A resonant sextuplet of sub-Neptunes transiting the bright star HD 110067.

Planets with radii between that of the Earth and Neptune (hereafter referred to as 'sub-Neptunes') are found in close-in orbits around more than half of all Sun-like stars1,2. However, their composition, formation and evolution remain poorly understood3. The study of multiplanetary systems offers an opportunity to investigate the outcomes of planet formation and evolution while controlling for initial conditions and environment. Those in resonance (with their orbital periods related by a ratio of small integers) are particularly valuable because they imply a system architecture practically unchanged since its birth. Here we present the observations of six transiting planets around the bright nearby star HD 110067. We find that the planets follow a chain of resonant orbits. A dynamical study of the innermost planet triplet allowed the prediction and later confirmation of the orbits of the rest of the planets in the system. The six planets are found to be sub-Neptunes with radii ranging from 1.94R⊕ to 2.85R⊕. Three of the planets have measured masses, yielding low bulk densities that suggest the presence of large hydrogen-dominated atmospheres.

Absence of linkage of chromosome 21q21 markers to familial Alzheimer's disease.

Alzheimer's disease is the most common form of dementia among the elderly population. Although the etiology is unknown, inheritance plays a role in the pathogenesis of the disease. Recent work indicates that an autosomal dominant gene for Alzheimer's disease is located on chromosome 21 at band q21. In the present study of a group of autopsy-documented kindreds, no evidence for linkage was found between familial Alzheimer's disease (FAD) and chromosome 21q21 markers (D21S1/D21S72 and the amyloid beta gene). Linkage to the D21S1/D21S72 locus was excluded at recombination fractions (theta) up to 0.17. Linkage to the amyloid gene was excluded at theta = 0.10. Apparent recombinants were noted in two families for the amyloid gene and in five families for the D21S1/D21S72 locus. These data indicate that FAD is genetically heterogeneous.

Interleukin-22 drives nitric oxide-dependent DNA damage and dysplasia in a murine model of colitis-associated cancer.

The risk of colon cancer is increased in patients with Crohn's disease and ulcerative colitis. Inflammation-induced DNA damage could be an important link between inflammation and cancer, although the pathways that link inflammation and DNA damage are incompletely defined. RAG2-deficient mice infected with Helicobacter hepaticus (Hh) develop colitis that progresses to lower bowel cancer. This process depends on nitric oxide (NO), a molecule with known mutagenic potential. We have previously hypothesized that production of NO by macrophages could be essential for Hh-driven carcinogenesis, however, whether Hh infection induces DNA damage in this model and whether this depends on NO has not been determined. Here we demonstrate that Hh infection of RAG2-deficient mice rapidly induces expression of iNOS and the development of DNA double-stranded breaks (DSBs) specifically in proliferating crypt epithelial cells. Generation of DSBs depended on iNOS activity, and further, induction of iNOS, the generation of DSBs, and the subsequent development of dysplasia were inhibited by depletion of the Hh-induced cytokine IL-22. These results demonstrate a strong association between Hh-induced DNA damage and the development of dysplasia, and further suggest that IL-22-dependent induction of iNOS within crypt epithelial cells rather than macrophages is a driving force in this process.

Effects of chromosome constitution on growth and longevity of human skin fibroblast cultures.

Employing standardized cell-culture methods, 10 euploid and 22 constitutionally aneuploid human skin fibroblast strains were assessed in triplicate for total growth potential, growth rates, population-doubling times, and cloning. In addition, longitudinal growth rate studies were carried out with otherwise isogenic 45,X and 47,XXX clonal cultures derived from a mosaic parental strain. Growth rates and longevities were cell-strain specific and highly reproducible among sister cultures of a given strain. There was no systematic correlation between chromosome constitution and any of the measured growth parameters. Trisomic as well as monosomic strains showed the same degree of variability with respect to these parameters as did euploid cultures. In particular, 4 trisomy 21 strains were not unusually short-lived, nor were clones with the 47,XXX constitution compared to those with 45,X karyotypes. We therefore conclude that the cumulative number of in vitro doublings preceding senescence of fibroblast-like cells cultured from skin does not differ significantly among cultures derived from humans who have a normal karyotype, trisomy 13, 18, or 21, the 45,X constitution, or various combinations of extra X and Y chromosomes.

Acute megakaryoblastic leukemia in children: treatment with bone marrow transplantation.

Seven children underwent BMT for acute megakaryoblastic leukemia (AMKL). They were assessed for clinical, hematologic, and cytogenetic findings as well as response to treatment. The diagnosis of AMKL was established by cytochemistry, immunophenotyping and/or platelet-peroxidase reactivity. Patients had received various prior chemotherapies. One was in first remission, another in second remission and five were in relapse at the time of admission for transplant. Marrow donors included an HLA identical sibling (one), phenotypically HLA identical unrelated (two) and partially HLA identical family members (four). Five patients achieved engraftment, one rejected the graft and died on day 20 after a second unrelated transplant and one died from infection on day 5. Two patients relapsed within the first month after transplant and died of recurrent leukemia. Another died of a second malignancy on day 2232. Two patients survive disease-free more than 3.8 and 4.3 years after transplant.

Multidimensional flow cytometry of marrow can differentiate leukemic from normal lymphoblasts and myeloblasts after chemotherapy and bone marrow transplantation.

Serial bone marrow aspirates from patients previously given a diagnosis of acute lymphoblastic leukemia (ALL) who had undergone chemotherapy, bone marrow transplantation (BMT), or both were analyzed by multidimensional flow cytometry (MDF) to detect residual disease (lower limit of detection 0.3%). Correlation between the results of morphologic examination and MDF showed concordant results on 100 of 118 specimens. The MDF-positive, morphologic examination-negative specimens were positive by cytogenetic examination or were obtained from patients in whom the ALL eventually relapsed. Similar correlations between MDF and the results of cytogenetic examination were obtained. Leukemic cells were detected in 29 of 62 patients before BMT and 12 of 52 after BMT Normal regenerating lymphoblasts were identified and quantified by MDF in patients without detectable leukemic lymphoblasts. Patients with leukemic lymphoblasts found by MDF in specimens obtained immediately before BMT were 3.28 times more likely to experience relapse after BMT compared with MDF-negative patients, even when leukemic lymphoblasts were undetectable by histopathologic examination, cytogenetic examination, or both. All patients who had undergone BMT with leukemic lymphoblasts found by MDF, with or without morphologic or cytogenetic confirmation, experienced relapse according to conventional criteria within 42 days of the MDF analysis. The detection of residual disease before overt relapse may provide information for early intervention, while definitive recognition of normal recovering blasts may prevent unnecessary treatment.

Increased poly-(R)-3-hydroxybutyrate concentrations in streptozotocin (STZ) diabetic rats.

Poly-(R)-3-hydroxybutyrate, a linear polymer of the ketone body, R-3-hydroxybutyric acid, is an amphiphilic, water-insoluble, salt-solvating polymer. In humans, shortchain, complexed polyhydroxybutyrate has been found in a wide variety of tissues and in atherosclerotic plaques. In the circulation, plasma polyhydroxybutyrate concentrations correlate strongly with atherogenic lipid profiles. We compared polyhydroxybutyrate levels in plasma, kidney, eye, sciatic nerve, aorta, and brain of streptozotocin-diabetic and healthy control Sprague-Dawley rats, three weeks after injection. With the exception of brain, which showed only a marginal increase (1.3-fold), polyhydroxybutyrate levels were 3- to 8-fold greater in tissues from diabetic vs. control rats. Increases in polyhydroxybutyrate levels between normal and diabetic rat tissues were in order: sciatic nerve (9.0-fold), kidney (7.2-fold), plasma (6.0-fold), aorta (4.4-fold), and whole eye (2.9-fold). These data indicate a significant increase in polyhydroxybutyrate levels in organs affected by complications of diabetes, and further suggest that plasma polyhydroxybutyrate levels may serve as a marker for the disease.

Infection control knowledge, practice, and attitudes of Mississippi dental hygienists.

PURPOSE: The purpose of this study was to assess Mississippi dental hygienists' knowledge and use of infection control techniques, attitudes pertaining to universal precautions and the risk of clinician/patient cross-infection, and attitudes toward treatment of patients with infectious diseases. METHODS: A 41-item questionnaire was mailed to all 508 licensed dental hygienists in Mississippi. Inactive, retired, and out-of-state hygienists (n = 59) were deleted from this study. The data were tested for significant associations using Chi-square. RESULTS: After adjusting for the 59 unusable returns, the response rate for analysis was 58% (n = 297). Dental hygienists reported using infection control techniques including sterilization or disposal of common items such as prophylaxis angles, suction tips, and air/water syringe tips. Although 98% of the respondents believed that barrier techniques were effective, some believed patients infected with HIV/AIDS (43%), hepatitis B (31%), or tuberculosis (40%) are best treated in public clinics rather than in private settings and that these clients pose a threat to dental hygiene practitioners. Further, a majority of the respondents believed that all oral healthcare workers and patients should be tested for HIV/AIDS. CONCLUSIONS: The incongruity between perceived knowledge, reported practice, and attitudes suggests the need for continuing education courses designed to allow dental hygienists to explore the affective domain regarding the care of patients with infectious diseases. In addition, courses on working with patients with HIV/AIDS should be offered in smaller cities for greater accessibility.

The replicative life spans of euploid hybrids derived from short-lived and long-lived human skin fibroblast cultures.

Two recent technical advances facilitate the derivation of proliferating hybrids from human diploid fibroblast strains without recourse to biochemical selection: (1) a new chemically-mediated method of somatic cell fusion (PEG-DMSO) yields hybrids at rates as high as 1 in 160 colonies after dilute plating of treated cell mixtures, and (2) a simple technology for assessment of DNA content (flow microfluorometry) permits rapid and highly sensitive monitoring of ploidy. Employing these techniques, we isolated 43 chromosomally stable hybrid clones from 12 crosses between seven different strains representing a wide range of longevities. Crosses between short-lived strains resulted in short-lived hybrid offspring, whereas hybrids derived from long-lived parents tended to be long-lived. Crosses between strains of contrasting longevities gave clones with intermediate growth potentials relative to the other types of hybrids. The failure to observe complementation (enhanced longevity) of hybrids argues against random recessive single-copy gene mutations as important determinants of clonal senescence.

Fragile X expression studied by clonal analysis and somatic cell hybridization.

The expression of the fragile site on the X chromosome was examined in euploid somatic cell hybrids to determine if a normal genome could complement the abnormal genome and suppress fragile X expression. Fibroblasts from the patient showed the fragile X in 8% to 12% of cells, and fibroblasts from the normal individual showed no fragile X expression. Six fibroblast clones from the patient showed a variable frequency of fragile X expression (from 6.6% to 12%), suggesting that the fragile X is not expressed in a clonal fashion. Three clones from the normal individual did not show the fragile X. Four hybrid clones showed the fragile X in 5.6%, 4.0%, 7.0%, and 4.0% of cells, respectively, indicating that fragile X expression is not completely suppressed by the normal genome.

Cytogenetic analysis of eight human papillomavirus immortalized human keratinocyte cell lines.

Cytogenetic analysis was performed on human papillomavirus (HPV)-immortalized cell lines. Lines were established by co-transfection of primary human keratinocyte cells with HPV type 16 or 18 DNA and pSV2neo. The resulting clonal lines contained integrated HPV DNA and exhibited extended life spans in culture but were non-tumorigenic in nude mice. Two HPV16-immortalized lines (FEPE1L8 and FEPE1L9) and 4 HPV18-immortalized lines (FEA, FEH18L, FEP18-5 and FEP18-11) were established. Two additional lines were derived by subsequent treatment of the FEA line with TPA and by further transfection with HSVII DNA. Cytogenetic analysis revealed that all lines were abnormal, containing a variety of numerical and structural aberrations. Six of the 8 lines were hyper-triploid and 2 were near-diploid. Examination of lines FEA, FEH18L and FEP18-11 at multiple passages in culture revealed that the lines were clonal and chromosomally stable over extended passage in culture. Structural rearrangements were most common in chromosomes 1 and 3 but also occurred in chromosomes 5, 7, 8, 12, 16 and 22. Marker chromosomes were present in all cell lines. A small metacentric marker, possibly an isochromosome for the short arm of chromosome 5, was consistently present in the FEA line and its derivatives (FEAB10 and FEAT) as well as the FEH18L line. A loss or reduction in copy number of chromosome 13 was seen in 5 of the 8 cell lines.

Regulation of growth and gene activity in euploid hybrids between human neonatal fibroblasts and epithelioid amniotic fluid cells.

Pure populations of proliferating synkaryons were obtained from polyethylene glycol-mediated crosses between diploid human foreskin fibroblasts and epithelioid amniotic fluid cells. These hybrids proved to be chromosomally stable tetraploids. They continuously produced heteropolymeric G6PD and showed strictly additive patterns of silver staining of both parental sets of nucleolar organizing chromosomes. Collagenous proteins characteristic of the fibroblast parent were synthesized, while fibronectin production appeared to be directed by the epithelioid portion of the genome. Even though these heterotypic hybrids proliferated at a reduced rate and achieved fewer population doublings relative to homotypic (fibroblast X fibroblast) crosses, they survived passage by trypsinization better than pure populations of epithelioid cells. These observations suggest a concerted action of both parental genomes with respect to proteins responsible for "household" functions, but complementation and possibly modulation of gene action with respect to "luxury" protein synthesis and cell growth.

Fetal liver cell transplantation for the creation of lymphohematopoietic chimerism in fetal baboons.

OBJECTIVE: Our purpose was to create xenogeneic lymphohematopoietic chimerism by in utero transplantation of human fetal liver cells in the midgestation fetal baboon. STUDY DESIGN: Human fetal liver cell suspensions obtained from preimmune human fetuses (< 80 days' gestation) were injected into the peritoneal cavity of three fetal baboons (85, 95, and 104 days' gestation). A total of 9 x 10(6) cells, in a volume of 1 ml, were injected percutaneously into the fetal abdominal cavity under ultrasonographic guidance. The success of the injection was assessed by observing ascites and free loops of fetal bowel after injection. Fetal umbilical cord blood (35 days posttransplantation) and neonatal blood and bone marrow were obtained to be assayed for the presence of donor hematopoietic cells. Chimerism was detected by fluorescence in situ hybridization with a human Y-chromosome specific probe. RESULTS: All the animals survived the in utero procedures. Thirty-five days after transplantation engraftment was noted in one animal. Postnatally the same animal showed engraftment in both the peripheral blood and bone marrow. The rate of chimerism was 1.5% (1.5% of the cells were human) in both the peripheral blood and bone marrow. CONCLUSIONS: This study demonstrates that creation of xenogeneic lymphohematopoietic chimerism is possible in the midgestation fetal baboon. However, the level of chimerism was too low to study the biologic activity of the transplanted cells or to potentially ameliorate lymphohematopoietic disorders. Future studies using allogeneic tissue, evaluating cells obtained from both fetal and adult donors, and comparisons between purified stem cells and fetal liver cells are needed.

Viral integration and fragile sites in human papillomavirus-immortalized human keratinocyte cell lines.

Human papillomavirus (HPV) types 16 and 18 integration sites were mapped in six HPV-immortalized human keratinocyte cell lines by fluorescence in situ hybridization (FISH). Mapping of HPV sequences in these cell lines revealed that HPV integration varied in copy number and location but that integration sites were stable over extended passages in culture. Integration occurred at different sites throughout the genome and did not correspond to the location of specific cellular genes. However, integration sites were consistent with integration near or within known fragile sites in five of the six cell lines. Induction of aphidicolin-sensitive fragile sites in one cell line prior to in situ hybridization revealed that integrated HPV DNA was disrupted by fragile-site expression, suggesting that integration occurred within a fragile site.

A simple method of rapid freezing adequately preserves brain tissue for immunocytochemistry, light and electron microscopic examination.

A simple and reproducible method for cryopreservation of brain tissue from patients with Alzheimer's disease is described. Fresh brain slices (1 cm thick) obtained less than 6 h postmortem are placed in sealed plastic bags, sandwiched between 0.3-cm-thick aluminium sheets, and frozen by placing the entire "sandwich" between layers of dry ice pellets. The frozen brain slices are stored at -85 degrees C. Specific anatomic areas can be retrieved at any time for light and electron microscopic, immunocytochemical, autoradiographic and neurochemical studies.

Y chromosome loss in chronic myeloid leukemia detected in both normal and malignant cells by interphase fluorescence in situ hybridization.

Loss of the Y chromosome in bone marrow (BM) cells is a normal age-associated event. Y chromosome loss is also observed in the Philadelphia chromosome (Ph) positive BM cells of some patients with chronic myeloid leukemia (CML) in chronic phase, but at a younger age than in normal individuals. While the significance of loss of the sex chromosome in normal males is uncertain, -Y marrow cells are not believed to be of clonal origin. However, because CML is a clonal disease, CML sub-populations with Y loss may constitute a disease-related sub-clone. We used a PCR-amplified yeast artificial chromosome containing the BCR gene region for single color interphase analysis of BCR rearrangement by fluorescence in situ hybridization (FISH). Then, using two color FISH, with one fluorochrome detecting the BCR gene region and the other detecting Y chromosome repeat sequences, we surveyed peripheral and BM Y loss in both normal Ph- (BCR not disrupted) and CML Ph+ (BCR rearranged) interphase nuclei of two patients with Y loss in Ph positive cells observed by metaphase analysis. -Y was seen in a proportion of Ph+ cells in both cases, and the proportion matched that seen in Ph- cells, indicating that Y loss is probably sporadic in both normal and CML populations, and that the propensity for Y loss in normal BM cells may be a phenotype that can be retained by malignant cells in CML.

Cultivated cells from diagnostic amniocentesis in second trimester pregnancies. II. Cytogenetic parameters as functions of clonal type and preparative technique.

From a total of 418 primary amniotic fluid colonies, 5.5% were fibroblast-like (F), 33.7% epithelioid (E) and 60.8% had characteristics of what was previously shown to be the principal class of clonable amniotic fluid cells (AF). Polyploidy occurred in all three categories, although both pure tetraploidy and mixoploidy were more frequent in E colonies. The incidence of non-constitutional chromosomal changes was identical in AF and E type colonies if primary spreads were analyzed in situ without prior trypsinization. Spreads from pooled cell suspensions showed higher base-line levels of both aneuploidy and structural changes. Analysis of individual colonies employing an in situ preparative technique is clearly the method of choice for a reliable cytogenetic prenatal diagnosis within the shortest possible period of time.

Cultivated cells from diagnostic amniocentesis in second trimester pregnancies. III. The fetal urine as a potential source of clonable cells.

Four independent fetal urine specimens yielded clonal growth. The mature colonies were similar to certain classes of amniotic fluid cell clones, and to those obtained from fetal kidney. Kidney specific LDH isozyme patterns, however, were not observed in any of these primary clones.