Dioxin-inducible transactivation in a chromosomal setting. Analysis of the acidic domain of the Ah receptor.

We analyzed the transactivation function of the acidic segment of the Ah receptor (amino acids 515-583) by reconstituting AhR-defective mouse hepatoma cells with mutants. Our data reveal that both hydrophobic and acidic residues are important for transactivation and that these residues are clustered in two regions of the acidic segment of AhR. Both regions are crucial for function, because disruption of either one substantially impairs transactivation of the chromosomal CYP1A1 target gene.

Conserved worldwide linkage disequilibrium in the human factor XI gene.

We have identified, in four diverse human populations, five common single-nucleotide polymorphisms (SNPs) in the coding region of the gene for the blood coagulation protease factor XI. Each SNP has an allele frequency >5% in at least one population. Three of the SNPs (C472T, A844G, and T1234C), spread out over approximately 10 kb of genomic DNA, are in marked linkage disequilibrium (LD) with one another (P < 10(-4)).

Classification of antibiotic resistance patterns of indicator bacteria by discriminant analysis: use in predicting the source of fecal contamination in subtropical waters.

The antibiotic resistance patterns of fecal streptococci and fecal coliforms isolated from domestic wastewater and animal feces were determined using a battery of antibiotics (amoxicillin, ampicillin, cephalothin, chlortetracycline, oxytetracycline, tetracycline, erythromycin, streptomycin, and vancomycin) at four concentrations each. The sources of animal feces included wild birds, cattle, chickens, dogs, pigs, and raccoons. Antibiotic resistance patterns of fecal streptococci and fecal coliforms from known sources were grouped into two separate databases, and discriminant analysis of these patterns was used to establish the relationship between the antibiotic resistance patterns and the bacterial source.

Panhandle PCR for cDNA: a rapid method for isolation of MLL fusion transcripts involving unknown partner genes.

Identifying translocations of the MLL gene at chromosome band 11q23 is important for the characterization and treatment of leukemia. However, cytogenetic analysis does not always find the translocations and the many partner genes of MLL make molecular detection difficult. We developed cDNA panhandle PCR to identify der(11) transcripts regardless of the partner gene.

Survey and host fitness effects of red-cockaded woodpecker blood parasites and nest cavity arthropods.

Blood parasites and nest cavity arthropods associated with the red-cockaded woodpecker (Picoides borealis) were surveyed and the impact of blood-feeding arthropods on woodpecker fitness traits was assessed. Five woodpeckers (8%) were infected with unidentified microfilariae, and 1 woodpecker (2%) was infected with 2 species of haemoproteid (Haemoproteus velans and Haemoproteus borgesi). This is the first record of haemoproteids in this species and the first observation of H.

Digital imaging improves upright stereotactic core biopsy of mammographic microcalcifications.

Aim: This comparative study was carried out to assess the effect of using digital images compared to conventional film-screen mammography on the accuracy of core biopsy of microcalcifications using upright stereotactic equipment.

Materials And Methods: The biopsy results from a consecutive series of 104 upright stereotactic 14-gauge core biopsies performed with conventional X-ray (Group A) were compared with 40 biopsies carried out using stereotaxis with digital imaging (Group B). In all cases specimen radiography was performed and analysed for the presence of calcifications.

Prevalence of Ehrlichia chaffeensis (Rickettsiales: Rickettsiaceae) in Amblyomma americanum (Acari: Ixodidae) from the Georgia coast and Barrier Islands.

Human monocytic ehrlichiosis is an emerging zoonosis caused by infection with Ehrlichia chaffeensis Anderson, Dawson, Jones & Wilson, which is transmitted to mammals by ixodid ticks. Prevalence of infected ticks and distribution of infection foci indicate relative risk of human exposure to ehrlichiosis and may be influenced by factors such as geographic isolation, human disturbance, and the availability of suitable mammalian reservoir hosts. To test, this, individual and pooled lone star ticks, Amblyomma americanum (L.

The aromatic hydrocarbon receptor, transcription, and endocrine aspects of dioxin action.

The widespread and persistent environmental contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin elicits adaptive and adverse biological responses by inducing changes in gene transcription. Some of dioxin's effects reflect disruption of endocrine homeostasis. The aromatic hydrocarbon receptor protein, together with its heterodimerization partner, the aromatic hydrocarbon receptor nuclear translocator protein, mediates dioxin action.

A comparison of 14 and 12 gauge needles for core biopsy of suspicious mammographic calcification.

This study was carried out to compare the efficacy of 14 vs 12 G needles in stereotactic core biopsy of mammographic calcification. A consecutive series of 100 impalpable mammographic calcifications, without an associated mass and requiring stereotactic core biopsy were randomly allocated to either 14 G or 12 G needle sampling. All biopsies were performed using an upright stereotactic digital unit (Senovision GE) and a Bard automated biopsy gun.

Phase I study of topotecan administered as a 21-day continous infusion in children with recurrent solid tumors: a report from the Children's Cancer Group.

The purpose of this study was to determine the toxicity, maximum tolerated dose, and pharmacokinetics of a 21-day continuous infusion of topotecan in children with relapsed solid tumors. Fifteen patients received 40 courses of continuous ambulatory infusions of topotecan every 28 days or when there was resolution of hematological toxicity and any grade 2 or greater nonhematological toxicity. The starting dose was 0.

Familial clustering of Langerhans cell histiocytosis.

Langerhans cell histiocytosis (LCH) is considered a non-hereditary disorder. Evaluation of the few familial cases might provide insight into its aetiology and pathogenesis. We conducted a survey to identify familial LCH cases.

Nucleoside analogues in the therapy of Langerhans cell histiocytosis: a survey of members of the histiocyte society and review of the literature.

Background: Previous reports have suggested activity of the nucleoside analogues 2-chlorodeoxyadenosine (2-CdA) and 2'-deoxycoformycin (2'-DCF) in Langerhans cell histiocytosis (LCH).

Procedure: To assess the efficacy of 2-CdA and 2'-DCF as salvage therapy for LCH, a survey of members of the Histiocyte Society and a literature review were undertaken. Twenty-three patients treated with 2-CdA and 4 treated with 2'-DCF were found, age range 2 months to 49 years.

Regulation of GLUT1 gene transcription by the serine/threonine kinase Akt1.

We used mouse hepatoma (Hepa1c1c7) cells to study the role of the serine/threonine kinase Akt in the induction of GLUT1 gene expression. In order to selectively turn on the Akt kinase cascade, we expressed a hydroxytamoxifen-regulatable form of Akt (myristoylated Akt1 estrogen receptor chimera (MER-Akt1)) in the Hepa1c1c7 cells; we verified that hydroxytamoxifen stimulates MER-Akt1 activity to a similar extent as the activation of endogenous Akt by insulin. Our studies reveal that stimulation of MER-Akt1 by hydroxytamoxifen induces GLUT1 mRNA and protein accumulation to levels comparable to that induced by insulin; therefore, activation of the Akt cascade suffices to induce GLUT1 gene expression in this cell system.

Pre-steady state transport by erythrocyte band 3 protein: uphill countertransport induced by the impermeant inhibitor H2DIDS.

Pre-steady state Cl- efflux experiments have been performed to test directly the idea that the transport inhibitor H2DIDS (4,4'-diisothiocyanatodihydrostilbene-2,2'-disulfonate) binds preferentially to the outward-facing state of the transporter. Cells were equilibrated with a medium consisting of 150 mM sodium phosphate, pH 6.2, N2 atmosphere, and 80-250 microM 36Cl-.

Induction of cytochrome P4501A1.

Cytochrome P4501A1 is a substrate-inducible microsomal enzyme that oxygenates polycyclic aromatic hydrocarbons, such as the carcinogen benzo(a)pyrene, as the initial step in their metabolic processing to water-soluble derivatives. Enzyme induction reflects increased transcription of the cognate CYP1A1 gene. The environmental toxicant 2,3,7,8-tetrachlorodibenzo-p-dioxin is the most potent known cytochrome P4501A1 inducer.

Management of pleural effusions in children with malignant lymphoma.

Purpose: The aim of this study was to determine potential problems in the diagnosis and management of children with pleural effusions and malignant lymphoma as well as the efficacy of thoracentesis.

Methods: The case histories of six children with malignant lymphoma who presented with pleural effusions were reviewed. Thoracentesis was performed using the Seldinger technique.

Nasogastric tube feedings in children with high-risk cancer: a pilot study.

Purpose: To avoid the cost and complications of total parenteral nutrition (TPN), this study was initiated to determine the feasibility of administrating nasogastric tube feedings in children receiving intensive chemotherapy (CTX) or bone marrow transplantation (BMT).

Patients And Methods: Seventeen children (aged 2 to 19 years) were entered into the study. Continuous nasogastric feedings of a glutamine-supplemented elemental diet were administered during CTX and at the time of rehospitalization for fever, neutropenia, and mucositis.

Detection of mutations by automated fluorescence/RNA-based dideoxy fingerprinting (ARddF).

Dideoxy fingerprinting (ddF) is a hybrid technique which combines aspects of single strand conformational polymorphism (SSCP) and dideoxy sequencing to detect the presence of single base changes in a defined fragment of nucleic acid. ddF is no more technically demanding than SSCP, yet it is more sensitive in detecting point mutations. We describe here the adaptation of conventional ddF to an automated sequencing system using fluorescent Cy5 labeled primers.

The porphyromonas gingivalis prtP/kgp homologue exists as two open reading frames in strain 381.

P. gingivalis is considered to be a major pathogen of adult periodontitis. Among its cadre of putative virulence factors are hemagglutinins (adhesins) and proteases.

Identification of mutations and polymorphisms in the factor XI genes of an African American family by dideoxyfingerprinting.

Congenital deficiency of factor XI is a rare condition associated with a mild to moderate bleeding diathesis that is most commonly found in persons of Jewish ancestry. The disorder has been reported sporadically in a number of other ethnic groups, but rarely in the black population. We report on the genetic analysis of the factor XI genes of two African American patients: a 9-year-old boy (the propositus) with mild factor XI deficiency and his mother.

Prenatal exposure to metronidazole and risk of childhood cancer: a retrospective cohort study of children younger than 5 years.

Background: To evaluate the role of in utero exposure to metronidazole (a carcinogen in some animal models) and the risk of subsequent cancer, the authors conducted a retrospective cohort study of childhood cancer.

Methods: The cohort included 328,846 children younger than 5 years born to women enrolled in Tennessee Medicaid at any time between the last menstrual period (LMP) and the date of delivery. The cohort was identified by linking files of Tennessee Medicaid mothers ages 15-44 years and children and the children's birth and death certificates for the period January 1, 1975 through December 31, 1992.

The number of direct repeats in hagA is variable among Porphyromonas gingivalis strains.

The coding sequence for the surface protein hemagglutinin A (HagA) of Porphyromonas gingivalis 381 has previously been shown to contain four direct 1.35-kb repeats, designated repHA. This study was performed to determine if the number of repHA units in hagA is consistently 4 or if allelic polymorphism exists among strains and/or upon multiple passage of P.

Hypoxia-inducible mammalian gene expression analyzed in vivo at a TATA-driven promoter and at an initiator-driven promoter.

We have analyzed protein-DNA interactions in vivo at transcriptional control elements for two hypoxia-inducible genes in mouse hepatoma cells. The promoter for the phosphoglycerate kinase 1 (PGK1) gene contains an initiator element, but no TATA sequence, whereas the promoter for the glucose transporter 1 (Glut1) gene contains a TATA element but no initiator sequence. Our findings reveal hypoxia-inducible, Arnt-dependent occupancy of DNA recognition sites for hypoxia-inducible factor 1 (HIF-1) upstream of both target genes.

MLL genomic breakpoint distribution within the breakpoint cluster region in de novo leukemia in children.

Purpose: To assess translocation breakpoint distribution within the MLL genomic breakpoint cluster region (bcr), 40 cases of de novo leukemia in children were examined by karyotype and Southern blot analysis.

Patients And Methods: Criteria for inclusion were karyotypic or molecular rearrangement of chromosome band 11q23. Of the 40 cases, 31 occurred in infants.