PubMed Health⌕ Search

Biomedical subjects

E Dore

Publications and source records attributed to E Dore.

At least 19 recordsLinked to original sources
PubMed2004

[Thyroid dysfunction after haematopoietic stem cell transplantation during childhood].

UNLABELLED: To evaluate the percentage and risk factors of thyroid dysfunction in 79 children who underwent bone marrow transplantation in a single centre. PATIENTS AND METHODS: The mean age of the cohort was 6.8 and mean follow-up 5.5 years. The 79 patients were divided in two groups according to the pretransplant conditioning regimen: fractionated total body irradiation (TBI)(N=54), chemotherapy with Busulphan (N=25). Thyroid function was evaluated by thyroid-stimulating hormone (TSH) and free thyroxine (fT4) tests. Overt hypothyroidism was defined by low fT4 blood levels and TSH > 4 mU/l, and compensated hypothyroidism by normal fT4 index and TSH >4 mU/L. RESULTS: The six-year probability of hypothyroidism was 36 +/-6% for the whole group of 79 patients, 49 +/-8% after TBI and 9 +/-6% in the Busulphan group (P <0.001). Neither gender, nor primary disease, nor presence of graft versus host disease were found to be statistically significant for occurrence of hypothyroidism in the TBI group. However, a younger age seemed to influence statistically the 6-year probability of hypothyroidism in the TBI group: 59 +/-9% if age <7.7 years versus 34 +/-13% if age >7.7 years (P =0.02). CONCLUSION: A careful follow-up of thyroid function is recommended even without TBI conditioning regimen. Young age as a potential risk factor of hypothyroidism has never been described and needs to be studied in a larger cohort.

Adolescent↗
PubMed2004

High-intensity intermittent activities at school: controversies and facts.

In comparison to continuous aerobic type activity, little is known about high-intensity intermittent physical activity in children. Repeated short-term high-intensity activities (> maximal aerobic speed and <10 s) are more characteristic of the spontaneous physical activity of children. Recent studies have shown during repetitive bouts of sprints separated by short recovery intervals, that prepubescent children compared with adults are more able to maintain their performance without substantial fatigue. Moreover, repetitive runs at high velocities (near and higher than the maximal aerobic speed) separated by short recovery periods may elicit a high oxygen consumption in children. Several studies using interval training programmes for 7 weeks, twice a week for 30 min in physical education lessons showed that children's aerobic performance (maximal O2 uptake, maximal aerobic speed) could be enhanced. Training based on these repeated short-term high-intensity exercises could also improve children's anaerobic performance (short-term muscle power, strength and speed). Current evidence suggests that recovery from high-intensity exercises is faster in children than in adults and that repeated runs at high velocities separated by short recovery intervals can improve both aerobic and anaerobic performance. Although continuous aerobic type activity is more scientifically established as a training mode, repeated short-term high-intensity exercises in physical education programmes should be considered to enhance aerobic, as well as, anaerobic fitness in children.

Child↗
PubMed2003

HLA genes associated with autoimmunity and progression to disease in type 1 diabetes.

Insulin dependent diabetes mellitus (type I DM) is caused by an autoimmune process which culminates in destruction of pancreatic beta cells with resultant loss of insulin production. Preceding the clinical diagnosis of type I DM is a preclinical stage characterized by autoantibodies to insulin, glutamic acid decarboxylase (GAD) and a tyrosine phosphatase-like molecule (IA-2). We have studied both HLA class I and class 2 allele distributions in diabetic probands and autoantibody positive individuals in members of 452 families recruited for the Australian type I diabetes DNA repository. The results demonstrate that progression to autoimmunity as measured by the appearance of autoantibodies is strongly associated with the class 2 alleles DRB1*03 and DRB*04 and with DRB1*03/04 heterozygosity. In contrast, the progression to clinical disease appears associated with class I alleles A24, A30 and B18 while A1, A28, B14 and B56 appear negatively associated. The class 2 alleles appear to have a minimal role in the progression from autoantibody positivity to clinical disease. These results are consistent with the view that CD4+ T cells responding to peptides in the context of class 2 molecules are responsible for initiating autoantibody production, while the destruction of islet cells leading to clinical expression of the disease is the function of CD8+ T cells recognizing relevant peptides in the context of class I molecules.

Alleles↗
PubMed2001

Effects of plyometric training followed by a reduced training programme on physical performance in prepubescent soccer players.

BACKGROUND: In adult population, stretch-shortening cycle exercise (plyometric exercise) is often used to improve leg muscle power and vertical jump performance. In children, limited information regarding this type of exercise is available. The purpose of this study was to examine the effectiveness of plyometric training and maintenance training on physical performances in prepubescent soccer players. METHODS: Twenty boys aged 12-13 years was divided in two groups (10 in each): jump group (JG) and control group (CG). JG trained 3 days/week during 10 weeks, and performed various plyometric exercises including jumping, hurdling and skipping. The subsequent reduced training period lasted 8 weeks. However, all subjects continued their soccer training. Maximal cycling power (Pmax) was calculated using a force-velocity cycling test. Jumping power was assessed by using the following tests: countermovement jump (CMJ), squat jump (SJ), drop jump (DJ), multiple 5 bounds (MB5) and repeated rebound jump for 15 seconds (RRJ15). Running velocities included: 20, 30 and 40 m (V20, V30, V40 m). Body fat percentage (BF percent) and lean leg volume were estimated by anthropometry. RESULTS: Before training, except for BF percent, all baseline anthropometric characteristics were similar between JG and CG. After the training programme, Pmax (p<0.01), CMJ (p<0.01), SJ (p<0.05), MB5 (p<0.01), RRJ15 (p<0.01) and V20 m (p<0.05), performances increased in the JG. During this period no significant performance increase was obtained in the CG. After the 8-week of reduced training, except Pmax (p<0.05) for CG, any increase was observed in both groups. CONCLUSIONS: These results demonstrate that short-term plyometric training programmes increase athletic performances in prepubescent boys. These improvements were maintained after a period of reduced training.

Adolescent↗
PubMed1994

Dynamics of telomere turnover in Plasmodium berghei.

Non-uniform composition in telomeric repeats at the extremities of Plasmodium chromosomes was exploited in order to obtain data on intraclonal diversification of telomeric sequences, relevant for the study of telomere regeneration dynamics. Families of sibling telomeric clones were obtained from several chromosomal ends of Plasmodium berghei, and analysed so as to determine the exact points from which individual clones start to diverge. As much as 90% of the telomeric tract appears to be subject to events causing abrupt changes in the sequence of telomeric repeats. The results are compatible with the hypothesis that breakpoint probability is a continuously increasing function over the entire telomeric tract.

Animals↗
PubMed1992

Extensive turnover of telomeric DNA at a Plasmodium berghei chromosomal extremity marked by a rare recombinational event.

The dynamics of telomere turnover were studied in Plasmodium, whose telomeric structures consist of linear, recognisable sequences of two distinct repeats (TTTAGGG and TTCAGGG). Independent recombinant clones containing a well-defined chromosomal extremity of Plasmodium berghei, both before and after a rare insertion event took place, were obtained from clonal parasite populations and analysed. The insertion, which splits the original telomere and causes a significant reduction in the size of the telomeric structure, is shown to consist of an integer number of subtelomeric repeats typical of P.berghei, flanked on both sides by telomere-derived motifs. Analysis of the telomeric repeat sequence heterogeneity in the otherwise homogeneous populations examined, is compatible with a model in which diversification of a given telomere is driven by the occurrence of breakpoints whose frequency rapidly increases along the telomeric tract when moving in the outward direction. The breakpoints might be due either to terminal deletions followed by random serial addition of the two repeat versions, or to recombination events. The shortening/elongation mechanism is favoured against the recombination hypothesis because of the absence of higher-order patterns in the sequence of telomeric repeats.

Animals↗
PubMed1990

Generation of chromosome size polymorphism during in vivo mitotic multiplication of Plasmodium berghei involves both loss and addition of subtelomeric repeat sequences.

Extensive chromosome size polymorphism arises in Plasmodium berghei during in vivo mitotic multiplication. Size differences between homologous chromosomes involve rearrangements occurring in the subtelomeric portions while internal chromosomal regions do not contribute significantly to chromosome size polymorphism. Differences in the copy number of a 2.3-kb subtelomeric repeated unit are shown to correlate with size variations, and in at least one case to account completely for the size difference between two variants of the same chromosome.

Animals↗
PubMed1990

Long insertions within telomeres contribute to chromosome size polymorphism in Plasmodium berghei.

During prolonged in vivo mitotic multiplication of a Plasmodium berghei ANKA clone (8417HP), parasites that contained an enlarged version of chromosome 4 were observed. Restriction mapping and hybridization results demonstrated that the extra DNA present in the enlarged chromosome consists of 2.3-kb tandem repeats, known to be normally located in subtelomeric position at several chromosomal ends but absent in the original chromosome. The inserted 2.3-kb units appeared to interrupt one of the original telomeres and to create an internal (approximately 1-kb-long) telomeric sequence.

Animals↗
PubMed1990

Organization of subtelomeric repeats in Plasmodium berghei.

Several (but not all) Plasmodium berghei chromosomes bear in the subtelomeric position a cluster of 2.3-kilobase (kb) tandem repeats. The 2.3-kb unit contains 160 base pairs of telomeric sequence. The resulting subtelomeric structure is one in which stretches of telomeric sequences are periodically spaced by a 2.1-kb reiterated sequence. This periodic organization of internal telomeric sequences might be related to chromosome-size polymorphisms involving the loss or addition of subtelomeric 2.3-kb units.

Animals↗
PubMed1989

Presence of contaminating mitochondrial DNA from host reticulocytes in experimental infections of Plasmodium berghei.

Superposition of two unrelated processes, namely terminal reticulocyte differentiation and synchronous plasmodial development, takes place in experimental infections of Plasmodium berghei. The first process is shown to be responsible for the appearance of some discrete restriction bands of host origin when DNA is extracted from leucocyte-free blood containing synchronous parasites at early stages of infection. These discrete DNA fragments cross-hybridize with host cell mitochondrial DNA. Purification steps are suggested to reduce this effect, which might be relevant also in the case of other plasmodial species exhibiting preference for reticulocytes as host cell.

Animals↗
PubMed1987

Telomeric motifs are present in a highly repetitive element in the Plasmodium berghei genome.

Using as probes the subfragments of the telomeric sequence previously cloned by us from Plasmodium berghei DNA, we identified and cloned a 2.3 kb repeat, largely overlapping the original telomeric insert. Restriction mapping indicated that cloned inserts (2.3 kb in length) represented circularly permutated versions of a rather well conserved repeated element, at least in part organized in tandem. The 2.3 kb repeat family with a copy number of about 300 occupies about 4% of the whole genome. The copies are unevenly distributed among the chromosome-sized molecules revealed by pulsed field gradient electrophoresis. Complete sequence determination of the 2.3 kb element revealed that telomere-related motifs are present with a characteristic pattern in a set of tandem repeats, 27 bp long. The perfect conservation of these motifs as well as the pattern of chromosomal distribution suggest that we are dealing with a specialised structure subject to selective mechanisms of amplification and maintenance.

Animals↗
PubMed1986

Homologous telomeric sequences are present in different species of the genus Plasmodium.

The telomeric sequence cloned from Plasmodium berghei (see M. Ponzi et al. (1985) EMBO J. 4, 2991-2995) was tested for species specificity. A telomeric and a subtelomeric fragment of the cloned insert served as separate, labelled probes on pulsed field gradient electrophoretical patterns and on genomic digests from the rodent malarias Plasmodium yoelii, Plasmodium chabaudi and from the human malaria Plasmodium falciparum. Results indicate that the subtelomeric fragment, abundantly represented in two chromosomes of P. berghei, is not present in the other DNA tested, while the telomeric fragment is present in every chromosome-sized molecule in all the species tested. The telomeric location in the other genomes of the sequences homologous to the P. berghei telomeric probe is confirmed by experiments with Bal 31 exonuclease. In all cases, the TaqI site appears to delimit the common telomeric portion.

Animals↗
PubMed1985

Identification of a telomeric DNA sequence in Plasmodium berghei.

A fragment of Plasmodium berghei DNA was cloned using a technique designed to select for telomeric sequences. The cloned fragment recognizes Bal31-sensitive bands in P. berghei genomic digests. It contains at its distal end at least 70 tandem repeats of the heptanucleotide sequence CCCTGAAA. The presence of natural single strand discontinuities in the telomeric regions of P. berghei DNA is demonstrated by the selective incorporation of deoxyribonucleoside triphosphates in the absence of DNase. The number of copies of the cloned sequence present in each genome agrees with an estimate of 6-12 chromosomes per nucleus.

Animals↗