Library

Notes: Abstract Comparative genomic in situ hybridization (CGH) provides a new possibility for searching genomes for imbalanced genetic material. Labeled genomic test DNA, prepared from clinical or tumor specimens, is mixed with differently labeled control DNA prepared from cells with normal chromosome complements. The mixed probe is used for chromosomal in situ suppression (CISS) hybridization to normal metaphase spreads (CGH-metaphase spreads). Hybridized test and control DNA sequences are detected via different fluorochromes, e.g., fluorescein isothiocyanate (FITC) and tetraethylrhodamine isothiocyanate (TRITC). The ratios of FITC/TRITC fluorescence intensities for each chromosome or chromosome segment should then reflect its relative copy number in the test genome compared with the control genome, e.g., 0.5 for monosomies, 1 for disomies, 1.5 for trisomies, etc. Initially, model experiments were designed to test the accuracy of fluorescence ratio measurements on single chromosomes. DNAs from up to five human chromosome-specific plasmid libraries were labeled with biotin and digoxigenin in different hapten proportions. Probe mixtures were used for CISS hybridization to normal human metaphase spreads and detected with FITC and TRITC. An epifluorescence microscope equipped with a cooled charge coupled device (CCD) camera was used for image acquisition. Procedures for fluorescence ratio measurements were developed on the basis of commercial image analysis software. For hapten ratios 4/1, 1/1 and 1/4, fluorescence ratio values measured for individual chromosomes could be used as a single reliable parameter for chromosome identification. Our findings indicate (1) a tight correlation of fluorescence ratio values with hapten ratios, and (2) the potential of fluorescence ratio measurements for multiple color chromosome painting. Subsequently, genomic test DNAs, prepared from a patient with Down syndrome, from blood of a patient with Tcell prolymphocytic leukemia, and from cultured cells of a renal papillary carcinoma cell line, were applied in CGH experiments. As expected, significant differences in the fluorescence ratios could be measured for chromosome types present in different copy numbers in these test genomes, including a trisomy of chromosome 21, the smallest autosome of the human complement. In addition, chromosome material involved in partial gains and losses of the different tumors could be mapped to their normal chromosome counterparts in CGH-metaphase spreads. An alternative and simpler evaluation procedure based on visual inspection of CCD images of CGH-metaphase spreads also yielded consistent results from several independent observers. Pitfalls, methodological improvements, and potential applications of CGH analyses are discussed.

Notes: Abstract We report on multicolor fluorescence in situ hybridization protocols for the simultaneous visualization of deletion-prone regions for carrier detection of Duchenne/ Becker (DMD/BMD) muscular dystrophy. Cosmid and yeast artificial chromosome (YAC) clones specific for preferentially deleted subregions of the dystrophin gene were labeled differentially and detected with three different fluorochromes using digital imaging microscopy. This approach allows for an assessment of the carrier status of female relatives even in families where no index patient is available. Cosmid and YAC clones, and different probe-generation protocols are compared with respect to their feasibility for carrier detection. The use of histone-depleted interphase nuclei (Halo-preparations) for deletion mapping is demonstrated and shown to have a resolution power of 5 kb.

Notes: We obtain phase space representations of the Poincaré group for zero mass particles of all helicities, including photons. A natural quantization scheme for massless particles arises, and a covariant phase space localization operator is found. © 1996 American Institute of Physics.

Notes: The formulation of the uncertainty principle based on entropy is given with the (noncommuting) observables described via positive operator-valued measures.

Notes: We report the molecular characterization and the detailed study of the recombinant maltooligosyl trehalose synthase mechanism from the thermoacidophilic archaeon Sulfolobus acidocaldarius. The mts gene encoding a maltooligosyl trehalose synthase was overexpressed in Escherichia coli using the T7-expression system. The purified recombinant enzyme exhibited optimum activity at 75°C and pH 5 with citrate–phosphate buffer and retained 60% of residual activity after 72 h of incubation at 80°C. The recombinant enzyme was active on maltooligosaccharides such as maltotriose, maltotetraose, maltopentaose and maltoheptaose. Investigation of the enzyme action on maltooligosaccharides has brought much insight into the reaction mechanism. Results obtained from thin-layer chromatography suggested a possible mechanism of action for maltooligosyl trehalose synthase: the enzyme, after converting the α-1,4-glucosidic linkage to an α-1,1-glucosidic linkage at the reducing end of maltooligosaccharide glc(n) is able to release glucose and maltooligosaccharide glc(n−1) residues. And then, the intramolecular transglycosylation and the hydrolytic reaction continue, with the maltooligosaccharide glc(n−1) until the initial maltooligosaccharide is reduced to maltose. An hypothetical mechanism of maltooligosyl trehalose synthase acting on maltooligosaccharide is proposed.

Notes: This paper examines the perception of moral issues in nursing as presented in the literature and in themes of meetings, discussions and study days devoted to the subject. It offers an account of moral issues perceived by nursing students and qualified nurses as being relevant to discussions of moral aspects in nursing. The second part of this paper presents a closer examination of the problems related to professional truth telling and deception as an illustration of an ‘everyday’ moral issue in nursing and in health care generally.

Notes: On political consciousness in nurses The argument presented in this paper centres around the proposition that all nurses need to develop their critical abilities in the understanding and analysis of the socio-economic and political background to the services of which they are a part as a potentially powerful group of health care workers.The topics under examination in this paper, The Welfare State, Social Thought and Social Planning and Politics of Health Care, are used as examples to demonstrate the kind of critical understanding which nurses need to acquire in order to deal with some of the fundamental assumptions that influence their work either directly or indirectly.From the argument follows the conclusion that it is an illusion, and possibly a dangerous one, if nurses continue to believe in the unpolitical nature of nursing as a professional activity.

Notes: The classical limit (h-dash-bar)→0 of stochastic quantum mechanics is investigated. An algebra of stochastic classical observables is canonically associated to the algebra of stochastic quantum observables with a product inherited from sequential instruments and also with a Lie commutator. It is shown that the sharp-point limit (limit of no stochasticity), which implies (h-dash-bar)→0, yields the usual algebra of classical observables.