Myeloid- and lymphoid-specific breakpoint cluster regions in chromosome band 13q14 in acute leukemia.

Abnormalities of chromosome band 13q14 occur in hematologic malignancies of all lineages and at all stages of differentiation. Unlike other chromosomal translocations, which are usually specific for a given lineage, the chromosomal translocation t(12;13)(p12;q14) has been observed in both B-cell and T-cell precursor acute lymphoblastic leukemia (BCP-, TCP-ALL), in differentiated and undifferentiated acute myeloblastic leukemia (AML), and in chronic myeloid leukemia (CML) at progression to blast crisis. The nature of these translocations and their pathologic consequences remain unknown. To begin to define the gene(s) involved on chromosome 13, we have performed fluorescence in situ hybridization (FISH) using a panel of YACs from the region, on a series of 10 cases of acute leukemia with t(12;13)(p12;q14) and 1 case each with "variant" translocations including t(12;13)(q21;q14), t(10;13)(q24;q14) and t(9;13)(p21;q14). In 8/13 cases/cell lines, the 13q14 break fell within a single 1.4 Mb CEPH MegaYAC. This YAC fell immediately telomeric of the forkhead (FKHR) gene, which is disrupted in the t(2;13)(q35;q14) seen in pediatric alveolar rhabdomyosarcoma. Seven of the 8 cases with breaks in this YAC were AML. In 4/13 cases, the 13q14 break fell within a 1.7-Mb YAC located about 3 Mb telomeric of the retinoblastoma (RB1) gene: all 4 cases were ALL. One case of myelodysplastic syndrome exhibited a break within 13q12, adjacent to the BRCA2 gene. These data indicate the presence of myeloid- and lymphoid-specific breakpoint cluster regions within chromosome band 13q14 in acute leukemia.     

Exploring the utility of whole‐exome sequencing as a diagnostic tool in a child with atypical episodic muscle weakness

The advent of whole‐exome next‐generation sequencing (WES) has been pivotal for the molecular characterization of Mendelian disease; however, the clinical applicability of WES has remained relatively unexplored. We describe our exploration of WES as a diagnostic tool in a 3½‐year old female patient with a 2‐year history of episodic muscle weakness and paroxysmal dystonia who presented following a previous extensive but unrevealing diagnostic work‐up. WES was performed on the proband and her two parents. Parental exome data was used to filter potential de novo genomic events in the proband and suspected variants were confirmed using di‐deoxy sequencing. WES revealed a de novo non‐synonymous mutation in exon 21 of the calcium channel gene CACNA1S that has been previously reported in a single patient as a rare cause of atypical hypokalemic periodic paralysis. This was unexpected, as the proband's original differential diagnosis had included hypokalemic periodic paralysis, but clinical and laboratory features were equivocal, and standard clinical molecular testing for hypokalemic periodic paralysis and related disorders was negative. This report highlights the potential diagnostic utility of WES in clinical practice, with implications for the approach to similar diagnostic dilemmas in the future.     

Serum concentrations of oestradiol-17beta, progesterone, relaxin and chorionic gonadotrophin during blastocyst implantation in natural pregnancy cycle and in embryo transfer cycle in the rhesus monkey

The present study was undertaken to assess the temporal association between the profiles of serum concentrations of oestradiol-17beta, progesterone, chorionic gonadotrophin (CG) and relaxin in pregnancies established naturally, and after embryo transfer, as well as in failed pregnancies in rhesus monkeys. In naturally mated cycles (group 1) a conception rate of 75% was obtained. In group 1, the mean day of CG detection in serum was 11.5 +/- 1.9 day post-ovulation, and for relaxin, 9.0 +/- 2.5 day post-ovulation. In group 2, embryo transfer to synchronous, non-mated surrogate recipients was performed; seven embryo transfer cycles yielded three pregnancies which were allowed to continue to term and normal infants were delivered. In embryo transfer cycles the mean day of CG detection was 14.8 +/- 1.8 day post- ovulation, and for relaxin, 11.4 +/- 2.6 day post-ovulation. A delay of about 3 days was observed in the appearance in circulation of CG (P < 0.05) and also of relaxin (P < 0.05) between natural mated and embryo transfer conception cycles. Significant differences (P < 0.05 for progesterone and P < 0.03 for oestradiol) were obtained for the areas under the curves for progesterone and oestradiol between days 12 and 16 in conception cycles compared with failed pregnancies. These data provide the first observation of the normal hormonal signals associated with maternal recognition of transferred embryos during the peri- implantation period, and suggest that the use of such an experimental primate embryo transfer model may help to elucidate components of maternal and embryonic signal-response mechanisms during embryo implantation.      

Sequence comparison of human and yeast telomeres identifies structurally distinct subtelomeric domains

We have sequenced and compared DNA from the ends of three human chromosomes: 4p, 16p and 22q. In all cases the pro-terminal regions are subdivided by degenerate (TTAGGG)n repeats into distal and proximal sub- domains with entirely different patterns of homology to other chromosome ends. The distal regions contain numerous, short (<2 kb) segments of interrupted homology to many other human telomeric regions. The proximal regions show much longer (approximately 10-40 kb) uninterrupted homology to a few chromosome ends. A comparison of all yeast subtelomeric regions indicates that they too are subdivided by degenerate TTAGGG repeats into distal and proximal sub-domains with similarly different patterns of identity to other non-homologous chromosome ends. Sequence comparisons indicate that the distal and proximal sub-domains do not interact with each other and that they interact quite differently with the corresponding regions on other, non- homologous, chromosomes. These findings suggest that the degenerate TTAGGG repeats identify a previously unrecognized, evolutionarily conserved boundary between remarkably different subtelomeric domains.      

Regional variation among vacA alleles of Helicobacter pylori in China

Allelic variation among Helicobacter pylori vacA occurs in the signal and middle region of the gene. The aim of the study was to investigate alleleic variation of vacA among H. pylori strains from three regional areas of China and the relationship between vacA alleles and PUD. DNA extracted from 88 clinical isolates of H. pylori was analyzed by type-specific PCR and reverse hybridization line probe assay (LiPA) to determine the genotype of vacA and presence of cagA. In 87 isolates, all of the vacA alleles could be classified as either type s1c or type s1a, and all could be classified as m1, m2a, or m2b. One strain could not be typed. In all, 41% of patients were infected with multiple vacA genotypes, with the highest level being observed in Shanghai (63%). In strains from Beijing, s1a was dominant; by contrast, s1c was dominant in Guangxi and Shanghai. The prevalence of m2b strains in Shanghai (63%) was significantly higher than that in Beijing (3%) or Guangxi (0%). Thirty of the 87 patients had peptic ulcers. However, there was no association between vacA genotype and PUD. This study demonstrates that there is significant geographic diversity of genotype of vacA within China. The absence of vacA s2 genotypes precluded analysis of an association of vacA s genotypes and clinical disease.     

Terminal deletion (14)(q32.3): a new case.

A mildly dysmorphic, 2 year old girl with mental retardation was found to have a small de novo terminal deletion of the long arm of chromosome 14, del(14)(q32.3). She was found to have features in common with two previous terminal deletion cases and particularly with the well documented ring 14 syndrome, although seizures, a characteristic feature of ring 14, were notably absent.     

Standardization of medium for culturing Lyme disease spirochetes.

To standardize the procedure for isolating and culturing Lyme disease spirochetes, we modified the composition of the medium generally used for this purpose (BSK-II) and developed a system for its distribution. This medium contains no gelatin or agarose, and various components are used in proportions that differ from those in BSK-II. Each of the major proteinacious components was screened by substitution in samples of the complete product. The final medium was evaluated for the capacity to grow related spirochetes including Borrelia burgdorferi N40, Guilford, and JD-1 as well as strains of Borrelia hermsii (HS-1) and of Borrelia coriaceae (CO53). Each isolate developed from inocula containing as few as one to five organisms. Doubling time of B. burgdorferi during log-phase growth at 37 degrees C was 10 to 12 h. Lyme disease spirochetes were isolated in this medium from ear punch biopsies and dermal aspirates from naturally infected mice and rabbits, from dermal biopsies from a human patient, and by sampling field-collected deer ticks (Ixodes dammini). Cultured spirochetes remained infective to mice and to ticks. The medium can be stored at -20 degrees C or lower temperatures for at least 8 months without effect on its ability to support growth of small inocula to densities exceeding 10(8) spirochetes per ml. Lyme disease spirochetes remained infective to mice after being stored at -80 degrees C in this medium for at least 8 months. We anticipate that the availability of this standardized medium (Sigma Chemical Co.), supplemented with prescreened rabbit serum, will facilitate comparison of research results between laboratories and may eventually permit definitive clinical diagnosis of Lyme disease based on demonstration of the pathogen. The standardized medium is designated BSK-H.