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Biomedical subjects

A Fraile

Publications and source records attributed to A Fraile.

At least 19 recordsLinked to original sources
PubMed2005

Total anorectal reconstruction: a novel technique.

The aim of this report is to describe a novel technical approach to total anorectal reconstruction after a Miles operation for rectal cancer. Recreation of an internal neosphincter with colonic muscle, the implant of an artificial bowel sphincter (ABS), and the association of a coloplasty constitute a complete substitution of the lost structures and functions. Although the patient developed a late complication which required removal of the ABS, the functional result of the technique can be considered as excellent, to be demonstrated by the incontinence score and quality of life with and without the colostomy.

Aged↗
PubMed2004

Variability and genetic structure of the population of watermelon mosaic virus infecting melon in Spain.

The genetic structure of the population of Watermelon mosaic virus (WMV) in Spain was analysed by the biological and molecular characterisation of isolates sampled from its main host plant, melon. The population was a highly homogeneous one, built of a single pathotype, and comprising isolates closely related genetically. There was indication of temporal replacement of genotypes, but not of spatial structure of the population. Analyses of nucleotide sequences in three genomic regions, that is, in the cistrons for the P1, cylindrical inclusion (CI) and capsid (CP) proteins, showed lower similar values of nucleotide diversity for the P1 than for the CI or CP cistrons. The CI protein and the CP were under tighter evolutionary constraints than the P1 protein. Also, for the CI and CP cistrons, but not for the P1 cistron, two groups of sequences, defining two genetic strains, were apparent. Thus, different genomic regions of WMV show different evolutionary dynamics. Interestingly, for the CI and CP cistrons, sequences were clustered into two regions of the sequence space, defining the two strains above, and no intermediary sequences were identified. Recombinant isolates were found, accounting for at least 7% of the population. These recombinants presented two interesting features: (i) crossover points were detected between the analysed regions in the CI and CP cistrons, but not between those in the P1 and CI cistrons, (ii) crossover points were not observed within the analysed coding regions for the P1, CI or CP proteins. This indicates strong selection against isolates with recombinant proteins, even when originated from closely related strains. Hence, data indicate that genotypes of WMV, generated by mutation or recombination, outside of acceptable, discrete, regions in the evolutionary space, are eliminated from the virus population by negative selection.

Citrullus↗
PubMed2001

Variability and genetic structure of plant virus populations.

Populations of plant viruses, like all other living beings, are genetically heterogeneous, a property long recognized in plant virology. Only recently have the processes resulting in genetic variation and diversity in virus populations and genetic structure been analyzed quantitatively. The subject of this review is the analysis of genetic variation, its quantification in plant virus populations, and what factors and processes determine the genetic structure of these populations and its temporal change. The high potential for genetic variation in plant viruses, through either mutation or genetic exchange by recombination or reassortment of genomic segments, need not necessarily result in high diversity of virus populations. Selection by factors such as the interaction of the virus with host plants and vectors and random genetic drift may in fact reduce genetic diversity in populations. There is evidence that negative selection results in virus-encoded proteins being not more variable than those of their hosts and vectors. Evidence suggests that small population diversity, and genetic stability, is the rule. Populations of plant viruses often consist of a few genetic variants and many infrequent variants. Their distribution may provide evidence of a population that is undifferentiated, differentiated by factors such as location, host plant, or time, or that fluctuates randomly in composition, depending on the virus.

Gene Frequency↗
PubMed2000

Pathologic gambling in Parkinson's disease: a behavioral manifestation of pharmacologic treatment?

We describe 12 patients with Parkinson's disease and pathologic gambling. This association has apparently never been reported. The patients were selected from a Parkinson's disease unit of 250 patients. They met Diagnostic and Statistical Manual of Mental Disorders, 4th edition, criteria for pathologic gambling. All patients underwent a neurologic, psychiatric, and psychologic examination, specifically noting the presence or absence of psychopathology in the spectrum of impulse control disorder and the nature of the gambling. Ten patients started gambling after the onset of Parkinson's disease and treatment with levodopa. The pathologic behavior was exclusively present or was markedly increased in "on" periods in 11 patients. All patients had motor fluctuations at the time of the study. Slot machines were the preferred source of gambling for 10 patients, similar to the Spanish gambling population. That the gambling behavior appears more often in the "on" periods of motor fluctuations and that it begins after the onset of Parkinson's disease in most patients and worsens with levodopa therapy suggest that it could be related to the dopaminergic tone in patients with Parkinson's disease and motor fluctuations (that is, it could represent a behavioral manifestation of pharmacologic treatment).

Adult↗
PubMed2000

Molecular epidemiology of Cucumber mosaic virus and its satellite RNA.

Molecular analysis of viral isolates can yield information that facilitates an understanding of virus epidemiology and has been termed molecular epidemiology. This approach has only recently been applied to plant viruses. Results on the molecular epidemiology of Cucumber mosaic virus (CMV) and its satellite RNA (satRNA) in Spain, where CMV is endemic in vegetable crops are presented here. To characterise the genetic structure of CMV populations, c. 300 isolates, representing 17 outbreaks (i.e. sub-populations) in different crops, regions and years, were compared. Genetic analyses of CMV isolates were done by ribonuclease protection assay of cRNA probes representing RNA1, RNA2 and the two open reading frames in RNA3. All isolates belonged to one of three genetic types: Sub-group II and two types of Sub-group I. The genetic structure of the 17 sub-populations varied randomly, without correlation with location, year, or host plant species. Thus, CMV in Spain shows a metapopulation structure with local extinction and random recolonisation from local or distant virus reservoirs. The frequency of mixed infections and of new genetic types generated by reassortment of genomic segments or by recombination was also estimated. Results indicate that heterologous genetic combinations are not favoured. About 30% of CMV isolates were supporting a satRNA. The frequency of CMV isolates with a satRNA differed for each sub-population, being c. 1 in eastern Spain in 1990 and decreasing to c. 0 in distant regions and in subsequent years. Molecular analyses of CMV-satRNA isolates show high genetic diversity, due both to the accumulation of point mutations and to recombination. The CMV-satRNA population is a single, unstructured one. Thus, the CMV-satRNA population has a genetic structure and dynamics different from those of its helper virus. This indicates that CMV-satRNA has spread epidemically on the extant virus population from an original reservoir in eastern Spain. The relevance of these results for the control of CMV infections is discussed.

Cucumber Mosaic Virus Satellite↗
PubMed2000

Multiple infection, recombination and genome relationships among begomovirus isolates found in cotton and other plants in Pakistan.

Begomoviruses occur in many plant species in Pakistan and are associated with an epidemic of cotton leaf curl disease that has developed since 1985. PCR analysis with primer pairs specific for each of four already sequenced types of DNA-A of cotton leaf curl virus (CLCuV-PK types a, 26, 72b and 804a), or for okra yellow vein mosaic virus (OYVMV), indicated that many individual naturally infected plants of cotton and other malvaceous species contained two or three begomovirus sequences. Similarly, sequence differences among overlapping fragments of begomovirus DNA-A, amplified from individual naturally infected plants, indicated much multiple infection in malvaceous and non-malvaceous species. Some cotton plants contained DNA-A sequences typical of begomoviruses from non-malvaceous species, and some non-malvaceous plants contained sequences typical of CLCuV-PK. Some DNA-A sequences were chimaeric; they each included elements typical of different types of CLCuV-PK, or of different malvaceous and/or non-malvaceous begomoviruses. Often an apparent recombination site occurred at the origin of replication. No complete CLCuV-PK DNA-A sequence was found in malvaceous or non-malvaceous species collected in Pakistan outside the area of the cotton leaf curl epidemic but chimaeric sequences, including a part that was typical of CLCuV-PK DNA-A, did occur there. We suggest that recombination among such pre-existing sequences was crucial for the emergence of CLCuV-PK. Recombination, following multiple infection, could also explain the network of relationships among many of the begomoviruses found in the Indian subcontinent, and their evolutionary divergence, as a group, from begomoviruses causing similar diseases in other geographical regions.

Base Sequence↗
PubMed2000

TAP1 and TAP2 polymorphism in Spanish patients with ankylosing spondylitis.

OBJECTIVE: HLA-B27 is strongly associated with ankylosing spondylitis (AS); however, the association is not absolute and additional susceptibility factors in the MHC region could play a role. We studied the influence of polymorphism in the transporter associated with antigen processing (TAP) genes, including point mutations not previously analyzed. METHODS: HLA-B*27 typing and subtyping as well as TAP1 and TAP2 typing were performed by PCR-RFLP. Forty-four AS individuals were compared to 61 ethnically matched random individuals and 35 B*27-positive healthy unrelated individuals as controls. RESULTS: The frequency of the TAP1B allele was significantly greater in the patient group compared with the random controls (corrected p value (p(c)) = 0.035; odds ratio = 15.8, p = 0.01). A greater frequency was also evident when B*27-positive patients and B*27- positive healthy controls were compared, although it did not reach statistical significance. No differences were observed in TAP2 alleles between the groups studied. DISCUSSION: We did not find a primary association between TAP2 polymorphism and AS susceptibility. Formal confirmation of a linkage between the TAP and HLA-B loci would probably require family studies.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1999

Genetic variability of natural populations of cotton leaf curl geminivirus, a single-stranded DNA virus

Reports on the genetic variability and evolution of natural populations of DNA viruses are scarce in comparison with the abundant information on the variability of RNA viruses. Geminiviruses are plant viruses with circular ssDNA genomes that are replicated by the host plant DNA polymerases. Whitefly-transmitted geminiviruses (WTG) are the agents of important diseases of crop plants and best exemplify emerging plant viruses. In this report we have analyzed the genetic diversity of cotton leaf curl geminivirus (CLCuV), a typical emerging WTG. No genetic differentiation was observed between isolates from different host plant species or geographic regions. Thus, the analyzed isolates represented a unique, undifferentiated population. Genetic variability, estimated as nucleotide diversities at synonymous positions in open reading frames (ORFs) for the AC1 (=replication) protein and coat protein (CP = AV1), was very high, exceeding the values reported for different genes in several plant and animal RNA viruses. This was unexpected in a virus that uses the DNA replication machinery of its eukaryotic host. Diversities at nonsynonymous positions, on the other hand, indicated that variability may be constrained in the genome of CLCuV. The ratio of nonsynonymous-to-synonymous substitutions varied for the different ORFs: they were higher for CP than for AC1 and lower still for the AC4 and AV2 ORFs, which overlap AC1 and CP ORFs, respectively. Analysis of nucleotide diversities at synonymous and nonsynonymous positions of the AC4 and AV2 ORFs suggest that their evolution is constrained by AC1 and CP, respectively. Data suggest that AC4 and AV2 are new genes that may have originated by overprinting on the preexistent AC1 and CP genes. Evidence for recombination was found for the AC1 and CP ORFs and for the noncoding intergenic region (IR). Data indicate that the origin of replication is a major recombination point in the IR, but not the only one. Analyses of the IR also suggest that recombinants may be frequent in the population and that recombination may have an important role in the generation of CLCuV variability.

Journal Article↗
PubMed1998

HSP70 gene polymorphisms in ankylosing spondylitis.

Despite the strength of the association of ankylosing spondylitis (AS) with HLA-B27, other genetic elements could play a possible role in the pathophysiology of AS. Because of the localization, in the proximity of the HLA-B locus, and the involvement of heat shock proteins (HSP) in the immune response, we analyzed the influence of HSP70 gene polymorphism on the susceptibility to AS. HSP70-1, HSP70-2 and HSP70-hom genotypes were analyzed by PCR-RFLP in patients with AS and in healthy controls. The results obtained in the present study showed that there are not significant differences in the distribution of HSP70-hom genotypes, whereas significant differences in HSP70-1 and HSP70-2 genotypes between AS patients and random controls were found. However, when the distribution of these genotypes were compared in B*27-matched AS patients and controls, the differences disappeared. These data suggest that the polymorphism of HSP70 genes was not independently associated with AS, and that the differences in HSP70-1 and HSP70-2 genotypes among AS patients and controls appears to be due to the linkage disequilibrium between HSP70 alleles and HLA-B*27.

Alleles↗
PubMed1998

Tumor necrosis factor gene polymorphisms in ankylosing spondylitis.

Despite the strength of the association of ankylosing spondylitis (AS) with HLA-B27, other genetic elements could play a possible role in the pathophysiology of AS. In view of its gene location, in the proximity of the HLA-B locus, and biological effects, tumor necrosis factor (TNF) genes are potential candidates for additive susceptibility factors to AS. TNFalpha and TNFbeta genotypes were analyzed by PCR-RFLP in 57 patients with AS, 102 random controls and 30 HLA-B*27-positive controls. No significant differences of TNFalpha promoter variations at position -308 and -238 were found in AS patients in comparison with controls. The -244 polymorphism was not detected in our population. The TNFbeta genotype frequency was significantly different between AS patients and random controls. However, when the distribution of the TNFbeta genotype was compared in B*27-positive AS patients and controls, these differences disappeared. In addition, we demonstrated that the TNFbeta*1 was in strong linkage disequilibrium with the B*27 allele, which may explain the differences observed for the TNFbeta genotype among AS patients and random controls. Our data suggest that the polymorphisms of TNFalpha and TNFbeta genes do not have an independent effect on AS susceptibility.

Alleles↗
PubMed1998

HLA-B*27 subtyping by PCR-RFLP in Spanish patients with ankylosing spondylitis.

We describe the use of restriction analysis on PCR-amplified DNA for detecting all B*27 subtypes except B*2710 and B*2711 (i.e. from B*2701 to B*2709). After detecting B*27 by Sty I, double digestions consisting of Sty I plus another informative enzyme led to subtype assignment. We used mismatched primers to create restriction sites when necessary. The method avoids group-specific amplifications and other laborious optimization procedures. It was successfully tested on a panel of well characterized cell lines covering different B*27 subtypes. Then, we studied a group of 57 ankylosing spondylitis patients and 746 controls from the south of Spain. B*27 showed a very strong association with the disease (OR=211.27, P=10(-7)). B*2702 and B*2705 distribution in controls (20% and 77.1%, respectively) differed from previously reported data in the Spanish population. We unexpectedly found the B*2707 allele in our population (one control).

HLA-B27 Antigen↗
PubMed1998

Analysis of LMP and TAP polymorphisms by polymerase chain reaction-restriction fragment length polymorphism in rheumatoid arthritis.

OBJECTIVE: The aim of this study was to investigate the relation between the polymorphism of large molecular weight proteasome (LMP) (LMP2-LMP7) and transporter associated with antigen processing (TAP) (TAP1-TAP2) genes and rheumatoid arthritis (RA). METHODS: Sixty RA patients and 102 ethnically matched unrelated healthy subjects were typed for LMP, TAP, and disease associated HLA-DRB1 alleles by using a new strategy based on polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) with amplification created restriction sites. RESULTS: The polymorphism of LMP (LMP2-LMP7) and TAP (TAP1-TAP2) genes was examined in shared epitope positive and negative RA patients and controls. No significant differences in the LMP or TAP allele frequencies were observed between the total patient and control groups or the patients and controls groups or the patients and controls positive or negative for the shared epitope. CONCLUSION: The data suggest that the polymorphisms of LMP and TAP genes do not have an important influence in the pathogenesis of RA, although larger studies will be needed to provide more conclusive evidence on the role of these genes in RA. A new, highly reliable strategy for typing LMP alleles is also described.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1997

Contribution of mutation and RNA recombination to the evolution of a plant pathogenic RNA.

The nucleotide sequence of 17 variants of the satellite RNA of cucumber mosaic virus (CMV-satRNA) isolated from field-infected tomato plants in the springs of 1989, 1990, and 1991 was determined. The sequence of each of the 17 satRNAs was unique and was between 334 and 340 nucleotides in length; 57 positions were polymorphic. There was much genetic divergence, ranging from 0.006 to 0.141 nucleotide substitutions per site for pairwise comparisons, and averaging 0.074 for any pair. When the polymorphic positions were analyzed relative to a secondary structure model proposed for CMV-satRNAs, it was found that there were significantly different numbers of changes in base-paired and non-base-paired positions, and that mutations that did not disrupt base pairing were preferred at the putatively paired sites. This supports the concept that the need to maintain a functional structure may limit genetic divergence of CMV-satRNA. Phylogenetic analyses showed that the 17 CMV-satRNA variants clustered into two subgroups, I and II, and evolutionary lines proceeding by the sequential accumulation of mutations were apparent. Three satRNA variants were outliers for these two phylogenetic groups. They were shown to be recombinants of subgroup I and II satRNAs by calculating phylogenies for different molecular regions and by using Sawyer's test for gene conversion. At least two recombination events were required to produce these three recombinant satRNAs. Thus, recombinants were found to be frequent ( approximately 17%) in natural populations of CMV-satRNA, and recombination may make an important contribution to the generation of new variants. To our knowledge this is the first report of data allowing the frequency of recombinant isolates in natural populations of an RNA replicon to be estimated.

Base Sequence↗
PubMed1997

Polymorphism at the TNF loci in rheumatoid arthritis.

The purpose of this work was to analyze the possible influence of TNF loci polymorphism on the susceptibility and/or the disease profile of rheumatoid arthritis (RA). Tumor necrosis factor (alpha and beta) genotypes were determined in 60 patients with RA and 102 healthy subjects by a method based on PCR-RFLP with amplification-created restriction sites. The results obtained in the present study showed that there is not a significant association of either TNF alpha promoter variation (at positions -308 and -238) or TNF beta polymorphism with susceptibility to RA. However, a significant difference in the mean age at disease onset was found between -238 TNF alpha genotypes. In addition, a difference in the presence of nodular disease was observed between -308 TNF alpha genotype. The results of this study suggests that the TNF alpha gene may play a role in the disease profile of rheumatoid arthritis.

Alleles↗
PubMed1997

HLA-B*27 typing by PCR-restriction fragment length polymorphism.

In this study we describe the use of PCR-RFLP for genotyping HLA-B*27. A 557 bp fragment from HLA-B locus is amplified and subjected to digestion with StyI. The presence of B*27 is detected on electrophoresis by the appearance of 431 + 126 bp pattern. The same pattern could be obtained only for the very infrequent allele B*7301. However, this allele was not amplified in the B73 sample tested with the primers and conditions used in this study. Nevertheless, we have designed two PCR-RFLP approaches for separating these alleles. The PCR-RFLP method was tested on a panel of forty-three cell lines and applied to fifty spondyloarthritic patients and one-hundred-eighty healthy subjects. Given its robustness, technical simplicity and cost-effectiveness, we think that this method can be incorporated for routine use in most laboratories.

Cell Line↗
PubMed1997

Heat shock protein 70 gene polymorphisms in rheumatoid arthritis.

A role for heat shock proteins (hsp) in rheumatoid arthritis has been suggested. In addition, the specific binding of human HSP70 protein to QKRAA and RRRAA motifs within the HV3 region of disease-associated DRB1*0401 and DRB1*1001 molecules, respectively, has been proposed as being relevant to rheumatoid arthritis. The purpose of this work was to analyze the influence of HSP70 gene polymorphism on the susceptibility to or severity of rheumatoid arthritis and to investigate the possible contribution of these HSP70 polymorphisms in determining HLA-DRB1*0401/*1001 disease association. The frequencies of the HSP70-1, HSP70-2 and HSP70-hom genotypes were analyzed by PCR-RFLP using BsrBI, PstI and NcoI enzymes, respectively, in patients with rheumatoid arthritis and in healthy controls. No significant differences were observed when HSP70 allele distribution between the groups under study were compared. Moreover, we did not observe any significant difference in HSP70 allele frequencies between patients positive for HLA-DRB1*0401/*1001 alleles and matched controls. Our data indicate that HSP70 gene polymorphisms do not appear to be relevant in the susceptibility to or severity of rheumatoid arthritis.

Arthritis, Rheumatoid↗
PubMed1997

A century of tobamovirus evolution in an Australian population of Nicotiana glauca.

The evolution over the past century of two tobamoviruses infecting populations of the immigrant plant Nicotiana glauca in New South Wales (NSW), Australia, has been studied. This plant species probably entered Australia in the 1870s. Isolates of the viruses were obtained from N. glauca specimens deposited in the NSW Herbarium between 1899 and 1972, and others were obtained from living plants in 1985 and 1993. It was found that the NSW N. glauca population was infected with tobacco mosaic tobamovirus (TMV) and tobacco mild green mosaic tobamovirus (TMGMV) before 1950 but only with TMGMV after that date. Half the pre-1950 infections were mixtures of the two viruses, and one was a recombinant. Remarkably, sequence analyses showed no increase in the genetic diversity among the TMGMV isolates over the period. However, for TMV, the genetic diversity of synonymous (but not of nonsynonymous) differences between isolates varied and was correlated with their time of isolation. TMV accumulated to smaller concentrations than TMGMV in N. glauca plants, and in mixed experimental infections, the accumulation of TMV, but not of TMGMV, was around 1/10 that in single infections. However, no evidence was found of isolate-specific interaction between the viruses. We conclude that although TMV may have colonized N. glauca in NSW earlier or faster than TMGMV, the latter virus caused a decrease of the TMV population below a threshold at which deleterious mutations were eliminated. This phenomenon, called Muller's ratchet, or a "mutational meltdown," probably caused the disappearance of TMV from the niche.

Australia↗