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PubMed1990

[Evaluation of FCR (Fuji Computed Radiography) images applied to standard radiography for the diagnosis of chest diseases].

FCR (Fuji Computed Radiography) was added to plain chest radiography in order to evaluate its image characteristics and to determine the best image characteristics and to determine the best image processing program by comparing the visibility of shadows on conventional X-rays and on six FCR hard copy images processed by six mutually different image processing program. FCR showed excellent ability to visualize abnormal lung shadows as well as normal chest structures when processed by a moderate spatial frequency enhancement (spatial frequency 0.11 cycle/mm, level of enhancement). FCR also proved superior to the conventional film-screen system in the visualization of hilar and mediastinal structure as well as lung shadows. The effects of the image processing program on the visibility of shadow, granular and linear shadows were clearly demonstrated when a more intense spatial frequency enhancement (spatial frequency 0.18 cycle/mm, level of enhancement) was performed. The same results were obtained in terms of reticular and linear shadows and calcified lesions. On the contrary, low density shadows with poorly defined margins the lung field and infiltrates from mycoplasma pneumonia were well depicted by a program with a slightly steeper gradation (gamma; 1.0) and minimal frequency enhancement. Accordingly, FCR was found to be useful for the screening of abnormal chest X-ray shadows whereas it was also likely to demonstrate the best image when processed by the most appropriate image processing programs, depending on the characteristics of the shadows.

Adult↗
PubMed1999

A role for ADP ribosylation factor in the control of cargo uptake during COPI-coated vesicle biogenesis.

ARF-mediated hydrolysis of GTP has been demonstrated to regulate coat disassembly of Golgi-derived COPI transport vesicles (Tanigawa, G., Orci, L., Amherdt, M., Ravazzola, M., Helms, J.B. and Rothman, J.E. (1993) J. Cell Biol. 123, 1365-1371). In addition, a requirement for GTP hydrolysis at an early stage of COPI vesicle biogenesis has been established since cargo uptake is impaired in the presence of GTPgammaS (Nickel, W., Malsam, J., Gorgas, K., Ravazzola, M., Jenne, N., Helms, J.B. and Wieland, F.T. (1998) J. Cell Sci. 111, 3081-3090), a non-hydrolyzable analogue of GTP. We now demonstrate that the GTPase involved in the regulation of cargo uptake is ARF, revealing a multi-functional role of this GTPase in COPI-mediated vesicular transport. The molecular mechanism of cargo uptake as well as the functional implications of these findings on the overall process of COPI vesicle biogenesis are discussed.

ADP-Ribosylation Factors↗
PubMed1989

Breakage--reunion and copy choice mechanisms of recombination between short homologous sequences.

To study recombination between short homologous sequences in Escherichia coli we constructed plasmids composed of the pBR322 replicon, M13 replication origin and a recombination unit inserted within and inactivating a gene encoding chloramphenicol resistance. The unit was composed of short direct repeats (9, 18 or 27 bp) which flanked inverted repeats (0, 8 or 308 bp) and a gene encoding kanamycin resistance. Recombination between direct repeats restored a functional chloramphenicol resistance gene, and could be detected by a simple phenotype test. The plasmids replicated in a double-stranded form, using the pBR322 replicon, and generated single-stranded DNA when the M13 replication origin was activated. The frequency of chloramphenicol-resistant cells was low (10(-8)-10(-4] when no single-stranded DNA was synthesized but increased greatly (to 100%) after induction of single-stranded DNA synthesis. Recombination between 9 bp direct repeats entailed no transfer of DNA from parental to recombinant plasmids, whereas recombination between 18 or 27 bp repeats entailed massive transfer. The presence or length of inverted repeats did not alter the pattern of DNA transfer. From these results we propose that direct repeats of 9 bp recombine by a copy choice process, while those greater than or equal to 18 bp can recombine by a breakage-reunion process. Genome rearrangements detected in many organisms often occur by recombination between sequences less than 18 bp, which suggests that they may result from copy choice recombination.

Base Sequence↗
PubMed1999

Assessment of pollutant emissions from dry-process photocopiers.

Processes involved in pollutant emissions from a dry-process photocopier have been investigated in a controlled room dynamic environmental chamber. Volatile organic compound (VOC) emissions occurred at a constant rate dependent on copy speed. However, VOC emission rates per copy were increased by increases in chamber temperature (e.g., a 20% increase resulted from increasing temperature from 23 degrees C to 32 degrees C) or changing from single- to double-sided operation (40% increase). Respirable particle emissions occurred under copier-idle mode (probably from residues in the machine) as well as with copying. No significant chamber sink effects were observed for VOCs or respirable particles. Small emissions of nitrogen dioxide, ozone and formaldehyde were observed but were difficult to interpret. A procedure for assessing pollutant emissions from photocopiers is recommended.

Air Pollution, Indoor↗
PubMed1998

The mouse gene encoding the testis-specific isoform of Poly(A) binding protein (Pabp2) is an expressed retroposon: intimations that gene expression in spermatogenic cells facilitates the creation of new genes.

The gene encoding the testis-specific isoform of mouse poly(A) binding protein (Pabp2) has been isolated and sequenced. Unexpectedly, comparison of the sequence of genomic and cDNAs demonstrated that the Pabp2 gene lacks introns, whereas all other functional Pabp genes in plants, amphibians, and mammals contain introns. Thus, the mouse Pabp2 gene is a retroposon, created by synthesizing a reverse transcriptase copy of a processed mRNA and inserting the copy into the genome. The Pabp2 retroposon is unusual because it is functional: previous work demonstrates that its promoter drives the accumulation of Pabp2 mRNA in meiotic and early haploid spermatogenic cells, and the Pabp2 mRNA encodes a protein whose size and RNA-binding specificities are characteristic of PABP in plants, yeast, and mammals (Kleene et al. 1994). Two novel factors can be implicated in the retention of function of the Pabp2 retroposon. First, the promoter of the Pabp2 gene is not derived from its intron-containing progenitor, Pabp1. Second, mRNAs encoding somatic PABP isoform, PABP1, are present at high levels in meiotic and haploid spermatogenic cells. Both features contrast with the phosphoglycerate kinase 2 retroposon, which is believed to compensate for the depletion of the somatic isoform due to X-chromosome inactivation in meiotic spermatogenic cells. We also document that more functional retroposons are expressed in meiotic and haploid spermatogenic cells than in any other tissue and speculate that transcriptional derepression in spermatogenic cells favors the creation of expressed retroposons.

Amino Acid Sequence↗
PubMed1990

Immunochemical evidence for intramolecular interaction of the carboxy terminal A alpha-appendages of plasma fibrinogen.

A monoclonal antibody (Mab), 45J, which reacts with intact fibrinogen, has been employed to demonstrate the interaction of the carboxy terminal regions of the A alpha-chain in non-denatured plasma fibrinogen. The 45J Mab recognizes an epitope in the mid section of the carboxy terminal end of the A alpha chain. The epitope is destroyed by plasmin and trypsin digestion. The 45J Mab and a horseradish peroxidase conjugate of the 45J Mab (45J-HRP) were used in an ELISA to demonstrate that the antibody could recognize two copies of the same epitope on purified fibrinogen or denatured plasma fibrinogen. Fibrinogen in non-denatured plasma could not be detected by this single antibody ELISA. This immunochemical study demonstrates that only one copy of the epitope on the C-terminal protuberance of the A alpha-chain is exposed in non-denatured plasma. However, once the plasma fibrinogen has been denatured, as in the purification process, both copies of the epitope are available for antibody binding. This finding suggests that in plasma there is an intramolecular interaction between the carboxy terminal ends of the fibrinogen A alpha-chains which can be destroyed by denaturation.

Antibodies, Monoclonal↗
PubMed1997

Different domains of mammalian ADP-ribosylation factor 1 mediate interaction with selected target proteins.

Mammalian ADP-ribosylation factor 1 (mARF1) is a small GTP-binding protein that is activated by a Golgi guanine nucleotide exchange factor. Once bound to the Golgi membranes in the GTP form, mARF1 initiates the recruitment of the adaptor protein 1 (AP-1) complex and coatomer (COPI) onto these membranes and activates phospholipase D1 (PLD1). To map the domains of mARF1 that are important for these activities, we constructed chimeras between mARF1 and Saccharomyces cerevisiae ARF2, which functions poorly in all of these processes except COPI recruitment. The carboxyl half of mARF1 (amino acids 95-181) was essential for activation by the Golgi guanine nucleotide exchange factor, whereas a separate domain (residues 35-94) was required to effectively activate PLD1 and to promote efficient AP-1 recruitment. Since residues 35-94 of mARF1 are critical for optimal activity in both PLD1 activation and AP-1 recruitment, we hypothesize that this region of ARF contains residues that interact with effector molecules.

ADP-Ribosylation Factors↗
PubMed2001

Variations in the emissions of volatile organic compounds from the toner for a specific photocopier.

A laboratory thermal desorption apparatus was used to measure emissions from a number of nominally identical photocopier toners--manufactured to meet the specifications of one specific model copier--when these toners were heated to fuser temperature (180-200 degrees C). The objective was to assess how potential volatile organic compound (VOC) emissions from the toner for a given copier can vary, depending upon the production run and the supplier. Tests were performed on a series of toner (and associated raw polymer feedstock) samples obtained directly from a toner manufacturer, representing two production runs using a nonvented extrusion process, and on toner cartridges purchased from two local retailers, representing three different production lots (histories unknown). The results showed that the retailer toners consistently had up to 350% higher emissions of some major compounds (expressed as microgram of compound emitted/g of toner), and up to 100% lower emissions of others, relative to the manufacturer toners (p < or = 0.01). The manufacturer toners from one production run had emissions of certain compounds, and of total VOCs, that were modestly higher (13-18%) than those from the other run (p < or = 0.01). The emission differences between the retailer and manufacturer toners are probably due to differences in the manufacturing processes and/or feedstocks used to produce the toners from these different sources.

Air Pollution, Indoor↗
PubMed1991

A practical technique for the fabrication of transparent bite mark overlays.

A quick, inexpensive, and accurate technique for generating transparent overlays, using office photocopy machines, for use in bite mark case analysis is presented. The critical step in the fabrication process involves determination of the accuracy of the product produced by the photocopy machine. A reliable method for making such a determination is discussed.

Bites, Human↗
PubMed1996

Copy-choice recombination mediated by DNA polymerase III holoenzyme from Escherichia coli.

Formation of deletions by recombination between short direct repeats is thought to involve either a break-join or a copy-choice process. The key step of the latter is slippage of the replication machinery between the repeats. We report that the main replicase of Escherichia coli, DNA polymerase III holoenzyme, slips between two direct repeats of 27 bp that flank an inverted repeat of approximately equal 300bp. Slippage was detected in vitro, on a single-stranded DNA template, in a primer extension assay. It requires the presence of a short (8 bp) G+C-rich sequence at the base of a hairpin that can form by annealing of the inverted repeats. It is stimulated by (i) high salt concentration, which might stabilize the hairpin, and (ii) two proteins that ensure the processivity of the DNA polymerase III holoenzyme: the single-stranded DNA binding protein and the beta subunit of the polymerase. Slippage is rather efficient under optimal reaction conditions because it can take place on >50% of template molecules. This observation supports the copy-choice model for recombination between short direct repeats.

Base Sequence↗
PubMed1996

Fluorescence resonance energy transfer analysis of ribozyme kinetics reveals the mode of action of a facilitator oligonucleotide.

A defining characteristic of catalysts is the rate at which they can process multiple copies of substrate. In the case of synthetic hammerhead ribozymes that cleave an RNA sequence, binding of the ribozyme to the substrate and products is through base-paired duplexes. The kinetics of formation and dissociation of these duplexes can determine the turnover of the ribozyme. We have followed these processes in real time by using fluorescent labels that can interact through fluorescence resonance energy transfer (FRET). This approach has been used to identify the rate-limiting steps for a particular ribozyme and to reveal how turnover was improved by a facilitator oligonucleotide. It was found that dissociation of the ribozyme-substrate complex is faster than cleavage to products. Hence, to undergo cleavage, most substrate molecules must interact with a ribozyme more than once. In the presence of a facilitator oligonucleotide, the complex is stabilized so that cleavage is faster than dissociation. Under these circumstances, cleavage of the substrate becomes the most likely outcome following binding to the ribozyme.

Base Sequence↗
PubMedDate not supplied

Reproduction of radiologic images on plain paper.

Skyrocketing health care costs and pressures from managed care have combined to promote cost-cutting strategies in radiology and radiation oncology departments. A study was conducted to evaluate the use of a high-resolution laser printer for printing plain-paper images as substitutes for both original and duplicate radiologic film images. A variety of radiologic images were used to evaluate the image reproduction capabilities of the printer in terms of linearity, detail, and contrast. In many cases, printed images had a quality comparable to that of the original images. Six computed tomographic (CT) scans and six radiation therapy simulator radiographs were compared with printed reproductions by each of seven board-certified radiation oncologists, who rated the reproductions as acceptable for documentation, acceptable for diagnostic purposes (CT scans only), or unacceptable. Ninety-five percent of printed CT images and 90% of printed simulation images were rated acceptable for documentation. The quality of printed images of radiation therapy port films was not quantitatively measured but was improved by adjusting image contrast and brightness and using various image enhancement techniques. The use of printed images is less expensive than that of processed film and eliminates the environmental, time, storage, and delivery problems associated with film. Technologic advances in imaging, networking, and printing have made possible the inexpensive duplication of medical images.

Copying Processes↗
PubMed1975

[Neonatal information system II: computer-adapted examination form for the newborn (author's transl)].

For the documentation of the neonatal status we use computer-adapted optic mark reader forms since 1972. All important symptoms and signs are scheduled on two sheets and are assigned by pencil marking. The forms can be read automatically and are suitable for data processing. A copy remains in the patients clinical file and can be used like a conventionally written status. The mark reader forms improved singificantly our knowledge about the newborn's status. The problems of introducing the new documentation into the hospital routine are reported.

Computers↗
PubMed1987

Variable copy number DNA sequences in rice.

We have cloned two types of variable copy number DNA sequences from the rice embryo genome. One of these sequences, which was cloned in pRB301, was amplified about 50-fold during callus formation and diminished in copy number to the embryonic level during regeneration. The other clone, named pRB401, showed the reciprocal pattern. The copy numbers of both sequences were changed even in the early developmental stage and eliminated from nuclear DNA along with growth of the plant. Sequencing analysis of the pRB301 insert revealed some open reading frames and direct repeat structures, but corresponding sequences were not identified in the EMBL and LASL DNA databases. Sequencing of the nuclear genomic fragment cloned in pRB401 revealed the presence of the 3'rps12-rps7 region of rice chloroplast DNA. Our observations suggest that during callus formation (dedifferentiation), regeneration and the growth process the copy numbers of some DNA sequences are variable and that nuclear integrated chloroplast DNA acts as a variable copy number sequence in the rice genome. Based on data showing a common sequence in mitochondria and chloroplast DNA of maize (Stern and Lonsdale 1982) and that the rps12 gene of tobacco chloroplast DNA is a divided gene (Torazawa et al. 1986), it is suggested that the sequence on the inverted repeat structure of chloroplast DNA may have the character of a movable genetic element.

Base Sequence↗
PubMedDate not supplied

An evaluation of line quality in photocopied signatures.

Qualified forensic document examiners from Canada, USA, Great Britain and Australia participated in this study. They were sent one photocopied signature, together with a set of original known standards to evaluate the line quality of the photocopied signature and compare these characteristics with the standards. They were asked to assess the photocopies for the presence of tremor, hesitation, pen lifts, patching, blunt initial or terminal strokes, and abrupt changes in direction. The authors compared the assessments with the corresponding original signatures. It was possible to determine which line quality characteristics were the most difficult to detect, which indicia of simulation were concealed and what anomalies were introduced by the photocopying process. Results indicated that line quality characteristics can be identified in average quality photocopies. Furthermore, accurate judgements can be made regarding similarities and differences in line quality when comparing a photocopied signature with original known standards. In a few instances, ink line morphology was problematic when striation patterns and ink gooping were misinterpreted as pen lifts, hesitation and patching on the photocopies.

Copying Processes↗
PubMed1997

Manual and computer-aided space analysis: a comparative study.

Recently, computers have been used to measure key landmarks from photocopies of upper and lower study models to increase simplicity, accuracy, and informatics. This is a comparative study to evaluate the accuracy and reliability of computer-aided space analysis. Data were collected from a series of randomly selected study models. All subjects had Angle Class I molar relationships with minor malocclusions such as crowding, rotations, or diastemas. Two investigators independently measured teeth on models with a Vernier gauge that had sharpened caliper tips. Intraexaminer and interexaminer reliability was determined at 0.2 mm. All teeth, to and including the first molars, were measured. Two photocopies of each set of models were made on a photostat machine (Xerox, Japan) and were coded. A template with a ruler was used, to allow the investigator to compensate for any reduction or enlargement error during the photocopying process. The mesiodistal sizes were measured with a digitizer, and results were processed by using a dedicated computer program. Evaluations were done in a double-blind manner. The nonparametric Wilcoxon signed rank test for paired observations to compare median differences between measurements was used. Intraexaminer digitized measurements were almost identical and differed (p < 0.0001) for only one measurement. However, interexaminer manual and digitized measurements differed significantly (p < 0.001) for 20 of the 24 teeth. Nineteen of these digitized tooth measurements were smaller. The mean arch length measurements differed by 4.7 mm (p < 0.0001) in the maxilla and by 3.1 mm (p < 0.0001) in the mandible. The difference between the manual and digitized analyses may be due to the photocopying process. The inability to accurately measure a three-dimensional study cast that has been duplicated in two dimensions, convex structure of teeth, curve of Spee, tooth inclination, and tooth position may play a role. The computer-aided measuring system is reliable, but accurate mesiodistal measurements cannot be made from photocopies of dental models. Manual measurements that use a calibrated gauge produce the most accurate, reliable, and reproducible results.

Calibration↗
PubMed1996

Maintaining confidentiality: health care's ongoing dilemma.

Confidentiality of patient information is an ethical obligation of health care professionals. The exercise of confidentiality is not a simple process; it is dynamic rather than static and must be upgraded with changes in technology. This article discusses some of the common issues that arise in maintaining confidentiality in the health care environment, including spoken and written breaches of confidentiality, use of the computer, confidentiality as an ethical rather than legal obligation, and the use of programs in health care institutions to maintain confidentiality.

Attitude of Health Personnel↗