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The presurgical management with erythrocytapheresis of a patient with a high-oxygen-affinity, unstable Hb variant (Hb Bryn Mawr).

BACKGROUND: Hemoglobin (Hb) Bryn Mawr is an unstable Hb variant resulting in congenital hemolytic anemia. This variant Hb also has an increased affinity for oxygen. The perioperative transfusion management of this disorder is described, and the first genomic analysis of this Hb variant is given. CASE REPORT: An 11-year-old boy, heterozygous for Hb Bryn Mawr, was referred for cholecystectomy. Sequence analysis of genomic DNA confirmed that the patients was heterozygous for a T-->C transition in the codon for amino acid 85, causing a substitution of serine for phenylalanine in the beta-globin chain. On the basis of whole-blood O2 dissociation studies, projected tissue O2 delivery would have been suboptimal during general anesthesia; therefore, a partial red cell exchange transfusion was performed to lower variant Hb and prevent tissue hypoxia during surgery. The red cell mass to be exchanged (50%) was determined from the calculated increase in O2 delivery capacity required to maintain an O2 extraction of 4 to 5 mL of O2 per dL of whole blood. The p50 of whole blood from the patients immediately after the exchange transfusion was 16.0 torr. At the time of surgery, the p50 was normal (25.9 torr). The patient's whole blood 2,3 DPG levels were 4.70 mmol per mL of red cells (before transfusion) (normal range = 4.8 +/- 0.3 mmol/mL red cells), 4.07 mmol per mL of red cells (immediately after transfusion), and 4.55 mmol per mL of red cells (48 hours after transfusion). CONCLUSION: This patient with Hb Bryn Mawr was prepared for surgery with a partial exchange transfusion to prevent tissue hypoxia during anesthesia. Decreased 2,3 DPG levels immediately after transfusion resulted in increased O2 affinity of whole blood; however, 48 hours after exchange transfusion, a normal p50 (due to both removal of variant Hb and regeneration of 2,3, DPG) was observed. Partial exchange transfusion is useful in the preoperative management of patients with Hb variants characterized by increased O2 affinity.

2,3-Diphosphoglycerate↗

Extreme nuclear disproportion and constancy of enzyme activity in a heterokaryon of Neurospora crassa.

Heterokaryons of Neurospora crassa were generated by transformation of multinucleate conidia of a histidine-3 auxotroph with his-3(+) plasmid. In one of the transformants, propagated on a medium with histidine supplementation, a gradual but drastic reduction occurred in the proportion of prototrophic nuclei that contained an ectopically integrated his-3(+) allele. This response was specific to histidine. The reduction in prototrophic nuclei was confirmed by several criteria: inoculum size test, hyphal tip analysis, genomic Southern analysis, and by visual change in colour of the transformant incorporating genetic colour markers. Construction and analyses of three-component heterokaryons revealed that the change in nuclear ratio resulted from interaction of auxotrophic nucleus with prototrophic nucleus that contained an ectopically integrated his-3(+) gene, but not with prototrophic nucleus that contained his-3(+) gene at the normal chromosomal location. The growth rate of heterokaryons and the activity of histidinol dehydrogenase - the protein encoded by the his-3(+) gene - remained unchanged despite prototrophic nuclei becoming very scarce. The results suggest that not all nuclei in the coenocytic fungal mycelium may be active simultaneously, the rare active nuclei being sufficient to confer the wild-type phenotype.

Alcohol Oxidoreductases↗

Chlamydia pneumoniae genome sequence analysis and identification of HLA-A2-restricted CD8+ T cell epitopes recognized by infection-primed T cells.

In the present study, we performed in silico analysis of Chlamydia pneumoniae genome sequence to identify human HLA-A2-restricted T cell epitopes. Thirty-one Chlamydia-specific protein antigens were selected and peptides were derived thereof using an HLA-A2 epitope predictive algorithm. Firstly, we tested binding of 55 selected 9mer peptides to HLA-A2 in vitro. Next, infection of HLA-A2 transgenic mice with C. pneumoniae elementary bodies and assessment of effector CD8+ T cells allowed us to identify which of the epitopes binding to HLA-A2 in vitro were recognized by C. pneumoniae infection-primed CD8+ T cells. Finally, we could confirm that CD8+ T cells in association with HLA-A2 recognized the most reactive peptides when the corresponding full-length genes were used to DNA-immunize HLA-A2 transgenic mice. By using this approach, a novel HLA-A2-restricted epitope in the outer membrane protein A (OmpA) of C. pneumoniae was identified, which proved to mediate specific lysis of peptide-loaded target cells.

Animals↗

Gametic and somatic tissue-specific heterogeneity of the expanded SCA1 CAG repeat in spinocerebellar ataxia type 1.

Spinocerebellar ataxia type 1 is associated with expansion of an unstable CAG repeat within the SCA1 gene. Male gametic heterogeneity of the expanded repeat is demonstrated using single sperm and low-copy genome analysis. Low-copy genome analysis of peripheral blood also reveals somatic heterogeneity of the expanded SCA1 allele, thus establishing mitotic instability at this locus. Comparative analysis of a large normal allele and a small affected allele suggests a role of midstream CAT interspersions in stabilizing long (CAG)n stretches. Within the brain, tissue-specific mosaicism of the expanded allele is also observed. The differences in SCA1 allele heterogeneity between sperm and blood and within the brain parallels the findings in Huntington disease, suggesting that both disorders share a common mechanism for tissue-specific instability.

Alleles↗

Class III POU genes of zebrafish are predominantly expressed in the central nervous system.

POU genes encode a family of transcription factors involved in a wide variety of cell fate decisions and in the regulation of differentiation pathways. We have searched for POU genes in the zebrafish, a popular model organism for the study of early development of vertebrates. Besides five putative pseudogenes we have identified five POU genes that are expressed during embryogenesis. Probes obtained by PCR were used to isolate full-length cDNAs. Four of the isolated genes encode proteins with class III POU domains. Analysis of genomic clones suggests that the fish genes in general do not contain introns, similar to class III genes of mammals. However, the C-termini of two of the encoded proteins vary due to facultative splicing of a short intervening sequence. These two genes show very strong similarities in their sequence. They have probably arisen by gene duplication, possibly as part of a larger scale duplication of part of the zebrafish genome. Analysis of the expression of the class III genes shows that they are predominantly expressed in the central nervous system and that they may play important roles in patterning the embryonic brain.

Amino Acid Sequence↗

Structure of 29-kDa protein from ascidian (Halocynthia roretzi) body wall muscle.

Preparations of thin filament from ascidian (Halocynthia roretzi) body wall muscle were found to be contaminated with large amounts of an unknown protein which, when purified, migrated to 29 kDa on SDS-PAGE and was thus named HR-29. To elucidate its physiological function, we have determined the primary structure of HR-29 by peptide and cDNA sequence analysis. Genomic sequence analysis showed that HR-29 is divided to four exons by three introns. It is composed of 251 amino acid residues and the N-terminal Ser is blocked by an acetyl group. The N-terminal domain of 150 residues is hydrophilic, and from residue 36 to 92 there are three similar repeated sequences of 19 residues. The N-terminal domain showed no significant sequence homology with other proteins. On the other hand, the C-terminal domain of 100 residues has homology with those of small heat-shock proteins and alpha-crystallin of lens protein. HR-29 is thought to be a fusion protein of two different origins. Recently alpha B-crystallin was identified in skeletal muscle and suggested to be a myofibril-stabilizing protein [Atomi, T. et al. (1991) J. Biochem. 110, 2360-2364]. Thus, HR-29 may also be a myofibril-stabilizing protein, as suggested by the sequence similarity of the C-terminal domain with alpha-crystallin, although the origin and role of the N-terminal domain are not clear.

Amino Acid Sequence↗

Focusing on the genetics of hearing: you ain't heard nothin' yet.

The complexity of genetic pathways for hearing is beginning to be amenable to unraveling by systematic functional genomic analysis. Genome-wide mutagenesis studies in the mouse are beginning to shed further light on the structure and regulation of the machinery of hearing.

Animals↗

Prenatal diagnosis of sporadic neurofibromatosis type 1 (NF1) by RNA and DNA analysis of a splicing mutation.

Neurofibromatosis type 1 (NF1) is one of the most common genetic disorders in humans with an incidence of 1 in 3500. Most of the NF1 mutations reported so far (over 240 mutations) are unique. Specific prenatal diagnosis can only be provided to familial cases by an indirect linkage analysis or to families with a previously identified mutation. Here we report the first prenatal diagnosis in sporadic NF1 by direct characterization of the mutation. We first identified the skipping of exon 10b of NF1 in the mRNA from a woman affected by NF1 and without familial history of the disease. The analysis of genomic DNA identified mutation IVS10b+1G-->A as the cause of the skipping of exon 10b. Chorionic villus sampling (CVS) was performed at 10 weeks of gestation and total RNA was directly extracted from the sample. After reverse transcription (RT) and polymerase chain reaction (PCR) of the cDNA, the skipping of exon 10b was not identified in the CVS upon agarose gel electrophoresis. The fetal origin of the CVS was confirmed via polymorphic markers and the absence of the IVS10b+1G-->A mutation was confirmed by genomic analysis.

Adult↗

[Importance of the Genome Project].

Methodological and technological development of the molecular biology during the last decades of the twenties century has shifted our interest from the particular to synthetic problems. Studies has been undertaken both at the level of structure of the individual genetic information and on the level of its function and mutual relation within a single cell or in a multicellular organism. This crucial period culminated in the human genome analysis project, which is now celebrating its first major success. Parallel to it came the analysis of genomes of many other, though usually much thinner organisms.

Human Genome Project↗

[Genetic techniques--chances--risks--limits (from the viewpoint of the legislator--ethical questions--status of medical research].

Gene technology is still a very young area of research. Advantages or disadvantages of this development cannot be tangibly predicted. Irrational desires and fears have surfaced resulting from the fact that we are now in a position of cultivate certain biological characteristics hitherto impossible to reproduce. Individual cases of genome analysis under working conditions, genome analysis as a genetic fingerprint, outdoor plant experiments and gene testing procedures in prenatal diagnoses should all be considered. Analysis uncertainty exists in all these fields, not least caused by multifunctional factors affecting genetic features. The question regarding the right to know or not to know, and the data protection problem irrevocably connected to this, is constantly being raised. It must be recorded that, in spite of the latest scientific findings, opportunities for therapy are frequently lacking. In all our efforts, the psychological conflicts of those concerned and the resulting socio-economic consequences must be taken into consideration.

Ethics, Medical↗

Identification of rare maternal copy number variants by genome-wide analysis of noninvasive prenatal screening data in 113,017 pregnant women.

OBJECTIVES: Knowledge of copy number variants (CNVs) is relevant to maternal and fetal health and can be obtained from noninvasive prenatal screening (NIPS) of pregnancy. However, genome-wide analysis of maternal CNVs using NIPS data has not been conducted in large populations. METHODS: For CNV analysis, the human genome was segmented into 10 kilobase pairs (Kb) bins, and the relative sequencing depth of each bin was calculated. The circular binary segmentation algorithm was used to estimate CNVs. Detected CNVs from two pregnancies of the same participant were compared to validate the reproducibility. All CNVs were merged into CNV regions (CNVRs) to evaluate their frequency, distributions, and relationship with disease-related genes and regions. RESULTS: In this study, 113,017 pregnant women were recruited. A total of 363,886 CNVs larger than 50 Kb were detected in 101,779 individuals and merged into 43,005 CNVRs. For evaluating the reproducibility of CNVs, 90.18% of deletions and 88.07% of duplications were consistent. In general, 78.13% of individuals carried CNVRs that overlapped protein-coding genes, while 14.76% overlapped OMIM genes. We detected 246 novel CNVRs, 134 (54.47%) involving protein-coding genes. For the perspective of maternal-fetal health, we identified 4,984 (4.41%) individuals as carriers of 5,243 CNVs containing known pathogenic or likely pathogenic regions, including 22q11.2 region and DMD gene.. CONCLUSIONS: NIPS sequencing data is a reliable source for maternal CNV detection. These CNVs constitute an integrate component in maternal-fetal health management.

Humans↗

Automated genome sequence analysis and annotation.

MOTIVATION: Large-scale genome projects generate a rapidly increasing number of sequences, most of them biochemically uncharacterized. Research in bioinformatics contributes to the development of methods for the computational characterization of these sequences. However, the installation and application of these methods require experience and are time consuming. RESULTS: We present here an automatic system for preliminary functional annotation of protein sequences that has been applied to the analysis of sets of sequences from complete genomes, both to refine overall performance and to make new discoveries comparable to those made by human experts. The GeneQuiz system includes a Web-based browser that allows examination of the evidence leading to an automatic annotation and offers additional information, views of the results, and links to biological databases that complement the automatic analysis. System structure and operating principles concerning the use of multiple sequence databases, underlying sequence analysis tools, lexical analyses of database annotations and decision criteria for functional assignments are detailed. The system makes automatic quality assessments of results based on prior experience with the underlying sequence analysis tools; overall error rates in functional assignment are estimated at 2.5-5% for cases annotated with highest reliability ('clear' cases). Sources of over-interpretation of results are discussed with proposals for improvement. A conservative definition for reporting 'new findings' that takes account of database maturity is presented along with examples of possible kinds of discoveries (new function, family and superfamily) made by the system. System performance in relation to sequence database coverage, database dynamics and database search methods is analysed, demonstrating the inherent advantages of an integrated automatic approach using multiple databases and search methods applied in an objective and repeatable manner. AVAILABILITY: The GeneQuiz system is publicly available for analysis of protein sequences through a Web server at http://www.sander.ebi.ac. uk/gqsrv/submit

Amino Acid Sequence↗

Genomic sequence analysis tools: a user's guide.

The wealth of information from various genome sequencing projects provides the biologist with a new perspective from which to analyze, and design experiments with, mammalian systems. The complexity of the information, however, requires new software tools, and numerous such tools are now available. Which type and which specific system is most effective depends, in part, upon how much sequence is to be analyzed and with what level of experimental support. Here we survey a number of mammalian genomic sequence analysis systems with respect to the data they provide and the ease of their use. The hope is to aid the experimental biologist in choosing the most appropriate tool for their analyses.

Internet↗

Detrended fluctuation analysis of genome-wide copy number profiles of glioblastomas using array-based comparative genomic hybridization.

We examined whole genomic aberrations of biopsied samples from 19 independent glioblastomas by array-based comparative genomic hybridization analysis. The highest frequencies of copy number gains were observed on RFC2 (73.3%), EGFR (63.2%), and FGR, ELN, CDKN1C , FES, TOP2A, and ARSA (57.9% each). The highest frequencies of copy number losses were detected on TBR1 (52.6%), BMI1 (52.6%), EGR2 (47.4%), DMBT1 (47.4%), MTAP (42.1%), and FGFR2 (42.1%). The copy number gains of CDKN1C and INS and the copy number losses of TBR1 were significantly correlated with longer survival of patients. High-level amplifications were identified on EGFR, SAS/CDK4, PDGFRA, MDM2, and ARSA. These genes are assumed to be involved in tumorigenesis or progression of glioblastomas. The first attempts to apply detrended fluctuation analysis to copy number profiles by considering the reading direction as the time axis demonstrated that higher long-term fractal scaling exponents (alpha2) correlated well with longer survival of glioblastoma patients. The present study indicates that array-based comparative genomic hybridization analysis has great potential for assessment of copy number changes and altered chromosomal regions of brain tumors. Furthermore, we show that nonlinear analysis methods of whole genome copy number profiles may provide prognostic information about glioblastoma patients.

Adult↗

Comparative genomic hybridization analysis of benign and invasive male breast neoplasms.

Comparative genomic hybridization (CGH) analysis was performed for the identification of chromosomal imbalances in two benign gynecomastias and one malignant breast carcinoma derived from patients with male breast disease and compared with cytogenetic analysis in two of the three cases. CGH analysis demonstrated overrepresentation of 8q in all three cases. One case of gynecomastia presented gain of 1p34.3 through pter, 11p14 through q12, and 17p11.2 through qter, and loss of 1q41 through qter and 4q33 through qter. The other gynecomastia presented del(1)(q41) as detected by both cytogenetic and CGH analysis. CGH analysis of the invasive ductal carcinoma confirmed a gain of 17p11.2 through qter previously detected by cytogenetic analysis. These regions showed some similarity in their pattern of imbalance to the chromosomal alterations described in female and male breast cancer.

Adolescent↗

LARALink: a web application for cytogenetic linkage analysis.

Genomic and expression data have increased dramatically over the last several years. This is primarily due to the completion of the human genome project as well as an upsurge in the use of various high-throughput technologies. Recent attempts to correlate genomic and expression data have stimulated the scientific community to determine how this data can be used within a clinical setting (P Khatri et al., Genomics 2002: 79: 266; LJ van't Veer et al., Nature 2002: 415: 530). LARALink (Loci Analysis for Rearrangements Link) is a database-driven web application that utilizes several public datasets to analyze clinical cytogenetic data to identify candidate genes. LARALink allows UniGene clusters or single-nucleotide polymorphisms (SNPs) to be queried for multiple patients by cytoband, chromosome marker, or base pair. The results can be further refined with the use of an anatomical site, developmental stage, pathology, or cell-type expression filter. Once a set of UniGene clusters (expressed genes) has been identified either for a single patient or for a shared region among multiple patients, the expression-distribution profile, expressed sequence tags (ESTs), or online mendelian inheritance in man (OMIM) entries are displayed. The utility of this tool is shown by its application to both research and clinical medicine. LARALink is a public resource available at: http://www.laralink.bioinformatics.wayne.edu:8080/unigene.

Alzheimer Disease↗

Genome-wide analysis of HDAC function.

This article focuses on new developments in the genome-wide analysis of histone deacetylase (HDAC) function in yeast. HDACs are highly conserved in many organisms; therefore, their basic functions can be investigated using experimentally tractable model organisms, such as the budding yeast Saccharomyces cerevisiae and the fission yeast Schizosaccharomyces pombe. New microarray techniques have enabled the systematic study of HDACs by identifying their direct and indirect gene targets in addition to their physiological functions and enzymatic specificity. These new approaches have already provided new surprising insights into the basic function of HDACs.

Amino Acid Sequence↗

Frequent increase of DNA copy number in the 2q24 chromosomal region and its association with a poor clinical outcome in hepatoblastoma: cytogenetic and comparative genomic hybridization analysis.

In a cytogenetic and comparative genomic hybridization (CGH) study of 38 hepatoblastomas, we found gain of 1q in 17 tumors (44.7%), that of 2 / 2q in 14 (36.8%), that of 20 / 20q in 9 (23.7%) and that of 8 / 8q in 8 (21.0%), loss of 4q in 4 (10.5%) and no DNA copy changes with normal karyotype or no mitotic cells in 11 (28.9%). Eleven tumors with 2 / 2q gain detected by CGH had a total chromosome 2 gain, a partial 2q gain, or a total chromosome 2 gain with an augmented partial 2q region; the common region for DNA copy gain was 2q24. Two-color fluorescence in situ hybridization (FISH) analyses using probes covering the centromere of chromosome 2 or HOXD13 (2q31) confirmed the CGH findings, and showed that the common region for gain in 2q was centromeric to HOXD13. Event-free survival (EFS) +/- standard error (SE) at 5 years was lowest in patients with 2q gain [37 +/- 15%], highest in those with no DNA copy changes [82 +/- 12%], and intermediate in those with DNA copy changes other than 2q gain [74 +/- 13%] (P = 0.0549). Multivariate analysis showed that 2q gain was an independent factor predicting a poor outcome. These findings suggest the presence of a growth-promoting gene or an oncogene in the 2q24 chromosome band, and a tumor suppressor gene in terminal 4q, which have important roles in the development and progression of hepatoblastoma.

Antineoplastic Agents↗