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Biomedical subjects

D O'Brien

Publications and source records attributed to D O'Brien.

At least 91 records · Page 5Linked to original sources
PubMed1988

Prevention of postoperative pericardial adhesions with hydrophilic polymer solutions.

Pericardial adhesions subject patients requiring cardiac reoperation to potential injuries of the heart, great vessels, and extracardiac grafts during resternotomy. We evaluated polyvinylpyrrolidone (PVP) and a methlycellulose derivative (MCD) as intraoperative irrigating solutions in the prevention of postoperative pericardial adhesions. Fifteen dogs weighing 15 to 20 kg were divided into three equal cohorts and subjected to left thoracotomy with pericardiotomy. Prior to surgical manipulation, the pericardial cavity was irrigated with either PVP, MCD, or Ringer's lactate (RL). Serosal injury stimulating intraoperative trauma was induced by gauze sponge abrasion of the epicardium and inner surface of the pericardium and by allowing desiccation of serosal surfaces for 30 min. The pericardial cavity was evaluated for adhesion formation 6 weeks postoperatively by reoperation. Two independent observers, unaware of the study solution, evaluated the extent and severity of pericardial adhesions on a 0-4 scale. All dogs in the RL control group had surgically significant adhesions and a mean adhesion score of 3.2 +/- 1.1. In contrast, no PVP- or MCD-treated dog had surgically significant adhesions. The mean adhesion scores were 0.2 +/- 0.4 for PVP and 0.5 +/- 0.7 for MCD. Our results indicate that PVP (P less than 0.004) and MCD (P less than 0.024) significantly reduce pericardial adhesion formation when compared to RL. Clinical application of PVP or MCD for the prevention of pericardial adhesions should reduce morbidity and mortality of cardiac reoperation.

Animals↗
PubMed1988

Neurogenic disorders of micturition.

Anatomic considerations of micturition are reviewed as well as the effects of lesions at various levels on the urinary system as a whole. Proper diagnostic approach, interpretation of results, and recommendations for therapy are outlined to aid the practitioner in handling neurogenic disorders of micturition.

Animals↗
PubMed1987

Diagnosis of pre-type I diabetes.

Islet cell antibodies were found in 71 of 1169 first-degree relatives (6.1%) from 448 families who had a proband with type I diabetes. Seven children have since become insulin dependent. All had islet cell antibodies and were followed up prospectively with measurement of first-phase insulin production during intravenous glucose tolerance testing. In this group the statistical probability of developing type I diabetes within 12 months with 95% confidence was found to be 59% to 100% when the first-phase insulin secretion was less than 25 microU/mL. The identification of the prediabetes time period should allow an opportunity for intervention in the underlying disease process to determine if the onset of type I diabetes can be altered.

Adolescent↗
PubMed1987

Respirable dust control in grinding gray iron castings.

High speed grinding of gray iron castings long has been associated with excessive exposure to crystalline silica. Not all workers engaged in these operations are protected by conventional ventilation techniques. Dust in the air that has been entrained by the spinning grinding wheel and not captured in the grinder hood has been postulated to be a major exposure source. A pilot grinding operation was constructed, and the size distribution and concentration of airborne particles were measured with the aerodynamic particle sizer (APS). Various control measures proved effective in reducing the respirable dust concentration: increased exhaust ventilation, and installation of baffles and/or the use of an air jet to deflect the entrained air stream. The concentration of respirable dust is the breathing zone was reduced approximately 20-fold through the combined use of increased ventilation, interior baffles, and an air jet. The air jet and baffle utilized at the base ventilation rate reduced the respirable dust concentration by a factor of three to four, whereas the baffle alone halved the concentration.

Air Pollutants, Occupational↗
PubMed1986

Recovery of hormonal regulation in protein kinase defective adrenal cells through DNA-mediated gene transfer.

A cAMP-resistant mutant (Kin-8) isolated from Y1 mouse adrenocortical tumor cells harbors a specific lesion in the regulatory subunit of the type 1 cAMP-dependent protein kinase. This mutant also is resistant to the effects of corticotropin and cAMP on steroidogenesis, growth and morphology, suggesting an obligatory role for the protein kinase in regulation of adrenocortical functions. In this study, the cAMP-resistant phenotype of the Kin-8 mutant was reverted by transformation with DNA from cAMP-responsive Y1 cells, and the biochemical basis of the transformation was explored. Initially, Y1 mouse adrenocortical tumor cells were evaluated for their competence as recipients in DNA-mediated transformation experiments, by measuring their ability to incorporate and express a bacterial gene (neo) encoding resistance to neomycin. Y1 cells were transfected with the plasmid pSV2-neo (an SV40-neo hybrid vector designed for expression in animal cells) and screened for resistance to the neomycin analog, G418. Neomycin-resistant transformants were recovered from Y1 cells at a frequency of approximately one per 10(3) cells per 10 micrograms of DNA, and had specific neo sequences integrated into their high molecular weight (mw) DNA. The Y1 mutant, Kin-8, then was transformed with pSV2-neo DNA plus high mw DNA prepared from cAMP-responsive Y1 cells. Cells competent for transformation were recovered by selective growth in the neomycin analog G418, and these transformants were screened for recovery of morphological responses to cAMP. Several colonies capable of rounding up in the presence of cAMP were recovered after transformation with DNA from Y1 cells. These transformants also recovered the ability to round up in the presence of corticotropin, and were able to respond to both corticotropin and cAMP with increased steroidogenesis. Transformants generated from either Y1 or Kin-8 cells were unstable. Y1 cells lost resistance to neomycin when grown in the absence of G418 at a frequency of 4% per generation. Similarly, Kin-8 transformants lost their sensitivity to cAMP in subsequent culture passages. In some of the cAMP-responsive transformants, cAMP-dependent protein kinase activity was recovered and approached the activity seen in cAMP-responsive Y1 cells. The recovery of a normal protein kinase by transformation appeared to have been sufficient to reverse the cAMP-resistant phenotype of Kin-8 cells. In other cAMP-responsive transformants, protein kinase activity was not appreciably affected by cAMP.(ABSTRACT TRUNCATED AT 400 WORDS)

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1986

Size and concentration measurement of an industrial aerosol.

Several real-time particle sizing instruments were evaluated for measuring the size distribution and concentration of the aerosol produced during the high speed grinding of gray iron castings. Aerosol was sampled in the airstream entrained by the motion of a spinning grinding wheel in a pilot grinding operation. Measurement methods based on differing physical principles were selected for evaluation and compared: particle inertia (aerodynamic particle sizer and quartz crystal microbalance cascade impactor); light scattering (laser aerosol spectrometer); and projected-area microscopy (scanning electron microscope). Inferences of aerodynamic diameter based on measurements by the laser aerosol spectrometer consistently undersized that determined by the aerodynamic particle sizer by a factor of 1.5. Estimates of aerodynamic diameters from projected area diameters determined by scanning electron microscopy differed from those obtained by the aerodynamic particle sizer by a factor of 2. Differences appeared to be a non-linear function of particle diameter. Estimates of respirable mass determined from mass-weighted particle size spectra varied by a factor of 6 between the largest estimate (scanning electron microscope) and the smallest estimate (laser aerosol spectrometer).

Aerosols↗
PubMed1986

The roles of cAMP and cAMP-dependent protein kinase in the regulation of adrenocortical functions: analysis using DNA-mediated gene transfer.

DNA-mediated gene transfer was used to evaluate the cause and effect relationship between mutations in cAMP-dependent protein kinase activity and cellular resistance of adrenocortical tumor cells to ACTH and cAMP. Protein kinase defective, Kin 8 adrenocortical tumor cells were transformed with genomic DNA from an ACTH- and cAMP-responsive adrenocortical cell line and screened for the recovery of morphological responses to the cAMP analog 8-bromo-cAMP (8BrcAMP). 8BrcAMP-responsive transformants were recovered with a frequency of approximately 0.5 per 10(3) transformation-competent cells. These transformants recovered the ability to round up in the presence of ACTH and were able to respond to both ACTH and 8BrcAMP with increased steroidogenesis. They also recovered cAMP-dependent protein kinase activity. The transformants, however, were unstable and concomitantly lost cAMP-dependent protein kinase activity and steroidogenic and morphological responses to ACTH and 8BrcAMP. These observations suggest that a single gene, probably the gene encoding the regulatory subunit of cAMP-dependent protein kinase, is responsible for the resistance of the Kin 8 mutant to ACTH and cAMP.

Adrenal Cortex Neoplasms↗
PubMed1985

Expression of the cloned subunits of bacterial luciferase from separate replicons.

The lux A and lux B genes of Vibrio harveyi, encoding the alpha and beta subunits of bacterial luciferase, were cloned individually into Escherichia coli in two different compatible plasmids. Active luciferase was formed in an amount equal to that produced in cells carrying a plasmid with the cloned genes on a single fragment.

DNA, Recombinant↗
PubMed1985

Fibre-optic assessment of tracheal tube position. A comparison of tracheal tube position as estimated by fibre-optic bronchoscopy and by chest X-ray.

The distance between the tip of a tracheal tube and the carina was measured in twenty five patients who required tracheal intubation and artificial ventilation of the lungs. Two methods of evaluation of this distance--limited-optic bronchoscopy and chest X-ray--were compared. There was no significant difference between the distance measured by either method. The advantages of checking tracheal tube placement by fibre-optic bronchoscopy are discussed.

Adult↗
PubMed1984

Evaluation of an undergraduate nursing course.

During the past two decades there has been a substantial growth in the number of British universities and polytechnics offering undergraduate nursing degree programmes. However, little attempt has been made to evaluate these courses systematically or to assess the potential impact of graduates on the provision of patient care. This study is concerned with the opinions of former undergraduates and ward sisters with experience of supervising the undergraduate nursing students. It also gives an account of the career progression of the students since graduation. The results indicate that the high academic and clinical demands made upon the students are a major problem and that a number of students encounter serious problems of adjustment during clinical placements. The ward sisters consistently rated the students' clinical abilities as high and the vast majority would like undergraduates allocated to their wards if a similar course was run again in the future. The career progression of the graduates demonstrates that the majority opt for clinical nursing posts.

Education, Nursing, Baccalaureate↗
PubMed1983

Epidural buprenorphine for pain relief after major abdominal surgery. A controlled comparison with epidural morphine.

In a controlled trial epidural buprenorphine was compared with epidural morphine as the sole means of analgesia after major abdominal surgery. Bolus injections of buprenorphine 60 micrograms in 10 ml or morphine 2 mg in 10 ml of normal saline were given on demand for the first 48 hours postoperatively. Both drugs produced significant reduction in pain scores as assessed by the linear visual analogue scale and both produced prolonged analgesia at this dosage, which could be extended by further 'top-ups'. The authors conclude that, for postoperative epidural analgesia, buprenorphine may be the opiate of choice and the reasons for this are discussed.

Adult↗