Biomedical subjects
R Sutherland
Publications and source records attributed to R Sutherland.
Adults' understanding of young children's testimony.
In many legal settings, judges and jurors must gain an understanding of a crime solely on the basis of a child's testimony. In the present experiment, the authors examined adults' ability to understand young children's accounts of a past event. Adults were given a transcript of an interview with a 3- and a 6-year-old child. In addition, half of the adults were given a summary of the event (informed) and half were not (naive). All adults were asked to extract as many details as possible from the transcripts. Naive adults were also asked to write a paragraph summarizing what happened during the event. Overall, adults gleaned more information from transcripts of 6-year-olds than from transcripts of 3-year-olds. Furthermore, naive adults were more accurate than informed adults. The authors concluded that adults' ability to understand children's testimony increases as a function of the child's age and may be impaired rather than enhanced by additional sources of information.
Postantibiotic and post-beta-lactamase inhibitor effects of amoxicillin plus clavulanate.
The postantibiotic effect (PAE) of amoxicillin-clavulanate was studied for strains of Staphylococcus aureus, Haemophilus influenzae, Moraxella catarrhalis, Klebsiella pneumoniae, and Escherichia coli. A PAE of approximately 2 h was seen for beta-lactamase-positive and -negative strains of S. aureus following 2 h of exposure to twice the MIC and did not increase at 16 times the MIC. The PAE observed with H. influenzae was clearly related to the growth rate of the organism. A PAE of 0.8 h was found for amoxicillin (four times the MIC) against a beta-lactamase-negative strain of H. influenzae (generation time, 26.3 min) and a PAE of 1.74 h was found for amoxicillin-clavulanate (twice the MIC) against a beta-lactamase-positive strain (generation time, 32.2 min). When the beta-lactamase-positive strain was growing more slowly (generation time, 120 min), the PAE of amoxicillin-clavulanate increased to > 3.32 h. The PAE of amoxicillin-clavulanate at 2/1 micrograms/ml on a beta-lactamase-producing strain of M. catarrhalis was > 2.9 h, and, as expected, the PAEs of twice the MIC on K. pneumoniae and E. coli were generally short (< 1 h). The post-beta-lactamase inhibitor effect (PLIE), determined after removal of only clavulanate, was also examined for beta-lactamase-positive strains. This was more prolonged (approximately 3 to 4 h) than the corresponding PAE for S. aureus, H. influenzae, and M. catarrhalis. The PLIE was related to the amount of beta-lactamase produced and required the presence of amoxicillin in the initial exposure period. These data may have implications for reducing the dosage of amoxicillin-clavulanate.
Managing cancer through synergy. Radiation and molecular medicine.
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Pathology of MHV-A59 infection in beta 2 microglobulin negative mice.
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The response of human dermal microvascular endothelial cells to hypoxia.
Dermal microvascular endothelial cells (DMEC) exposed to hypoxic conditions show a rapid induction of several proteins that do not increase in other cell types placed in a similar environment. These DMEC proteins differ from the well-characterized stress proteins that have been observed in a wide variety of cultured cell types. The DMEC proteins are induced rapidly, within 2-4 h, and are expressed transiently. They include a group of acidic proteins (pI approximately 5-5.2) with molecular weights in the range 100,000-120,000 and at least one glycoprotein (pI 5.1, M(r) 57,000) that is probably expressed on the cell surface. In some primary DMEC cell strains, this response is accompanied by a transient overall increase in protein synthesis. The oxygen-regulated proteins (ORP) that are induced in most other cell types under hypoxic conditions show little variation in their rate of synthesis in DMEC within the first 24 h. The response of DMEC differs from that of umbilical vein endothelial cells (UVEC) and from spindle-shaped cells derived from DMEC, that show a response to hypoxia that is similar to most other cell types. The changes seen in DMEC proteins take place in the same time scale as ischemia-reperfusion injury and may reflect the specialized change of functions of the microvasculature observed under conditions of hypoxic stress in vivo.
The effect of position and different manoeuvres on internal jugular vein diameter size.
Internal jugular vein (IJV) cannulation is a popular approach for central venous access as it has few complications, of which failure to locate the vein and carotid artery puncture are the most common. A variety of manoeuvres and body positioning has been used to maximise IJV size and thereby increase cannulation success rate and decrease complications. Realtime 2D ultrasound can be used to view neck vascular anatomy in vivo and allow IJV size to be measured. Thirty-five volunteers had the lateral diameter of their IJV measured using the SiteRite ultrasound machine to discover the most effective methods of increasing its diameter. No correlation was found between the IJV lateral diameter and subject height, weight, age or neck circumference. Carotid artery palpation and full neck extension reduced its diameter considerably. Increasing Trendelenberg increased diameter. Abdominal binder and the Valsalva manoeuvre were the most efficient methods of increasing its size.
Is this the way forward?
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Day surgery in Wales.
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Circumvention of tamoxifen resistance by the pure anti-estrogen ICI 182,780.
Both primary and acquired resistance to the growth-inhibitory effects of anti-estrogens (e.g., tamoxifen) limits the clinical usefulness of these drugs in the treatment of breast cancer. The new, steroidal anti-estrogen ICI 182,780 was tested for its ability to inhibit the proliferation of a tamoxifen-resistant variant of the parental MCF-7 human breast-cancer cell line. Two cell lines cloned from the MCF-7 line were used for these experiments: a tamoxifen-sensitive line, MCF 5-21, and a tamoxifen-resistant line, MCF 5-23. Compared with tamoxifen, ICI 182,780 appeared to be 150 and 1540 times more effective in inhibiting cell growth in the 5-21 and 5-23 sub-lines respectively. ICI 182,780 completely circumvented tamoxifen resistance at a concentration of (5 to 10) x 10(-9) M in this model. Based on IC50 concentrations, the 5-23 line was 22-fold more resistant to tamoxifen than the 5-21 line, but only 2-fold more resistant to ICI 182,780, reducing relative resistance by 10-fold in the resistant line. There were no differences in ER parameters between the 2 lines. ER numbers/cell were: 40500 and 34800 and the KD 0.48 and 0.15 x 10(-9) M in the 5-21 and 5-23 cells respectively. In the 5-23 cells, the concentrations of ICI 182,780 and tamoxifen resulting in a 50% inhibition of 3H-estradiol binding were 2.3 x 10(-8) M and 1 x 10(-6) M, respectively (cf. estradiol 0.89 x 10(-9) M). Thus, one potential mechanism for the increased effectiveness of ICI 182,780 may relate to the increased affinity of this drug for the estrogen receptor as compared with tamoxifen.
Viraemia in Egyptian children with hepatitis E virus infection.
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Bacterial resistance to beta-lactam antibiotics: problems and solutions.
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Physiological and psychological responses to a university fitness session.
The purpose of this study was to examine the physiological and psychological responses to a university fitness session entitled 'popmobility'. A popmobility session consists of 20 min of aerobic activities, 5 min of local muscular endurance exercises and 5 min of flexibility exercises. Ten regular participants of these sessions, women of mean(s.d.) age 21.2(1.5) years, took part in the study. A maximal oxygen uptake (VO2max) treadmill test was performed by each subject to obtain VO2max and maximum heart rate values. In a laboratory, heart rate and VO2 were measured throughout a popmobility session for each subject. Rate of perceived exertion (RPE) was measured every 5 min throughout the session. The mean intensity of the aerobic part of the session ranged from 67.7-82.6% of the subject's VO2max (mean of 76.4% VO2max). The mean heart rate reserve for the aerobic section was 75.6%. While the relative oxygen consumption remained fairly static during the aerobic section, the RPE score rose. The mean(s.d.) total energy expenditure was 236.6(28.4) kcal (range 203-288). The popmobility session is of adequate intensity to improve the aerobic fitness of its participants. Heart rate, as used as a measure of intensity during a popmobility session, would appear to be a fairly accurate indicator of intensity. However, the use of RPE for exercise prescription in popmobility sessions is inappropriate. Popmobility could also be useful in a weight-reduction programme.
Mandatory drug testing: boon for public safety or launch of a witch-hunt?
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Medicine without moralizing is the aim of Montreal's "street doctors".
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Activity of amoxycillin-clavulanic acid against Legionella pneumophila in vitro and in an experimental respiratory infection model.
Amoxycillin and clavulanic acid show good activity against Legionella pneumophila in vitro, and synergy has been observed between the two agents. However, in tissue culture studies, amoxycillin was inactive against intracellular legionellae, whereas clavulanic acid and amoxycillin plus clavulanic acid were as effective as erythromycin in preventing bacterial growth. These latter findings were reflected in the results of therapy of a L. pneumophila pneumonia in the neutropenic rat. Amoxycillin was ineffective in reducing bacterial counts in the lungs of infected animals, but clavulanic acid and amoxycillin-clavulanic acid produced bactericidal effects similar to those of erythromycin. The data illustrate the bactericidal activity of amoxycillin-clavulanic acid and clavulanic acid against intracellular L. pneumophila in contrast to the lack of activity of amoxycillin.
Bactericidal effects of co-amoxiclav (amoxycillin clavulanic acid) against a Legionella pneumophila pneumonia in the immunocompromised weanling rat.
To evaluate the activity of co-amoxiclav (amoxycillin/clavulanic acid) against Legionella pneumophila in vivo, a model of L. pneumophila pneumonia was developed in weanling rats rendered leukopenic by pre-administration of cyclophosphamide. Assessment of therapy was by lung bacterial counts and histological examination. Amoxycillin was ineffective in reducing bacterial counts in the lungs of infected rats, whereas erythromycin, the standard agent, was significantly more effective (P < 0.01). Co-amoxiclav and erythromycin, administered parenterally, produced significant bactericidal effects (P < 0.01), reducing the counts of L. pneumophila strain 1624 at 96 h to 1.2 log10 cfu/lungs compared with counts of 6 log10 cfu/lungs in the untreated animals. Clavulanic acid was also highly effective in preventing development of the infection, and was as efficacious as co-amoxiclav. Because of the significant reduction in bacterial numbers, a marked reduction in inflammation and consolidation of lung tissue was seen in rats treated with erythromycin, clavulanic acid or co-amoxiclav. The activity of co-amoxiclav was no greater than clavulanic acid alone, and no synergy was noted between the two components. When therapy was delayed until 48 h after infection, co-amoxiclav was as effective as erythromycin, with both treatments reducing bacterial numbers to 3.3 and 3.6 log10 cfu/lungs by 96 h, after only two days of therapy, in comparison with non-treated rats (5.6 log10 cfu/lungs). In a prolonged infection, produced by extending the period of leucopenia, co-amoxiclav and erythromycin were equally effective in preventing growth of the organism, with 1.5 and 1.6 log10 cfu/lungs, respectively, present at 96 h, in contrast to the non-treated rats with 5.7 log10 cfu/lungs (P < 0.01). After cessation of therapy, regrowth of L. pneumophila occurred in the erythromycin-treated group to such a degree that by 168 h, lung viable counts from these rats were significantly higher (4.8 log10 cfu/lungs) than in co-amoxiclav-treated rats (2.1 log10 cfu/lungs) (P < 0.05). Oral therapy of this infection with erythromycin or clavulanic acid, either alone or in combination with amoxycillin, resulted in counts of 3.3, 3.6 and 3.5 log10 cfu/lungs at 96 h, respectively. Although oral therapy was significantly less effective than parenteral therapy (P < 0.05), the bacterial counts in the treated groups were significantly lower than in the non-treated animals. The data show that co-amoxiclav displayed bactericidal activity consistently against intracellular L. pneumophila in vivo.