Aspects of nonrandom turnover involved in the concerted evolution of intergenic spacers within the ribosomal DNA of Drosophila melanogaster

Polymerase chain reaction (PCR)-amplified, sequenced, and digitally typed intergenic spacers (IGSs) of the ribosomal (r)DNA in D. melanogaster reveal unexpected features of the mechanisms of turnover involved with the concerted evolution of the gene family. Characterization of the structure of three isolated IGS length variants reveals breakage "hot spots" within the 330-base-pair (bp) subrepeat array found in the spacers. Internal mapping of variant repeats within the 240-bp subrepeat array using a novel digital DNA typing procedure (minisatellite variant repeat [MVR]-PCR) shows an unexpected pattern of clustering of variant repeats. Each 240-bp subrepeat array consists of essentially two halves with the repeats in each half identified by specific mutations. This bipartite structure, observed in a cloned IGS unit, in the majority of genomic DNA of laboratory and wild flies and in PCR-amplified products, has been widely homogenized yet is not predicted by a model of unequal crossing over with randomly placed recombination breakpoints. Furthermore, wild populations contain large numbers of length variants in contrast to uniformly shared length variants in laboratory stocks. High numbers of length variants coupled to the observation of a homogenized bipartite structure of the 240-bp subrepeat array suggest that the unit of turnover and homogenization is smaller than the IGS and might involve gene conversion. The use of PCR for the structural analysis of members of the rDNA gene family coupled to digital DNA typing provides powerful new inroads into the mechanisms of DNA turnover affecting the course of molecular evolution in this family.

A phylogenetic analysis of the family Pseudonocardiaceae and the genera Actinokineospora and Saccharothrix with 16S rRNA sequences and a proposal to combine the genera Amycolata and Pseudonocardia in an emended genus Pseudonocardia

The 16S rRNAs of 15 species of actinomycetes belonging to the genera Actinokineospora and Saccharothrix and the family Pseudonocardiaceae, including Amycolatopsis, Amycolata, Pseudonocardia, Saccharomonospora, and Saccharopolyspora species, were sequenced by using reverse transcriptase. The sequences were analyzed along with the sequences of reference actinomycetes by using distance matrix and parsimony methods. The wall chemotype IV genus Actinokineospora was found to be closely related to species of the genus Saccharothrix which have chemotype III walls. Together, these two genera formed a clade which was closely related to members of the family Pseudonocardiaceae which have chemotype IV walls. However, the phylogenetic branching pattern did not unambiguously resolve whether the members of all three taxa should be placed in a single family. We suggest, therefore, that the genera Actinokineospora and Saccharothrix should remain outside the family Pseudonocardiaceae until additional sequence or phenotypic data are available to decide the issue. The sequences of species belonging to the genera Amycolata and Pseudonocardia were always recovered as a mixed group in phylogenetic trees, and we propose that these organisms should be classified in an emended genus Pseudonocardia. This proposal is strongly supported by previously published lipid, ribosomal protein, and ultrastructure data.

Computerizing records for continuing education

The system was devised as a joint project by members of the Nursing Education Department, secretarial staff, and Information Services. The nursing education department members identified needed outcomes. The secretaries described what was necessary to simplify data entry. The information services personnel had the technical expertise to interpret the input from the others and put the system together. All members of this project were essential to its development. The reports provide information about classes, attendees, and educational budgets. The reports also meet requirements of the Joint Commission on Accreditation of Healthcare Organizations (JCAHO), Occupational Safety and Health Administration (OSHA), and state continuing education regulations.

Recognition of an in vivo immune response to human neuroblastoma modulation of antigen expression by retinoic acid

Neuroblastoma is one of the most common solid tumors of childhood and is notable for its ability to spontaneously regress and, in some instances, to differentiate to less malignant ganglioneuromas. Since immune mechanisms may account for these phenomena, identification of in vivo immune responses to tumor cell surface antigens may be important to the progression of the disease. As determined by analysis on the fluorescence-activated cell sorter, sera from 10 of 18 neuroblastomas patients were found to contain antibodies to a cell surface antigen present on subpopulations of cells from human neuroblastoma cell lines maintained in vitro. Eight human neuroblastoma cell lines were examined and found to vary in reactivity with sera. Induction of differentiation of cell lines with retinoic acid (RA) in vitro resulted in most cell lines bearing higher percentages of positive cells but with a decreased mean cell fluorescence. Preliminary Western blot analysis of lysates of the human cell lines NMB/N7, SMS-KAN, and SK-N-MC showed two principal antigen bands on reducing gels. Comparison of sera from different individuals on lysates of cell lines showed reactivity principally with bands of 105-110 kD and 65-70 kD and an additional minor band of slightly lower molecular weight with the higher titer sera. The ability of different sera to recognize a common antigen pattern suggests that this represents an immunodominant cell surface antigen. Examination of reactivity of other cell lines in this system showed that positive sera reacted with all neuroblastoma lines examined, one neuroepithelioma (SK-N-MC), two melanoma lines (MeWo, G361), and one adrenal-derived adenocarcinoma (SW-13).

Expert systems for performance review

A microcomputer-based expert system to interpret hospital and community health service data is described. The system analyses performance indicators, which are key statistics describing levels of achievement in terms both of policy objectives and efficiency. The system is being used to support annual performance reviews of English health authorities. The potential for application of similar systems is discussed.

Essential thrombocythemia associated with recurrent abortions and fetal growth retardation

Essential thrombocythemia (ET) is one of the myeloproliferative disorders characterized by an elevated platelet count, usually greater than 1,000 X 10(9)/L. It may be associated with either hemorrhagic or thrombotic tendencies. Although it usually affects older people, we have recently encountered two young women with ET who had a total of six spontaneous abortions before the end of the first trimester. During her most recent pregnancy, one of the patients underwent plateletpheresis on four separate occasions before the 12th week. She reached 34 weeks but demonstrated evidence of fetal growth retardation and pre-eclampsia. At delivery there were scattered villus infarcts in the placenta. Based on this patient and previous reports in the literature, we postulate that the spontaneous abortions, fetal growth retardation, and pre-eclampsia may be related to the thrombocytosis and suggest that the use of antiplatelet agents throughout pregnancy should be seriously considered in such cases.

Bone marrow transplantation for acute monocytic leukemia following the treatment of Hodgkin's disease

A 32-year-old woman developed acute monocytic leukemia within a year of treatment for Hodgkin's disease with chemotherapy and radiation. Residual leukemia was present in the bone marrow after two induction courses of high-dose Ara-C. She received a bone marrow transplant from an HLA- and DR-identical sister and remains in complete remission more than 2 years after transplantation. Only one other instance of a remission greater than 2 years after transplantation for secondary acute leukemia could be found in the literature. Although bone marrow transplantation may be carried out successfully in these patients, it is possible that they may be more vulnerable to transplant-related complications because of their previous exposure to chemotherapy and radiation. Only further study can clarify this matter and determine the best time for the procedure and which regimen should be used.

Hepatitis B virus DNA is enriched in polymorphonuclear leukocytes

DNA hybridization and cell separation techniques were used to determine which blood components contained hepatitis B viral DNA sequences. Free monomer-length hepatitis B virus was found in large amounts in the polymorphonuclear leukocyte cell fraction in two of five HBsAG-positive patients. In these two patients, viral DNA sequences were not detected in the plasma or platelet fraction, whereas the mononuclear cell DNA contained small amounts of a 7.2 kb size unintegrated hepatitis B genome. These studies indicate that the major reservoir of unit-length viral DNA in the asymptomatic hepatitis B carriers studied here was in the polymorphonuclear leukocyte fraction. The basis for the presence of the viral DNA within these cells is presently unknown, but may relate to viral replication within, or phagocytosis of virus by, these cells.

Compliance with postpartum Rh isoimmunization prophylaxis in Alberta

A retrospective review of obstetric records for 1979 in two major Calgary hospitals was undertaken to determine the rate of compliance with postpartum Rh isoimmunization prophylaxis in Alberta. The charts of 4528 women ranging in age from 13 to 46 years were reviewed. The prevalence rate of Rh negativity was found to be 16%. Of the 710 Rh-negative women 490 (69%) were eligible to receive Rh immune globulin (RhIG); that is, they had no anti-D antibodies, and the baby/fetus was Rh-positive or Rh-unknown. RhIG had been administered to 93.6% of the eligible women; the compliance rate ranged from 66.7% for obstetric emergencies (i.e., spontaneous abortion, antepartum or early-pregnancy hemorrhage, or ectopic pregnancy) to 98.2% for postpartum diagnoses. In more than half (54.7%) of the women who underwent amniocentesis Rh type was not determined; the implications of this finding are discussed. Although poor compliance with postpartum RhIG administration is not a reason for withholding antepartum administration of RhIG, maximum compliance with the more cost-effective programs should be attained before antepartum programs are fully implemented.

In vivo temperature dependence of ultrasound speed in tissue and its application to noninvasive temperature monitoring

Measurements of the speed of ultrasound as a function of temperature in the 35 °C to 45 °C range were made on mammalian (canine) tissue both in vitro and in vivo at 5 MHz using a pulsed transmission technique. Cored samples coinciding with the ultrasonically irradiated tissue were obtained and assayed for water and total lipid content. Results indicate about 2 percent agreement between in vivo and in vitro data, and that, on the basis of kidney data, lipid content and temperature coefficient of ultrasound speed are more highly correlated (0.76 correlation coefficient) than are lipid content and speed of sound (0.17 correlation coefficient).