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21.
Usdin K; Chevret P; Catzeflis FM; Verona R; Furano AV 《Molecular biology and evolution》1995,12(1):73-82
The single most difficult problem in phylogenetic analysis is deciding
whether a shared taxonomic character is due to common ancestry or one that
appeared independently due to convergence, parallelism, or reversion to an
ancestral state. Mammalian L1 retrotransposons undergo periodic
amplifications in which multiple copies of the elements are interspersed in
the genome. Because these elements apparently are transmitted only by
inheritance and are retained in the genome, a shared L1 amplification event
can only be an inherited ancestral character. We propose that L1
amplification events can be an excellent tool for analyzing mammalian
evolution and demonstrate here how we addressed several refractory problems
in rodent systematics using L1 DNA as a taxonomic character.
相似文献
22.
Ana B. Rodríguez Eduardo Ortega Robert W. Lea Carmen Barriga 《Molecular and cellular biochemistry》1997,168(1-2):185-190
A functional connection between the pineal gland and the immune system in mammals and birds has been established. This study investigates the effect of melatonin upon the non-specific immunity of heterophils isolated from the ring dove. The different stages of the phagocytic process: adherence to nylon fiber, spontaneous and induced mobility, ingestion of latex beads and digestion were evaluated for heterophils incubated in the presence of 5, 25, 50, 75, or 100 \sgmaelig;M of melatonin. In addition, the chemoattractant power of the hormone for heterophils was studied. The 100 \sgmaelig;M melatonin dose possessed a significant chemoattractant ability for heterophils whilst ingestion of latex particles was enhanced at all doses studied. The superoxide anion level, as measured by the free radicals produced during the metabolic burst, is decreased after incubation with 100 \sgmaelig;M of melatonin. 相似文献
23.
24.
Montserrat Barriga Roi Cal Nuria Cabello Anna Llach Alexander Vallmitjana Raúl Benítez Lina Badimon Juan Cinca Vicenta Llorente-Cortés Leif Hove-Madsen 《PloS one》2013,8(3)
The damaging effects of high plasma levels of cholesterol in the cardiovascular system are widely known, but little attention has been paid to direct effects on cardiomyocyte function. We therefore aimed at testing the hypothesis that Low Density Lipoprotein (LDL) cholesterol affects calcium dynamics and signal propagation in cultured atrial myocytes. For this purpose, mRNA and protein expression levels were determined by real time PCR and western blot analysis, respectively, and intracellular calcium was visualized in fluo-4 loaded atrial HL-1 myocyte cultures subjected to field stimulation. At low stimulation frequencies all cultures had uniform calcium transients at all tested LDL concentrations. However, 500 µg LDL/mL maximally reduced the calcium transient amplitude by 43% from 0.30±0.04 to 0.17±0.02 (p<0.05). Moreover, LDL-cholesterol dose-dependently increased the fraction of alternating and irregular beat-to-beat responses observed when the stimulation interval was shortened. This effect was linked to a concurrent reduction in SERCA2, RyR2, IP3RI and IP3RII mRNA levels. SERCA2 protein levels were also reduced by 43% at 200 µg LDL/mL (p<0.05) and SR calcium loading was reduced by 38±6% (p<0.001). By contrast, HDL-cholesterol had no significant effect on SERCA expression or SR calcium loading. LDL-cholesterol also slowed the conduction velocity of the calcium signal from 3.2+0.2 mm/s without LDL to 1.7±0.1 mm/s with 500 µg LDL/mL (p<0.05). This coincided with a reduction in Cx40 expression (by 44±3%; p<0.05 for mRNA and by 79±2%; p<0.05 for Cx40 protein at 200 µg/ml LDL) whereas the Cx-43 expression did not significantly change. In conclusion, LDL-cholesterol destabilizes calcium handling in cultured atrial myocytes subjected to rapid pacing by reducing SERCA2 and Cx40 expression and by slowing the conduction velocity of the calcium signal. 相似文献
25.
Gunnel Hellgren Björn Andersson Andreas FM Nierop Jovanna Dahlgren Ze'ev Hochberg Kerstin Albertsson-Wikland 《Proteome science》2008,6(1):35
Background
The broad range in growth observed in short prepubertal children receiving the same growth hormone (GH) dose is due to individual variation in GH responsiveness. This study used a pharmaco-proteomic approach in order to identify novel biomarkers that discriminate between short non-GH-deficient (GHD) children who show a good or poor growth response to GH treatment. 相似文献26.
Sina Babazadeh Matthew L Broadhead John L Slavin Peter FM Choong 《International Seminars in Surgical Oncology : ISSO》2009,6(1):18
A presacral mass can present a diagnostic dilemma for the surgical oncologist. Differential diagnoses include congenital causes such as teratoma or chordoma, neurological causes such as neurilemoma or neurofibroma or other malignancies such as lymphoma or sarcoma. Diagnosis usually requires imaging such as CT and MRI and tissue biopsy. We present an unusual cause of a presacral mass being extramedullary haematopoiesis, found incidentally in a 71 year old female. Extramedullary haematopoiesis is defined as the production of myeloid and erythroid elements outside of the bone-marrow. This diagnosis is extremely rare in the presacral area especially in a patient with no haematological abnormalities. A review of the literature is presented. 相似文献
27.
Elisabeth APM Romme Piet Geusens Willem F Lems Erica PA Rutten Frank WJM Smeenk Joop PW van den Bergh Peter ThW van Hal Emiel FM Wouters 《Respiratory research》2015,16(1)
Although osteoporosis and its related fractures are common in patients with COPD, patients at high risk of fracture are poorly identified, and consequently, undertreated. Since there are no fracture prevention guidelines available that focus on COPD patients, we developed a clinical approach to improve the identification and treatment of COPD patients at high risk of fracture. We organised a round-table discussion with 8 clinical experts in the field of COPD and fracture prevention in the Netherlands in December 2013. The clinical experts presented a review of the literature on COPD, osteoporosis and fracture prevention. Based on the Dutch fracture prevention guideline, they developed a 5-step clinical approach for fracture prevention in COPD. Thereby, they took into account both classical risk factors for fracture (low body mass index, older age, personal and family history of fracture, immobility, smoking, alcohol intake, use of glucocorticoids and increased fall risk) and COPD-specific risk factors for fracture (severe airflow obstruction, pulmonary exacerbations and oxygen therapy). Severe COPD (defined as postbronchodilator FEV1 < 50% predicted) was added as COPD-specific risk factor to the list of classical risk factors for fracture. The 5-step clinical approach starts with case finding using clinical risk factors, followed by risk evaluation (dual energy X-ray absorptiometry and imaging of the spine), differential diagnosis, treatment and follow-up. This systematic clinical approach, which is evidence-based and easy-to-use in daily practice by pulmonologists, should contribute to optimise fracture prevention in COPD patients at high risk of fracture. 相似文献
28.
Phylogenetic relationships of artiodactyls and cetaceans as deduced from the comparison of cytochrome b and 12S rRNA mitochondrial sequences 总被引:8,自引:0,他引:8
A data set of complete mitochondrial cytochrome b and 12S rDNA sequences is
presented here for 17 representatives of Artiodactyla and Cetacea, together
with potential outgroups (two Perissodactyla, two Carnivora, two
Tethytheria, four Rodentia, and two Marsupialia). We include seven
sequences not previously published from Hippopotamidae (Ancodonta) and
Camelidae (Tylopoda), yielding a total of nearly 2.1 kb for both genes
combined. Distance and parsimony analyses of each gene indicate that 11
clades are well supported, including the artiodactyl taxa Pecora,
Ruminantia (with low 12S rRNA support), Tylopoda, Suina, and Ancodonta, as
well as Cetacea, Perissodactyla, Carnivora, Tethytheria, Muridae, and
Caviomorpha. Neither the cytochrome b nor the 12S rDNA genes resolve the
relationships between these major clades. The combined analysis of the two
genes suggests a monophyletic Cetacea +Artiodactyla clade (defined as
"Cetartiodactyla"), whereas Perissodactyla, Carnivora, and Tethytheria fall
outside this clade. Perissodactyla could represent the sister taxon of
Cetartiodactyla, as deduced from resampling studies among outgroup
lineages. Cetartiodactyla includes five major lineages: Ruminantia,
Tylopoda, Suina, Ancodonta, and Cetacea, among which the phylogenetic
relationships are not resolved. Thus, Suiformes do not appear to be
monophyletic, justifying their split into the Suina and Ancodonta
infraorders. An association between Cetacea and Hippopotamidae is supported
by the cytochrome b gene but not by the 12S rRNA gene. Calculation of
divergence dates suggests that the Cetartiodactyla could have diverged from
other Ferungulata about 60 MYA.
相似文献
29.
30.
VG Minero D De Stefanis P Costelli FM Baccino G Bonelli 《Cell cycle (Georgetown, Tex.)》2015,14(7):1090-1102
High mortality among hepatocellular carcinoma (HCC) patients reflects both late diagnosis and low curability, due to pharmacoresistance. Taxol (TAX) is toxic for many human HCC-derived cell lines, yet its clinical efficacy on HCCs is poor. Combining TAX with other drugs appears a promising possibility to overcome such refractoriness. We analyzed whether combining tumor necrosis factor (TNF) with TAX would improve their toxicity. Human HCC-derived cell lines were treated with TAX or TNF, alone or combined. Apoptosis was assessed by morphology and flow-cytometry. Several pro- and anti-apoptotic molecules were evaluated by western blotting and/or enzymatic assay. After a 24 hour treatment, TNF was ineffective and TAX modestly cytotoxic, whereas HCC cells were conditionally sensitized to TNF by TAX. Indeed some relevant parameters were shifted to a prodeath setting: TNF-receptor 1 was increased, SOCS3, c-FLIP and pSTAT3 were markedly downregulated. These observations provide a significant clue to critically improve the drug susceptibility of HCC cells by combining 2 agents, TAX and TNF. The sequential application of TAX at a low dosage followed by TNF for only a short time triggered a strong apoptotic response. Of interest, prior TAX administration could also sensitize to TNF-induced apoptosis in the Yoshida AH-130 hepatoma transplanted in mice. Therefore, scrutinizing the possibility to develop similar combination drug regimens in suitable preclinical models seems highly advisable. 相似文献