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Biomedical subjects

D G Ross

Publications and source records attributed to D G Ross.

At least 19 recordsLinked to original sources
PubMed1992

Use of the polymerase chain reaction mismatch technique to identify the HLA-DQw8 allele in patients with insulin-dependent diabetes mellitus.

The allelic forms of the HLA-DQB gene have been recognized as susceptibility markers of type 1 diabetes mellitus. One of these alleles, the DQw3.2 (DQw8), accounts for the well-documented association of the DQw3 locus with the disease. This report describes a method using the polymerase chain reaction mismatch technique to amplify the three different DQw3 allele sequences in 26 insulin-dependent diabetic patients. Primers were designed that differed only at one base at the growing end of their sequences. Using a common oligonucleotide primer located downstream in the first domain of the DQB gene and three other primers located at the other end of the sequence being amplified, it was possible to identify and distinguish the DQw8 allele from the other two closely related alleles (DQw7, DQw9). This method, which could be useful in excluding HLA-related susceptibility to diabetes mellitus, is rapid and nonisotopic, and indeed could be adapted to investigate any DNA sequence polymorphism.

Alleles↗
PubMed1992

Rapid detection and species identification of mycobacteria in paraffin-embedded tissues by polymerase chain reaction.

The sensitivity and specificity of the polymerase chain reaction (PCR) in the detection of mycobacteria in paraffin-embedded tissues and in crude lysates of mycobacterial cultures were assessed. Sections of formalin-fixed, paraffin-embedded tissues were deparaffinized and then subjected to a simple proteinase K and boiling lysis procedure. These preparations were used directly for PCR amplification of the 383 bp segment of the gene encoding the 65 kDa mycobacterial surface antigen. Crude lysates of mycobacteria were used as positive controls. The specificity of the PCR products was confirmed by Southern blot using a region-specific digoxigenin-labeled oligonucleotide probe and chemiluminescent detection. The 383 bp diagnostic fragment was visualized in 11 of 12 acid-fast bacilli (AFB) stain/culture-proven-positive blocks. Crude lysates of mycobacteria were detected to a sensitivity of approximately 80 organisms. Amplified fragments from paraffin-embedded tissues and mycobacterial cultures of M. tuberculosis, M. avium-intracellulare, and saprophytic mycobacteria were distinguished by digestion with Nar 1 restriction endonuclease. These results suggest that PCR amplification followed by restriction enzyme digestion of the PCR product is a rapid, specific, and highly sensitive technique for the detection and speciation of mycobacteria in paraffin-embedded tissues.

Base Sequence↗
PubMed1991

Human factors and computerisation in intensive care units: a review.

Current literature on the computerisation of Intensive Care Units indicates that many human factor considerations are relevant to the design and introduction of computer systems and to the evaluation of such systems within this environment. This paper aims to review and summarise essential points from the literature.

Attitude to Computers↗
PubMed1990

ABICUS: ABerdeen Intensive Care Unit System.

Specialised ICUs have improved the care of the critically ill patient, but in doing so produce a deluge of patient data. Microprocessor based systems can optimise both collection and efficient utilisation of such data. In Aberdeen we have developed a general ICU shell which is portable and can be configured to individual ICU needs. The following article describes the Aberdeen ICU System built around this shell.

Expert Systems↗
PubMed1989

Additive solution for the suspension and storage of deglycerolized red blood cells.

The additive solution, ADSOL, was evaluated for its suitability in the extended storage of previously frozen, deglycerolized red blood cells. In vitro comparison with red cells suspended in 0.2% dextrose 0.9% saline showed that ADSOL allowed for significantly enhanced adenosine triphosphate preservation throughout the storage period (greater than 2.2 mumol/g Hb beyond 14 days) and for significantly reduced hemolysis (less than 1% beyond 14 days). After 10 days of storage in ADSOL the mean recovery after transfusion was 90% (index of therapeutic effectiveness, 77%). No bacterial contamination was observed. The results suggest that this currently approved additive solution could be used to store red cells for 14 days following thawing, thus avoiding one of the principal drawbacks of frozen red cells.

Adenine↗
PubMed1989

In vitro and in vivo comparison of platelet concentrates collected by automated versus manual apheresis.

Platelet concentrates collected by continuous flow automated apheresis (Fenwal CS-3000) were compared with those collected by manual apheresis to determine whether the prolonged centrifugation and vigorous resuspension affected platelet viability and in vitro function. Paired autologous reinfusion studies (111Indium) of 5 normal donors showed no significant differences in the mean percent recoveries (50.8 +/- 7.0% vs 53.8 +/- 4.0%) or survivals (174 +/- 23 h vs 188 +/- 10 h) for platelets collected by manual versus automated apheresis. Platelets collected by automated apheresis had a significantly higher level of beta-thromboglobulin release, but there were no significant differences between platelets collected by the two methods in regard to other in vitro parameters (ATP levels, LDH released, hypotonic shock response) believed to reflect platelet activation, injury, and malfunction. These results suggest that only slight activation of platelets takes place during automated apheresis.

Adenosine Triphosphate↗
PubMed1979

Physical structures of Tn10-promoted deletions and inversions: role of 1400 bp inverted repetitions.

We report here the physical structures of deletions and inversions promoted by the translocatable tetracycline-resistance element Tn10. DNA/DNA heteroduplex and restriction enzyme analyses of alterations in the genome of bacteriophage lambda suggest that both types of DNA alterations almost always originate at the internal termini of the 1400 bp terminal inverted repetitions of Tn10. Tn10-promoted deletions remove a single contiguous DNA segment beginning at one such terminus; Tn10-promoted inversions are more complex, and involve both an inversion and a specific deletion of Tn10 DNA.

Chromosome Deletion↗
PubMed1979

Nearly precise excision: a new type of DNA alteration associated with the translocatable element Tn10.

We describe an unusual DNA alteration, "nearly precise excision," which has been identified among tetracycline-sensitive deletion derivatives of lambda phages carrying the translocatable tetracycline-resistance element Tn10. DNA sequence analysis of two such derivatives demonstrates that each retains exactly 50 bp of Tn10 material. The original junctions between lambda and Tn10 sequences remain intact; however, an internal deletion has occurred within Tn10 which eliminates all but the last few base pairs at each end of the element. This deletion occurs within a short A + T-rich inverted repeat which is present near each end of Tn10. Nearly precise excisions occur at frequencies comparable to Tn10-promoted deletions, inversions and translocations, and, like these other events, are independent of phage and bacterial functions for homologous recombination (recA, recB, red). It is not yet clear, however, whether nearly precise excisions are specifically promoted by Tn10 or whether they arise during the course of normal DNA replication processes as a consequence of unusual symmetries present in the DNA sequence at the ends of Tn10.

Base Sequence↗
PubMed1979

A paediatric ventilator with a fluidic control system.

A paediatric ventilator has been designed basically as a fluidic-logic controlled T-piece occluder. Inspiratory and expiratory time, inflation pressure limit, positive end-expiratory pressure (PEEP), continuous positive airway pressure (CPAP) and inspiratory flow-rate are controlled independently and intermittent mandatory ventilation (IMV) is available. Warning systems are provided for failure of the driving as, low airway pressure and inspiratory pressure limit. The breathing circuit is isolated from the control and warning systems for ease of sterilization.

Air Pressure↗
PubMed1979

Translocation and other recombination events involving the tetracycline-resistance element Tn10.

Insertions of Tn10 are characterized by the presence of a direct repetition of a 9-bp target gene sequence on either side the insertion. The occurrence of these repetitions undoubtedly reflects an important feature of the way in which DNA molecules are broken and joined during translocation. Our experiments further suggest, however, that these 9-bp sequences are probably not responsible for Tn10-insertion specificity and that their presence is not required for normal Tn10 translocation elsewhere. We therefore suggest that the genetic information which controls the quality and quantity of Tn10 translocation actually resides somewhere other than these 9-bp sequences. We presume that much of this information lies within the ends of Tn10 itself and that signals on the target DNA which guide Tn10 to preferred positions must occur near, but not actually at, the eventual physical site of the integration event. Consideration of Tn10-promoted deletions and inversions reemphasizes the role of these ends in Tn10-promoted recombination events. Since Tn10-promoted events almost always consist in joining the physical end of one of the putative IS sequences of Tn10 to some other DNA segment, one comes again to the conclusion that these ends must contain important genetic information governing recombination events.

Bacteriophage lambda↗
PubMed1979

The ends of Tn10 are not IS3.

By heteroduplex and hybridization analysis we showed that the inverted repetition (here called IS10) at the ends of the translocatable tetracycline resistance element Tn10 is not IS3, as had previously been reported by Ptashne and Cohen (J. Bacteriol. 122:776--781, 1975). Further analysis confirmed the homology between IS3 and the alpha beta sequence of F and demonstrated that IS10 was not present in the genomes of Salmonella typhimurium LT2 or Escherichia coli K-12.

Base Sequence↗
PubMed1979

Discharge planning.

Explore the source record for details and available documents.

Architectural Accessibility↗
PubMed1978

Properties of the translocatable tetracycline-resistance element Tn10 in Escherichia coli and bacteriophage lambda.

A number of independent insertions into bacteriophage lambda of the translocatable tetracycline-resistance element Tn10 have been isolated and characterized. The physical positions and relative orientations of several such insertions were determined. Two independent insertions appear to lie in the same orientation at or very near the same site in the cI gene, and two more lie in opposite orientations at or near the same position in or near the rex gene. Insertions in or near genes cI, rex, and cIII have been characterized genetically for their effects on expression of nearby genes. Tn10 appears to exert a polar effect on expression of distal genes when it is inserted within an operon, even when expression of that operon is under the influence of lambda N-function. In addition, Tn10 insertions in rex appear to influence in some way expression of an "upstream" gene, cI. Lambda derivatives carrying Tn10 give rise to spontaneously occurring, tetracycline-sensitive deletions at high frequencies. It is likely that formation of these deletions is promoted in some way by the Tn10 element. Lambda::Tn10 phages carrying a Tn10 element that has undergone several successive cycles of translocation since its first isolation and characterization have been analyzed. The results confirm that Tn10 often retains its physical and functional integrity during many cycles of translocation. Lambda derivatives carrying Tn10 have been used to generate insertions of Tn10 in the chromosome of Escherichia coli. This process is independent of recA function, and seems to be quite analogous to the translocation of Tn10 in Salmonella typhimurium as studied previously.

Coliphages↗