Search PubMed⌕ Search

Biomedical subjects

W A Scott

Publications and source records attributed to W A Scott.

At least 37 records · Page 2Linked to original sources
PubMed1997

Successful treatment of severe dysrhythmias in infants with respiratory syncytial virus infections: two cases and a literature review.

OBJECTIVES: To describe severe myocardial manifestations in two infants with respiratory syncytial virus infection and to review published literature reporting cardiac involvement in patients with respiratory syncytial virus disease. DESIGN: Case report and literature review. SETTING: Tertiary care pediatric intensive care unit (ICU). PATIENTS: Two infants admitted to the pediatric ICU for dysrhythmias and severe myocardial dysfunction and infected with respiratory syncytial virus. INTERVENTIONS: Conventional cardiovascular, antidysrhythmic, and respiratory support, as well as extracorporeal membrane oxygenation and high-frequency oscillatory ventilation. MEASUREMENTS AND MAIN RESULTS: Both patients had respiratory syncytial virus infections and clinical evidence of severe myocarditis, with dysrhythmias, cardiomegaly, and cardiogenic shock. Both infants survived their hospitalizations. To our knowledge, these two patients are the first reported cases of myocarditis in infants with respiratory syncytial virus infection. CONCLUSIONS: Severe myocardial dysfunction and dysrhythmias may accompany respiratory syncytial virus infection in some infants and may be reversible with aggressive supportive therapy.

Anti-Arrhythmia Agents↗
PubMed1996

Otitis in a weaned pig: a new pathological role for Actinobacillus (Haemophilus) pleuropneumoniae.

A weaned pig exhibiting clinical signs characteristic of a vestibular syndrome (abnormal head tilt and abnormal gait including a tendency to circle) was examined as a representative example of a condition which, in a 12-month period, affected approximately 400 other pigs on the farm of origin. The condition caused significant morbidity and financial loss but the directly attributable mortality was negligible. Post mortem examination revealed a severe suppurative, left-sided otitis media and interna. Mixed growths of bacteria, including Actinobacillus pleuropneumoniae, were isolated from the pus from the middle ear. Otitis caused by mixed bacterial infections has been described previously in pigs and cattle but infection of the porcine middle ear cavity by A pleuropneumoniae is considered to be a new pathological role for this organism. Other findings in this case indicated that otitis media had followed from bacterial colonisation of the auditory (Eustachian) tube. The condition was effectively controlled by prophylactic antibiotic therapy. The authors consider that vestibular syndrome due to otitis media and interna, whether caused by infection with A pleuropneumoniae or not, is probably a relatively common condition in England but its significance may be underestimated and for this reason it may be underrecorded.

Actinobacillus Infections↗
PubMed1996

Evaluation of an infectivity standard for real-time quality control of human immunodeficiency virus type 1 quantitative micrococulture assays. Participating Laboratories of The AIDS Clinical Trials Group.

Quantitative microculture assays of cryopreserved human immunodeficiency virus type 1-infected cell suspensions and culture supernatants were compared among seven assays sites. There was no significant change in titer during 1 year of storage. The overall standard deviation for infected cell suspensions was approximately 0.8 log10 virus titer. A method for detecting deviant assay results was developed and was used to identify two donor cell preparations (n = 54) that gave consistently low titers.

Cell Culture Techniques↗
PubMed1996

Injection techniques and use in the treatment of sports injuries.

Corticosteroid injections are powerful, effective adjuncts in treating exercise-related musculoskeletal injuries. This article describes a variety of different injection techniques that can be applied to many types of injuries. Specific attention is placed on knowing the exact location of the injury, so the injection can be properly administered. The injections were applied to a variety of chronic conditions that 'seem to fail all the usual conservative measures'. The vast majority had an excellent response to the injections and were able to progress with the rehabilitation programme. The effectiveness of the injections is primarily dependent on 'hitting the target site', and following the injections with a comprehensive rehabilitation programme.

Adrenal Cortex Hormones↗
PubMed1995

Arterial oxygenation during one-lung ventilation. A comparison of enflurane and isoflurane.

BACKGROUND: Because maintaining arterial oxygenation (PaO2) during one-lung ventilation (OLV) can be a clinical problem, it is useful to be aware of factors that influence PaO2 in this situation and are under the control of the anesthesiologist. It is unknown whether, among the commonly used volatile anesthetic agents, one is associated with higher PaO2 levels. Clinical studies suggest that isoflurane provides superior PaO2 during OLV than does halothane. These have not been compared to enflurane. The authors studied PaO2 and hemodynamics during OLV with 1 MAC enflurane versus 1 MAC isoflurane. METHODS: Twenty-eight adults who had prolonged periods of OLV anesthesia with minimal trauma to the nonventilated lung (thoracoscopic or esophageal surgery) were studied in a cross-over design. Patients were randomized to two groups: Group 1 received 1 MAC enflurane in oxygen from induction until after the first 30 min of OLV, then were switched to 1 MAC isoflurane. In group 2, the order of the anesthetics was reversed. RESULTS: Isoflurane was associated with higher PaO2 values during OLV (P < 0.0001). Mean PaO2 (+/- SD) after 30 min OLV isoflurane was 231 (+/- 125) mmHg versus 184 (+/- 106) mmHg after 30 min OLV enflurane. The difference in PaO2 between the two anesthetics was most marked in the patients with the highest PaO2 during OLV: PaO2 isoflurane PaO2 enflurane varies; is directly proportional to PaO2 isoflurane (r = 0.65, P < 0.001). There were no other significant differences between anesthetic gases in the measured hemodynamic or respiratory variables. In the subgroup of patients with pulmonary artery catheters (n = 7), PaO2 correlated with cardiac output during OLV for both anesthetics (r = 0.81, P < 0.001). CONCLUSIONS: During OLV, the PaO2 values with 1 MAC isoflurane were greater than those with enflurane. The dependence of PaO2 on cardiac output does not support the hypothesis that an increase in cardiac output will cause a decrease in hypoxic pulmonary vasoconstriction and a decrease in PaO2 during OLV.

Adult↗
PubMed1994

Catalytically distinct conformations of the ribonuclease H of HIV-1 reverse transcriptase by substrate cleavage patterns and inhibition by azidothymidylate and N-ethylmaleimide.

The RNase H activity of recombinant HIV-1 reverse transcriptase (RT) has been characterized with respect to inhibition by azidothymidylate (AZTMP) and N-ethylmaleimide (NEM) and to cleavage patterns using either poly(rA)/poly(dT) or poly(rG)/poly(dC) as model substrate and either Mg2+ or Mn2+ as divalent cation activator. The inhibitory potency of AZTMP and other nucleotide analogues was found to be dependent on both the composition of the substrate and the divalent cation. The enzyme was significantly more sensitive to AZTMP inhibition with poly(rG)/poly(dC) than with poly(rA)/poly(dT) as substrate and in Mn2+ than in Mg2+ with either substrate. Kinetic studies indicated that AZTMP is a competitive inhibitor with respect to the substrate in Mn2+ whereas it behaves as an uncompetitive inhibitor in Mg2+. These results suggest that the enzyme may exist in two distinct forms depending on whether Mg2+ or Mn2+ is the divalent cation activator. Consistent with this suggestion is the alteration in the mode of cleavage of the substrate upon substitution of Mg2+ with Mn2+. In Mg2+, hydrolysis of poly(rA)/poly(dT) appears to be solely endonucleolytic, whereas in Mn2+, hydrolysis is both endonucleolytic and exonucleolytic. With poly(rG)/poly(dC) as substrate, hydrolysis is both endonucleolytic and exonucleolytic in either Mg2+ or Mn2+. There is a positive correlation between sensitivity to AZTMP and production of mononucleotides, suggesting that the exonuclease activity of RNase H is preferentially inhibited by AZTMP. The sensitivity of RNase H to inhibition by N-ethylmaleimide was also found to be markedly influenced by the substrate composition and the divalent cation activator, being most sensitive under conditions in which endonucleolytic activity predominates.(ABSTRACT TRUNCATED AT 250 WORDS)

Catalysis↗
PubMed1994

Sedation for upper gastrointestinal endoscopy: a comparison of alfentanil-midazolam and meperidine-diazepam.

The authors studied the efficacy and cost of substituting sedation using midazolam and alfentanil for the existing regimen of diazepam and meperidine in patients requiring upper gastrointestinal endoscopy. Sixty consenting subjects were randomized to receive either meperidine 50 mg with diazepam approximately 90 micrograms.kg-1 (Group D) or alfentanil 250 micrograms with midazolam approximately 50 micrograms.kg-1 (Group M). Endoscope insertion time, patient acceptance, apnoeic or desaturation episodes were noted by a physician observer. Pulse oximetry was used to monitor heart rate and oxygen saturation (SpO2) during endoscopy. Subjects performed four-choice reaction time (4CRT) tests before, 30 and 60 min after endoscopy, and were assessed for nausea or dizziness and their ability to stand and walk. During endoscopy, insertion time was shorter (84 +/- 45 sec vs 122 +/- 83 sec, P < 0.03) and fewer aversive movements occurred (0.4 +/- 0.6 vs. 1.7 +/- 2.4, P < 0.005) in Group M than Group D. No subject in either group suffered any apnoea or prolonged desaturation requiring supplemental oxygen. Irrespective of treatment group, greater decreases in SpO2 (6.1 +/- 3.4% vs 3.6 +/- 2.2% P < 0.001) occurred in subjects > 45 yr of age than in subjects < or = 45 yr. During recovery 4CRT values at 30 min after endoscopy were longer (723 +/- 226 msec vs 594 +/- 139 msec, P < 0.005) in Group M than in Group D but not after 60 min. It was concluded that the small differences in endoscopy conditions and greater sedation during the first 30 min of recovery did not justify the additional cost of using midazolam and alfentnil.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1994

Clinical and immunological correlates of immune-complex-dissociated HIV-1 p24 antigen in HIV-1-infected children.

It has been reported that HIV-1 p24 antigen (p24 Ag) detection is improved after dissociation of immune complexes using acid treatment (ICD assay). In order to evaluate the clinical significance of p24 Ag detected by the standard assay and by the ICD assay in pediatric patients, we related these measurements to clinical status, level of p24 antibody, and percentage of CD4+ lymphocytes. Fifty-nine plasma specimens from 20 symptomatic HIV-1-infected children, collected prospectively over a 1-year period, were tested for these markers. Plasma was collected at the beginning of zidovudine therapy and approximately 7 and 12 months thereafter. Compared with the standard assay, the ICD assay showed a higher number of samples positive for p24 Ag (78% versus 34%) and an increase in the levels of p24 Ag (median value of 129 versus 24 pg/ml). The anti-p24 antibody level was inversely correlated with the p24 Ag level measured by either assay. Four children negative for p24 Ag by both assays had a stable clinical course. In contrast, 50% of the children negative by the standard assay but positive for ICD p24 Ag and 75% of the children positive by both assays had progression of disease. No patients were positive by the standard assay but negative by the ICD assay. Children whose plasma tested positive by both assays had lower percentages of lymphocytes that were CD4+ by comparison with children who were negative by both assays; children whose plasma tested positive only by the ICD assay formed an intermediate group.(ABSTRACT TRUNCATED AT 250 WORDS)

Antigen-Antibody Complex↗
PubMed1993

Evaluation of temporary atrial pacing leads.

Thirty-five patients were randomized to receive either the Medtronic 6500 or one of two braided multifilament temporary pacing leads in the atrium following open heart surgery. Sensing performance was judged by amplitude, slew rate, and the proportion of patients with an adequate sensing threshold. Pacing performance was assessed with measures of impedance, threshold voltage, current, and energy. The Medtronic 6500 demonstrated superior sensing and lower energy consumption compared to braided multifilament leads. This type of lead may offer advantages when using atrial synchronous temporary pacing systems.

Adolescent↗
PubMed1992

Superiority of a vertical sternal lead for detection of arrhythmias during ambulatory electrocardiographic monitoring.

In a preliminary study comparing 7 sets of bipolar leads with standard modified V1 and V5 leads, a vertical sternal lead system with the negative lead just below the suprasternal notch, and the positive lead over the xiphoid had the greatest P-wave area. In the current study, the vertical sternal and modified V1 leads were obtained simultaneously using 2-channel ambulatory electrocardiographic recorders in 50 consecutive patients undergoing diagnostic ambulatory electrocardiography for suspected arrhythmias. The vertical sternal lead provided tracings with a larger P-wave area compared with that of the modified V1 (0.58 +/- 0.44 vs 1.23 +/- 0.69 mm2; p less than 0.0001), and a greater QRS complex (9.23 +/- 4.16 vs 11.78 +/- 4.90 mm; p = 0.006). During premature atrial contractions and supraventricular tachycardia, P-wave visibility was significantly better in the sternal lead than in V1 (p less than 0.001). Furthermore, sternal lead tracings were superior with regard to overall quality and noise level. It is suggested that the vertical sternal lead replace the currently used modified V1 during ambulatory electrocardiographic monitoring. This lead system in conjunction with the standard modified V5 lead should be useful in the differential diagnosis of atrial arrhythmias.

Adolescent↗
PubMed1992

Quantitative analysis of human immunodeficiency virus type 1 antibody reactivity by western immunoblots: evaluation of relative antibody levels in seropositive individuals and mothers.

A quantitative analysis of antibody responses to human immunodeficiency virus type 1 (HIV-1) proteins using Western immunoblots and 125I-labeled protein A is reproducible and can be validated. The antibody levels obtained by Western immunoblots were compared with stoichiometric p24 radioimmunoassay over a wide range of antibody (correlation coefficient, .94; P less than .001). Antibody levels to gp160 and gp120 were validated using purified antigens. Analysis of antibody levels from 31 seropositive individuals revealed a statistically significant correlation between antibody levels to p24 and the other viral proteins except gp120. Anti-gag p24 antibody was strongly correlated with antibodies to other env products, specifically gp41 and gp160. Using the validated assay, HIV-1-infected mothers of infants were found to have highly variable levels of antibody to all viral proteins. Mothers of infected infants did not differ significantly from mothers of uninfected infants in antibody pattern or levels to any viral protein including gp120.

Adult↗