Biomedical subjects

L Barrios

Publications and source records attributed to L Barrios.

At least 19 recordsLinked to original sources

PubMed2006

Analysis of gamma-rays induced chromosome aberrations: a fingerprint evaluation with a combination of pan-centromeric and pan-telomeric probes.

PURPOSE: To evaluate the types of induced chromosome aberrations after the exposure of peripheral blood to gamma-rays by the simultaneous detection of all centromeres and telomeres; and to analyse the suitability of different radiation fingerprints for the assessment of radiation quality in cases of recent exposures. MATERIAL AND METHODS: Peripheral blood samples were irradiated at 2, 4 and 6 Gy of gamma-rays. Cytogenetic analysis was carried out by fluorescence in situ hybridization (FISH) technique with pan-centromeric and peptide nucleic acid (PNA)-telomeric DNA probes. Cells were analysed using a Cytovision FISH workstation, chromosome aberrations and the length of the acentric fragments were recorded. RESULTS: The total number of the incomplete chromosome elements was 276. The ratio between incomplete elements and multicentrics was 0.38. The number of acentrics was 1096, 71% were complete acentrics, 15% incomplete acentrics, and 14% interstitial fragments. The relative length of complete, incomplete and interstitial acentrics fragments were 2.70 +/- 0.04, 1.91 +/- 0.07, and 1.42 +/- 0.04 respectively. The mean value of the F-ratio was 11.5 higher than the one, 5.5, previously obtained for alpha-particles. For the G-ratio there was no difference between gamma-rays and alpha-particles, 2.8 and 2.8 respectively. The mean value of the H-ratio for gamma-rays, 0.25, was lower than for alpha-particles 0.40. CONCLUSION: The results support that the percentage of incomplete chromosome aberrations depends on radiation type; low-linear energy transfer (LET) radiation would produces less incomplete aberrations than high-LET radiation. The F- and H-ratios seem to be good indicators of radiation quality, although a real estimation of the H-ratio is only possible using pan-telomeric probes.

Adult↗

PubMed2006

Lercanidipine is an effective and well tolerated antihypertensive drug regardless the cardiovascular risk profile: The LAURA study.

To determine whether the antihypertensive effectiveness of lercanidipine was independent of the different cardiovascular risk levels. Patients with treated or untreated mild-to-moderate essential hypertension were included in a multicentre, prospective, non-comparative, open-label study. Patients received lercanidipine (10 mg/day, uptitrated to 20 mg/day) during 6 months. A total of 3175 patients, age 63 +/- 10 years, 51% women, were included. The cardiovascular risk was low in 237 patients, medium in 1396, high in 722, and very high in 820. At baseline, blood pressure (BP) was 159.5 +/- 11.7/95.2 +/- 7.4 mmHg. BP was progressively higher according to increase in cardiovascular risk. After 6 months of treatment, BP was 136.0 +/- 9.7/79.7 +/- 6.8 mmHg. The decrease in systolic BP and diastolic BP at each follow-up visit compared with baseline was statistically significant both in the intergroup and intragroup comparisons (p < 0.001). Mean decreases of systolic blood pressure (SBP) and diastolic blood pressure (DBP) were -18.5/-13.8 mmHg in the low risk group, -23/-15.2 mmHg in the medium risk group, -24.4/-16.1 mmHg in the high risk group, and -27.4/-17.4 mmHg in the very high risk group. Most frequent side effects were oedema (5.1%), headache (3.3%), flushes (2.5%), and asthenia (1%). Only 1.7% of patients discontinued antihypertensive medication because of adverse events. Tolerability of lercanidipine was independent of the cardiovascular risk group. Lercanidipine was effective and well-tolerated in patients with mild-to-moderate hypertension in the daily practice. The effectiveness and safety of the drug were independent of the degree of cardiovascular risk.

Aged↗

PubMed2005

Translocation yields in peripheral blood lymphocytes from control populations.

PURPOSE: To record the latest information on control levels of translocations in cultured human lymphocytes. MATERIALS AND METHODS: Control-level data from seven European laboratories that are using fluorescence in situ hybridization (FISH) techniques for retrospective biological dosimetry have been combined in a meta-analysis. After correction for the differing probe combinations used, tests of consistency are performed. The combined data have been used to test for individual variation, systematic variation with age, gender and smoking habits. RESULTS: There is a strong variation of translocation yield with age but no variation was detectable with gender or smoking habits. After correction for age, homogeneity tests showed that about 10% of individuals were outside the 95% confidence limits as opposed to 5% expected. From a total of 385, there is an excess of about 20 individuals most of whom have an unexpectedly high yield of translocations. CONCLUSIONS: For retrospective biological dosimetry purposes a generic age-dependent control level can be assumed. No other lifestyle factors such as smoking appear to have a significant effect on translocation yield.

Adolescent↗

PubMed2005

Review of translocations detected by FISH for retrospective biological dosimetry applications.

Several European laboratories have combined their research efforts to arrive at a consensus view on using fluorescence in situ hybridisation (FISH) for retrospective dosimetry. The aim of this review is to report these views and to highlight some areas where further work is needed. Translocations in the stable cells should be measured only in the cells that contain the full complement of the painted material. Two-way and one-way translocations should be combined with equal weight. The control level of translocations has a strong dependence on age, which has now been measured and the system has been calibrated. In conclusion, the technique works and a lifetime dose to the bone marrow from low-linear energy transfer radiation of 0.5 Gy above normal background levels can be measured for any individual. The main application is considered to provide an independent verification of lifetime doses to individuals who might form a part of an epidemiological study.

Calibration↗

PubMed2005

Assessment by cytogenetic analysis of the radioprotection properties of propolis extract.

Propolis obtained from honeybee hives has been used in folk medicine as an anti-inflammatory, anti-carcinogenic or immunomodulatory agent. In animal studies, the radioprotector effect of propolis has been attributed to its free-radical scavenging properties. The present study was carried out to show the protective properties of propolis extract against DNA damage induced by gamma irradiation. The evaluation of the radioprotective effect of propolis has been carried out by the analysis of chromosome aberration induction after several doses of gamma rays. The results of an analysis in the presence of ethanol extract of propolis (EEP) were compared with the dose-effect calibration curve for gamma-rays by analysis of chromosome aberrations without propolis, a decrease in the radiation-induced chromosome aberrations has been observed to be higher than 50% for all the doses.

Cells, Cultured↗

PubMed2005

Biological dosimetry in a group of radiologists by the analysis of dicentrics and translocations.

The results of a cytogenetic study carried out in a group of nine radiologists are presented. Chromosome aberrations were detected by fluorescence plus Giemsa staining and fluorescence in situ hybridization. Dose estimates were obtained by extrapolating the yield of dicentrics and translocations to their respective dose-effect curves. In seven individuals, the 95% confidence limits of the doses estimated by dicentrics did not include 0 Gy. The 99 dicentrics observed in 17,626 cells gave a collective estimated dose of 115 mGy (95% confidence limits 73-171). For translocations, five individuals had estimated doses that were clearly higher than the total accumulated recorded dose. The 82 total apparently simple translocations observed in 9722 cells gave a collective estimated dose of 275 mGy (132-496). The mean genomic frequencies (x100 +/- SE) of complete and total apparently simple translocations observed in the group of radiologists (1.91 +/- 0.30 and 2.67 +/- 0.34, respectively) were significantly higher than those observed in a matched control group (0.53 +/- 0.10 and 0.87 +/- 0.13, P < 0.01 in both cases) and in another occupationally exposed matched group (0.79 +/- 0.12 and 1.14 +/-0.14, P < 0.03 and P < 0.01, respectively). The discrepancies observed between the physically recorded doses and the biologically estimated doses indicate that the radiologists did not always wear their dosimeters or that the dosimeters were not always in the radiation field.

Adult↗

PubMed2004

A cytogenetic follow-up of some highly irradiated victims of the Chernobyl accident.

A follow-up of 10 highly irradiated men, mostly reactor crew, from the Chernobyl accident is described. Their pre-accident medical conditions and relevant medical status approximately 10-13 y later are listed. A comparison is made between estimates of their average whole-body penetrating radiation doses derived from several biological parameters. First estimates were based on their presenting severity of prodromal sickness, early changes in blood cell counts and dicentric chromosome aberrations in lymphocytes. In three cases ESR measurements on tooth enamel were also made. Retrospective dosimetry using FISH translocations was attempted 10-13 y later. This showed good agreement for those patients with the lower earlier dose estimates, up to about 3 Gy. For the others, extending up to about 12 Gy, the translocations indicated lower values, suggesting that in these cases translocations had somewhat declined. Repeated chromosomal examinations during the follow-up period showed an expected decline in dicentric frequencies. The pattern of decline was bi-phasic with a more rapid first phase, with a half-life of approximately 4 months followed by a slower decline with half-lives around 2-4 y. The rapid phase persisted for a longer time in those patients who had received the highest doses. 10-13 y later dicentric levels were still above normal background, but well below the translocation frequencies.

Adult↗

PubMed2004

Intraventricular craniopharyngiomas: topographical classification and surgical approach selection based on an extensive overview.

BACKGROUND: This retrospective study analyzes the clinical, neuroradiological, pathological and surgical characteristics of well-described intraventricular craniopharyngiomas with the aims of: (i) critically to review the criteria used to affirm the diagnosis of an intraventricular location (ii) defining more accurately this topographical diagnosis preoperatively, and (iii) to investigate factors influencing the surgical outcome. METHOD: Clinical, neuroradiological, pathological and surgical objective data of 104 well-described intraventricular craniopharyngiomas (IVC) reported in the literature, in addition to a new case, were analyzed. On the basis of the proofs provided for third ventricle intactness, a new topographical classification for IVC was developed, distinguishing between: (i) strict IVC, with a proved third ventricle floor integrity and (ii) non-strict IVC, without any reliable proof confirming the intactness of the third ventricle floor. Following this classification, clinical features, pathology and surgical outcome for strictly and non-strictly IVC were compared. FINDINGS: For 105 IVC compiled, 36 belonged to the strictly group and 69 to the non-strictly group. Two pathological features were associated with the non-strictly IVC group: a preferentially adamantinomatous pattern (p=0.106) and wider and tighter adherences to third ventricle margins (p=0.01). The non-strict topography was also associated with a worse postoperative outcome (p=0.046). There was a significant relationship between the surgical approach and the final outcome (p=0.05), being the translamina terminalis approach associated with the best outcome. CONCLUSIONS: Two different topographies might be considered among IVC: strict and non-strict intraventricular location. Non-strictly IVC have wider and tighter adhesions to third ventricle boundaries and this subtype is associated with a worse outcome.

Adolescent↗

PubMed2004

Allele-frequency determination of BsmI and FokI polymorphisms of the VDR gene by quantitative real-time PCR (QRT-PCR) in pooled genomic DNA samples.

The vdr gene is a candidate for osteoporosis susceptibility, with conflicting results in association studies. We have designed and optimized an individual allele-specific and DNA pooling PCR-based methodology to quantitate BsmI and FokI polymorphisms of the vdr gene and studied single-nucleotide polymorphisms (SNPs) from pooled DNA samples. The allele frequency in DNA pooling experiments has been analyzed by kinetic PCR: quantitative real-time PCR (QRT-PCR). A Spanish cohort of 225 healthy postmenopausal women was studied. Bone mineral density (BMD) was measured by dual-energy X-ray absorptiometry (DEXA) and quantitative ultrasound calcaneous densitometry. Allele-specific PCR amplification of BsmI and FokI genes showed full concordance with the PCR-RFLP approach. The prevalence of the three BsmI VDR genotypes was 19.1, 44.9 and 36.0% for BB, Bb and bb, respectively. In the case of the FokI locus, the prevalence of genotypes was 40.4, 48.0 and 11.6% for FF, Ff and ff, respectively. No positive correlation was found between polymorphism and BMD. The DNA pooling procedure was validated. No differences were found in allele frequencies and T-score data obtained using the high throughput DNA pooling approach, as compared to known individual frequencies. In our hands, this is a very useful approach to study quantitative (thus polygenic) traits like osteoporosis susceptibility.

Absorptiometry, Photon↗

PubMed2004

Analysis of alpha-particle induced chromosome aberrations in human lymphocytes, using pan-centromeric and pan-telomeric probes.

PURPOSE: The aim of the present study has been the evaluation of the incomplete chromosome aberrations induced after alpha-particle irradiation by the simultaneous detection of all centromeres and telomeres present in human lymphocytes. Moreover, a study on the lengths of the different acentric fragments is presented. MATERIALS AND METHODS: Attached lymphocytes were irradiated at doses of 0.2, 0.5, 0.7 and 1 Gy using a 241Am source. Flourescent in-situ hybridization (FISH) techniques were applied using pan-centromeric and pan-telomeric probes. All abnormal cells were digitalised and analysed using a Cytovision FISH workstation. The description of all abnormalities observed, and the length of the acentric fragments was recorded. RESULTS: A total of 378 incomplete chromosomes plus incomplete acentrics was found. Cases with more than 92 telomeres were not detected. The ratio between total incomplete elements and multicentrics was 1.00. The total number of acentric (ace) fragments was 822; 57% of them were complete fragments ace (+,+), 26% incomplete fragments ace (+,-), and 17% interstitial fragments ace(-,-); the mean relative lengths were 2.91 +/- 0.06, 1.91 +/- 0.07 and 1.63 +/- 0.07, respectively. In all three cases a secondary peak in the length distribution was found, corresponding to a relative length between 3.5 and 4. CONCLUSION: The percentage of incomplete rejoinings is higher after alpha-particle exposure than that described previously for low-linear energy transfer (LET) radiation exposures. The results seem to indicate that compared to low-LET radiation, after alpha-particle exposure centromere-containing elements are more likely to be repaired.Many interstitial fragments are large linear forms that cannot be considered as non-distinguishable acentric rings.

Alpha Particles↗

PubMed2004

Effect of DMSO on radiation-induced chromosome aberrations analysed by FISH.

The purpose of the present work was to determine if the described reduction in the frequency of radiation-induced chromosome aberrations by DMSO is homogeneous within different human chromosomes. Blood samples were irradiated with 4 Gy of X-rays in absence and presence of 0.5 M DMSO. FISH painting was carried out independently for human chromosomes 1, 2, 3, 4, 7, 11 and 12. The observed frequencies of apparently simple translocations and dicentrics for all these chromosomes, showed a homogeneous reduction when the irradiation was done in the presence of DMSO. Moreover, a better fit between the observed and expected frequencies was obtained when (DNA content)2/3 was used to calculate the expected frequencies, instead of just the DNA content. This result supports the idea that for exchange type aberrations, a better adjustment is obtained when the surface area of spherical chromosome territories is considered.

Chromosome Aberrations↗

PubMed2004

Analysis of translocations in stable cells and their implications in retrospective biological dosimetry.

The aim of the present study was to evaluate the influence of the exclusion of cells with unstable aberrations in the elaboration of dose-effect curves for translocations and their implications in biological dosimetry of past exposures. To establish dose-effect curves, peripheral blood samples were irradiated with 60Co gamma rays at ten different doses and the yield of translocations analyzed by FISH was considered in all cells and in stable cells (those without dicentrics, acentrics or rings). To discriminate transmissible translocations, the dose- effect curve for total apparently simple translocations in stable cells was chosen as the reference. In stable cells, dose- effect curves for apparently simple translocations without pseudosimple and complex-derived one-way patterns, tAbtBa and total translocations were obtained. None of these curves differed from the reference curve. When all cells were considered, only the curve for total translocations was significantly different from the reference curve. From the results obtained it can be concluded that the use of dose-effect curves for apparently simple translocations in stable cells and in all cells will give similar dose estimates in retrospective biological dosimetry studies. However, the use of dose-effect curves for total translocations in all cells will lead to underestimations of the dose mainly at high doses.

Adult↗

PubMed2002

Suitability of FISH painting techniques for the detection of partial-body irradiations for biological dosimetry.

Peripheral blood was irradiated with 2, 3, 4 or 5 Gy of X rays and was mixed with nonirradiated blood at five different dilutions to simulate partial-body irradiations. Analysis by FISH was performed using whole-chromosome painting probes for chromosomes 1, 4 and 11 in combination with a pancentromeric probe. Chromosome aberrations affecting the painted fraction were classified according to the PAINT nomenclature; other unstable aberrations affecting the unpainted material were also recorded. To evaluate the suitability of painting for dose assessment in partial-body irradiations, the ability of the u test and a proposed s test to detect the expected overdispersion and the similarity between the real doses and the doses estimated using Dolphin's approach were considered. For short-term biodosimetry, compared with solid-stained dicentric analyses, the suitability of FISH painting techniques for the detection of partial-body exposures is reduced, because of the decrease in the frequency of aberrations detected by FISH and in the number of cells with two or more aberrations. For reconstruction of past doses, when only complete apparently simple translocations in cells free of unstable aberrations were considered, the detection of the overdispersion and the accuracy of dose estimations were dramatically reduced. In a partial-body exposure, as the original dose increased, the whole-body dose estimated a long time after irradiation would tend to be lower, and the difference from the original dose would tend to be greater.

Adult↗

PubMed2001

School-associated violent deaths in the United States, 1994-1999.

CONTEXT: Despite the public alarm following a series of high-profile school shootings that occurred in the United States during the late 1990s, little is known about the actual incidence and characteristics of school-associated violent deaths. OBJECTIVE: To describe recent trends and features of school-associated violent deaths in the United States. DESIGN, SETTING, AND SUBJECTS: Population-based surveillance study of data collected from media databases, state and local agencies, and police and school officials for July 1, 1994, through June 30, 1999. A case was defined as a homicide, suicide, legal intervention, or unintentional firearm-related death of a student or nonstudent in which the fatal injury occurred (1) on the campus of a public or private elementary or secondary school, (2) while the victim was on the way to or from such a school, or (3) while the victim was attending or traveling to or from an official school-sponsored event. MAIN OUTCOME MEASURES: National estimates of risk of school-associated violent death; national trends in school-associated violent deaths; common features of these events; and potential risk factors for perpetration and victimization. RESULTS: Between 1994 and 1999, 220 events resulting in 253 deaths were identified; 202 events involved 1 death and 18 involved multiple deaths (median, 2 deaths per multiple-victim event). Of the 220 events, 172 were homicides, 30 were suicides, 11 were homicide-suicides, 5 were legal intervention deaths, and 2 were unintentional firearm-related deaths. Students accounted for 172 (68.0%) of these deaths, resulting in an estimated average annual incidence of 0.068 per 100 000 students. Between 1992 and 1999, the rate of single-victim student homicides decreased significantly (P =.03); however, homicide rates for students killed in multiple-victim events increased (P =.047). Most events occurred around the start of the school day, the lunch period, or the end of the school day. For 120 (54.5%) of the incidents, respondents reported that a note, threat, or other action potentially indicating risk for violence occurred prior to the event. Homicide offenders were more likely than homicide victims to have expressed some form of suicidal behavior prior to the event (odds ratio [OR], 6.96; 95% confidence interval [CI], 1.96-24.65) and been bullied by their peers (OR, 2.57; 95% CI, 1.12-5.92). CONCLUSIONS: Although school-associated violent deaths remain rare events, they have occurred often enough to allow for the detection of patterns and the identification of potential risk factors. This information may help schools respond to this problem.

Adolescent↗

PubMed2001

Cytogenetic sensitivity of three Fanconi anemia heterozygotes to bleomycin and ionizing radiation.

It is well known that Fanconi anemia (FA) patients show a hypersensitivity to the effect of cross-linking agents such as mitomycin C and diepoxybutane, while the sensitivity of these patients to ionizing radiation is controversial. Fanconi anemia heterozygotes do not show a hypersensitivity to the above-mentioned agents. However, bleomycin it is used to identify mutagen sensitive individuals, especially among head and neck cancer patients. We present here a preliminary study in which the mean frequencies of bleomycin-induced chromatid breaks (ctb) from three FA heterozygotes (X = 0.90, range 0.80-1.01) and 11 controls (X = 0.40, range 0.21-0.66) differ significantly (P<.001), indicating a high sensitivity to bleomycin of G(2) lymphocytes from these three FA heterozygotes. An increased sensitivity was not observed after exposure of G0 lymphocytes to 2 Gy of ionizing radiation.

Antimetabolites, Antineoplastic↗

PubMed2001

Cytogenetic analyses by fluorescence in situ hybridization (FISH) in hospital workers occupationally exposed to low levels of ionizing radiation.

An occupationally exposed population has been studied to evaluate the suitability of FISH painting techniques to detect chronic exposures to very low doses of ionizing radiation by the analysis of translocations. Whole-chromosome painting probes for chromosomes 1, 4 and 11 in combination with a pancentromeric probe have been employed. For comparison, a matched control population has also been studied. The mean genomic frequencies per 100 cells of total translocations in the control and exposed populations were 0.90 +/- 0.12 and 1.04 +/- 0.11, respectively. In the occupationally exposed population, no correlation between the frequencies of translocations and the doses received was found. When the two populations were compared, no significant differences were observed for the frequencies of the different chromosomal abnormalities examined. The absence of differences between control and exposed populations could be attributed to the very low-dose exposures recorded in the occupationally exposed population and to the wide range of individual frequencies of translocations observed.

Adult↗

PubMed2001

[Prevalence of low height and related risk factors in school children from Corrientes (Argentina)].

BACKGROUND: Height is the anthropometric indicator that best reflects the interaction between genetic and environmental factors. OBJECTIVE: The objective of this study was to measure height and to identify risk factors for low height in school children from Corrientes in Argentina. POPULATION AND METHODS: Between March and December 2000, a cross-sectional study was performed in 2,282 school children of both sexes, aged 6-14 years old, from two inner-city schools and two schools in the outskirts of the city. The variables studied were age, height, weight, birth weight, breastfeeding, maternal education and socioeconomic status. The values for height were turned into Z scores, and then compared with the reference standards of the National Center for Health Statistics in the United States. The statistical analysis was performed using the Chi-squared test for qualitative variables and ANOVA for quantitative variables. A significance of p < 0.05 was accepted. RESULTS: Prevalence of height below 2 standard deviation units and below 1 standard deviation unit was 4.6 % and 25.1 %, respectively. Maternal illiteracy, low birth weight, absence of breastfeeding and low socioeconomic status were significantly associated with low height. CONCLUSIONS: The prevalence of low height in this study was similar to that in other Latin-American countries. In our study the absence of breastfeeding, maternal illiteracy, low birth weight and low socioeconomic status were risk factors for low height.

Adolescent↗

PubMed2000

The influence of recombinant human granulocyte colony-stimulating factor on granulopoiesis in mice recovering from cyclophosphamide treatment.

Recombinant human granulocyte colony-stimulating factor (rhG-CSF) was evaluated for its effects on granulopoiesis recovery in mice pretreated with cyclophosphamide. The cytotoxic agent was administered on days 0 and 7. rhG-CSF therapy (injected from days 8 to 28) accelerated the recovery and maintained an increased level of peripheral blood neutrophils. Marrow granuloid precursors depression, due the second dose of cyclophosphamide, was prevented by rhG-CSF, but this hemopoietic growth factor was unable to increase these cells in a similar way to that observed in normal mice. This suggests a decreased granuloid marrow proliferation capacity in cyclophosphamide treated mice. In contrast, in the spleen, rhG-CSF highly increased granuloid precursors. However, the contribution of spleen to granuloid recovery was scarce. Mice receiving rhG-CSF after cyclophosphamide demonstrated a biphasic recovery pattern in bone marrow GM-CFU population. A first rebound of GM-CFUs was followed by a nadir and then a second recovery where GM-CFU progenitor cells were significantly increased was observed. On the other hand, rhG-CSF therapy highly increased the spleen GM-CFU numbers at days 24 to 28. Although rhG-CSF increased splenic granulopoiesis, this result shows that the bulk of granulopoiesis recovery due to rhG-CSF therapy in cyclophosphamide pretreated mice occurred in the marrow.

Animals↗