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E U Griese

Publications and source records attributed to E U Griese.

31 records · Page 2Linked to original sources
PubMed1994

Competitive nested polymerase chain reaction for quantification of human MDR1 gene expression.

Tumor cell resistance to cytotoxic drugs is considered one of the major obstacles to successful chemotherapy. Multidrug resistance (MDR) describes the simultaneous expression of cellular resistance to a wide range of structurally and functionally unrelated drugs. The development of the multidrug resistance phenotype is accompanied by multiple morphological and biochemical changes: (a) increased glutathione levels in the cytoplasm, (b) modified levels of enzymes in the nucleus, particularly topoisomerase II, (c) increased DNA repair capacity and (d) overexpression of the (human) MDR1 gene encoding a transmembrane efflux pump (P-glycoprotein, gp-170), which leads to decreased intracellular accumulation and therefore to resistance to a variety of cytotoxic drugs. In this report we describe a competitive polymerase chain reaction (PCR) assay for the absolute quantification of MDR1 mRNA. This assay uses a transcript generated in vitro as an internal standard which is later coamplified together with the MDR1 cDNA. Both cDNAs exhibit the same MDR1 primer sites but differ in the length of the amplicon. For a second round of amplification we applied nested MDR1 primers and were successful in improving the sensitivity of this competitive PCR system. This test for characterizing the MDR1 expression offers high sensitivity and specificity and is therefore of great clinical relevance. It should be useful in improving monitoring and design of chemotherapy.

Base Sequence↗
PubMed1994

The influence of environmental and genetic factors on CYP2D6, CYP1A2 and UDP-glucuronosyltransferases in man using sparteine, caffeine, and paracetamol as probes.

The impact of gender, use of oral contraceptive steroids (OCS), coffee consumption and of smoking on the metabolism of sparteine, caffeine, and paracetamol was studied in 194 randomly selected subjects (98 male and 95 female). Thirty-eight of the male volunteers were cigarette smokers, 40 of the female subjects were smokers and/or users of OCS. The metabolic ratio of sparteine oxidation (MRs) showed a trimodal distribution. 7.7% of the subjects had a MRs > 20 and thus were poor metabolizers (PMs). Within the extensive metabolizer (EM) subjects, a distinct subgroup accounting for 11% was observed with 20 > MRs > 1.2. Six of the 15 phenotypical PMs were heterozygous EMs by genotyping. This indicates the existence of one or several CYP2D6 mutations which cannot be identified by the currently employed genotyping methods. In each subgroup, i.e. smokers/OCS and non-smokers/non-OCS, the cumulative frequency distribution of the heterozygous (wt/B) phenotype caused a shift to higher MRs compared with the wild-type homozygotes (wt/wt). Thus, for the in vivo activity of CYP2D6, genetic determinants prevail over environmental factors. Smoking, use of oral contraceptive steroids, caffeine consumption, or gender had no influence on sparteine metabolism. The distribution of the paracetamol glucuronide/paracetamol metabolic ratio appeared to be unimodal although skewed. Glucuronidation capacity was clearly affected by gender, OCS use and smoking. It was higher in male than in female subjects. Male smokers had the highest, and female non-smokers/non-OCS users the lowest metabolic ratio. CYP1A2 activity, as determined by a caffeine metabolic ratio ((AFMU + 1X + 1U)/1, 7U), was multimodally distributed and was clearly increased in smokers. It was significantly correlated to paracetamol glucoronidation in male heavy smokers (r=0.85), suggesting an element of co-regulation of CYP1A2 and of paracetamol conjugating UDP-glucuronosyltransferase isozymes, including UGTI.6.

Acetaminophen↗
PubMed1990

[Alpha-thalassemia as a rare differential diagnosis of hydrops fetalis et placentae].

alpha-Thalassaemia is a disturbance of the alpha-chain synthesis of the haemoglobin, which occurs mostly in the Far East. On account of the total absence of alpha-chains, the homozygous form is considered to be fatal. However, beta and lambda chains exist abundantly. Abortion, intrauterine or perinatal death are the results of the extreme anaemia (Hb-Bart's syndrome), despite modern intensive medical care. The prenatal diagnosis is possible by: 1. DNA analysis of material obtained by chorion villi sampling or culture of fibroblasts, when a risk of re-occurrence is known to the physician. 2. Hb-electrophoresis from foetal blood in cases of hydrops of uncertain origin. When the diagnosis of this fatal disease is established, there is no foetal indication for delivery by Caesarian section.

Adult↗
PubMed1990

Inactivation of human alpha-globin gene expression by a de novo deletion located upstream of the alpha-globin gene cluster.

Synthesis of normal human hemoglobin A, alpha 2 beta 2, is based upon balanced expression of genes in the alpha-globin gene cluster on chromosome 16 and the beta-globin gene cluster on chromosome 11. Full levels of erythroid-specific activation of the beta-globin cluster depend on sequences located at a considerable distance 5' to the beta-globin gene, referred to as the locus-activating or dominant control region. The existence of an analogous element(s) upstream of the alpha-globin cluster has been suggested from observations on naturally occurring deletions and experimental studies. We have identified an individual with alpha-thalassemia in whom structurally normal alpha-globin genes have been inactivated in cis by a discrete de novo 35-kilobase deletion located approximately 30 kilobases 5' from the alpha-globin gene cluster. We conclude that this deletion inactivates expression of the alpha-globin genes by removing one or more of the previously identified upstream regulatory sequences that are critical to expression of the alpha-globin genes.

Adult↗
PubMed1987

Hemoglobin M Iwate is caused by a C----T transition in codon 87 of the human alpha 1-globin gene.

DNA restriction, molecular cloning, and sequencing methods have been used to characterize the mutation leading to the methemoglobinemia HbM Iwate. It could be demonstrated that the HbM Iwate defect is caused by a point mutation involving a transition from C to T in the first position of codon 87 of the alpha 1-globin gene. Furthermore, the HbM Iwate mutation can directly be identified upon RsaI digestion. This direct detection of the mutation on the gene level is of significant advantage for differential diagnostic purposes.

Base Sequence↗
PubMed1987

[Experiences with prenatal diagnosis of sickle cell anemia and thalassemias in the first trimester of pregnancy: various aspects for the obstetrician].

After an extensive educational campaign for the medical community in the area of the Westf. Wilhelms-University Münster five pregnancies at risk for sickle cell anemia and thalassemias were investigated during the first trimester of pregnancy. Following chorionic villi sampling in one case a sickle cell anemia and in two other cases a beta-thalassemia could be excluded. In two additional cases a homozygous beta-thalassemia was proven and in one of the cases the first trimester diagnosis was confirmed in the second trimester by fetal blood sampling. Because of the migration patterns in Europe there is currently a considerable demand for prenatal diagnosis of beta-thalassemias in West-Germany after proper information of the population at risk.

Anemia, Sickle Cell↗
PubMed1985

Heterogeneity of the alpha-globin gene defects in German alpha-thalassemia affected families.

Analysis of alpha-thalassemia syndromes in several German families revealed DNA deletion as well as non-deletion forms as the molecular basis for the defects. Thus, the alpha-thalassemia haplotype was identified as the (-alpha)3.7 rightward deletion form, and the region of the putative recombination process generating such a deletion was further characterized. In addition three different alpha(0)-thalassemia haplotypes, (--)MED, (--) > 26, and (alpha alpha)T, could be detected using alpha- and zeta-globin gene-specific probes.

Chromosome Deletion↗
PubMed1985

Detection of a restriction site polymorphism within the human alpha-globin gene complex.

A mutant Rsa I restriction endonuclease site of high frequency has been identified in individuals of German, Greek, Italian, and Turkish origin. The mutation was found within the alpha-globin gene complex and is located 0.7 kb 5' to the alpha 2-globin gene. In individuals of central European origin 34 out of 58 chromosomes exhibited the alpha-gene linkage to the presence of the polymorphic site, and thus a preliminary estimate of the gene frequency for this allele would be 0.59. DNA analysis data of individuals derived from Mediterranean populations indicate a distribution of this polymorphic marker in similar frequencies.

Alleles↗
PubMed1984

Alpha-globin gene deletion causes alpha-thalassemia syndromes in two German families.

Restriction endonuclease mapping of chromosomal DNA has been used to determine whether the alpha-globin gene deletion or non-deletion form of alpha-thalassemia is the underlying molecular defect in individuals of two unrelated German families with alpha-thalassemia syndromes. The obtained DNA pattern in all cases indicated loss of alpha-globin genes resulting in -alpha/alpha alpha, --/alpha alpha, and --/-alpha genotypes in alpha-thalassemia-2, alpha-thalassemia-1, and Hb H individuals respectively. The chromosomes showing loss of one alpha-globin gene in alpha-thalassemia-2 and Hb H disease were characterized by the so-called rightward deletion form exhibiting loss of a 3.7 kb DNA fragment in the alpha-gene cluster.

Chromosome Deletion↗
PubMedDate not supplied

Interaction of modafinil and clomipramine as comedication in a narcoleptic patient.

Modafinil is a psychostimulant compound that is just now becoming available in many countries for treatment of narcoleptic and hypersomnic patients. Whereas sleep attacks and drowsiness can be effectively improved, the drug does not sufficiently reduce cataplectic seizures. It therefore is often used in combination with tricyclic antidepressant medication, although little is known about the possible interactions. This case report describes a narcoleptic patient chronically treated with clomipramine who started receiving modafinil. The blood concentrations of clomipramine and its metabolite showed a significant dose-dependent and reversible increase under modafinil. Since the patient was genotypically and phenotypically a cytochrome P450 2D6 poor metabolizer, the authors attribute the relevant pharmacokinetic interaction to another clomipramine-metabolizing enzyme.

Antidepressive Agents, Tricyclic↗