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1.
2.
The alpha-like globin gene cluster in rabbits contains embryonic zeta-
globin genes, an adult alpha-globin gene, and theta-globin genes of
undetermined function. The basic arrangement of genes, deduced from
analysis of cloned DNA fragments, is 5'-zeta 0-zeta 1-alpha 1-theta 1- zeta
2-zeta 3-theta 2-3'. However, the pattern of restriction fragments
containing zeta- and theta-globin genes varies among individual rabbits.
Analysis of BamHI fragments of genomic DNA from 24 New Zealand white
rabbits revealed eight different patterns of fragments containing
zeta-globin genes. The large BamHI fragments containing genes zeta 0 and
zeta 1 are polymorphic in length, whereas a 1.9-kb fragment containing the
zeta 2 gene and the 3.5-kb fragment containing the zeta 3 gene do not vary
in size. In contrast to this constancy in the size of the restriction
fragments, the copy number of the zeta 2 and zeta 3 genes does vary among
different rabbits. No length polymorphism was detected in the BamHI
fragments containing the theta-globin genes, but again the copy number
varies for restriction fragments containing the theta 2 gene. The alpha 1-
and theta 1-globin genes are located in a nonpolymorphic 7.2-kb BamHI
fragment. The combined data from hybridization with both zeta and theta
probes shows that the BamHI cleavage pattern does not vary within the
region 5'-alpha 1-theta 1- zeta 2-zeta 3-theta 2-3', but the pattern
genomic blot-hybridization patterns for the progeny of parental rabbits
with different zeta-globin gene patterns shows that the polymorphic
patterns are inherited in a Mendelian fashion. Two different haplotypes
have been mapped based on the genomic blot-hybridization data. The
variation in the alpha-like globin gene cluster in the rabbit population
results both from differences in the copy number of the duplication block
containing the zeta-zeta-theta gene set and from the presence or absence of
polymorphic BamHI sites.
相似文献
3.
Histamine stimulated adenylate cyclase from guinea-pig fundic mucosa and 3H-tiotidine binding in guinea-pig cerebral cortex were used to assess the in-vitro histamine H2-activity of the novel H2-antagonist HUK 978. The results showed that HUK 978 was a more potent H2-antagonist than either cimetidine or ranitidine. HUK 978 was also shown to be devoid of activity at the histamine H1-receptor, the muscarinic receptor and the alpha and beta-adrenergic receptors. 相似文献
4.
Assignment of orthologous relationships among mammalian alpha-globin genes by examining flanking regions reveals a rapid rate of evolution 总被引:1,自引:0,他引:1
In order to study the relationships among mammalian alpha-globin genes, we
have determined the sequence of the 3' flanking region of the human alpha 1
globin gene and have made pairwise comparisons between sequenced
alpha-globin genes. The flanking regions were examined in detail because
sequence matches in these regions could be interpreted with the least
complication from the gene duplications and conversions that have occurred
frequently in mammalian alpha-like globin gene clusters. We found good
matches between the flanking regions of human alpha 1 and rabbit alpha 1,
human psi alpha 1 and goat I alpha, human alpha 2 and goat II alpha, and
horse alpha 1 and goat II alpha. These matches were used to align the
alpha-globin genes in gene clusters from different mammals. This alignment
shows that genes at equivalent positions in the gene clusters of different
mammals can be functional or nonfunctional, depending on whether they
corrected against a functional alpha-globin gene in recent evolutionary
history. The number of alpha-globin genes (including pseudogenes) appears
to differ among species, although highly divergent pseudogenes may not have
been detected in all species examined. Although matching sequences could be
found in interspecies comparisons of the flanking regions of alpha- globin
genes, these matches are not as extensive as those found in the flanking
regions of mammalian beta-like globin genes. This observation suggests that
the noncoding sequences in the mammalian alpha-globin gene clusters are
evolving at a faster rate than those in the beta-like globin gene clusters.
The proposed faster rate of evolution fits with the poor conservation of
the genetic linkage map around alpha-globin gene clusters when compared to
that of the beta-like globin gene clusters. Analysis of the 3' flanking
regions of alpha-globin genes has revealed a conserved sequence
approximately 100-150 bp 3' to the polyadenylation site; this sequence may
be involved in the expression or regulation of alpha-globin genes.
相似文献
5.
6.
J Meirion Thomas W H Redding R C Coombes J P Sloane H T Ford J-C Gazet T J Powles 《BMJ (Clinical research ed.)》1978,2(6131):157-159
Two studies were performed to assess the accuracy of non-invasive methods in detecting intra-abdominal metastases from breast cancer. Firstly, the sites of spread detected at the time of first presentation with metastases were compared with the sites of spread shown at necropsy in the same patients. Although about two-thirds of the patients with bone and lung metastases at necropsy had had metastases detected at these sites when they first presented with metastases, only a third of the patients with liver metastases and none of those with other intra-abdominal metastases had had evidence of disease at first presentation with metastases. The second study confirmed a poor detection rate of liver and other intra-abdominal metastases in patients with breast cancer undergoing laparotomy and oophorectomy who were staged immediately before operation.Pre-mastectomy staging laparotomy should be considered in those patients with primary breast cancer who are most likely to have disseminated disease beyond the regional nodes. In the presence of occult gross metastases detected by staging laparotomy, mastectomy will not provide additional protection against loca recurrence of disease. Patients with occult gross metastases should also be excluded from studies on adjuvant chemotherapy (designed to treat micrometastases). Aggressive methods of staging are justified to protect the patient as far as possible against unnecessary mastectomy and to identify those patients who should be treated by therapeutic chemotherapy rather than adjuvant chemotherapy. 相似文献
7.
J C Gazet R M Rainsbury H T Ford T J Powles R C Coombes 《BMJ (Clinical research ed.)》1985,290(6484):1793
A postal survey of current management of breast cancer among surgeons in Great Britain was carried out. The results showed that there is no consensus among surgeons about the treatment of primary breast cancer. Many different types of primary surgery are practised, and patterns of referral for postoperative radiotherapy vary widely. Adjuvant systemic treatment is given often by some surgeons and not at all by others. Few patients are entered into controlled randomised trials. 相似文献
8.
OBJECTIVE--To determine the relation between maternal serum alpha fetoprotein and free beta human chorionic gonadotrophin concentrations in pregnancies complicated by trisomy 18 and establish whether prenatal biochemical screening for this condition could be developed in a way similar to that proposed for trisomy 21. DESIGN--Serum alpha fetoprotein and free beta human chorionic gonadotrophin concentrations in women with singleton pregnancies affected by cytogenetically confirmed trisomy 18, uncomplicated by neural tube defect or ventral wall defect, were identified from prospective trisomy 21 screening programmes. Additionally, stored maternal serum from similar pregnancies was analysed retrospectively. Analyte concentrations from singleton unaffected pregnancies were identified from a prospective screening programme as controls. Statistical parameters of the affected and unaffected populations were compiled. SETTING--Biochemical screening laboratories in Britain and the United States. SUBJECTS--52 women with singleton pregnancies complicated by trisomy 18; control population of 6661 women with unaffected singleton pregnancies. MAIN OUTCOME MEASURES--Median values of each analyte and their distribution in the affected and unaffected populations; detection rate of trisomy 18 and the false positive rate. RESULTS--Maternal serum alpha fetoprotein and free beta human chorionic gonadotrophin concentrations were significantly lower in pregnancies complicated by trisomy 18 (median values 0.71 and 0.37 respectively). By using a multivariate risk algorithm incorporating maternal age risk of trisomy 18 and the concentration of the two biochemical markers it was predicted that 50% of trisomy 18 cases (unaffected by neural tube defect or ventral wall defect) could be detected with a 1% false positive rate. CONCLUSION--Second trimester biochemical screening for trisomy 18 could be a valuable addition to trisomy 21 screening programmes. 相似文献
9.
Adriana Vergs Alexandra H. Campbell Georgina Wood Lana Kajlich Aaron M. Eger Derrick Cruz Madelaine Langley Damon Bolton Melinda A. Coleman Jennifer Turpin Michaelie Crawford Nigel Coombes Adam Camilleri Peter D. Steinberg Ezequiel M. Marzinelli 《Ecological Management & Restoration》2020,21(2):74-85
Operation Crayweed focuses on the restoration of underwater forests that disappeared from the coastline of Sydney, Australia’s largest city, 40 years previously. We show how a combination of science, hands‐on restoration, community engagement and art has helped the project to reach its goals as well as raise awareness about the importance of underwater kelp forests that are experiencing global decline. 相似文献
10.
Karen Page David S. Guttery Nathalie Zahra Lindsay Primrose Shona R. Elshaw J. Howard Pringle Kevin Blighe Stephanie D. Marchese Allison Hills Laura Woodley Justin Stebbing R. Charles Coombes Jacqueline A. Shaw 《PloS one》2013,8(10)
Circulating nucleic acids (CNAs) are under investigation as a liquid biopsy in cancer. However there is wide variation in blood processing and methods for isolation of circulating free DNA (cfDNA) and microRNAs (miRNAs). Here we compare the extraction efficiency and reproducibility of 4 commercially available kits for cfDNA and 3 for miRNA using spike-in of reference templates. We also compare the effects of increasing time between venepuncture and centrifugation and differential centrifugation force on recovery of CNAs. cfDNA was quantified by TaqMan qPCR and targeted deep sequencing. miRNA profiles were assessed with TaqMan low-density arrays and assays. The QIAamp® DNA Blood Mini and Circulating nucleic acid kits gave the highest recovery of cfDNA and efficient recovery (>90%) of a 564bp spike-in. Moreover, targeted sequencing revealed overlapping cfDNA profiles and variant depth, including detection of HER2 gene amplification, using the Ion AmpliSeq™Cancer Hotspot Panel v2. Highest yields of miRNA and the synthetic Arabidopsis thaliana miR-159a spike-in were obtained using the miRNeasy Serum/Plasma kit, with saturation above 200 µl of plasma. miRNA profiles showed significant variation with increasing time before centrifugation (p<0.001) and increasing centrifugation force, with depletion of platelet associated miRNAs, whereas cfDNA was unaffected. However, sample replicates showed excellent reproducibility on TaqMan low density arrays (ρ = 0.96, p<0.0001). We also successfully generated miRNA profiles for plasma samples stored > 12 years, highlighting the potential for analysis of stored sample biobanks. In the era of the liquid biopsy, standardisation of methods is required to minimise variation, particularly for miRNA. 相似文献