Primitive hematopoietic stem cells differentiate into committed progenitors that are thought to selectively express hematopoietic growth factor receptor(s), thereby acquiring hematopoietic growth factor responsiveness. To assess whether hematopoietic stem cells express hematopoietic growth factor receptors, the progenitor activity of bone marrow (BM) fractions, isolated by expression of receptors for macrophage/monocyte colony-stimulating factor (M-CSF), were examined. Recovery of day-12 spleen colony-forming units (CFU-S) is diminished in both M-CSF receptor-positive (M-CSFR+) and M-CSFR- fractions, indicating antibody inhibition of day-12 CFU-S. Incubation of BM cells with antibody without fractionation inhibits 50% to 60% of day-12 CFU- S. This inhibition is specific (control antibodies have no effect) and reversible by removal of bound antibody at low pH. Incubating BM cells with control or antireceptor antibody does not affect day-8 CFU-S, which are predominantly erythroid. Treating sublethally irradiated mice with antibody inhibits endogenous day-12 CFU-S. These results indicate that some early progenitors express M-CSFRs, and blocking M-CSFRs inhibits the ability of these progenitors to form colonies, possibly because of inactivation caused by prolonged receptor blockade. 相似文献
The color complementation assay (CCA) is a method of allele-specific DNA amplification by which competitive priming and extension of fluorescently labeled oligonucleotide primers determine the color of DNA amplification product. This diagnostic method precludes the need for radioisotopes, electrophoresis, and multiple high-stringency reaction conditions. The multiplicity of mutant globin genes present in Southeast Asians complicates clinical diagnosis and underscores the importance of DNA-based diagnostic methods. We have applied CCA to distinguish beta A and beta E alleles. Competing 15mer primers were a fluorescein-labeled complement to beta A and a rhodamine-labeled complement to beta E, identical except for their central nucleotides. A common unlabeled primer was used to amplify DNA product, the color of which was determined by the perfectly complementary primer. Color photography and spectrofluorometry, as well as a method of black-white photography that we developed to distinguish fluorescein- and rhodamine- labeled DNA, were used to record results. We applied CCA to define the complex genotype of a Thai woman with thalassemia intermedia, 96% HbE, and 4% HbF whose possible genotypes included several permutations of alpha-thalassemia, beta-thalassemia, and beta E genes. zeta-Globin gene mapping of DNA doubly digested with Bg/II and Asp 718 showed the -alpha 3.7/--SEA genotype, and CCA confirmed homozygous beta E/beta E. The CCA is useful for diagnosing the compound hemoglobin genotypes of Southeast Asians and could be applied also to prenatal diagnosis in this population. 相似文献
Opinion statement Anemia is a frequent extraintestinal manifestation of inflammatory bowel disease (IBD) that is commonly overlooked, despite
its significant impact on quality of life. Characteristic symptoms include chronic fatigue, headache, and subtle impairment
of cognitive function, although some less common symptoms include dyspnea, dizziness, pica, angular stomatitis, shortened
attention span, and esophageal webs. Several types of anemia are associated with IBD, but iron deficiency anemia (IDA) accounts
for the majority of cases and others include anemia of chronic disease, anemia associated with vitamin deficiency (vitamin
B12 and folate), autoimmune anemia, and anemia caused by medication used to treat IBD. The diagnosis of IDA relies on laboratory
blood tests. Therefore, these tests should be obtained on a regular basis because characteristic symptoms may be absent or
not readily recognized by patients and their clinicians. Complete blood count may suffice; however, iron studies and serum
vitamin levels may be necessary to differentiate between specific types of anemia. During the diagnostic process, it is important
to consider coexistence of different types of anemia, especially if no response to therapy is noted. The therapy for anemia
is directed towards treatment of the underlying inflammatory process and supplemental therapy, depending on the type of deficiency.
Iron deficiency anemia is treated with iron preparations, first orally, and if unresponsive or if associated with untoward
adverse events leading to decrease in adherence with the therapeutic regimen, with intravenous preparations. Intramuscular
therapy has been abandoned due to high rate of complications. Intravenous therapy may be administered as a multiple-dose regimen
(intravenous iron sucrose and gluconate) or as a single intravenous dose (iron dextran), which is associated with a higher
risk of allergic infusion reactions and requires obligatory test dose administration. Treatment with erythropoietin is reserved
for a select subgroup of patients with anemia of chronic disease. With appropriate treatment, the majority of patients with
IBD will have significant improvement or resolution of anemia, which can lead to a better quality of life. However, a high
index of suspicion should be maintained in order to identify the precise cause of anemia and to prescribe the appropriate
therapy. 相似文献
Four patients with Philadelphia (Ph') positive chronic myeloid leukemia (CML) were studied before, after, and on relapse following allogeneic bone marrow transplantation (BMT). Southern analysis of DNA from cells collected before and at relapse after BMT was performed in order to investigate the origin of the leukemia at relapse. Using minisatellite probes we showed that the relapse occurred in cells of host origin in all four patients and this was confirmed with a Y chromosome specific probe in two male patients who had a female donor. Furthermore, using two probes for the breakpoint cluster region (bcr) on chromosome 22, we showed that leukemic cells at relapse bore identical rearrangements to those in the disease at time of presentation of each patient. We conclude that relapse in all four patients is due to re-emergence of the original leukemic clone. 相似文献
Kawasaki disease (KD) is an acute medium vessel vasculitis seen in children. The most significant long-term complication is related to coronary artery abnormalities. Use of intravenous immunoglobulins, however, has led to significant reduction in incidence of coronary aneurysms. What is more alarming is the fact that higher risk of cardiovascular disease is seen in even those children who do not have coronary artery aneurysms during subacute phase. Various factors like abnormal lipid profiles, abnormal vessel wall reactivity and endothelial dysfunction have been implicated for this. Carotid intima-media thickness (cIMT) has been used as a surrogate marker for atherosclerosis. This study was planned to evaluate cIMT in children with KD. Twenty-seven children with diagnosis of KD at least 1 year prior to enrolment were evaluated for cIMT at enrolment and then after 3 months. Fasting lipid profile was done for all patients. Mean cIMT was significantly higher in children with KD compared to controls. In lipid profiles, undesirable HDL-C and triglyceride levels were seen in 2 and 3 children, respectively. Undesirable and borderline LDL-C levels were seen in 1 and 2 patients, respectively. Undesirable and borderline total cholesterol levels were seen in 1 and 3 patients, respectively. Higher cIMTs were seen in our cohort of KD patients. Proatherogenic abnormalities in lipid profile were seen in a few patients. Both abnormalities may predict a higher risk of atherosclerosis in future. The results of this study need to be replicated on a larger study sample and over longer follow-up periods. 相似文献
Conflicting evidence exists on whether smoking acts as an effect modifier of the association between APOE genotype and risk of coronary heart disease (CHD).
Methods and results
We searched PubMed and EMBASE to June 11, 2013 for published studies reporting APOE genotype, smoking status and CHD events and added unpublished data from population cohorts. We tested for presence of effect modification by smoking status in the relationship between APOE genotype and risk of CHD using likelihood ratio test.In total 13 studies (including unpublished data from eight cohorts) with 10,134 CHD events in 130,004 individuals of European descent were identified. The odds ratio (OR) for CHD risk from APOE genotype (ε4 carriers versus non-carriers) was 1.06 (95% confidence interval (CI): 1.01, 1.12) and for smoking (present vs. past/never smokers) was OR 2.05 (95%CI: 1.95, 2.14). When the association between APOE genotype and CHD was stratified by smoking status, compared to non-ε4 carriers, ε4 carriers had an OR of 1.11 (95%CI: 1.02, 1.21) in 28,789 present smokers and an OR of 1.04 (95%CI 0.98, 1.10) in 101,215 previous/never smokers, with no evidence of effect modification (P-value for heterogeneity = 0.19). Analysis of pack years in individual participant data of >60,000 with adjustment for cardiovascular traits also failed to identify evidence of effect modification.
Conclusions
In the largest analysis to date, we identified no evidence for effect modification by smoking status in the association between APOE genotype and risk of CHD. 相似文献
The aim of this research was to evaluate the impact of variability in ice sublimation rate (dm/dt) measurement and vial heat transfer coefficient (Kv) on product temperature prediction during the primary drying phase of lyophilization. The mathematical model used for primary drying uses dm/dt and Kv as inputs to predict product temperature. A second-generation tunable diode laser absorption spectroscopy (TDLAS)–based sensor was used to measure dm/dt. In addition, a new approach to calculate drying heterogeneity in a batch during primary drying is described. The TDLAS dm/dt measurements were found to be within 5%-10% of gravimetric measurement for laboratory- and pilot-scale lyophilizers. Intersupplier variability in Kv was high for the same “type” of vials, which can lead to erroneous product temperature prediction if “one value” of vial heat transfer coefficient is used for “all vial types” from different suppliers. Studies conducted in both a laboratory- and a pilot-scale lyophilizer showed TDLAS product temperature to be within ±1°C of average thermocouple temperature during primary drying. Using TDLAS data and calculations to estimate drying heterogeneity (number of vials undergoing primary drying), good agreement was obtained between theoretical and experimental results, demonstrating usefulness of the new approach. 相似文献
Nature is integrated, being simultaneously controlled by different natural aspects. Genetics, bioinformatics, biostatistics and geology are four diverse and broad scientific disciplines. But we believe that these can offer important insights into species distribution and evolution, if integrated. This perspective is grounded on a case study of the family Salvadoraceae, where species distribution and phylogeny show high correlation with the geological records. The results obtained from published and ongoing research indicate that we are pointing toward better visualizing the overlapping boundaries of these specific disciplines, which will be able to more accurately answer key evolutionary questions. We highlight: (1) the combined application of bedrock-soil geological data and bioinformatics to resolve evolutionary questions regarding species eco-distribution, niche prediction and bio-evolution; and (2) signifies the importance of relaxing boundaries between the disciplines to come to a better conclusion on species diversity and distribution-driven controls. Overall, we express and briefly explain our hypothesis to integrate modern analytical tools, viz., statistical correlation of geological data via. geo-statistics (Geo), and spatiotemporal biostatistics via. geo-informatics (Geo), with gene-based paleontological shreds of evidence, and sequence-based bioinformatics, to devise a practical analysis tool, namely “Geo2 gene-bioinformatics”. We invoke the development of algorithms through computational-based programs that can provide useful correlations to understand evolutionary systematics and phylogeny, species distribution, and niche prediction.