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At least 613 records · Page 34Linked to original sources
PubMed2006

Association between telomere length and BCL2 gene rearrangements in low- and high-grade non-Hodgkin lymphomas.

Telomere length based on terminal restriction fragment (TRF) assay was evaluated in cells of bone marrow, lymph node, or both from 53 non-Hodgkin lymphoma (NHL) patients: 44 with follicular lymphoma (FL) and 9 with secondary diffuse large B-cell lymphoma (S-DLBCL) to FL. The TRF data were correlated with BCL2 gene rearrangement evaluated by nested and long-distance polymerase chain reaction approaches. Peripheral blood cells from 12 healthy donors were studied as controls. Both groups of NHL patients revealed significant telomere shortening compared with controls (8.50 +/- 0.50 kb; P < 0.001), with significantly shorter TRFs in S-DLBCL (3.49 +/- 0.26 kb) than in FL cases (4.09 +/- 0.12 kb; P = 0.047). Patients carrying BCL2 gene rearrangements showed longer telomere length (4.19 +/- 0.14 kb) than those without (3.51 +/- 0.14 kb; P = 0.05). Among patients with FL, telomere length was shortest in patients without t(14;18), intermediate when breakpoints occurred in the minor breakpoint cluster region (3.97 +/- 0.33 kb), and greater when breakpoints occurred in the major breakpoint region (MBR) (4.24 +/- 0.15 kb), with significant differences between MBR and BCL2-negative cases (P = 0.033). Our findings support the existence of alternative genetic pathways involved in the origin of these FL subsets. Even though the number of S-DLBCL cases was small, they showed the shortest telomere length, suggesting that this parameter reflects another genetic alteration involved in the progression from FL to a higher-grade lymphoma.

Adult↗
PubMed2005

Effects of internal displacement and resettlement on the mental health of Turkish children and adolescents.

AIMS: To evaluate the effects of internal displacement and resettlement within Turkey on the emotional and behavioral profile of children, age 5-18 after controlling for possible confounding and demographic variables. METHOD: We conducted a national population survey using a self-weighted, equal probability sample. We compared the CBCL, TRF and YSR responses regarding children with (n = 1644) and without (n = 1855) experience of internal displacement. We examined the effects of gender, age, paternal employment, resettlement, urban residence and physical illness. RESULTS: The children and adolescents with internal displacement had significantly higher internalizing, externalizing and total problem scores on the CBCL and YSR, and higher internalizing scores on the TRF. The effect of displacement was related to higher internalizing problems when factors like physical illness, child age, child gender and urban residence were accounted. The overall effect was small explaining only 0.1-1.5% of the total variance by parent reports, and not evident by teacher reports. DISCUSSION: To our knowledge the present study is the first to examine Turkish children and adolescents with and without experience of internal displacement. The results are consistent with previous immigration studies: child age, gender, presence of physical illness and urban residence were more important predictors of internalization and externalization problem scores irrespective of informant source.

Adolescent↗
PubMed2004

Rapid telomere attrition in cardiac tissue of the ageing Wistar rat.

Many studies show an association between ageing and mean telomere length in DNA isolated from peripheral blood mononuclear cells, few studies have examined less accessible tissues. This study has two objectives: (i) to define the best method to prepare rodent DNA for telomere length measurement by Southern blotting and (ii) to determine whether there are differential rates of telomere attrition in different rodent tissues. We found that the use of agarose plugs for DNA isolation was essential for the accurate measurement of rodent telomere length. Tissue was collected from neonatal (3 days) or aged (18-24 months) male Wistar rats and terminal restriction fragment (TRF) length was measured by Southern blotting. Cardiac tissue from aged rats showed a 38% loss of TRF length compared with newborn animals (p<0.001, n=13), this contrasts with much smaller reductions in brain (1.6%), liver (14.2%), kidney (8.9%) and lung (9.7%). This study demonstrates that the methods of DNA preparation are critical for accurate measurement of telomeres in rodent tissues. Moreover, we show differential rates of telomere attrition in rat tissues, the heart being most susceptible to telomere loss. These observations could have important implications for the study of age-specific changes in tissue function.

Aging↗
PubMed2005

Genomic organization of telomeric and subtelomeric sequences of Leishmania (Leishmania) amazonensis.

Telomeres are DNA-protein complexes that protect linear chromosomes from degradation and fusions. Telomeric DNA is repetitive and G-rich, and protrudes towards the end of the chromosomes as 3'G-overhangs. In Leishmania spp., sequences adjacent to telomeres comprise the Leishmania conserved telomere associated sequences (LCTAS) that are around 100 bp long and contain two conserved sequence elements (CSB1 and CSB2), in addition to non-conserved sequences. The aim of this work was to study the genomic organization of Leishmania (Leishmania) amazonensis telomeric/subtelomeric sequences. Leishmania amazonensis chromosomes were separated in a single Pulsed Field Gel Electrophoresis (PFGE) gel as 25 ethidium bromide-stained bands. All of the bands hybridized with the telomeric probe (5'-TTAGGG-3')3 and with probes generated from the conserved subtelomeric elements (CSB1, CSB2). Terminal restriction fragments (TRF) of L. amazonensis chromosomes were analyzed by hybridizing restriction digested genomic DNA and chromosomal DNA separated in 2D-PFGE with the telomeric probe. The L. amazonensis TRF was estimated to be approximately 3.3 kb long and the telomeres were polymorphic and ranged in size from 0.2 to 1.0 kb. Afa I restriction sites within the conserved CSB1 elements released the telomeres from the rest of the chromosome. Bal 31-sensitive analysis confirmed the presence of terminal Afa I restriction sites and served to differentiate telomeric fragments from interstitial internal sequences. The size of the L. amazonensis 3' G-overhang was estimated by non-denaturing Southern blotting to be approximately 12 nt long. Using similar approaches, the subtelomeric domains CSB1 and CSB2 were found to be present in a low copy number compared to telomeres and were organized in blocks of 0.3-1.5 kb flanked by Hinf I and Hae III restriction sites. A model for the organization of L. amazonensis chromosomal ends is provided.

Animals↗
PubMed2006

Hormonal differences between psychotic and non-psychotic melancholic depression.

BACKGROUND: The dexamethasone suppression test (DST) is the main hormonal disturbance in psychotic depression compared to non-psychotic depression. However, although there have been many studies of individual hormonal axes in depression, few multi-axial studies have been reported. This study aims to examine hormonal differences between these groups of patients through three functional hormonal tests: DST, thyroid stimulating hormone response to thyroid releasing hormone (TSH-TRF) and growth hormone response to growth hormone releasing factor (GH-GRF). METHODS: Forty inpatients meeting DSM-III-R criteria for major depressive episode with melancholia (21 non-psychotic and 19 psychotic) were studied. Dexamethasone suppression test, TSH-TRF and GH-GRF tests were undertaken for all patients. RESULTS: In the whole melancholic sample, 80.0% showed disturbances in at least one hormonal axis, 40.0% in two axes and 5.0% in all three axes. Basal and post-dexamethasone cortisol levels were significantly higher in psychotic than in non-psychotic patients. An association between post-dexamethasone cortisol and blunted GH-GRF response was demonstrated in those with psychotic depression. In the whole sample, GH blunting was found in 62.5% of patients, DST non-suppression in 37.5% and TSH blunting in 25.0% (no differences were found between psychotic and non-psychotic patients). LIMITATIONS: Sample was restricted to melancholia and unknown factors may influence hormonal responses to stress. CONCLUSIONS: Hormonal disturbances in depression are more evident when studying several axes, being the HPA and the GH axes the most prominents. Psychotic depression showed more HPA disturbance than non-psychotic depression. Influence of the HPA on the GH axis is discussed.

Depressive Disorder↗
PubMed2005

Lanthanide-based luminescent assays for ligand-receptor interactions.

The evaluation of receptor ligand interactions is important in the field of drug discovery and development. Currently these interactions are typically measured with cumbersome (low throughput) radiolabels. Higher throughput screens are available such as fluorescent measurements of G-protein coupled receptor-induced Ca2+ increases or fluorescence anisotropy, yet these have limited applicability and/or low signal to noise. Hence, there is a need to develop more widely applicable and more sensitive labels that can be used to monitor ligand-receptor interactions. Lanthanides provide an attractive alternative to the traditional labels used for monitoring ligand-receptor interactions. The incorporation of lanthanide labels into traditional assays used to assess receptor-ligand interactions can make these assays more affordable, less time consuming and amenable to automation. Lanthanides can be coupled to ligands and provide strong luminescent signals that can be detected using time-resolved fluorescence (TRF) methods. This approach takes advantage of the long fluorescence lifetime of the lanthanide and can detect less than one attomole of europium in a multiwell plate sample. This short review provides a basic introduction into lanthanides and TRF and describes some of the recent assays which have utilized lanthanides as labels to assess ligand-receptor interactions.

Affinity Labels↗
PubMed2005

How to assess post-occlusive reactive hyperaemia by means of laser Doppler perfusion monitoring: application of a standardised protocol to patients with peripheral arterial obstructive disease.

The standardisation of manoeuvres to perform clinically discriminative microvascular flow reserve tests is still poorly developed, as well as the response analysis. The aim of this study was to establish a reproducible analysis method for the post-occlusive reactive hyperaemia (PORH) test measured using laser Doppler perfusion monitoring (LDPM). LDPM data were measured from the PORH response of 24 Fontaine class II-III peripheral atherosclerotic/arterial obstructive disease (PAOD) patients and 30 healthy subjects. The PORH response was recorded from the dorsum of the foot after 3 min of arterial occlusion at the thigh. The resulting tracings were analysed by describing their morphology through five defined parameters: resting flux (RF), time to RF level (tRF), maximum flux (MF) during reactive hyperaemia, time to maximum flux (tMF), and time to half recovery (tHR). While the time parameters were discriminative between patients and controls, flux parameters were not. The time to resting flux (tRF) led to the most discriminative model that correctly predicted 88.5% of the cases. Hence, we concluded that obtaining t(RF) with the presented procedures provides an optimal model to quantify the patient's microvascular condition from the PORH response.

Adult↗
PubMed2005

Comparison of the antibody in lymphocyte supernatant (ALS) and ELISPOT assays for detection of mucosal immune responses to antigens of enterotoxigenic Escherichia coli in challenged and vaccinated volunteers.

In the present study we compared the ELISPOT and antibody in lymphocyte supernatants (ALS) assays as surrogate measures of mucosal immunity. In separate studies, 20 inpatient volunteers received oral doses of 6 x 10(8) or 4 x 10(9)cfu of ETEC strain E24377A (LT+, ST+, CS1+, CS3+) and 20 subjects received 1 (n = 9) or 2 (n = 11) oral doses of the attenuated ETEC vaccine, PTL-003 expressing CFA/II (CS1+ and CS3+) (2 x 10(9)cfu/dose). Peripheral blood mononuclear cells (PBMCs) from all subjects were assayed for anti-colonization factor or toxin-specific IgA antibody responses using the ALS and ELISPOT procedures. ALS responses were measured using a standard ELISA, as well as by time-resolved fluorescence (TRF). Following challenge with E24377A, significant anti-CS3, CS1 and LT ALS responses were detected in the lymphocyte supernatants of 75-95% of the subjects. A similar proportion (75%) of subjects mounted an ALS response to CFA/II antigen after vaccination with the PTL-003 vaccine. Inter-assay comparisons between ALS and ELISPOT methods also revealed a high degree of correlation in both immunization groups. ALS sensitivity versus the ELISPOT assay for LT, CS3 and CS1-specific responses following challenge were 95%, 94% and 78%, respectively and 83% for the ALS response to CFA/II antigen after vaccination with PTL-003. Correlation coefficients for the LT and CS3 antigens were 0.94 (p<0.001) and 0.82 (p<0.001), respectively after challenge and 0.78 (p<0.001) after vaccination. The association between ALS and ELISPOT for the CS1 antigen was however, significant only when ALS supernatants were tested by TRF (r = 0.91, p<0.001). These results demonstrate the value and flexibility of the ALS assay as an alternative to ELISPOT for the measurement of mucosal immune responses to ETEC antigens, particularly when the complexities of ELISPOT may make it impractical to perform.

Adult↗
PubMed2002

[Relationship between acute phase reactant proteins (APRP) and fatigue during post-operative convalescence].

Surgery originates an inflammatory state which triggers an acute phase response (APR). In this study, variations in the acute phase reactant proteins (APRP) and their relationship with fatigue were assessed. A total of 58 candidate patients for elective abdominal surgery participated in this study. In the preoperative period (PRE) and in the post-operative period (9 days [9-P], 27 days [27-P] and 45 days [45-P]), variations in serum APRP and fatigue were analyzed. In the post-operative period (9-P), a significant decrease in PT, ALB, PAB, TRF, and an increase in CER were observed. In 27-P, significant decreases were observed in PAB and PBR, with increased PT and CER, and without significant variations in ALB ad TRF. In the 45-P day, a concomitant increase in PT and CER was observed. Dynamometric parameters also decreased significantly in the post-operative period (9-P). In conclusion, our results demonstrate the existence of changes in serum proteins and in APRP after an elective abdominal surgical intervention, which are associated with fatigue, evaluated both by subjective and objective (dynamometry) means and the use of a mathematical model that considers weight, proteins and APRP.

Acute-Phase Proteins↗
PubMed1997

Ozone depletes tocopherols and tocotrienols topically applied to murine skin.

To evaluate ozone damage to hairless mouse skin, two parameters of oxidative damage, vitamin E depletion and malondialdehyde (MDA) production, were measured in vitamin E-enriched and in control skin from mice exposed to ozone (10 ppm). A 5% vitamin E solution (tocotrienol-rich fraction, TRF) in polyethylene glycol (PEG) was applied to 2 sites on the back of hairless mice, PEG to 2 sites. After 2 h, the sites were washed, one of each pair of sites covered and the mice exposed ozone for 2 h. Ozone exposure (compared with covered sites) increased epidermal MDA in PEG-treated sites, while vitamin E was unchanged. In contrast, ozone exposure significantly depleted vitamin E in TRF-treated sites, while significant MDA accumulation was prevented. This is the first demonstration that ozone exposure causes damage to cutaneous lipids, an effect which can be attenuated by vitamin E application.

Administration, Topical↗
PubMed1998

Detection of HLA-B27 alleles by group-specific amplification and time-resolved fluorometry.

This newly developed HLA-B27 assay combines a polymerase chain reaction (PCR) from blood spot samples with solution hybridisation in microtitration plate and with time-resolved fluorometry (TRF) as the detection system. In a multiplex amplification reaction, the 144 base pair region of HLA-B27 alleles is amplified with allele-specific primers simultaneously with the region of beta-actin gene as an internal control. Amplified products are collected onto streptavidin (SA)-coated microtitration wells, denatured and hybridised with a europium (Eu)-labelled HLA-B27 specific probe and a samarium (Sm)-labelled beta-actin specific probe. Finally, Eu and Sm fluorescence is enhanced and detected in a time-resolved fluorometer. The typing results obtained with 110 blood spot samples showed an exact match with serological class I HLA-typing. When this technique was further evaluated, 348 blood spot samples were clearly categorised into two populations, HLA-B27 positives and negatives. This new PCR-TRF method permits the automation of HLA-B27 assays and saves time and labour in routine diagnostics.

Alleles↗
PubMed1999

Exercise induces recruitment of lymphocytes with an activated phenotype and short telomeres in young and elderly humans.

This study was performed in order to investigate the type of T cells recruited to the blood in response to an acute bout of exercise with regard to mean lengths of telomeric terminal restriction fragments (TRF) and surface activation markers and with special emphasis on age-associated differences. Ten elderly and ten young humans performed maximal bicycle exercise. There was no difference in the number of recruited CD4+ and CD8+ cells between the young and elderly group. In both age groups the immediate increases could be ascribed to recruitment of CD28- cells (CD8+ and CD4+ cells) and memory cells (only CD8+ cells). Furthermore, after exercise mean TRF lengths were significantly reduced in blood mononuclear cells and in CD8+ cells from young subjects and in CD4+ cells from elderly subjects compared with lengths pre-exercise. These findings suggest that the mobilization of T lymphocytes during acute exercise is mainly a redistribution of previously activated cells with an increased replicative story than cells isolated from the blood at rest. Furthermore, elderly humans fulfilling the Senieur protocol have a preserved ability to recruit T lymphocytes in response to acute physical stress.

Adult↗
PubMed2001

Telomere shortening and decline in replicative potential as a function of donor age in human adrenocortical cells.

Telomere shortening is the cause of replicative senescence of mammalian cells in culture and may be a cause of cellular aging in vivo. Some tissues clearly show telomere shortening during aging in humans, but the relationship between replication history and telomere length is obscured by complex relationships between stem cells and more differentiated cell types. Previous experiments on the adrenal cortex and human adrenocortical cells in culture indicate that the proliferative biology of this tissue is relatively simple; cell division occurs continuously throughout life, without evidence for a distinct stem cell compartment. In this tissue we investigated the relationship between telomere biology and replicative senescence by measuring replicative capacity and telomere length as a function of donor age. Cells cultured from adrenal tissue from donors of different ages showed a strong age-related decline in total replicative capacity, falling from about 50 population doublings for fetal cells to an almost total lack of division in culture for cells from older donors. Telomere restriction fragment (TRF) length was analyzed in the same sets of cells and decreased from a value of about 12 kb in fetal cells to approximately 7 kb in cells from older donors. The latter value is consistent with that in fibroblasts which have reached replicative senescence. Furthermore, there was a good correlation in individual donor samples between TRF length and replicative capacity in culture. To confirm the relationship between telomere length, telomerase, and replicative capacity, we measured telomere length in cells before and after infection with a retrovirus encoding hTERT, the catalytic component of human telomerase. The adult adrenal cortex does not have telomerase activity; cells after transduction with the hTERT retrovirus had high telomerase activity. Whereas control cells underwent a replication-dependent shortening in telomeres during long-term growth in culture, hTERT-modified cells maintained telomere length and are probably immortalized. Symmetric cell division in human adrenocortical cells, occurring slowly over the life span, is associated with progressive telomere shortening and may result in proliferative defects in vivo in old age, which could partly account for the age-related changes in the structure and function of the human adrenal cortex.

Adolescent↗
PubMed2001

Telomere shortening in atherosclerosis.

Eukaryotic chromosomes end with telomeres, which shorten with cellular ageing. We investigated whether atherosclerosis is associated with systemic evidence of accelerated cellular ageing. We compared mean length of terminal restriction fragments (TRF), a measure of average telomere size, in leucocyte DNA of ten patients with severe coronary artery disease (CAD) with that of 20 controls without CAD. Adjusting for age and sex, cases had mean TRF lengths of 303 (SD 90) base pairs shorter than those of controls (p=0.002)-ie, equivalent in size to individuals with no CAD who are 8.6 years older. Although this is a pilot study, the findings could be relevant to the pathogenesis of atherosclerosis.

Adult↗
PubMedDate not supplied

Histocompatibility antigens, transferrin receptors and extra-embryonic markers of human amniotic epithelial cells in vitro.

This study has shown that fresh amniotic epithelial cells which are negative by indirect immunofluorescence for HLA and Trf receptors become positive for both of these markers following prolonged culture. In addition, the amniotic antigens which are characteristic of fresh amniotic epithelial cells are lost and replaced by trophoblast antigens subsequent to maintenance of the cells in vitro. These observations suggest that, although the expression of HLA and Trf receptors are apparently negative in vivo, such gene products become activated and manifest in plasma membranes following exposure of the cells to culture conditions. In addition, the normal manifestation of the amnion antigens is lost following prolonged periods of culture. These findings indicate that the coding and expression of normally accepted transplantation antigens undergo a significant perturbation in vitro, and that markers of normal extra-embryonic epithelium in vivo are lost after the cells have been cultured in vitro.

Amnion↗
PubMed1997

Progressive telomere shortening and telomerase reactivation during hepatocellular carcinogenesis.

Telomeres shorten progressively with age in normal somatic cells in culture and in vivo. The maintenance of telomere length is assumed to be an obligatory step in the progression and immortalization of most human tumor cells. To understand the role of telomere dynamics in the development of hepatocellular carcinoma (HCC), we examined the length of terminal restriction fragment (TRF), as an indicator for telomere length, in HCC and surrounding tissues with chronic active hepatitis (CAH) or liver cirrhosis (LC). The study was performed in 12 hepatitis C virus (HCV) antibody-positive, 12 hepatitis B virus (HBV) antigen-positive tissues, and 4 tissue samples from virus-negative patients with HCC. The peak TRFs in all 3 types of HCC were significantly shorter than those of the surrounding tissues (i.e., LC or CAH). TRFs examined in one patient with atypical adenomatous hyperplasia (AAH) also was shortened. Thus, progressive TRF shortening occurs from normal to CAH to LC to HCC(AAH). Telomerase, an enzyme that adds repeated telomere sequences onto the chromosome ends and stabilizes telomere length in immortal cells, also was examined in tissues and detected in high levels almost exclusively in HCCs. Interestingly, the intensity of telomerase activity in the AAH case was similar to that of HCC. In addition, the telomerase activity of biopsy samples with a fine 21-gauge needle also was examined in 10 HCCs, 2 adenomatous hyperplasias (AHs), 2 LCs, and 2 CAHs. We found strong telomerase activity in all the HCCs and surprisingly in the 2 cases that were pathologically diagnosed as AH. Thus, the findings strongly suggest that persistent cell proliferation or rapid cell turnover through damage of hepatic cells result in a process of multistep hepatocellular carcinogenesis. Thus, progressive shortening of telomeres and the activation of telomerase may be a useful marker for the early detection of malignant progression in liver disease.

Adolescent↗
PubMed2002

Acquisition, storage and release of iron by cultured human hepatoma cells.

BACKGROUND/AIMS: The recovery from iron overload is hampered by the limited number of pathways and therapeutic agents available for the augmentation of iron secretion/excretion. The present study was aimed to investigate the process of iron storage and release by cultured human hepatoma cells, the role of transferrin receptors and ferritin in this process as well as the effect of iron chelators. METHODS: We followed the acquisition, storage and release of iron by cultured cells HepG2 and Hep3B by biochemical means and electron microscopy. RESULTS: The uptake of iron from diferric transferrin (Trf) was extremely low, while iron as ferric-ammonium-citrate (FAC) was taken up readily, especially by Hep3B cells. Up to 80% of the iron taken up by hepatoma cells was released to the medium. The rate of spontaneous iron release depended on the extent of iron loading. ApoTrf and deferoxamine facilitated release after 1- and 7-day iron-exposure. Up to a third of the radio-iron released from the cells was associated with ferritin. The release of ferritin-iron was not enhanced by either deferoxamine or Trf. CONCLUSIONS: Ferritin-iron release appeared to be an important mechanism of iron discarding in cultured human hepatoma cells, independent of the activity of chelating agents.

Apoproteins↗
PubMedDate not supplied

Effects of prenatal marijuana exposure on child behavior problems at age 10.

This is a prospective study of the effects of prenatal marijuana exposure on child behavior problems at age 10. The sample consisted of low-income women attending a prenatal clinic. Half of the women were African-American and half were Caucasian. The majority of the women decreased their use of marijuana during pregnancy. The assessments of child behavior problems included the Child Behavior Checklist (CBCL), Teacher's Report Form (TRF), and the Swanson, Noland, and Pelham (SNAP) checklist. Multiple and logistic regressions were employed to analyze the relations between marijuana use and behavior problems of the children, while controlling for the effects of other extraneous variables. Prenatal marijuana use was significantly related to increased hyperactivity, impulsivity, and inattention symptoms as measured by the SNAP, increased delinquency as measured by the CBCL, and increased delinquency and externalizing problems as measured by the TRF. The pathway between prenatal marijuana exposure and delinquency was mediated by the effects of marijuana exposure on inattention symptoms. These findings indicate that prenatal marijuana exposure has an effect on child behavior problems at age 10.

Adult↗