Biomedical subjects
D G Ross
Publications and source records attributed to D G Ross.
'They are not proper doctors, are they?'.
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A search for mycobacterial DNA in sarcoidosis using the polymerase chain reaction.
The etiology of sarcoidosis is unknown, but mycobacteria have been considered as a possible etiologic agent. The authors used the polymerase chain reaction (PCR) to search for mycobacterial DNA in paraffin-embedded granulomatous tissues from patients with sarcoidosis. The target sequence used for PCR amplification is a 383-base pair segment of the gene encoding the 65 kD mycobacterial surface antigen. This assay can detect Mycobacterium tuberculosis and atypical mycobacteria in archival material. Its sensitivity, which is superior to Ziehl-Nielsen staining for acid-fast bacilli, is 1 bacterium per 2500 cells. Ten sarcoidosis blocks and 10 normal controls were negative with mycobacterial PCR but positive with beta-actin PCR, indicating the presence of amplifiable DNA. Mycobacterial PCR gave positive results for six acid-fast bacilli stain/culture-positive blocks from patients with tuberculosis. These results indicate that sarcoidosis probably does not represent an active mycobacterial infection. These data also suggest that mycobacterial PCR is helpful in differentiating tuberculosis and sarcoidosis.
Antibiotic therapy: a guide to adverse effects.
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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.
Missing O-ring causes unrecognised large gas leak.
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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.
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.
A new PVDF sensor for fluidic gas analysis.
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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.
Vecuronium and McArdle's disease.
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Fibreoptic intubation and double-lumen tubes.
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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.
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.
Evaluation of hemoglobin screening methods in prospective blood donors.
This study evaluates the performance characteristics of the copper sulfate screening test in routine bloodmobile operations and compares the performance of the copper sulfate test with that of a miniphotometer method of hemoglobin measurement. The copper sulfate and miniphotometer tests provide equivalent pass/fail classification of male donors with a high sensitivity and total efficiency. For female donors, both test methods show substantially lower sensitivity and total efficiency than for male donors; however, the miniphotometer is significantly more sensitive than the copper sulfate test in identifying eligible female donors. The distribution of donor hemoglobin values relative to cutoff values for acceptance may explain the male-female differences in screening test performance characteristics.
Papillary mucinous cystadenoma of probable renal pelvic origin in a horseshoe kidney.
A 59-year-old woman underwent a partial nephrectomy to remove a 7-cm cystic mass involving the left portion of a horseshoe kidney. Microscopically, the cyst was lined by tall columnar mucosecretory cells resembling endocervical cells. The lesion is believed to represent the benign counterpart of mucinous adenocarcinoma of the renal pelvis.
Disciplining the impaired nurse.
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Fluidic cycling devices for inspiratory and expiratory timing in automatic ventilators.
The theoretically desirable characteristics of fluidic timing devices for use in automatic ventilators are discussed. The principal limitation of most timers described is the separate control of inspiratory and expiratory time. It is more convenient to have one control for frequency and a separate control for I:E ratio. Two new circuits are described which allow this independent adjustment of frequency and I:E ratio.