摘要:

Enzyme catalase seems to be the main regulator of hydrogen peroxide metabolism. Hydrogen peroxide at high concentrations is a toxic agent, while at low concentrations it appears to modulate some physiological processes such as signaling in cell proliferation, apoptosis, carbohydrate metabolism, and platelet activation. Benign catalase gene mutations of 5′ noncoding region (15) and intron 1 (4) have no effect on catalase activity and are not associated with disease.Catalase gene mutations have been detected in association with diabetes mellitus, hypertension, and vitiligo. Decreases in catalase activity in patients with tumors is more likely to be due to decreased enzyme synthesis rather than to catalase mutations.Acatalasemia, the inherited deficiency of catalase has been detected in 11 countries. Its clinical features might be oral gangrene, altered lipid, carbohydrate, homocysteine metabolism and the increased risk of diabetes mellitus. The Japanese, Swiss, and Hungarian types of acatalasemia display differences in biochemical and genetic aspects. However, there are only limited reports on the syndrome causing these mutations.These data show that acatalasemia may be a syndrome with clinical, biochemical, genetic characteristics rather than just a simple enzyme deficiency.

ISSN:1084-8592    

出版商:ADIS    

年代:2004

数据来源: ADIS

摘要:

BackgroundHyperekplexia, also known as startle disease or stiff-person syndrome, is a neurological condition characterized by neonatal hypertonia and a highly exaggerated startle reflex. Genetic studies have linked mutations in the gene encoding glycine receptor α1 (GLRA1) with hereditary hyperekplexia.MethodsWe analyzed four Turkish families with a history of hyperekplexia. Genomic DNA was obtained from members of these families, and the entire coding sequence ofGLRA1was amplified by PCR followed by the sequencing of PCR products. DNA sequences were analyzed by direct observation using an electropherogram and compared with a published reference sequence.ResultsWe identified three novel mutations inGLRA1. These included a large deletion removing the first 7 of 9 exons, a single-base deletion in exon 8 that results in protein truncation immediately after the deletion, and a missense mutation in exon 7 causing a tryptophan-to-cysteine change in the first transmembrane domain (M1). These mutant alleles have some distinct features as compared to previously identifiedGLRA1mutations. Our data provides further evidence for mutational heterogeneity inGLRA1. The new mutant alleles reported here should advance our understanding of the etiology of hyperekplexia.

ISSN:1084-8592    

出版商:ADIS    

年代:2004

数据来源: ADIS

摘要:

IntroductionThe kallikrein-kinin system plays an important role in blood pressure homeostasis and renal sodium regulation, and some studies have reported that the kinins have a protective effect against hypertension and the development of renal disease. The B2-bradykinin receptor (B2R) mediates the majority of physiological actions of bradykinin. We investigated the effect of the C181→T polymorphism in exon 2 of theB2Rgene in patients with end-stage renal disease (ESRD).MethodsThis study involved 790 patients with ESRD and 510 healthy controls. All participants were genotyped for theB2RC181→T polymorphism by PCR followed by digestion of a PCR product withTaqI restriction endonuclease. DNA fragments were separated by agarose gel electrophoresis. Genotype and allele frequencies were compared between the groups. All calculations were performed using SPSS®5.0 for Windows®.ResultsB2Rgenotype distribution in patients and controls was in accordance with Hardy-Weinberg equilibrium. The frequency of the T allele was higher in ESRD patients than in controls. The significant difference was observed in the age at onset of renal disease; for patients with the T allele the mean age at onset was 36.8 years, compared with 52.4 years for those carrying only the C allele (p < 0.001). The frequencies of the T allele and carrier genotypes were not associated with gender, presence of hypertension, or underlying kidney disease.ConclusionOur results suggest that theB2Rpolymorphism has a potential role in the earlier development of chronic renal failure in susceptible individuals. We did not confirm the previously published reports that theB2Rgene polymorphism has a protective role in the development of ESRD.

ISSN:1084-8592    

出版商:ADIS    

年代:2004

数据来源: ADIS

摘要:

IntroductionResistance to the thyroid hormone (RTH) is an inherited syndrome of reduced tissue responsiveness to hormonal action caused by mutations located in the ligand-binding domain and adjacent hinge region of the thyroid hormone receptor β (TRβ) gene.PatientThe patient in this study, a 42-year-old Caucasian male, came to medical attention because he experienced atrial fibrillation. Clinical evaluation showed a small and diffuse goiter and biochemical tests revealed markedly elevated concentrations of total T4, total T3, and free T4, normal thyroid-stimulating hormone (TSH) values and slightly increased I131thyroid uptake at 24 hours. The thyroperoxidase, thyroglobulin, and TSH receptor antibodies were positive. He was treated with cabergoline plus methimazole. This treatment was stopped because of the inconsistent response, monotherapy with tri-iodothyroacetic acid (TRIAC) was then prescribed after molecular diagnosis confirmed RTH syndrome.MethodsThe exons 9 and 10 of theTRβgene, including splicing signals and the flanking intronic regions of each intron, were amplified with PCR. DNA sequences from each amplified fragment were performed with the Taq polymerase-based chain terminator method and using the specificTRβforward and reverse primers.ResultsDirect sequence analysis of the exons 9 and 10 of theTRβgene revealed an eight basepair deletion, 1297-1304delGCCTGCCA in exon 10. The mutation produces a frameshift at amino acid 433 and introduces a stop codon TGA at position 461, 85 nucleotides downstream from deletion. This alteration was not detected in either the father or mother of the patient, suggesting ade novomutation that was confirmed by DNA fingerprint analysis.ConclusionsIn the present study we have identified a novel sporadic mutation corresponding to 1297-1304delGCCTGCCA deletion in the activating function 2 (AF-2) region ofTRβ. To our knowledge, this is the first time that the presence of a partial deletion of eight nucleotides in theTRβhas been reported.

ISSN:1084-8592    

出版商:ADIS    

年代:2004

数据来源: ADIS

摘要:

ObjectiveTo search for molecular changes in two Argentinian sisters with a clinical and biochemical diagnosis of 17α-hydroxylase deficiency.SubjectsBoth patients had 46 XX karyotype, with sexual infantilism, primary amenorrhea, and hypertension. Other member of the first degree family did not have this deficiency.Hormonal resultsThe patients showed high levels of gonadotrophins and progesterone along with very low cortisol and androgen levels. Basal levels of corticosterone were very high, but aldosterone was normal. Both steroids had a high response after adrenocorticotropic hormone (ACTH) stimulation, with no changes in 17-hydroxyl progesterone and cortisol levels. Progesterone, corticosterone, and aldosterone decreased with the dexamethasone test, without modifications in 17-hydroxyl progesterone and cortisol levels. A corticosterone/aldosterone ratio was calculated from the results of the stimulation test; the ratios were similar in both patients. On administration of the ACTH test, both parents and one sister (S2) showed a marked response in corticosterone levels, their corticosterone/aldosterone ratios were also similar to each other and similar to the patients.Molecular resultsMolecular studies in the cytochrome P450 17 (CYP17) gene showed that exon 8 had a 4 bp duplication at codon 480 (CATC) in the two patients and their mother and in exon 1, a C to T transition at codon 96 was identified, changing CGG into TGG in the two patients, S2, and their father.ConclusionsBoth patients were shown to be compound heterozygous, carrying different alleles in exon 1 and exon 8, inherited from their father and mother, respectively. The molecular results obtained on S2 confirmed the heterozygosity suggested by the stimulated hormonal test and corticosterone/aldosterone ratio.

ISSN:1084-8592    

出版商:ADIS    

年代:2004

数据来源: ADIS

摘要:

IntroductionCompared with the classical urine culture method, PCR is more rapid, and can detect smaller numbers of bacteria, however it is inferior for quantification. Because of the lack of quantification in routine PCR, the meaning of a positive PCR test result has not been validated for all infections. We report on the development of a novel quantitative detection system for the urinary tract infection (UTI)Escherichia coliusing real-time PCR.PatientsWe enrolled 200 patients with suspected bacteriuria.MethodsThe gene encoding the universal stress protein (uspA) was found to be highly specific forE. coli. We quantified the copy numbers ofE. coliin the urine of patients with UTI by using a real-time PCR assay (the TaqMan®system) targetinguspAgenes in genomic DNAs isolated from urine samples (n = 200). To evaluate the feasibility of this method, the results were compared with those of a standard urine culture.ResultsThe incidence of positive urine cultures was 75% (150 of 200), and various doses ofE. coliwere detected in 84 of 150 specimens. The real-time PCR method also detected 84 cases of urinary infections ofE. coliin the same specimens. Furthermore, the result of the quantification ofE. coliusing real-time PCR strongly correlated (r2= 0.925) with the result of urine culture.ConclusionOur results suggest that using quantitative-PCR means a faster and simpler diagnosis ofE. coliurinary infection can be made compared with the traditional urine culture method.

ISSN:1084-8592    

出版商:ADIS    

年代:2004

数据来源: ADIS

摘要:

BackgroundThe gene expression of the myxovirus-resistant protein A (MxA) gene is a sensitive measure of the biological response of therapeutically applied interferon-β (IFNβ) and of its reduced bioavailability due to inhibiting factors such as IFNβ-induced neutralizing antibodies (NAbs).MethodsWe compared three methods forMxAmRNA quantification in 826 peripheral blood mononuclear cell (PBMC) samples obtained from patients with multiple sclerosis (MS).MxAmRNA measurements were performed using quantitative-competitive (qc)-PCR, real time-PCR, and the new semi-quantitative (sq)-PCR assay (MxA IBRIDOGEN®).ResultsAccording to the treatment status (untreated samples versus NAb-negative treated samples), real time-PCR gave the highest specificity (93%). Slightly lower specificities were obtained with qc-PCR and sq-PCR (both 91%). qc-PCR showed the highest sensitivity (97%) compared with both real time-PCR (94%) and sq-PCR (95%). A positive correlation was found between qc-PCR and real time-PCR measurements (rspearman= 0.776; p < 0.0001), which also showed 90% agreement based on a statistically calculated threshold. Likewise, sq-PCR evaluations showed 84% and 79% agreement with qc-PCR and real time-PCR measurements, respectively. In addition, we showed a concordance of 89% between three sq-PCR kits.ConclusionsAll three methods displayed high specificity forMxAgene expression analysis, allowing the detection of patients in whom IFNβ did not have any biological action. qc-PCR and real time-PCR are both useful during clinical trials demanding quantitative data of biological activity, whereas sq-PCR could prove useful for routine screening purposes because it is easy to perform and can be done in not specialized laboratories.

ISSN:1084-8592    

出版商:ADIS    

年代:2004

数据来源: ADIS