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41.
A back migration from Asia to sub-Saharan Africa is supported by high-resolution analysis of human Y-chromosome haplotypes 总被引:21,自引:0,他引:21
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Cruciani F Santolamazza P Shen P Macaulay V Moral P Olckers A Modiano D Holmes S Destro-Bisol G Coia V Wallace DC Oefner PJ Torroni A Cavalli-Sforza LL Scozzari R Underhill PA 《American journal of human genetics》2002,70(5):1197-1214
The variation of 77 biallelic sites located in the nonrecombining portion of the Y chromosome was examined in 608 male subjects from 22 African populations. This survey revealed a total of 37 binary haplotypes, which were combined with microsatellite polymorphism data to evaluate internal diversities and to estimate coalescence ages of the binary haplotypes. The majority of binary haplotypes showed a nonuniform distribution across the continent. Analysis of molecular variance detected a high level of interpopulation diversity (PhiST=0.342), which appears to be partially related to the geography (PhiCT=0.230). In sub-Saharan Africa, the recent spread of a set of haplotypes partially erased pre-existing diversity, but a high level of population (PhiST=0.332) and geographic (PhiCT=0.179) structuring persists. Correspondence analysis shows that three main clusters of populations can be identified: northern, eastern, and sub-Saharan Africans. Among the latter, the Khoisan, the Pygmies, and the northern Cameroonians are clearly distinct from a tight cluster formed by the Niger-Congo-speaking populations from western, central western, and southern Africa. Phylogeographic analyses suggest that a large component of the present Khoisan gene pool is eastern African in origin and that Asia was the source of a back migration to sub-Saharan Africa. Haplogroup IX Y chromosomes appear to have been involved in such a migration, the traces of which can now be observed mostly in northern Cameroon. 相似文献
42.
Mandibuloacral dysplasia is caused by a mutation in LMNA-encoding lamin A/C 总被引:18,自引:0,他引:18
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Novelli G Muchir A Sangiuolo F Helbling-Leclerc A D'Apice MR Massart C Capon F Sbraccia P Federici M Lauro R Tudisco C Pallotta R Scarano G Dallapiccola B Merlini L Bonne G 《American journal of human genetics》2002,71(2):426-431
Mandibuloacral dysplasia (MAD) is a rare autosomal recessive disorder, characterized by postnatal growth retardation, craniofacial anomalies, skeletal malformations, and mottled cutaneous pigmentation. The LMNA gene encoding two nuclear envelope proteins (lamins A and C [lamin A/C]) maps to chromosome 1q21 and has been associated with five distinct pathologies, including Dunnigan-type familial partial lipodystrophy, a condition that is characterized by subcutaneous fat loss and is invariably associated with insulin resistance and diabetes. Since patients with MAD frequently have partial lipodystrophy and insulin resistance, we hypothesized that the disease may be caused by mutations in the LMNA gene. We analyzed five consanguineous Italian families and demonstrated linkage of MAD to chromosome 1q21, by use of homozygosity mapping. We then sequenced the LMNA gene and identified a homozygous missense mutation (R527H) that was shared by all affected patients. Patient skin fibroblasts showed nuclei that presented abnormal lamin A/C distribution and a dysmorphic envelope, thus demonstrating the pathogenic effect of the R527H LMNA mutation. 相似文献
43.
44.
Padiglia A Medda R Scanu T Longu S Rossi A Floris G 《Journal of Protein Chemistry》2002,21(7):435-441
A cDNA encoding for a copper containing amine oxidase has been isolated and sequenced from young leaves of Euphorbia characias, a perennial mediterranean shrub. A single long open reading frame of 2068 pb encodes a protein composed of 653 amino acids with a molecular mass of about 74 kDa. A putative 24-aminoacid signal peptide precedes the sequence of the mature protein, with characteristics of a secretion signal peptide. Alignments of Euphorbia amine oxidase cDNA nucleotide sequence with that of amine oxidase from the seedlings of the pulses lentil, pea, and chickpea reveal several conserved regions, especially in the C-terminus, with a homology 90%–97%. The near 5 region shows several insertions, deletions, and different nucleotide sequence with ca. 60% homology. The enzyme contains 1%–2% carbohydrate deduced by deglycosylation experiments. Five cysteine residues are present in the deduced aminoacid sequence with a single disulfide bridge as judged by titration with cysteine reagents. 相似文献
45.
46.
Intracellular pH regulation in U-2 OS human osteosarcoma cells transfected with P-glycoprotein 总被引:2,自引:0,他引:2
Porcelli AM Scotlandi K Strammiello R Gislimberti G Baldini N Rugolo M 《Biochimica et biophysica acta》2002,1542(1-3):125-138
The molecular mechanisms responsible for intracellular pH regulation in the U2-OS osteosarcoma cell line were investigated by loading with 2',7'-bis(2-carboxyethyl)-5(6) carboxyfluorescein ester and manipulation of Cl(-) and Na(+) gradients, both in HEPES- and HCO(3)(-)/CO(2)-buffered media. Both acidification and alkalinisation were poorly sensitive to 4,4'-diisothiocyanate dihydrostilbene-2,2'-disulfonic acid, inhibitor of the anion exchanger, but sensitive to amiloride, inhibitor of the Na(+)/H(+) exchanger. In addition to the amiloride-sensitive Na(+)/H(+) exchanger, another H(+) extruding mechanism was detected in U-2 OS cells, the Na(+)-dependent HCO(3)(-)/Cl(-) exchanger. No significant difference in resting pH(i) and in the rate of acidification or alkalinisation was observed in clones obtained from U-2 OS cells by transfection with the MDR1 gene and overexpressing P-glycoprotein. However, both V(max) and K' values for intracellular [H(+)] of the Na(+)/H(+) exchanger were significantly reduced in MDR1-transfected clones, in the absence and/or presence of drug selection, in comparison to vector-transfected or parental cell line. NHE1, NHE5 and at a lower extent NHE2 mRNA were detected in similar amount in all U2-OS clones. It is concluded that, although overexpression of P-glycoprotein did not impair pH(i) regulation in U-2 OS cells, the kinetic parameters of the Na(+)/H(+) exchanger were altered, suggesting a functional relationship between the two membrane proteins. 相似文献
47.
Virgilio F Sciarrillo R Laforgia V Varano L 《Journal of experimental zoology. Part A, Comparative experimental biology》2003,296(2):137-142
Although endothelins were originally discovered as peptides with vasoconstrictor activity, recent studies have indicated a number of endothelin (ET) induced hormonal functions in various tissues. We have studied the interaction of ET-1 with thyroid gland of the lizard Podarcis sicula. The effects of ET-1 administration on the plasma levels of the thyroid hormones (T3 and T4) and TSH were stimulatory. Morphological changes in the thyroid after treatment with ET-1 were also detected: the height of the epithelial cells slightly increased and the apical surface acquired microvilli protruding into the follicular lumen. The colloid filled up the lumen and showed a rich peripheral vacuolation. In conclusion, a modulatory role in the control of the reptilian thyroid gland is suggested for ET-1. This is the first report on the interaction of ET-1 with the thyroid gland of reptilian. 相似文献
48.
Gary Rosenberg said of conchologists that they "are often characterized as lumpers or splitters. From one perspective, splitters recognize more species than really exist, and lumpers go around fixing the resulting damage." The recent explosion in the number of identified mutations within the LMNA gene, which encodes two protein products lamins A and C, has allowed the identification of an allelic series of disorders, all caused by mutations within this one gene. Hence, LMNA might be thought of as a "lumper" gene. These results have initiated analysis of the relationship between disease phenotype and gene, and have led to dramatic advances in our knowledge of the dynamic and complex organization of the nuclear architecture. 相似文献
49.
Long-term treatment with low doses of interleukin-2 and interferon-α: immunological effects in advanced renal cell cancer 总被引:2,自引:0,他引:2
Pavone L Andrulli S Santi R Majori M Buzio C 《Cancer immunology, immunotherapy : CII》2001,50(2):82-86
We aimed to determine the immunological effects of low doses of recombinant interleukin-2 (rIL-2) and recombinant interferon-α
(rIFN-α) in patients bearing advanced renal cell carcinoma.
Methods: Twenty-seven patients received therapeutic cycles consisting of subcutaneous rIL-2 for 5 days per week and intramuscular
rIFN-α twice weekly, for 4 consecutive weeks. The cycle was repeated indefinitely at regular 4-month intervals, for all patients.
rIL-2 (1 × 106 IU/m2) was administered every 12 h on days 1 and 2 and once a day on days 3–5 of each week; rIFN-α (1.8 × 106 IU/m2) was given on days 3 and 5.
In the enrolled patients, total and differential white blood cell counts, phenotypic analysis of some lymphocyte subsets,
and soluble IL-2 receptor (sIL-2R), were investigated before and after each of the first six cycles of therapy (about 24 months
of follow-up).
Results: The cycles of immunotherapy induced a significant increase of total lymphocytes (37%, P < 0.001), eosinophils (222%, P < 0.001), CD25+ cells (27%, P=0.004), sIL-2R (174%, P < 0.001) and natural killer (NK) cells (CD3-CD56+) (61%, P < 0.001); the subset that expresses CD56 with high density (CD56+ bright) expanded more (233%, P < 0.001) than the subset expressing the same marker with low density (CD56+ dimmer) (15%, P=0.043). Unlike the previous subsets, the treatment decreased significantly T-lymphocytes with NK cell marker (CD3+ CD56+)
(28%, P=0.011).
No significant differences of effectiveness were found among the subsequent treatment cycles, except for CD25+ cells and sIL-2R
(P=0.036 and P=0.005, respectively): the increase induced by immunotherapy was maximum after the first cycle and decreased progressively
thereafter.
Conclusions: Long-term repeated cycles of low-dose immunotherapy induced repeated and significant expansion of one of the most important
lymphocyte subsets for the non-MHC-restricted immune response to the tumour mass: CD3–CD56+ cells.
Received: 8 November 2000 / Accepted: 11 January 2001 相似文献
50.
The Activity of Differentiation Factors Induces Apoptosis in Polyomavirus Large T-Expressing Myoblasts 总被引:2,自引:0,他引:2
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Gian Maria Fimia Vanesa Gottifredi Barbara Bellei Maria Rosaria Ricciardi Agostino Tafuri Paolo Amati Rossella Maione 《Molecular biology of the cell》1998,9(6):1449-1463
It is commonly accepted that pathways that regulate proliferation/differentiation processes, if altered in their normal interplay, can lead to the induction of programmed cell death. In a previous work we reported that Polyoma virus Large Tumor antigen (PyLT) interferes with in vitro terminal differentiation of skeletal myoblasts by binding and inactivating the retinoblastoma antioncogene product. This inhibition occurs after the activation of some early steps of the myogenic program. In the present work we report that myoblasts expressing wild-type PyLT, when subjected to differentiation stimuli, undergo cell death and that this cell death can be defined as apoptosis. Apoptosis in PyLT-expressing myoblasts starts after growth factors removal, is promoted by cell confluence, and is temporally correlated with the expression of early markers of myogenic differentiation. The block of the initial events of myogenesis by transforming growth factor β or basic fibroblast growth factor prevents PyLT-induced apoptosis, while the acceleration of this process by the overexpression of the muscle-regulatory factor MyoD further increases cell death in this system. MyoD can induce PyLT-expressing myoblasts to accumulate RB, p21, and muscle- specific genes but is unable to induce G00 arrest. Several markers of different phases of the cell cycle, such as cyclin A, cdk-2, and cdc-2, fail to be down-regulated, indicating the occurrence of cell cycle progression. It has been frequently suggested that apoptosis can result from an unbalanced cell cycle progression in the presence of a contrasting signal, such as growth factor deprivation. Our data involve differentiation pathways, as a further contrasting signal, in the generation of this conflict during myoblast cell apoptosis. 相似文献