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1.
Folate deficiency significantly increases uracil content and chromosome breaks (as measured by micronucleated cells) in human leukocyte DNA. Folate supplementation reduces both the uracil content of DNA and the frequency of micronucleated cells, indicating that uracil misincorporation may play a causative role in folate deficiency-induced chromosome breaks. A calculation is presented to explain how the levels of uracil found in DNA could cause chromosome breaks. Based on this calculation, the frequency of uracil repair events that might result in double-strand DNA breaks increases by 1752-fold. These results are consistent with clinical and epidemiological evidence linking folate deficiency to DNA damage and cancer. 相似文献
2.
A Inbal O Epstein D Blickstein N Kornbrot B Brenner U Martinowitz 《Canadian Metallurgical Quarterly》1993,4(4):599-604
Haemostatic efficacy and pharmacokinetic analysis of solvent/detergent (S/D) treated, virus inactivated plasma (Octaplas, Germany) was evaluated in eight patients with hereditary factor VII, X and XI deficiency and in three patients with acquired coagulation disorders due to liver disease. The patients received the S/D plasma for treatment of haemarthrosis, menorrhagia or before surgical procedures. In all the patients the S/D plasma was sufficient to prevent or stop bleeding. Side effects included urticaria (one patient) and moderate anaphylactoid reaction (one patient). No evidence of plasma-born viral infections was observed up to 12 months after the treatment (95% confidence limits 0-22%). Calculated mean half-life of coagulation factors VII, X and XI was 4.36 h, 49.21 h and 44.5 h, respectively, similar to that observed with fresh-frozen plasma. Because of retained coagulation factor integrity and improved viral safety, S/D plasma could be considered a superior alternative to standard fresh-frozen plasma. 相似文献
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PURPOSE: To investigate the mechanisms underlying the induction of chromosome aberrations by ionizing radiation, focusing attention on DNA damage severity, interphase chromosome geometry and the distribution of DNA strand breaks. METHODS: An ab initio biophysical model of aberration induction in human lymphocytes specific for light ions was developed, based on the assumption that 'complex lesions' (clustered DNA breaks) produce aberrations, whereas less severe breaks are repaired. It was assumed that interphase chromosomes are spatially localized and that chromosome break free-ends rejoin pairwise randomly; the unrejoining of a certain fraction of free-ends was assumed to be possible, and small fragments were neglected in order to reproduce experimental conditions. The yield of different aberrations was calculated and compared with some data obtained using Giemsa or FISH techniques. RESULTS: Dose-response curves for dicentrics and centric rings (Giemsa) and for reciprocal, complex and incomplete exchanges (FISH) were simulated; the ratio between complex and reciprocal exchanges was also calculated as a function of particle type and LET. The results showed agreement with data from lymphocyte irradiation with light ions. CONCLUSIONS: The results suggest that clustered DNA breaks are a critical damage type for aberration induction and that interphase chromosome localization plays an important role. Moreover, the effect of a given particle type is related both to the number of induced complex lesions and to their spatial distribution. 相似文献
4.
Patients with acquired immune deficiency syndrome (AIDS) do not frequently have pleural complications. However, pneumothorax is a troublesome complication of patients with AIDS. At some medical centres, more than 50% of patients with spontaneous pneumothorax have AIDS. Most patients with spontaneous pneumothorax and AIDS have Pneumocystis carinii infection and necrotic subpleural blebs. The pneumothoraces in these patients usually cannot be managed with tube thoracostomy alone. Patients who do not respond to tube thoracostomy are best managed with a Heimlich valve or with thoracostomy with stapling of blebs and pleural abrasion. Approximately 2% of human immunodeficiency virus (HIV)-positive individuals will have a pleural effusion. Parapneumonic effusions or empyema, tuberculosis and Kaposi's sarcoma are the three leading causes. P. carinii infection is frequently responsible for pulmonary infections, but is only occasionally responsible for a pleural effusion. Pleural effusions may also develop from non-Hodgkin's lymphoma (NHL). There is one relatively rare NHL that is associated with the Kaposi's sarcoma associated virus that produces a lymphoma confined to the body cavity. 相似文献
5.
A 27 month old child presented with left hemiplegia and was found to have deep cerebral venous thrombosis. The deep cerebral venous thrombosis resolved on warfarin. Elevated and fluctuating anticardiolipin antibodies as well as protein S deficiency were detected. 相似文献
6.
M Romano P Dri L Dadalt P Patriarca FE Baralle 《Canadian Metallurgical Quarterly》1997,90(10):4126-4134
Hereditary myeloperoxidase (MPO) deficiency is a neutrophil disorder characterized by the lack of peroxidase activity. Cytochemical, biochemical, spectroscopic, immunocytochemical, and genetic studies were carried out on a 5-year-old MPO-deficient subject and on her parents. The father was also MPO-deficient, whereas the mother had 24% of normal MPO activity. Although the typical absorption spectrum of MPO was absent in both the father and daughter, the father's neutrophils, and not those of the daughter, contained material antigenically related to MPO. In the MPO gene of the father, two mutations were found, each located in a different allele: a T --> C transition, causing the nonconservative replacement M251T and a 14-base deletion within exon 9. The M251T substitution occurred in the carboxy-terminal region of the light chain that is included in the heme pocket. The daughter inherited the 14-base deletion from her father. The study of the MPO mRNAs present in liquid cultures of granulocyte precursors surprisingly showed that the same genetic defect, ie, the 14-base deletion, seemed to exhibit different mRNA phenotypes in the father and the daughter. In fact, mRNA derived from the 14-base-deleted allele was not found in the father and an aberrantly spliced MPO mRNA with a 77-base deletion of exon 9, which includes the 14-base deletion and leads to the generation of a premature stop codon, was found in the daughter. The possibility that Delta77 mRNA could derive from other mutations linked to the Delta14 allele was dismissed because no sequence differences were found in the region (exons and exon-intron junctions). Our data indicate that the alteration of the mRNA context caused by the 14-base deletion provide a basis for the 77-base deletion in the mRNA processing. Since the granulocyte precursors from the liquid cultures of the father were more differentiated than those from the daughter, the observed different behavior of the 14-base-deleted allele in the father and daughter may be the result of a differentiation-stage dependent control of altered spliced mRNA, which may be tolerated during the early stages of differentiation but degraded at later stages. In the liquid cultures of the daughter's cells, in addition to the mRNA with the 77-base deletion, a mRNA with the wild type sequence was also found. This mRNA was inherited from the mother, since no mutations were found in her MPO cDNA and MPO gene. The MPO defect might be caused by a regulatory mutation that induces the MPO gene switch off at an early stage of granulocyte differentiation. 相似文献
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MI Botez 《Canadian Metallurgical Quarterly》1976,2(4):135-140
The restless legs syndrome could represent a folate responsive disorder in both patients with acquired-folate deficiency and those with familial symptomatology. Patients with acquired folate-deficiency could be divided into two subgroups. (i) those with minor neurological signs (restless legs syndrome, vibration sense impairment and tactile hypoesthesia in both legs with diminished ankle jerks and a prolonged or assymetrical Achilles-reflex time) and (ii) those with major neurological signs (subacute combined degeneration with or without neuropathies). In some of these patients the classical triad of the malabsorption syndrome is replaced by another triad, constipation, abnormal jejunal biopsy and abnormal d-xylose absorption. A low folic serum acid level could induce minor neuropsychiatric symptoms while an additional low CSF folate could induce major neurological symptoms in spite of the presence of a normal erythrocyte folate level and in the absence of frank anemia. Possible further studies are described. 相似文献
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N Alloisio P Texier A Vallier ML Ribeiro L Morlé M Bozon E Bursaux P Maillet P Gon?alves MJ Tanner G Tamagnini J Delaunay 《Canadian Metallurgical Quarterly》1997,90(1):414-420
We present two novel alleles of the anion-exchanger 1 (AE1) gene, allele Coimbra and allele Mondego. Allele Coimbra (V488M, GTG --> ATG) affects a conserved position in the putative second ectoplasmic loop of erythrocyte band 3. In 15 simple heterozygotes, it yielded a mild form of hereditary spherocytosis (HS) with band 3 deficiency (-20% +/- 2%) and a reduced number of 4,4'-diisothiocyano-1,2-diphenylethane-2,2'-disulfonate (H2DIDS) binding sites (-35%). However, two additional heterozygotes presented with an aggravated HS and a more pronounced reduction of band 3 (-40%) and of H2DIDS binding sites (-48%). They carried, in trans to allele Coimbra, allele Mondego, defined by two mutations: E40K, GAG --> AAG, the known mutation Montefiore, and P147S, CCT --> TCT, a novel mutation, both located in the cytoplasmic domain of band 3. Allele Mondego itself resulted in no clinical or hematologic HS signs in the simple heterozygous state. Yet it yielded a slight decrease in band 3 (-6% to -12%) and in the number of H2DIDS binding sites (-19%). Thus, the more pronounced decrease in band 3 in the two compound heterozygotes derived from the additive effects of two unequally expressed AE1 alleles, resulting in a more severe clinical picture. 相似文献
12.
Inherited antithrombin (AT) deficiency is a major cause of venous thromboembolism, especially in relation to surgery and pregnancy. We present six AT deficient pregnant women, who successfully delivered seven babies at the Department of Gynaecology/Obstetrics, Aalborg Hospital. From conception, or if possible prior to conception, the women were treated with unfractionated (UFH) or low molecular weight heparin (LMWH) throughout the pregnancy. If the pregnancy was without complication, AT substitution was only used at delivery and for approximately a week post-partum, when warfarin treatment was re-instituted. 相似文献
13.
Congenital deficiency of the late components of the complement may predispose the individual to systemic meningococcal infection. Assuming that patients with acquired complement deficiencies may also have an increased risk of contracting meningococcal infections, a retrospective and prospective study to assess this association was conducted. Over 20 years (1970-1989), 30 patients with meningococcemia or meningococcal meningitis, proven by blood or CSF culture, were treated at the Beilinson Medical Center. Only one patient died of the infection. Risk factors were found in three patients (10%). One had a congenital deficiency of C7, and two had acquired complement deficiency due to systemic lupus erythematosus (SLE) and membranoproliferative glomerulonephritis (MPGN). These latter two patients had low serum concentration of C3 and C4 and reduced complement hemolytic activity before onset of the infection. Since the incidence of culture-proven systemic meningococcal infection in the Jewish population in central Israel is 1/100,000, and the prevalence of SLE and MPGN is, at most, 250/100,000, the finding of two patients with meningococcal infection and these rare disorders is over 100 times the expected incidence. We conclude that patients with acquired complement deficiency are at significant risk of meningococcal infection. 相似文献
14.
P Herranz J García R De Lucas J González JM Pe?a R Díaz M Casado 《Canadian Metallurgical Quarterly》1997,137(4):577-580
The samples of blood freshly taken from healthy men were gamma-irradiated with a dose of 10 Gy. It was shown that after the treatment the blood gained the capacity to emit secondary biogenic radiation. Emission lasted for some hours, passed through quartz-glass cuvette and was revealed by stimulating influence on biological detector (sprouting seeds). 相似文献
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CG BERGSTRAND 《Canadian Metallurgical Quarterly》1955,18(4):465-481
16.
Genomic analysis and detailed blood coagulation examinations of 22 family members of 18 families with repeatedly low protein C activity have been performed. Blood coagulation examinations: INR, fibrinogen, plasminogen, alpha-2-antiplasmin, lupus anticoagulant, APC resistance test, protein C activity and antigen, protein S activity and antithrombin activity. Genetic examinations: the presence of FII G20210A alle and FV:Q506 Leiden mutation were examined and for the mutation screening in the protein C gene combination of polymerase chain reaction (PCR) with denaturing gradient gelelectrophoresis (DGGE) or with single-strand conformation polymorphism (SSCP) analysis has been performed. The amplified DNA fragments with aberrant migration during DGGE and SSCP analysis were sequenced. Nine family members of seven families were identified carrying mutations in the protein C gene: one nonsense mutation in exon VII (Arg 157-Stop), two types of missense mutations in four patients in exon IXA (230 Arg-Lys, 254 Thr-Ile, the latter is a new mutation, Protein C Pécs), one missense mutation in two patients in exon IXB (325 Val-Ala), one missense mutation in exon IXC (359 Asp-Asn) and a rare frameshift deletion in exon IXC (364 Met-Trp, 378 Stop). Nine families were evaluated carrying no mutation in their protein C gene, but other genetic or blood coagulation disturbances have been identified, eight of them had borderline decrease in their protein C activity (60-70%). The presence of FV:Q506 mutation could be diagnosed in eight families (in 3 cases homozygous, in 5 cases heterozygous form), among them combination of the defects could be proved in three of the eight families: FV:Q506 Leiden mutation with antiphospholipoid antibodies in 2 families and the presence of Leiden mutation with prothrombin gene mutation in 1 family. Protein S deficiency in combination with prothrombin gene mutation has been identified in 1 family. There were 2 families where no genetic or blood coagulation alterations could be detected in the background of the repeatedly low protein C activity. Large deletions or insertions which are not detectable by our screening methods could not be excluded in these families and therefore sequencing of the total protein C gene had been performed with negative results. According to the literature and our experience the screening methods that were administered in this study are suitable for the detection of mutations in the protein C gene. 相似文献
17.
L Elsborg 《Canadian Metallurgical Quarterly》1976,55(3):140-147
The question of the point of impact of the electric current in the galvanic vestibular test is not solved. An important feature is that, after destruction of both the vestibular end organs, a galvanic nystagmus can still be provoked. The effect of a direct current on the spontaneous nystagmus following partial or total destruction of the vestibular end organs was investigated. The frequency of the spontaneous nystagmus diminishes when the electric stimulus causes an eye movement in the same direction as the fast phase of the nystagmus, the frequency increases when the polarity of the electric stimulation is reversed. Simultaneous application of torsion-swing and electric stimulation causes a summation of the separate effects. Our findings confirm the conculsions drawn by Ledoux (4, 5) from his findings in frogs. 相似文献
18.
BACKGROUND: It is unclear whether there is a relationship between lithium administration and vitamin B12 metabolism. METHODS: We compared serum B12, serum folate, and red blood cell folate concentrations in patients receiving and not receiving lithium at two Mood Disorders Clinics. As the two centers differed in vitamin assay methods, data were first analyzed separately and then combined. To rule out an in vitro effect of lithium on the assays, we also added varying amounts of lithium to lithium-free blood samples and measured vitamin concentrations. RESULTS: Mean serum B12 concentrations were approximately 20% lower in the lithium than in the nonlithium group at each center. This difference was statistically significant for each center and on combination (two-tailed p = .017, .021, and .0009). The parametric effect size for each center and the combined weighted mean effect size were moderate in magnitude (.605, .523, and .565). There was a nonsignificant trend toward an increased prevalence of assay-defined B12 deficiency in the lithium group at one center only, with no cases in either group at the other center and a nonsignificant combined relative risk. CONCLUSIONS: Our data may represent a lithium-associated decrease in serum B12 concentration. The clinical significance of these findings is not yet clear. 相似文献
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We investigated the regulation of COX-2 expression and activity by adenosine receptors in rat microglial cells. The selective adenosine A2a-receptor agonist CGS21680 and the non-selective adenosine A1- and A2-receptor agonist 5'-N-ethylcarboxiamidoadenosine (NECA) induced an increase in COX-2 mRNA levels and the synthesis of prostaglandin E2 (PGE2). The adenosine A1-receptor agonist cyclopentyladenosine (CPA) was less potent, and the adenosine A1-receptor-specific agonist N6-2-(-aminophenylo)ethyladenosine (APNEA) showed only marginal effects. Microglia expressed adenosine A1-, A2a-, and A3-, but not A2b-receptor mRNAs, whereas astroglial cells expressed adenosine A2b- but not A2a-receptor mRNA. The adenosine A2a-receptor selective antagonist (E)-8-(3,4-dimethoxystyryl)-1,3-dipropyl-7-methylxanthine (KF17837) inhibited both CGS21680-induced COX-2 expression and PGE2 release. CGS21680-increased PGE2 levels were inhibited by dexamethasone, by the nonsteroidal antiinflammatory drug meloxicam, and by the adenylyl cyclase inhibitor 9-(tetrahydro-2-furanyl)-9H-purine-6-amine (SQ22536). CGS21680 and NECA both increased intracellular cAMP levels in microglial cells. Dibutyryl cAMP as well as forskolin induced the release of PGE2. The results strongly suggest that adenosine A2a-receptor-induced intracellular signaling events cause an up-regulation of the COX-2 gene and the release of PGE2. Apparently, the cAMP second messenger system plays a crucial role in COX-2 gene regulation in rat microglial cells. The results are discussed with respect to neurodegenerative disorders of the CNS such as Alzheimer's disease, in which activated microglia are critically involved and COX inhibitors may be of therapeutic benefit. 相似文献
20.
KM Hambidge 《Canadian Metallurgical Quarterly》1997,65(1):160-161