Quantitative DNA analysis of low grade cervical intraepithelial neoplasia and human papillomavirus infection by static and flow cytometry.

Quantitative deoxyribonucleic acid (DNA) analysis of cervical biopsy specimens from 26 women with cytological, colposcopic, and histological evidence of mild cervical atypia consistent with cervical intraepithelial neoplasia grade I, reactive atypia, or human papillomavirus infection alone or in combination was performed in a comparative evaluation of Feulgen microspectrophotometry, the fast interval processor image analysis system, and flow cytometry. The fast interval processor image analysis system showed a distinct advantage over the other methods, being faster and allowing the operator to see the cells that were selected for measurement. The three methods of measurement together showed that the DNA content of at least 2% of the cells measured exceeded 5C (C being the haploid amount of DNA in a normal cell and 2C representing the diploid complement of a normal cell) in all cases of cervical intraepithelial neoplasia grade I and reactive atypia and in 87% of those reported as showing human papillomavirus infection alone. In contrast, the DNA content of cervical biopsy specimens from the transformation zone of 11 normal controls did not exceed 4C. This study shows the value of using a DNA threshold--that is, the "5C exceeding rate"--to distinguish between normal and neoplastic appearances of the cervix. These results support the view that cervical infection by human papillomavirus is a true precursor of neoplasia.     

List sizes and use of time in general practice.

The claim that list sizes in general practice should continue to fall towards a national average of 1700 patients rests heavily on the assumption that the extra time available to doctors would be used mainly for longer consultations, resulting in better standards of care. Evidence suggests, however, that the time is more likely to be used to increase rates of consultation in surgeries and home visits and to reduce the length of the working week. A national, random sample of 2104 principals in general practice in England and Wales were questioned about their allocation and use of time. The response rate was 67%, and no large biases in response were detected. The smaller their personal list size the less time general practitioners spent on all aspects of their work and the higher their rates of consultation and home visiting. The effects of further reductions in list sizes would be haphazard, being differentially distributed across the range of list sizes. Longer consultations would probably result, but most of the extra time would probably be used in higher rates of consultation in surgeries and home visits and some would be taken as free time.     

Fertility determinants in the oil region of Mexico

This study analyzes fertility determinants in the oil region of Mexico, consisting of the states of Veracruz, Tabasco, and Campeche. Data are from the 1980 Mexican census and the unit of analysis is the municipio. The regression models, in which the dependent variables of children ever born and child-woman ratio are examined, reveal religious variables to be most significant, with greater fertility for non-Catholics and persons with no religion than for Catholics. Also of great importance are economic variables. Literacy and urbanization, both "classical" Mexican fertility variables, reduce fertility. There are major differences among three urban/rural and three indigenous language subsamples. Results are discussed vis-a-vis demographic theories and prior research.     

Infants, pain and what health care professionals should want to know -- an issue of epistemology and ethics

Resolution of the question of pain relief in neonates and infants has been hampered by hesitation on the part of medical personnel to assign a high priority to consideration of the issue. Butler provides a partial explanation for this hesitation based on resistance to changes in belief and practice stemming from the history of neonatology and an epistemological need for coherence. She argues for suspension of both the hesitation and the resistance, and for quickly implementing changes in infant care practices. Showing that traditional reasons for denying or diminishing infant pain perception and its control have lost their persuasive power, she offers ethical arguments for recasting traditional concerns and adopting a new perspective.     

Use of carbon dioxide and natural or synthetic aggregation-attachment pheromone of the bont tick,Amblyomma hebraeum,to attract and trap unfed adults in the field

It was determined previously that unfed adults ofAmblyomma hebraeum become active in response to carbon dioxide but are not attracted by it. We have now shown in field experiments that males and females which are activated by carbon dioxide are attracted to the aggregation-attachment pheromone produced by males after a period of feeding on the host. Unfed adults were attracted too-nitrophenol, a component of the aggregation-attachment pheromone ofAmblyomma variegatum, pre-fed males ofA. hebraeum, and extracts of such males. Live males were more attractive than the extracts which, in turn, were more attractive thano-nitrophenol. The ticks were attracted to sources ofo-nitrophenol from as far away as 11 m in 90 min. Simple traps, baited with carbon dioxide and aggregation-attachment pheromone (from pre-fed males or extracts of pre-fed males), were used to capture unfed adults that had been released in the field. The response of unfed adults to carbon dioxide and the aggregation-attachment pheromone presents an obvious host-location mechanism and a means for the ticks to discriminate between suitable hosts (those with males already attached) and potentially unsuitable hosts (those with no males attached).     

Premeiotic Change of Nucleolus Organizer Size in Neurospora

We have investigated the heritability of nucleolus organizer region (NOR) size in Neurospora crassa. By pulsed-field gel electrophoresis, we followed in genetic crosses the size of the normal or "terminal" NORs and the size of a small interstitial NOR. Tetrad analysis revealed that changes in NOR size occur frequently in the sexual phase. Moreover, most size changes occurred in the period between fertilization and meiosis, although some changes occurred during and after meiosis. Unexpectedly, increases and decreases in NOR size were not equally frequent: decreases were more common. The NOR size changes generated during meiosis were not the result of unequal crossing over between NORs on homologous chromosomes.     

Multiple forms of SppI (secreted phosphoprotein, osteopontin) synthesized by normal and transformed rat bone cell populations: regulation by TGF-beta

Metabolic labeling has revealed that rat bone cell populations in culture synthesize several forms of the secreted phosphoprotein, SppI. Most cell populations produced two major [32PO4]-labeled forms that behaved anomolously on SDS-PAGE migrating at 60 kDa and 56 kDa on 10% gels and 55 kDa and 44 kDa on 15% gels. Minor forms of intermediate sizes were also resolved. In normal bone cells the 60 kDa form was predominant and was the only form produced by the clonal bone cell line, RCA 11, whereas the 56 kDa a form predominated in the transformed bone cell line, ROS 17/2.8. In all populations [35S]-methionine-labeling revealed SppIs at approximately 60 kDa but no 56 kDa form. Each form of SppI was specifically cleaved by thrombin which generated fragments of approximately 28 kDa. Transforming growth factor beta 1 increased SppI mRNA levels 3 to 6-fold within 24 h in the normal bone cells, but no increase occurred in the ROS 17/2.8 cells. The elevated expression of SppI was reflected in a selective increase in the synthesis of the [32PO4]-and [35S]-methionine-labeled 60 kDa SppIs.     

A novel, rapid method for the isolation of terminal sequences from yeast artificial chromosome (YAC) clones.

The recent development of yeast artificial chromosome (YAC) vectors has provided a system for cloning fragments that are over ten times larger than those that can be cloned in more established systems. We have developed a method for the rapid isolation of terminal sequences from YAC clones. The YAC clone is digested with a range of restriction enzymes, a common linker is ligated to the DNA fragments and terminal sequences are amplified using a vector specific primer and a linker specific primer. Sequence data derived from these terminal specific products can be used to design primers for a further round of screening to isolate overlapping clones. The method also provides a convenient method of generating Sequence Tagged Sites for the mapping of complex genomes.     

A 3.5 genome equivalent multi access YAC library: construction, characterisation, screening and storage.

The construction of a yeast artificial chromosome (YAC) primary gridded library of 35,000 clones from human lymphoblastoid (48,XXXX) cell line DNA is described. The average YAC size is approximately 350kb representing a greater than 3.5 times coverage of the genome. The library is stored at -70 degrees C as gridded clones on nylon filters impregnated with 20% glycerol and as glycerol suspensions of individual clones in microtitre plates providing a prolonged multi-user potential. To date we have used 14 single copy probes to screen this library by colony hybridisation as well as PCR and have isolated between 1 and 5 YAC clones for every probe.