Biomedical subjects

N Jaramillo

Publications and source records attributed to N Jaramillo.

11 recordsLinked to original sources

PubMed2006

Chromosomal variation and genome size support existence of cryptic species of Triatoma dimidiata with different epidemiological importance as Chagas disease vectors.

The wide geographical distribution of Triatoma dimidiata, one of the three major vectors of Chagas disease, ranges from Mexico to northern Peru. Since this species occupies a great diversity of artificial and natural ecotopes, its eradication is extremely difficult. In order to assist control efforts, we used chromosome analyses and DNA amount as taxonomic markers to study genetic variability in populations of T. dimidiata from Mexico, Guatemala, El Salvador and Colombia. We differentiated three groups or cytotypes defined by characteristic chromosome C-banding patterns and genome size measured by flow cytometry. The three cytotypes are restricted to different geographic locations. Cytotype 1 occurs in Mexico (excluding Yucatán), Guatemala (excluding Petén), El Salvador and Colombia. Cytotype 2 occurs in Yucatán and cytotype 3 occurs in Petén. Cytotype 1, commonly associated with domestic and peridomestic environments but also inhabiting sylvatic ecotopes, is the most widespread and with major epidemiological significance. In contrast, the Yucatán cytotype inhabits wild ecotopes but increasingly enters houses, while the Petén cytotype appears exclusively sylvatic. We suggest that these cytotypes represent cryptic species of T. dimidiata with different epidemiological relevance as Chagas disease vectors. Poor ability to colonize human dwellings, together with their restricted geographic distribution, indicate that the Yucatán and Petén putative species probably have much less epidemiological significance than cytotype 1. Thus, the genetic markers we describe are powerful tools to differentiate cryptic species in T. dimidiata with different epidemiological significance, contributing to planning the most effective control measures.

Animals↗

PubMed2004

Changes associated with laboratory rearing in antennal sensilla patterns of Triatoma infestans, Rhodnius prolixus, and Rhodnius pallescens (Hemiptera, Reduviidae, Triatominae).

We examined changes in the array of antennal sensilla of three species of Triatominae (Triatoma infestans, Rhodnius prolixus, and R. pallescens) following their establishment for different periods in laboratory culture. In each case, the laboratory colonies were compared with conspecific samples taken directly from the field, by quantitative analysis of the sensilla arrays on the three distal segments of the antenna in terms of the densities of three types of chemoreceptors (basiconics and thick and thin walled trichoids) and one type of mechanoreceptor (bristles). Sensilla densities were compared by ANOVA or non-parametric tests, and by multivariate discriminant analysis. Strains of the same species reared in different laboratories showed significant differences in their sensilla arrays, especially when compared to field-collected material from the same geographic origin. A Bolivian strain of T. infestans reared in the laboratory for 15 years and fed at monthly intervals, showed greatest differences from its conspecific wild forms, especially in terms of reductions in the number of chemoreceptors. By contrast, an Argentine strain of T. infestans reared for 25 years in the laboratory and fed weekly, showed a relative increase in the density of mechanoreceptors. A Colombian strain of R. prolixus reared for 20 years and fed weekly or fortnightly, showed only modest differences in the sensilla array when compared to its wild populations from the same area. However, a Colombian strain of R. pallescens reared for 12 years and fed fortnightly, did show highly significant reductions in one form of chemoreceptor compared to its conspecific wild populations. For all populations, multivariate analysis clearly discriminated between laboratory and field collected specimens, suggesting that artificial rearing can lead to modifications in the sensory array. This not only supports the idea of morphological plasticity in these species, but also suggests caution in the use of long-established laboratory material for experimental studies designed to extrapolate the natural behaviour and physiology of these species.

Animals↗

PubMed1999

Multiple sclerosis: association to HLA DQalpha in a tropical population.

Studies performed in subtropical populations have found significant association between the phenotype multiple sclerosis (MS) and the major histocompatibility complex (MHC). We present the results of a case-control study conducted on a tropical population (Antioquia, Colombia) in order to detect a possible association between MS and HLA DQalpha (HLA DQA1*) alleles. Forty chromosomes belonging to MS patients were compared to two sets of controls (40 and 910 chromosomes, respectively). The HLA DQA1*0101 and DQA1*0102 alleles were found in a significantly higher proportion among the cases than among the controls, whereas the HLA DQA1*0103 allele was found in a significantly lower proportion of the cases. These results suggest that the association of HLA DQA1*0101, DQA1*0102 and DQA1*0103 to the MS phenotype found in Caucasian subtropical populations remains in individuals with MS inhabiting the tropics. This finding could mean that the major genetic component associated to the MHC in subtropical populations is the same in the tropics.

Adult↗

PubMed1999

Genetic structure and phylogenetic relationships of Colombian Trypanosoma cruzi populations as determined by schizodeme and isoenzyme markers.

Twenty-four Trypanosoma cruzi stocks isolated from vectors and from human and Didelphis marsupialis hosts from highly separated sylvatic localities in Colombia were characterized by isoenzyme and schizodeme analyses. The stocks were collected primarily from sylvatic ecotopes representing areas of low, moderate, and high endemicity for Chagas' diseases in Colombia. Parasites were characterized mainly by schizodeme analysis with the restriction enzyme Eco RI and the isoenzyme analysis was performed at 10 genetic loci. These analyses demonstrated an agreement between the classifications based on the isoenzyme analysis and on the restriction fragment length polymorphism patterns obtained with the Colombian stocks. There is clear evidence of demic subdivision between the eastern (E) and western (W) stocks separated by the Andean Mountains and Magdalena River, which is likely due to the geographic isolation generated by these topographic features. Heterozygosity estimates indicate that the E group could be more ancient than the W group. As was postulated in a previous study, these results are also compatible with the existence of a clonal population structure in Colombian sylvatic T. cruzi. Evidence presented here failed to demonstrate a correlation between the degree of endemy and genetic clustering. Finally, schizodeme and isoenzymatic analyses comparing Colombian T. cruzi stocks with others from Chile confirm that Colombian isolates are genetically related to zymodeme 1 and distant from zymodeme 2.

Animals↗

PubMed1999

Genetic variability of Colombian populations of Trypanosoma cruzi and Trypanosoma rangeli.

This paper presents our study of genetic variability of Trypanosoma cruzi and Trypanosoma rangeli strains isolated from different Colombian biological hosts, using multilocus enzyme electrophoresis for 15 enzyme systems and electrophoretic analysis of kinetoplast DNA (kDNA) digested with EcoRI and MspI endonucleases. Isoenzyme profiles were used to determine genotypes for each of the strains. Populations of T. cruzi and T. rangeli were found to have a polymorphic average of 86.7% and 26.7%, respectively. Schyzodeme analysis showed high variability for T. cruzi, since its genetic distance values were found to be greater than 50%, considerably higher than those previously reported for several T. cruzi strains from other countries. These results suggest that Colombian strains should be considered as genetically independent entities and are worth studying independently from each other to clearly establish their biological and clinical characteristics.

Animals↗

PubMed1998

Clonal population structure of Colombian sylvatic Trypanosoma cruzi.

Isoenzyme variability and evidence of genetic exchange were evaluated in 75 wild stocks of Trypanosoma cruzi obtained from different hosts from 5 geographical regions within the endemic area in Colombia. Cluster analysis of genetic variability was attempted. Thirty-three multilocus enzyme genotypes (clonets) were identified from 75 stocks, 27 of which clustered with zymodeme Z1 and 6 with zymodeme Z3. Two stocks isolated from human infections showed the potential risk to rural communities in Colombia. The stocks exhibited departures from Hardy-Weinberg expectations, including both fixed heterozygote and fixed homozygote demes, where both segregation and recombination were absent. To inspect for population subdivision that might falsely imply clonality in these stocks, Wright's F statistics were calculated. Theta values (Fst) were significantly different from 0 when 33 clonets, 27 Z1-like clonets, and 5 geographical subpopulations were compared; thus, a significant amount of divergence has occurred between and within them. In addition, linkage disequilibrium was detected for most possible pairwise comparisons of loci. In conclusion, the above results all support a scenario of long-term clonal evolution in Colombian sylvatic T. cruzi populations.

Animals↗

PubMed1997

[Primary stent treatment in the acute phase of myocardial infaction].

INTRODUCTION: Although direct balloon angioplasty has emerged as an alternative to thrombolytic therapy in patients with acute myocardial infarction, reocclusion and restenosis rates are limiting factors. We postulated that these limitations could be partly overcome by primary stenting of the responsible lesion. MATERIAL AND METHODS: Since January/94 we have studied 59 patients with acute myocardial infarction who were treated in the early phase (3.1 +/- 2 hours since the onset of symptoms) by elective Palmaz-Schatz stent implantation. No adjunctive thrombolytic therapy was associated. Two patients were in cardiogenic shock and were treated under percutaneous cardiopulmonary support. At cardiac catheterization a left ventriculography and coronary angiograms were obtained. Then, mechanical recanalization of the responsible lesion was performed. If the angiographic anatomy was considered suitable, a stent was implanted at the lesion. RESULTS: The infarct related artery was the left anterior descending in 29 patients, the circumflex in 14 and the right coronary artery in 16. At baseline conditions, 40 patients had a totally occluded artery and 19 showed a TIMI-grande 1 antegrade flow. One patient had an early clinical recurrence 4 days later, which required an additional divided Palmaz-Schatz stent at the distal portion of the lesion, in order to seal a residual dissection. All remaining patients had a favourable clinical course without major complications. Immediately after treatment the minimal lumen diameter was 3.2 +/- 0.4 mm and no residual stenosis was detectable at the treated segment. Six-month angiographic reevaluation was performed in all 29 (49%) eligible patients. Restenosis (> 50% stenosis) was detected in 6 out of the 29 evaluated patients (21%). CONCLUSIONS: Primary stent implantation in selected patients with an evolving myocardial infarction provides good initial and 6-month results.

Acute Disease↗

PubMed1993

Computational structural analysis based on intravascular ultrasound imaging before in vitro angioplasty: prediction of plaque fracture locations.

OBJECTIVES: This in vitro study was designed to test the hypothesis that a structural analysis based on intravascular ultrasound images of atherosclerotic vessels obtained before angioplasty can be used to predict plaque fracture locations and balloon pressures required to cause fracture. BACKGROUND: Intravascular ultrasound imaging performed before interventional procedures has potential for providing information useful for guiding therapeutic strategies. METHODS: Intravascular imaging was performed on 16 atherosclerotic human iliac vessel segments obtained freshly at autopsy; balloon angioplasty was then performed with 1-min inflations at 2 atm, increasing in 2-atm increments until fracture of the lumen surface occurred. Fracture locations were confirmed by histopathologic examination. Structural analysis of these images was performed with a large strain finite element analysis of the image that calculated the distribution of stress in the vessel with 2 atm of lumen pressure. RESULTS: Structural analysis demonstrated a total of 30 high circumferential stress regions in the vessels (mean 1.9 high stress regions/vessel). A total of 18 plaque fractures occurred in the 16 vessel segments. Of the 17 fractures that occurred in the 15 specimens with regions of high circumferential stress, 14 (82%) occurred at a high stress region (p < 0.0001). However, there was no significant relation between the peak stresses estimated by structural analysis and the ultimate balloon inflation pressure required to cause fracture. CONCLUSIONS: Structural analysis based on intravascular ultrasound imaging performed before in vitro balloon angioplasty can predict the locations of plaque fracture that usually accompany angioplasty. However, these data suggest that intravascular ultrasound may not be useful for predicting the ultimate balloon inflation pressure necessary to cause fracture, possibly because of the variable fracture properties and microscopic structure of atherosclerotic tissues.

Angioplasty, Balloon↗

PubMed1992

Extremely divergent histone H4 sequence from Trypanosoma cruzi: evolutionary implications.

Trypanosoma cruzi presents six histones electrophoretically resolved in three gel systems. Indirect evidence shows that one of these histones, named e, corresponds to H4 in other species. We present evidence that histone e is H4 by sequencing its amino terminal end. The amino terminal of T. cruzi histone H4, unlike that of other H4s examined thus far is not blocked. Moreover, this protein presents two variants. This partial amino acid sequence of T. cruzi histone H4 differs greatly from homologous sequences of human, yeast, or Tetrahymena. Since the conservatism of the core histones (H2A, H2B, H3, and H4) is clearly illustrated by comparative sequence analyses, the data shown here demonstrates that T. cruzi histone H4 is the most divergent reported. Quantitative analysis of the data suggests that the rate of substitutions in the histone H4 amino terminal sequence varies among different lineages. We postulate a slow-down in the evolutionary rate of histone H4 amino terminal domain in the metazoa branch related perhaps to the appearance of a novel function for this domain.

Amino Acid Sequence↗

PubMedDate not supplied

[Multiple sclerosis: epidemiological-genetic studies in the population of Antioquia, Colombia. Disequilibrium of HLA DQ alpha].

INTRODUCTION AND OBJECTIVE: Discrimination and quantification of the environmental and genetic components involved in developing multiple sclerosis (MS) have not been made. In order to discriminate these components we have ascertained affected individuals by MS belonging to the Paisa community from Antioquia, Colombia, a state localized in the tropical area of South America, to detect eventual linkage disequilibrium to HLA, locus DQ alpha, which could demonstrate the relevance of the genetic component. DEVELOPMENT: A contingence analysis among case-control HLA DQ alpha genotype distributions, by using Monte Carlo resampling method to solve small number sample, showed that there are significant differences between the two groups. We observe that HLA DQ alpha 1.1, 1.2 allele frequencies were higher in the cases than in the controls. Also, there was significant HLA DQ alpha 3 allele lower frequency (p < 0.05) in the cases than in the controls. CONCLUSIONS: Similar results have been described in other Caucasian populations living in non tropical areas. Before results could indicate that the Caucasoid populations genetic component implied in the susceptibility to MS have remained in Paisa community, whether the environmental component, being meaningful to develop MS.

Adult↗

PubMedDate not supplied

[Factorial and discriminant analyses of neuropsychological variables in familial and sporadic late onset Alzheimer disease].

INTRODUCTION: Prevalence of late onset Alzheimer's disease (LOAD) both familial and sporadic is increasing with the raising proportion of third-age population. There are evidences either supporting or rejecting the existence of differences in the behavior of neuropsychological variables between familial and sporadic cases of LOAD. OBJECTIVE: To identify neuropsychological variables discriminating between familial and sporadic cases of LOAD, in order to detect clinical manifestations that may provide information on the pathological process of the neurodegenerative process. PATIENTS AND METHODS: Using sequential sampling, we selected individuals affected by LOAD according to the criteria of the DSM-IV and NINCS-ADRDA. The following neuropsychological protocol was used: CERAD, Wisconsin, Phonological Fluency, Rey's Figure, Raven, A Cancellation Test, WAIS (Arithmetic); also used were: Global Deterioration Scale, Functional Assessment Staging of Reisberg (FAST), Barthel and Yesavage. Parametrical and non-parametrical univariate, factorial (principal components) and discriminant analyses were performed. In total, 52 patients were analyzed (average age: 74.8 years; mean age at onset of the disease: 69 years; time of disease's evolution: 5.7 years; average of educational level: 6.4 years). RESULTS: No significant statistical differences were found in clinical or neuropsychological variables between familial and sporadic cases of LOAD. Additionally, neither variables nor models were detected discriminating significantly between them. CONCLUSION: Familial and sporadic cases of LOAD present the same clinical and neuropsychological phenotype which makes very probable that sporadic cases are low penetrance familial ones.

Age of Onset↗