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Biomedical subjects

C S Evans

Publications and source records attributed to C S Evans.

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

Antimicrobial action of essential oils: the effect of dimethylsulphoxide on the activity of cinnamon oil.

Fifty-one essential oils extracted from plants of known origin were tested for their antimicrobial activity against three bacteria, Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli and four yeasts, Torulopsis utilis, Schizosaccharomyces pombe, Candida albicans and Saccharomyces cerevisiae using the drop diffusion method. All showed antimicrobial activity against at least one of the micro-organisms. Following this preliminary screening, 13 essential oils showing antimicrobial activity against at least five of the micro-organisms were tested in the range 50 micrograms ml-1 to 500 micrograms ml-1 using broth micro dilution techniques with dimethylsulphoxide (DMSO) as a dispersing solvent. The concentration of most of the oils required for total inhibition of growth was > 500 micrograms ml-1. Further studies on the antimicrobial action of cinnamon oil in the range 10-150 micrograms ml-1 showed that 50-fold higher activity was found when no dispersing solvent was used.

Anti-Bacterial Agents↗
PubMed1997

Out-of-hospital transfusion.

Although issues regarding the provision of transfusions in nonhospital settings are still unresolved, there is now a considerable body of experience with such transfusions and a growing consensus that there are acceptable ways to make the service available to carefully selected patients. Besides the core of published information on the subject, there is ongoing interest and a comparison of experiences occurring at meetings such as those of the AABB and state organizations such as the California Blood Bank Society. These formal and informal exchanges of information by blood centers, hospitals, and outpatient facilities continue to improve the quality achieved by those just embarking on out-of-hospital transfusion programs and those already experienced in this approach. The ultimate beneficiaries of all this shared quality improvement are those patients for whom high-quality out-of-hospital transfusion is not only appropriate but even preferable to inpatient care.

Ambulatory Care↗
PubMed1995

Reducing blood donor exposures in low birth weight infants by the use of older, unwashed packed red blood cells.

We performed a prospective, randomized masked trial to determine whether the use of dedicated units of packed red blood cells equipped with seven satellite bags would reduce donor exposures in infants with birth weights < 1500 gm. We also examined the use of unwashed and older red blood cells. Red blood cells given to the study group were used without washing and until their expiration date (35 to 42 days). Changes in blood pH, potassium, ionized calcium, and hemoglobin were determined with each transfusion and compared with data collected from a control group that received washed, younger red blood cells. There was a 64% reduction in donor exposures in the study group. Changes in infants' blood pH and calcium levels with transfusion were the same in the two groups. There was a clinically unimportant difference in potassium levels. A greater rise in hemoglobin values occurred when washed cells were used. There was no correlation between changes in the blood levels measured and the age of unwashed cells infused. We conclude that the use of red blood cells from satellite bag-equipped dedicated units decreases donor exposures, and that the practices of using only younger red blood cells and of saline washing of red blood cells before infusion, are unwarranted.

Blood Donors↗
PubMed1994

Anisaldehyde and Veratraldehyde Acting as Redox Cycling Agents for H(2)O(2) Production by Pleurotus eryngii.

The existence of a redox cycle leading to the production of hydrogen peroxide (H(2)O(2)) in the white rot fungus Pleurotus eryngii has been confirmed by incubations of 10-day-old mycelium with veratryl (3,4-dimethoxybenzyl) and anisyl (4-methoxybenzyl) compounds (alcohols, aldehydes, and acids). Veratraldehyde and anisaldehyde were reduced by aryl-alcohol dehydrogenase to their corresponding alcohols, which were oxidized by aryl-alcohol oxidase, producing H(2)O(2). Veratric and anisic acids were incorporated into the cycle after their reduction, which was catalyzed by aryl-aldehyde dehydrogenase. With the use of different initial concentrations of either veratryl alcohol, veratraldehyde, or veratric acid (0.5 to 4.0 mM), around 94% of veratraldehyde and 3% of veratryl alcohol (compared with initial concentrations) and trace amounts of veratric acid were found when equilibrium between reductive and oxidative activities had been reached, regardless of the initial compound used. At concentrations higher than 1 mM, veratric acid was not transformed, and at 1.0 mM, it produced a negative effect on the activities of aryl-alcohol oxidase and both dehydrogenases. H(2)O(2) levels were proportional to the initial concentrations of veratryl compounds (around 0.5%), and an equilibrium between aryl-alcohol oxidase and an unknown H(2)O(2)-reducing system kept these levels steady. On the other hand, the concomitant production of the three above-mentioned enzymes during the active growth phase of the fungus was demonstrated. Finally, the possibility that anisaldehyde is the metabolite produced by P. eryngii for the maintenance of this redox cycle is discussed.

Journal Article↗
PubMed1994

Efficacy of pre-emptive analgesia and continuous extrapleural intercostal nerve block on post-thoracotomy pain and pulmonary mechanics.

OBJECTIVE: Thoracotomy results in severe pain and deleterious changes in pulmonary physiology. The literature suggests that these alterations in pulmonary mechanics are inevitable and can only be minimised but not prevented by effective analgesia. We have re-evaluated this concept and assessed the efficacy of pre-emptive analgesia [preincisional afferent block, premedication with opiate and/or non-steroidal anti-inflammatory drug (NSAID)] in conjunction with postoperative extrapleural continuous intercostal nerve block on postoperative pain and pulmonary function. MATERIALS AND METHODS: A prospective randomized study was conducted on 56 patients undergoing elective thoracotomy. Subjective pain relief was assessed on a linear visual analogue scale. Pulmonary function was measured on the day before operation and 12 hourly for 48 hours after operation. There were seven patients in each of the eight groups. RESULTS: The balanced analgesia group comprising preincisional block and premedication with opiate and NSAID (Group 1) had significantly better analgesia, needed less postoperative supplementary analgesics and maintained their preoperative pulmonary function postoperatively irrespective of the nature of the operation. The ranking of importance of the three components of the pre-emptive analgesia as assessed in this study are preincisional block, opiate premedication and premedication with NSAID's. No significant change in plasma levels of cortisol or glucose occurred in Group 1 patients from prior to induction of anaesthesia to 24 hours postoperatively, suggesting effective somatic and sympathetic afferent blockade had been achieved in these patients. There were no complications related to the infusion or the use of NSAID's. CONCLUSIONS: We conclude that a balanced analgesic regime comprising preoperative pain prophylaxis and postoperative maintenance analgesia by NSAID and continuous extrapleural intercostal nerve block will minimise and even reverse the expected decline in lung function after thoracotomy. The postoperative decline in lung function is not obligatory but primarily due to incisional pain and thus is preventable by effective analgesia. An ideal balanced pre-emptive analgesic regime should include preincisional local anaesthetic afferent block and premedication with opiates and a NSAID:

Administration, Rectal↗
PubMed1993

Continuous intercostal nerve block versus epidural morphine for postthoracotomy analgesia.

Twenty patients undergoing elective thoracotomy were randomized into two groups, receiving either lumbar epidural morphine (n = 10) or continuous extrapleural intercostal nerve block (n = 10). Subjective pain relief was assessed on a linear visual analogue scale. Pulmonary function (peak expiratory flow rate, forced expiratory volume in 1 second, and forced vital capacity) was measured on the day before operation and daily for 4 days after operation. Pulse oximetry monitoring was used to determine the incidence of hypoxemia. No significant difference was observed between the groups concerning pain relief (except at 28 hours, in favor of the intercostal nerve block group), respiratory performance, or arterial oxygen saturation. Vomiting, pruritus, and urinary retention occurred only in the epidural group, whereas nausea occurred significantly less frequently in the extrapleural group. We conclude that after thoracotomy continuous extrapleural intercostal nerve block is as effective as lumbar epidural morphine in reducing postoperative pain and restoring pulmonary mechanics. Because of the significantly lower complication rates we favor continuous extrapleural intercostal nerve block for postthoracotomy analgesia.

Adult↗
PubMed1992

Comparative evaluation of supplemental hepatitis C virus antibody test systems.

Implementation of routine blood donor screening using anti-hepatitis C virus (HCV) enzyme immunoassay (EIA) has resulted in an urgent need for well-characterized supplemental assays to confirm the presence of HCV antibodies. A comparative study of four commercially available supplemental assays is reported here: first- and second-generation versions of a strip recombinant immunoblot assay (RIBA-1 and RIBA-2), an HCV neutralization EIA, and HCV neutralization plus synthetic peptide EIA. Three hundred sixty-seven blood donor specimens that were repeatedly reactive on HCV EIA were studied. Most specimens (93%) were also evaluated by radioimmunoassay (RIA) with a six-antigen panel, and 60 selected specimens were tested for HCV RNA by the polymerase chain reaction (PCR). RIBA-1 and RIBA-2 gave concordant results with 86 percent of specimens, while an additional 13 percent were correctly classified by RIBA-2 but not RIBA-1. Neutralization EIA alone correctly identified 94 percent of the study group, while the remaining 6 percent required the peptide EIA or the combined neutralization-peptide assay system for correct classification. The RIBA-2 and neutralization-peptide assay system for correct classification. The RIBA-2 and neutralization-peptide assay systems yielded identical results for 86 percent of specimens, and these results were supported by RIA and selected PCR testing. Only 2 specimens (0.5%) were frankly discrepant, while 51 specimens were indeterminate on either (47) or both (4) assays. When either the RIBA-2 or neutralization-peptide assay yielded an indeterminate interpretation, the other system correctly classified the specimen (based on concordance with RIA and PCR data) in a high proportion (92%) of cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Viral↗
PubMed1992

Impact of specimen handling and storage on detection of hepatitis C virus RNA.

Direct detection of hepatitis C virus (HCV) RNA in serum or plasma is useful for validating the performance of anti-HCV assays and for the discrimination of persons with persistent HCV infections from those with resolved infections. Quantitation of HCV RNA may also be useful for disease prognosis and therapeutic monitoring. Previous studies have reported detection of HCV RNA in 50 to 70 percent of blood donors who were positive on anti-HCV supplemental tests. There is concern that specimen processing and storage conditions might influence the stability, and hence the detectability, of HCV RNA. To address this concern, the rate of detection of HCV RNA by the polymerase chain reaction (PCR) using donor pilot tube sera (PTS) previously subjected to routine donor screening and supplemental testing was compared with HCV PCR results obtained with fresh-frozen plasma (FFP) derived from the same donations. All 16 anti-HCV supplemental test-positive donations evaluated were HCV RNA positive with FFP, whereas only 10 (62.5%) were positive with PTS (p = 0.024). None of 11 FFP or PTS samples from HCV enzyme immunoassay-reactive donations not confirmed by supplemental anti-HCV assays tested positive for HCV RNA. Direct comparison of sample type (serum vs. plasma) and various storage conditions using specimens from two seropositive donors showed that room-temperature storage results in marked reduction in HCV RNA signal, while replicate freezing and thawing caused a moderate reduction. These data indicate that well-controlled sample processing and storage conditions are critical to the sensitive and potentially quantitative analysis of HCV RNA.

Blood Preservation↗
PubMed1990

Oxygen saturation during general anaesthesia in the dental chair. A comparison of the effect of position on saturation.

Oxygen saturation was measured in 135 children requiring general anaesthesia for multiple dental extractions. These were dental chair anaesthetics administered in a community dental clinic. Sessions were assigned to either sitting or supine, producing two groups for comparison. Saturation was monitored continuously for the duration of the procedure. There was no significant difference in the saturation changes of the two groups. Experience and familiarity with working in either position in the dental chair was found to be a key factor in avoiding problems for both the anaesthetist and the operator.

Adolescent↗
PubMed1985

Kikuchi's necrotizing lymphadenitis.

Kikuchi's necrotizing lymphadenitis has recently been reported in the United States where it has not previously been recognized. In the past year three cases were seen in a community hospital in San Francisco. The histologic appearance and clinical features were felt to be sufficiently characteristic to be diagnostic.

Adult↗
PubMed1984

Necrobiotic granulomas of the uterine cervix. A probable postoperative reaction.

Three cases of necrobiotic granulomas of the uterine cervix occurring in patients with a history of previous cervical surgery are described. This distinctive lesion histologically resembles a rheumatoid nodule but is not associated with infection or connective tissue disease. The clinicopathologic features of these cases are virtually identical to analogous postoperative lesions that have been described in the prostate. Such necrobiotic granulomas seem to be a result of prior surgery and should not be confused with other more portentous granulomatous diseases.

Adult↗