is an homotetramer of 145 kDa exhibiting absolute specificity for NAD. In its catalytic properties it is similar to other glycolytic GAPDHs. Chromatofocusing analysis showed the presence of only one basic GAPDH isoform with an isoelectric point of 8.8. Western blots using a monospecific polyclonal antibody raised against the T. pyriformis GAPDH showed a single 36-kDa band corresponding to the enzyme subunit in the cytosolic protein fraction of this strain and the closely related species, both from the class Oligohymenophorea, Paramecium tetraurelia. No bands were immunodetected in the ciliate Colpoda inflata (class Colpodea) and in the diverse eukaryotes and eubacteria tested. A 0.5-kb DNA fragment which corresponds to an internal region of a gapC gene was generated by polymerase chain reaction using cDNA of T. pyriformis as template. This gene codes for a basic GAPDH protein with eukaryotic-diplomonad signatures and exhibits a codon usage biased in the manner typical for T. pyriformis genes. Southern blots performed both under homologous and heterologous conditions using this amplified cDNA fragment as a probe, indicated that it should be the only gapC gene present in the macronuclear genome of this ciliate, its expression being confirmed by Northern blot analysis. These results are discussed in connection with the peculiar genomic organization of ciliates and in the context of protist evolution.

Amino Acid Sequence↗
PubMed1998

Differential expression of MHC class II genes in lung tumour cell lines.

Molecular characterization of HLA class II expression was investigated in five lung tumour cell lines at the protein and mRNA levels. The cell lines exhibited a differential expression of HLA-DR, HLA-DP and HLA-DQ products and also showed differences in the inducibility of HLA class II genes by gamma-IFN. Gamma-IFN stimulation induced only HLA-DR expression to varying degrees in three cell lines, while only one cell line showed stimulation for HLA-DP and none for HLA-DQ antigens. These results suggest locus-specific regulation for the three loci. The presence of DR protein on the cell-surface membrane was always positively correlated with the presence of HLA-DR mRNA in the cells. After treatment with 5-azacytidine in the A549 cell line, which expressed the lowest values, there was no effect on HLA class II levels. This suggested that methylation does not play an important role in the lack of MHC class II antigen expression. In addition to studying mRNA levels of HLA class II antigens, we analysed mRNA of the proto-oncogene c-myc and observed a positive correlation of two mRNA: the increments in HLA-DR expression were associated with increments in c-myc expression. This suggests a relationship between the regulatory and HLA-DR antigens control the expression of c-myc and HLA-DR antigens in lung tumour cell lines.

Actins↗
PubMed1998

Anaplastic carcinoma of the fimbriated end of the fallopian tube as an incidental finding.

Carcinoma of the fallopian tube is an uncommon gynecologic tumor that is usually diagnosed in an advanced stage. The majority are tubal in origin, and rarely arise in the fimbriae. It appears that the latter may have a worse prognosis than the equivalent stage of tubal tumors that do not arise from fimbriae. We present a case of a 53-year-old white woman with FIGO stage 1 primary anaplastic carcinoma of the fimbriated end of the fallopian tube that was incidentally found in a specimen resected during a total abdominal hysterectomy with bilateral salpingo-oophorectomy. The patient underwent surgery because of findings of severe cervical dysplasia, atypia and dyskaryosis on a routine Papanicolau smear. Postoperative recovery was uneventful, and follow-up abdominal and pelvic CT scans showed no evidence of disease. However, because of the poor degree of differentiation, focal serosal infiltration and fimbrial end tube site of the carcinoma she was considered to have a high risk of recurrence. Thus, it was recommended that she undergo adjuvant chemotherapy with cyclophosphamide and carboplatin. Eighteen months after diagnosis, the patient is alive and well with no evidence of disease.

Adenocarcinoma↗
PubMed1997

Functional complementation of an Escherichia coli gap mutant supports an amphibolic role for NAD(P)-dependent glyceraldehyde-3-phosphate dehydrogenase of Synechocystis sp. strain PCC 6803.

The gap-2 gene, encoding the NAD(P)-dependent D-glyceraldehyde-3-phosphate dehydrogenase (GAPDH2) of the cyanobacterium Synechocystis sp. strain PCC 6803, was cloned by functional complementation of an Escherichia coli gap mutant with a genomic DNA library; this is the first time that this cloning strategy has been used for a GAPDH involved in photosynthetic carbon assimilation. The Synechocystis DNA region able to complement the E. coli gap mutant was narrowed down to 3 kb and fully sequenced. A single complete open reading frame of 1,011 bp encoding a protein of 337 amino acids was found and identified as the putative gap-2 gene identified in the complete genome sequence of this organism. Determination of the transcriptional start point, identification of putative promoter and terminator sites, and orientation of the truncated flanking genes suggested the gap-2 transcript should be monocystronic, a possibility further confirmed by Northern blot studies. Both natural and recombinant homotetrameric GAPDH2s were purified and found to exhibit virtually identical physicochemical and kinetic properties. The recombinant GAPDH2 showed the dual pyridine nucleotide specificity characteristic of the native cyanobacterial enzyme, and similar ratios of NAD- to NADP-dependent activities were found in cell extracts from Synechocystis as well as in those from the complemented E. coli clones. The deduced amino acid sequence of Synechocystis GAPDH2 presented a high degree of identity with sequences of the chloroplastic NADP-dependent enzymes. In agreement with this result, immunoblot analysis using monospecific antibodies raised against GAPDH2 showed the presence of the 38-kDa GAPDH subunit not only in crude extracts from the gap-2-expressing E. coli clones and all cyanobacteria that were tested but also in those from eukaryotic microalgae and plants. Western and Northern blot experiments showed that gap-2 is conspicuously expressed, although at different levels, in Synechocystis cells grown in different metabolic regimens, even under chemoheterotrophic conditions. A possible amphibolic role of the cyanobacterial GAPDH2, namely, anabolic for photosynthetic carbon assimilation and catabolic for carbohydrate degradative pathways, is discussed.

Amino Acid Sequence↗
PubMed1997

[Experience with radical prostatectomy as treatment of localized cancer of the prostate at the Fundación Santa Fe de Bogotá, Colombia].

OBJECTIVE: To analyze the experience of the Fundación Santa Fe de Bogotá with radical prostatectomy in the treatment of localized prostatic cancer. METHODS: A retrospective study was conducted on 108 patients with localized carcinoma of the prostate stage T1-T2NxM0 submitted to radical prostatectomy from 1989 to 1994. RESULTS: Preoperatively, 50% of the patients had a PSA < 10 ng/ml and 14% had values that fell within the normal ranges of 0-4 mg/ml. A family history of prostate cancer was detected in 9.3% of the patients. The prostate cancer was clinically understaged in 75% of the patients, particularly those with stages T2a and T2b, and less significantly in those with stage T2c. Considering only those patients in whom the pathological staging had disclosed the cancer was not localized, this incidence accounted for 52% (n = 57). The presence of surgical margins was approximately 36%. The tumor recurrence rate was 26.9% and the complication rate was 6.8%. CONCLUSION: The relatively low complication rate in the present series shows that radical prostatectomy is a safe procedure that achieves good results if the cases are carefully selected and the diagnostic test are widely utilized.

Age Distribution↗
PubMed1996

Occurrence of a differential expression of the glyceraldehyde-3-phosphate dehydrogenase gene in muscle and liver from euthermic and induced hibernating jerboa (Jaculus orientalis).

A cDNA clone which contains the near-complete open reading frame (ORF) encoding glyceraldehyde-3-phosphate dehydrogenase (GAPDH, EC 1.2.1.12) was obtained by screening a muscle cDNA library of jerboa (Jaculus orientalis), a true hibernating rodent, with a PCR-amplified 0.5-kb genomic DNA probe from an internal region of the gene. The 1.1-kb cDNA clone consists of a 927-bp ORF which codifies for 309 aa, about 93% of the original GapC gene encoding the 36-kDa protein, and a 3'-noncoding region of 167 bp. The full-length aa sequence of GAPDH was achieved by sequencing the N-terminal region of the purified protein completing the missing part in the cDNA clone. Both nt and aa sequences exhibit a high degree of homology to other mammalian GAPDHs. The expression of the GapC gene was studied in skeletal muscle and liver of euthermic and hibernating jerboas both on the mRNA level by Northern blot hybridization using the cDNA clone as a probe and on the protein level by Western blot immunodetection using an antibody raised against muscle GAPDH. A clear decrease (about threefold) in the amount of GapC mRNA, a single 1.2-kb transcript, was observed in muscle of hibernating jerboa when compared with the same tissue from the euthermic animal. This mRNA level decrease directly correlates with a reduction in both protein amount and specific activity in crude protein extracts. In contrast, both GAPDH protein and GapC mRNA levels remained unchanged in liver from euthermic and hibernating jerboas although the enzymatic activity was also about threefold lower in the hibernating tissue. These result, together with previous data obtained from protein studies [Soukri et al. (1995) Biochim. Biophys. Acta 1243, 161-168 and (1996) 1292, 177-187] indicate that jerboa GAPDH is regulated by different mechanisms during hibernation in these tissues, that is, at transcriptional level in muscle and at posttranslational level in liver. The reduced GAPDH activity should result in both cases in a decrease of the glycolytic flux that would eventually contribute to the dramatic metabolic depression of this dormant state.

Amino Acid Sequence↗
PubMed1996

Methylated CpG points identified within MAGE-1 promoter are involved in gene repression.

The MAGE-1 gene, expressed in some tumors of different histological origins, codes for a tumor antigen recognized by cytotoxic T lymphocytes. The gene is not expressed in normal tissues with the exception of testes. The present study was designed to investigate the relationship between methylation of the MAGE-1 promoter and inactivation of the MAGE-1 gene. We examined the extent to which MAGE-1 B'B promoter sequences are methylated in tumor-cell lines, in order to determine whether methylation correlates with MAGE-1 expression. Using methylation-sensitive restriction analysis followed by polymerase chain reaction (PCR), we found an inverse correlation between methylation of the MAGE-1 B'B region and MAGE-1 expression. An unmethylated state was identified in DNA from sperm and some tumor-cell lines of different origins. In contrast, a hypermethylation state was found in leukocytes and other MAGE-1 non-expressing cells. Furthermore, treatment with 5-aza-2'-deoxycytidine, a demethylating agent, induced MAGE-1 expression in tumor-cell lines in which we found no direct relation between transcriptional activity of the B'B region and MAGE-1 expression. Binding of the nuclear factors to the B'-methylated probe was strongly inhibited, indicating that methylation of cytosine interferes directly in the binding of transcriptional factors.

Antigens, Neoplasm↗
PubMed1996

Thioesterase and protein deacylase activities of porcine pancreatic phospholipase A2.

The thioesterase activity of porcine pancreatic phospholipase A2 has been investigated with non-phospholipid substrates. The acyl-CoA hydrolase activity towards acyl-CoA derivatives is specific for long chain fatty acids (14 C, 16 C) but is unable to hydrolyze short chain acyl-CoA compounds (below 8 C). The same enzyme also shows protein deacylase activity liberating [3H]palmitic acid from [3H]palmitoyl-acyl carrier protein.

Acyltransferases↗
PubMed1996

Evidence for a posttranslational covalent modification of liver glyceraldehyde-3-phosphate dehydrogenase in hibernating jerboa (Jaculus orientalis).

The specific activity of D-glyceraldehyde-3-phosphate (G3P) dehydrogenase (phosphorylating) (GPDH, EC 1.2.1.12) found in liver of induced hibernating jerboa (Jaculus orientalis) was 2-3-fold lower than in the euthermic animal. However, the comparative analysis of the soluble protein fraction of these tissues by SDS-PAGE and Western blotting showed no significant changes in the intensity of the 36 kDa protein band of the GPDH subunit. After using the same purification procedure, the GPDH from liver hibernating jerboa exhibited lower values for both apparent optimal temperature and specific activity than the enzyme from the euthermic animal. Similar non-linear Arrhenius plots were obtained, but the Ea values calculated for the GPDH from hibernating tissue were higher. Although in both purified enzyme preparations four isoelectric GPDH isoforms were resolved by chromatofocusing, those of hibernating liver exhibited more acidic pI values (pI 7.3-6.1) than the hepatic isoforms of euthermic animals (pI 8.7-8.1). However, all liver GPDH isoforms exhibited similar native and subunit molecular masses and cross-reacted with an antibody raised against muscle GPDH. The comparison of the kinetic parameters of both purified preparations and the main isoforms isolated from euthermic and hibernating tissues showed the decreased catalytic efficiency of hibernating enzyme being exclusively due to a lower Vmax for both substrates G3P and NAD+. Phosphodiesterase treatment of cell-free extracts increased GPDH activity in the case of hibernating liver only. The pI of the main isoform purified from this tissue, about 6.9, changed after this treatment to an alkaline value (pI 8.44) similar to those of the euthermic GPDH isoforms. Differential ultraviolet absorption spectra of these isoforms indicated that a substance absorbing at 260 nm, that was released by the phosphodiesterase digestion, was present in the enzyme of hibernating tissue. Incubation of purified GPDH with the NO-releasing agent sodium nitroprussite produced under conditions that promote mono-ADP-ribosylation a dramatic decrease of activity (up to 60%) of both euthermic and phosphodiesterase-treated hibernating preparations but only a marginal inhibition of the hibernating enzyme. These data suggest that the liver GPDH of hibernating jerboa exhibits a posttranslational covalent modification, being probably a mono-ADP-ribosylation. The resulting inhibition of enzyme activity could contribute to the wide depression of the glycolytic metabolic flow associated with mammalian hibernation.

Alkaline Phosphatase↗
PubMed1996

Community outbreak of acute respiratory infection by Mycoplasma pneumoniae.

We present the results of the investigation of an epidemic outbreak of Mycoplasma pneumoniae infection which affected 95 schoolchildren from certain village in Catalonia. The investigation took an epidemiological, clinical and microbiological approach, detecting by capture enzyme-immunoassay technique the presence of IgM antibodies against M. pneumoniae. All cases occurred over a 9 week period. The attack rate in children under five was 18% and 8.2% in those from 5-14 years. The age mean and standard deviation of the cases was 5.2 +/- 3.5 years, the range being from 9 months to 14 years. Cough was the most common clinical manifestation (87.4%), followed by fever (67.4%), asthenia (21.1%), abdominal pain (18.9%), vomiting (13.7%), earache (8.4%) and sore throat (6.3%). There was no significant difference in the distribution of symptoms according to age groups. IgM anti M. pneumoniae was positive in 36 (37.9%) of the samples analysed. Treatment chosen in most cases (90) was eritromicin and there was a correct evolution in all cases except for two clinical and radiological recurrences. Hospitalization was only necessary in 5 cases. The present findings are important to emphasize the high incidence of M. pneumoniae respiratory disease in children under 5, and suggests that with respiratory processes affecting very young children, a possible Mycoplasma pneumoniae infection should also be considered and the necessary action taken in the form of early and appropriate treatment.

Adolescent↗
PubMed1996

Loss of an HLA haplotype in pancreas cancer tissue and its corresponding tumor derived cell line.

A combination of immunohistochemical, biochemical, and recombinant DNA techniques were used to investigate class I expression in 26 pancreatic adenocarcinomas and 6 autologous tumor-derived cells. The prevalence of HLA losses was found to be comparable to that observed in other tumor types (> 35%), using monomorphic and locus-specific antibodies. In one patient, the original tumor tissue, a tumor derived cell line (IMIM-PC-2), and EBV-transformed lymphocytes were available for study. The patient's phenotype was A25, A30, B18, B18. However, A30 allele product could not be detected in the original tumor not in the cultured tumor cells. In addition, A30 allele could not be isolated from cDNA or genomic clones from the cultured tumor cells whereas it was isolated from the autologous lymphoblastoid cell line. Using isoelectric focusing analysis a significant reduction in the B18 heavy chain product was also observed in the tumor cell line, IMIM-PC-2, suggesting the absence of expression of one allele. Further studies revealed loss of heterozygosity at DR and other loci of chromosome 6 and cytogenetic data strongly suggested deletion of a full chromosome 6. This work indicates for the first time that loss of a full HLA haplotype occurs in tumor tissue and suggests that this mechanism may contribute to the progression of human cancer.

Adenocarcinoma↗
PubMed1996

Characterization of a gastric tumor cell line defective in MHC class I inducibility by both alpha- and gamma-interferon.

Alpha/beta and gamma type interferons (IFN), act through distinct cell surface receptors and induce transcription of an overlapping sets of genes. MHC class I genes are inducible by both type of interferons. We have analyzed a gastric tumor cell line, AGS, which was completely defective in MHC class I response to interferon-alpha and gamma. Northern blot analysis demonstrated that the lack of IFN response was related with the absence of up-regulation of specific HLA class I mRNA. Electrophoretic mobility shift assays in various tumor cell lines after IFN-alpha and IFN-gamma treatment showed differential binding of the transcriptional factors to MHC class I regulatory elements. Comparison of kappa-B binding activity showed that IFN-alpha and IFN-gamma induced opposite changes in NF-kappa B binding activity in AGS cells, indicating that the absence of MHC class I response in AGS appears to be independent of kappa-B activity. In contrast, there were remarkable differences in the level of transcriptional factor binding to an interferon-responsive sequence element (IRSE), between AGS and other interferon-responsive tumor cell lines. This result suggests that the low level of transcriptional factor binding to IRSE in AGS cells was responsible of the lack of induction of MHC class I antigens. In this context, overlapping factors in the signal transduction pathway of both type I and II interferons may be involved in the non-responsiveness of this gastric carcinoma tumor cell line.

Adenocarcinoma↗
PubMed1996

[Granular cell tumor of the breast with lymph node neuro-naevic cell inclusions: a double pitfall to avoid].

AIMS: To draw attention to the possibility of simultaneous occurrence of pitfalls in breast pathology. MATERIAL AND METHODS: Presentation of a curious case with an association of granular cell tumour of the breast and neuro-naevic inclusions in axillary lymph nodes, first interpreted as metastatic mammary carcinoma. DISCUSSION: Non malignant inclusions in axillary lymph nodes, rare but not unusual, may be erroneously interpreted as metastasis of carcinoma, establishing a wrong diagnosis of malignity in the breast. It is important to recognize this type of lesion and the possibility of their coexistence to correct the diagnosis. An approach to the histogenesis of this lesion is presented.

Breast Neoplasms↗
PubMed1995

Biphasic transforming growth factor-beta production flanking the pro-inflammatory cytokine response in cerebral trauma.

We determined the time-course of the production of transforming growth factor-beta (TGF-beta) after fluid-percussion injury using a bioassay. Biophasic production of TGF-beta composed mainly of TGF-beta 2 was detected in the ipsilateral cortex, with a first peak 30 min and a second peak 48 h after the lesion, flanking the transient production of tumor necrosis factor-alpha and interleukin-6 occurring between 5 and 18 h after trauma. This temporal pattern suggested that TGF-beta plays alternatively a pro- and anti-inflammatory role in the regulation of the brain cytokine network in response to injury, providing an endogenous mechanism for the control of the inflammatory reaction in traumatic brain injury.

Animals↗
PubMed1995

Topography of the 27- and 31-kDa electron transport proteins in the onion root plasma membrane.

Plasma membranes purified from onion roots contain two distinct NAD(P)H-dehydrogenases of 27 and 31 kDa that differ in their physicochemical properties, substrate specificities and inhibitors sensitivities. The 27-kDa enzyme used both NADH and NADPH as electron donors. The 31-kDa enzyme was fully specific for NADH and accounted for the bulk of NADH-ferricyanide oxidoreductase. We have used NADPH- and NADH-ferricyanide oxidoreductase activities as markers for investigating the orientation of the 27- and 31-kDa enzymes at the plasma membrane, respectively. These activities were assayed in right-side-out vesicles isolated by two-phase partition, inside-out vesicles obtained by treatment with the detergent Brij 58 and membranes permeabilized with Triton X-100. Upon addition of Brij 58 to right-side-out plasma membrane vesicles, both NADPH- and NADH-ferricyanide oxidoreductases were activated to the same degree as the plasma membrane H(+)-ATPase. Redox activities were similar when measured in the presence of either Brij 58 or Triton X-100. Our results demonstrate that both enzymes expose their catalytic sites toward the cytoplasmic side of the plasma membrane.

Allium↗
PubMed1995

Coenzyme Q reductase from liver plasma membrane: purification and role in trans-plasma-membrane electron transport.

A specific requirement for coenzyme Q in the maintenance of trans-plasma-membrane redox activity is demonstrated. Extraction of coenzyme Q from membranes resulted in inhibition of NADH-ascorbate free radical reductase (trans electron transport), and addition of coenzyme Q10 restored the activity. NADH-cytochrome c oxidoreductase (cis electron transport) did not respond to the coenzyme Q status. Quinone analogs inhibited trans-plasma-membrane redox activity, and the inhibition was reversed by coenzyme Q. A 34-kDa coenzyme Q reductase (p34) has been purified from pig-liver plasma membranes. The isolated enzyme was sensitive to quinone-site inhibitors. p34 catalyzed the NADH-dependent reduction of coenzyme Q10 after reconstitution in phospholipid liposomes. When plasma membranes were supplemented with extra p34, NADH-ascorbate free radical reductase was activated but NADH-cytochrome c oxidoreductase was not. These results support the involvement of p34 as a source of electrons for the trans-plasma-membrane redox system oxidizing NADH and support coenzyme Q as an intermediate electron carrier between NADH and the external acceptor ascorbate free radical.

Animals↗