Mutations in the Chediak-Higashi syndrome gene (CHS1) indicate requirement for the complete 3801 amino acid CHS protein

Chediak-Higashi syndrome (CHS) is a rare, usually fatal, autosomal recessive disorder characterized by severe immunologic defects, reduced pigmentation, progressive neurologic dysfunction and a bleeding diathesis. The hallmark of CHS is giant organelles and giant granules in many different cell types, most likely the result of defective trafficking of specific organellar and granular proteins necessary for the normal genesis, structure or function of these cytoplasmic components. The CHS1 gene has recently been identified and shown to be homologous to the beige locus of the mouse; however, there has been disagreement as to the length of the functional CHS1 mRNA and protein. Here we report homozygous CHS1 gene mutations in two of the original probands we used to map the gene to 1q42-q44. One of these, a frameshift at codon 3197, supports our assertion that the functional CHS protein is a predicted 3801 amino acid polypeptide encoded by a 13.5 kb mRNA.      

Combined immunophenotyping and FISH identifies the involvement of B-cells in 5q- syndrome

The 5q- syndrome is a distinct subtype of myelodysplastic syndrome (MDS) characterized by refractory anemia, deletion of the long arm of chromosome 5, del(5q), as the sole cytogenetic abnormality, and a low frequency of transformation to acute leukemia. Using combined immunophenotyping and fluorescence in situ hybridization (FISH), studies were carried out on bone marrow smears of three 5q- syndrome cases to identify the cell lineages carrying the 5q deletion. In all three cases, the granulocytic, monocytic, and erythroid lineages possessed the del(5q) clonal marker, whereas the T-lymphocytes did not. Interestingly, in one case, cells of B-lymphoid lineage also showed the presence of the del(5q). This is the first report to date showing involvement of an acquired 5q deletion associated with MDS in B-cells. This result suggests that in some cases, MDS arises in a multipotent cell with a capacity to differentiate into both myeloid and lymphoid cells.     

t(7;12)(q36;p13), a new recurrent translocation involving ETV6 in infant leukemia

The ETV6 gene is rearranged as a result of translocations involving a wide variety of chromosomal partners. To date, 12 partner genes for ETV6 have been cloned, and a further 23 chromosomal regions have been described. We previously identified a cryptic t(7;12) with ETV6 involvement in two cases of infant leukemia. The finding of a third case of t(7;12), also in an infant, prompted a more focussed search based on the common features found in these patients and those reported in the literature. The selection criteria were age at diagnosis < 20 months and the presence of +19 and/or +8 in the karyotype; cases with abnormalities of 7q and/or 12p were also considered. FISH studies using whole chromosome paints and probes for the ETV6 gene revealed a t(7;12) in 10 out of 23 cases studied. Seven of these had evidence of ETV6 rearrangement. Of those with ETV6 involvement, six had a 7q36 and one a 7q22 breakpoint. Importantly, in three cases the 7q36 breakpoint was within the same PAC, suggesting the existence of a new nonrandom translocation. However, in at least one patient the 7q36 breakpoint was different. The identification of the 7q partner genes will determine whether it is the disruption of ETV6 alone, or the formation of fusion genes, that is important for leukemogenesis in these patients. As both 7q36 and 7q22 are critical regions of gene loss in del(7q) leukemias, the identification of partner genes from these regions may also be important in understanding the pathogenesis of these diseases.     

Estimation of the conduction velocity of muscle action potentials using phase and impulse response function techniques

Two new techniques are described for calculating the conduction velocity of action potentials in muscle fibres from surface EMG recordings in human subjects. In the first method the conduction velocity is determined from the impulse response function calculated from the two EMG signals. The peak of this function onsists of a single peak located at the delay between the signals. The velocity probability density distribution is then estimated from this impulse response function. The mode of this distribution occurred at 5 m s⁻¹. The second technique uses the phase part of the frequency response function relating the two EMG signals to determine the conduction velocity. These two new approaches overcome some of the limitations associated with estimating conduction velocity from the maximum absolute value of the cross-correlation function, and provide additional information about the conduction velocity.     

Identification of candidate disease genes by EST alignments, synteny, and expression and verification of Ensembl genes on rat chromosome 1q43-54

We aligned Incyte ESTs and publicly available sequences to the rat genome and analyzed rat chromosome 1q43-54, a region in which several quantitative trait loci (QTLs) have been identified, including renal disease, diabetes, hypertension, body weight, and encephalomyelitis. Within this region, which contains 255 Ensembl gene predictions, the aligned sequences clustered into 568 Incyte genes and gene fragments. Of the Incyte genes, 261 (46%) overlapped 184 (72%) of the Ensembl gene predictions, whereas 307 were unique to Incyte. The rat-to-human syntenic map displays rearrangement of this region on rat chr. 1 onto human chromosomes 9 and 10. The mapping of corresponding human disease phenotypes to either one of these chromosomes has allowed us to focus in on genes associated with disease phenotypes. As an example, we have used the syntenic information for the rat Rf-1 disease region and the orthologous human ESRD disease region to reduce the size of the original rat QTL to only 11.5 Mb. Using the syntenic information in combination with expression data from ESTs and microarrays, we have selected a set of 66 candidate disease genes for Rf-1. The combination of the results from these different analyses represents a powerful approach for narrowing the number of genes that could play a role in the development of complex diseases.     

Recombination between a 3-kilobase tobacco mosaic virus transgene and a homologous viral construct in the restoration of viral and nonviral genes

Summary.  Transgenic plants harboring various plant virus sequences have shown resistance to viral infections. An environmental risk associated with the use of these plants is the possibility of forming a novel virus by recombination between challenging viruses and transgenic viral mRNA. Two experiments were designed using tobacco mosaic virus (TMV) vectors and transgenic Nicotiana benthamiana to determine if recombinant viral RNA would be detectable. N. benthamiana was transformed with a nontranslatable portion of a TMV viral vector including part of the replicase gene, the movement protein gene, a gene for green fluorescent protein (GFP), and the coat protein gene. When transformed plants were inoculated with a TMV vector coat protein mutant which could not move efficiently through the host, recombinant RNA was detected in 32% of the infected plants, although virions were not detected. When transformed plants were infected with a TMV vector with a normal coat sequence but three base changes in the GFP sequence, no recombinant RNA or virions were detected. Thus, recombinant RNA between TMV RNA and host mRNA did not accumulate to detectable levels under nonselective conditions, and though recombinant RNA did accumulate in the presence of selective pressure, an encapsidated recombinant viral population did not develop. Received September 2, 1999/Accepted March 13, 2000     

Clinical and hematologic aspects of the X-linked α-thalassemia/mental retardation syndrome (ATR-X)

The hallmarks of the X-linked α-thalassemia/mental retardation (ATR-X) syndrome are severe psychomotor retardation, minor facial anomalies, genital abnormalities, and an unusual form of α-thalassemia. The demonstration of HbH inclusions in red blood cells after incubation with brilliant cresyl blue confirms the diagnosis. We describe 15 previously unreported cases and analyse the phenotypic and hematologic findings in these subjects and compare them with previously published cases. This study demonstrates the consistency of the main characteristics of this syndrome and extends the phenotype. Developmental changes in phenotype, in particular the coarsening of the facial appearance, are illustrated. The hematologic findings are shown to vary widely; in some cases the manifestation of α-thalassemia may be subtle and missed without repeated examination. © 1995 Wiley-Liss, Inc.     

Influences on older women's adherence to a low-fat diet in the Women's Health Initiative

OBJECTIVE: Most studies of dietary change during aging have focused on maintaining adequate intake by impaired elderly, and little is known about factors affecting dietary change for preventive purposes in older individuals. The purpose of this exploratory study was to determine the major behavioral influences on older women's adherence to a dietary fat reduction intervention. METHOD: A diverse sample of 92 women aged 55 to 80 was recruited from two East Coast sites of the Women's Health Initiative. All the women were participating in the dietary modification arm of WHI, had received the same dietary instruction, and were in the maintenance phase of the intervention. The women were classified by nutritionists as adherent or nonadherent to a diet limiting fat intake to <20% of total calories. Focus groups and telephone interviews were conducted, and textual data were coded and sorted using content analysis techniques within the four categories of the Stimuli-Organismic Factors-Response Repertoire-Consequences (SORC) behavioral model. Frequencies of responses within categories were tabulated and compared qualitatively. RESULTS: Adherent women were more likely to report assertiveness, a lifelong commitment to reduced dietary fat, satisfaction with their lifestyle changes, and having applicable knowledge and skills. Nonadherent women reported more difficulty resisting negative emotions and prior food preferences and habits; they were also more concerned about negative responses from others. CONCLUSIONS: Enhancing adherence of older women to a dietary fat reduction program will require shifting priorities away from conforming to social pressure and using high-fat foods for personal satisfaction and moving toward enhancing motivation and commitment to long-term health.     

Immunity and paralysis in mice. Serological and biological properties of two distinct antibodies to type III pneumococcal polysaccharide

The nature of two distinct anti-pneumococcal antibodies of mice has been further investigated. These antibodies, produced after the injection of purified SIII (the capsular polysaccharide of Diplococcus pneumoniae Type III), were examined for their serological properties in vitro and for their protective potency in vivo.The first anti-SIII antibody, distinguished by its ability to agglutinate antigen-coated erythrocytes, was not only unable to lyse these erythrocytes (with complement), but it protected them against lysis by the other antibody, because of its high affinity for the antigen. This haemagglutinating antibody did not precipitate soluble antigen, was of the IgA class, and could protect mice against challenge with virulent pneumococci. It was produced by mice given small doses (0.1 μg) of SIII, but not by mice given 50 μg. These latter were susceptible to pneumococcal challenge.The second antibody, which was haemolytic and precipitating but not haemagglutinating, had a comparatively low affinity for the antigen: thus it was not detectable when mixed with the first antibody, especially if the test erythrocytes were inadequately sensitized. This haemolytic antibody was of the IgM class. It was found in high titre in mice given 50 μg of SIII, but did not protect them against challenge.