Sodium hydrogen bis(phenoxyacetate).
In the title compound, Na(+) x H(+) x [2C(8)H(7)O(3)](-), the anion contains a short Speakman-type hydrogen bond [O...O = 2.413 (2) A]. The anions and the Na atoms lie across twofold axes.
Journal Article↗
Biomedical subjects
J Evans
Publications and source records attributed to J Evans.
Iris melanomas: are they more frequent in New Zealand?
Explore the source record for details and available documents.
Adult↗
Cardiovascular effects of hydrocortisone in preterm infants with pressor-resistant hypotension.
OBJECTIVE: To study the cardiovascular effects of hydrocortisone in preterm infants with hypotension unresponsive to volume and pressor administration. STUDY DESIGN: Retrospective review of the cardiovascular response to 23 courses of hydrocortisone administration during the first day of treatment in 21 preterm infants (gestational age: 26.9 +/- 3.9 weeks; postnatal age: 11.3 +/- 13.1 days). Hydrocortisone (2 mg/kg/d in 16 patients and 3-6 mg/kg/d in 5 patients) was administered when dopamine (22.2 +/- 11 microg/kg/min, range: 8-60) alone (n = 16) or in combination with dobutamine (8.4 +/- 4.9 microg/kg/min, range: 5-20, n = 7) and/or epinephrine (0.38 +/- 0.56 microg/kg/min, range: 0.01-1.2, n = 4) failed to normalize blood pressure. RESULTS: Mean blood pressure increased from 29.3 +/- 4.1 to 34.1 +/- 5.2, 38.0 +/- 8.0, and 41.8 +/- 6.6 mm Hg by 2, 4, and 6 hours of hydrocortisone administration, respectively, and remained stable thereafter. Urine output increased despite a decrease in fluid administration during the first day of hydrocortisone treatment. The dose of dopamine and the number of patients receiving dobutamine and/or epinephrine also decreased during the same period. Eighteen of the 21 patients survived. CONCLUSIONS: Preterm infants with volume- and pressor-resistant hypotension respond to hydrocortisone with rapid normalization of the cardiovascular status and sustained decreases in volume and pressor requirement.
Blood Glucose↗
Spontaneous tubal re-canalisation: a late complication of Falope ring sterilisation.
The case presented demonstrates the possibility of late failure of laparoscopic female sterilisation due to migration of a Falope ring with tubal recanalisation as a possible mechanism.
Adult↗
Human tooth enamel as a record of the comparative lead exposure of prehistoric and modern people.
There is a considerable body of evidence to support the contention that the atmospheric Pb burden is now considerably greater than it was in the remote past. However, as there are a diversity of potential environmental pathways leading to Pb ingestion, it is not clear how atmospheric Pb levels relate to human exposure. It is necessary to establish a baseline for human exposure to Pb from natural sources in the pre-metallurgical past, with which contemporary exposure can be compared. This paper addresses this issue by comparing the Pb content of human dental enamel--an established proxy for Pb exposure--from modern and archaeological, pre-metallurgical individuals using thermal and plasma ionisation mass spectrometry. It is shown that mean Neolithic enamel Pb contents are approximately 0.31 +/- 0.04 ppm. These values are only one order of magnitude lower than previously reported data for the same tissues for modern juveniles, despite an established 400-fold increase in the atmospheric Pb burden. The results suggest that 'natural' exposure to Pb in food and water may have been higher than previously thought, and that the link between atmospheric Pb and human exposure warrants further investigation.
Dental Enamel↗
Human immunodeficiency virus-associated polymyositis during immune restoration with combination antiretroviral therapy.
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AIDS-Related Opportunistic Infections↗
Structural requirements for catalysis and membrane targeting of mammalian enzymes with neutral sphingomyelinase and lysophospholipid phospholipase C activities. Analysis by chemical modification and site-directed mutagenesis.
The sequence similarity with bacterial neutral sphingomyelinase resulted in the isolation of putative mammalian counterparts and, subsequently, identification of similar molecules in a number of other eukaryotic organisms. Based on sequence similarities and previous characterization of the mammalian enzymes, we have chemically modified specific residues and performed site-directed mutagenesis in order to identify critical catalytic residues and determinants for membrane localization. Modification of histidine residues and the substrate protection experiments demonstrated the presence of reactive histidine residues within the active site. Site directed mutagenesis suggested an essential role in catalysis for two histidine residues (His-136 and His-272), which are conserved in all sequences. Mutations of two additional histidines (His-138 and His-151), conserved only in eukaryotes, resulted in reduced neutral sphingomyelinase activity. In addition to sphingomyelin, the enzyme also hydrolyzed lysophosphatidylcholine. Exposure to an oxidizing environment or modification of cysteine residues using several specific compounds also inactivated the enzyme. Site-directed mutagenesis of eight cysteine residues and gel-shift analysis demonstrated that these residues did not participate in the catalytic reaction and suggested the involvement of cysteines in the formation/breakage of disulfide bonds, which could underlie the reversible inactivation by the oxidizing compounds. Cellular localization studies of a series of deletion mutants, expressed as green fluorescent protein fusion proteins, demonstrated that the transmembrane region contains determinants for the endoplasmic reticulum localization.
Amino Acid Sequence↗
Risk factors for syncope in a community-based sample (the Framingham Heart Study).
The epidemiology of syncope has not been well described. Prior studies have examined risk factors for syncope in hospital-based or other acute or long-term care settings. To determine risk factors for syncope in a community-based sample, we performed a nested case-control study. We examined reports of syncope in Framingham Heart Study participants who underwent routine clinic visits from 1971 to 1990. For each syncope case (n = 543) 2 controls were matched for age, sex, and examination period. Mean age of subjects was 67 years (range 25 to 95); 59% were women. History of stroke or transient ischemic attack, history of myocardial infarction, high blood pressure, use of antihypertensive medication, use of other cardiac medication, smoking, alcohol intake, body mass index, systolic blood pressure, diastolic blood pressure, heart rate, atrial fibrillation, PR interval prolongation, interventricular block, and diabetes or elevated glucose level were examined as potential predictors. Using conditional logistic regression analysis, the predictors of syncope included a history of stroke or transient ischemic attack (odds ratio [OR] 2.56, 95% confidence interval [CI] 1.62 to 4.04), use of cardiac medication (OR 1.67, 95% CI 1.21 to 2. 30), and high blood pressure (OR 1.46, 95% CI 1.14 to 1.88). Lower body mass index was marginally associated with syncope (OR per 4 kg/m(2) decrement 1.10, 95% CI 0.99 to 1.22), as were increased alcohol intake (OR per 5 oz/week 1.11, 95% CI 0.99 to 1.26), and diabetes or an elevated glucose level (OR 1.29, 95% CI 0.96 to 1.75). To our knowledge, this study represents the first community-based study of risk factors for syncope.
Adult↗
Kinetics and Mechanism of the Sorption of Some Aromatic Amines onto Amberlite IRA-904 Anion-Exchange Resin.
The kinetics of the sorption of aromatic amines such as o-aminophenol (o-AP), o-phenylenediamine (o-PDA), and p-phenylenediamine (p-PDA) onto Amberlite anion-exchange resin in chloride form was investigated in batch experiments spectrophotometrically at different temperatures. The sorption rate is zero order in all amines sorbed, increasing directly in the order: p-PDA<o-PDA<o-AP, which corresponds to the sequence of the electrostatic contributions to the sorption interactions. The attainment of sorption equilibrium of aromatic amines is seen to be similar. The diffusion coefficients (D) have been calculated by using Fick's equation from the second portions of the sorption/desorption curves; D values ranged from 0.7 to 2.8x10(-9) cm(2)/s. These results, reflecting the diffusion mechanism, were ascribed to intraparticle diffusion. Arrhenius parameters for the diffusion process and the thermodynamic quantities for the process of equilibrium sorption have been estimated. The effect of a chemical oxidation reaction on intraparticle diffusion was investigated by measuring the intraparticle diffusion of amines during the redox reaction. Copyright 2000 Academic Press.
Journal Article↗
Aortic laceration secondary to palmaz stent placement for treatment of superior vena cava syndrome.
Aortic laceration secondary to Palmaz Stent placement for treatment of superior vena cava syndrome is reported. This potentially life-threatening complication should be considered when rigid balloon expandable stents are used to treat superior vena cava syndrome of benign origin. Cathet. Cardiovasc. Intervent. 49:160-162, 2000.
Adult↗
Photodynamic therapy for neovascular age-related macular degeneration.
BACKGROUND: In neovascular age-related macular degeneration, new vessels grow under the retina, distorting vision and leading to scarring. This is further exacerbated if the blood vessels leak. Photodynamic therapy, originally used in cancer treatment, has been investigated as a way to treat the neovascular membranes without affecting the retina. OBJECTIVES: The aim of this review is to examine the evidence for the safety and effectiveness of photodynamic therapy in the treatment of neovascular age-related macular degeneration. SEARCH STRATEGY: We searched for trials in the Cochrane Eyes and Vision Group trials register (available in the Cochrane Controlled Trials Register), the Cochrane Controlled Trials Register, Medline and Embase. We used the Science Citation Index to search for reports that cited identified relevant study reports. We contacted experts in the field for further trials information, and we searched the reference lists of identified relevant studies for further trial reports. Searches were conducted in December 1999. SELECTION CRITERIA: We included randomised trials of photodynamic therapy in people with choroidal neovascularisation due to age-related macular degeneration. DATA COLLECTION AND ANALYSIS: Two reviewers extracted the data independently. Meta analysis was not performed. MAIN RESULTS: One published trial was identified. Outcome data were available at 12 months after the first treatment. Patients received an average of 3.7 treatments. The relative risk of losing three or more lines of visual acuity at 12 months comparing the intervention with the control group was 0.72 (95% confidence interval 0.61 to 0.86). The relative risk of losing six or more lines of visual acuity at 12 months comparing the intervention with the control group was 0.62 (95% confidence interval 0.44 to 0.87). Subgroup analyses suggest that the benefits may be confined to people with no occult choroidal neovascularisation. REVIEWER'S CONCLUSIONS: Photodynamic therapy in people with classic choroidal neovascularisation due to age-related macular degeneration is effective in preventing visual loss. This evidence is drawn from a subgroup analysis of 143 participants in one trial. Outcomes and potential adverse effects of this treatment should be monitored closely. There is no evidence that photodynamic therapy is beneficial for people with evidence of occult choroidal neovascularisation. These people should be offered treatment in the context of a randomised trial.
Humans↗
Impulsiveness and the prolactin response to d-fenfluramine.
RATIONALE: A number of studies have reported abnormalities of serotonin function in aggressive and impulsive behaviours in psychiatric and forensic populations. It is unknown whether this is because serotonin function plays a part in determining the dimension of trait impulsiveness in the general population or whether this is restricted to these behaviourally extreme groups. METHOD: The prolactin response to d-fenfluramine was measured in subjects scoring high and low on a scale of impulsiveness selected from a panel of healthy volunteers screened for impulsiveness. Measures included the 17 impulsiveness scale, State Trait Anger Expression Inventory (STAngXI) and the Tridimensional Personality Questionnaire (TPQ). Plasma cortisol was also determined along with fenfluramine and its metabolite norfenfluramine. RESULTS: The high impulsive group had reduced AUC (PRL) compared with the low impulsive group; this remained significant after adjusting for baseline prolactin, cortisol and drug levels. There was no significant association between impulsiveness, the harm avoidance subscale of the TPQ or trait anger (STAngXI) and prolactin rise. Repeated serum prolactin measures were not significantly different between the two groups. CONCLUSIONS: This study provides some support to the hypothesis that reduced serotonin function contributes to high trait impulsiveness and is not restricted to behaviourally extreme populations.
Adult↗
A second-stage partogram.
OBJECTIVE: To describe a second-stage partogram based on a system of scoring the descent and position of the fetal head and to use this system for studying progress in the second stage of labor and predicting mode of delivery and obstetric outcome. METHODS: A prospective observational study of 1413 women at term with a singleton, cephalic presentation. The position and station of the fetal head were observed and scored at diagnosis of the second stage of labor, 1 hour later, and then at 30 minute intervals until delivery was achieved. The score at diagnosis of the second stage of labor was assessed for its ability to predict eventual mode of delivery and duration of labor. A normogram was defined for nulliparas and multiparas and was used to define normal and abnormal progress in the second stage, associated factors in the first stage of labor, and mode of delivery. RESULTS: Increasing total score at the start of the second stage of labor is associated with increasing chance of spontaneous vaginal delivery (odds ratio [OR] 1.68 for nulliparas, 1.59 for multiparas), decreasing chance of instrumental vaginal delivery (OR 0.67 for nulliparas, 0.64 for multiparas), and emergency cesarean delivery (OR 0.39 for nulliparas). Abnormal progress as defined by the normogram is associated with use of epidural anesthesia, induction of labor, augmentation, dystocia, and increased incidence of operative delivery. No significant difference is found between normal and abnormal second stages of labor in fetal outcome as determined by Apgar scores. CONCLUSION: The second-stage partogram offers an objective basis for management of the second stage of labor.
Delivery, Obstetric↗
Factors predictive of outcome in severe lupus nephritis. Lupus Nephritis Collaborative Study Group.
In 1992, we published the results of a prospective, controlled trial of aggressive therapy (high-dose prednisone plus oral cyclophosphamide alone or with plasmapheresis) in 86 patients with severe lupus nephritis. During this study, remission (serum creatinine < or =1.4 mg/dL [< or =123 micromol/L] and proteinuria < or =330 mg/d of protein) in renal disease occurred in 37 patients (43%). To assess the long-term effect of remission on patient and renal survival, we now report the results of our extended follow-up of these patients. After an average of 10 years of follow-up in the 86 patients, patient survival rates at both 5 and 10 years were 95% in the group that had a remission and 69% at 5 years and 60% at 10 years in the no-remission group (P < 0.001). Renal survival rates were 94% at both 5 and 10 years in the remission group compared with 46% at 5 years and 31% at 10 years in the no-remission group (P < 0. 0001). Features predictive of remission included stable renal function after 4 weeks on therapy, category IV lesion, lower chronicity index, white race, lower urine protein excretion level at baseline, and lower baseline serum creatinine level. The features predictive of end-stage renal disease were higher baseline serum creatinine level, presence of anti-Ro antibodies, and failure to attain a remission. Thus, in patients with the most severe forms of lupus nephritis, a remission of clinical renal abnormalities is associated with dramatic improvement in long-term patient and renal survival.
Adult↗
The continuing risk of domestic hot water scalds to the elderly.
Elderly people are particularly at risk of accidents in the home and with an ageing population, they constitute a large proportion of scald victims. We have seen several elderly patients every year in our own unit who had sustained domestic hot water burns. We decided to ascertain the temperature of water in the private homes of elderly people and in residential care homes in our community. Twenty-five private homes and 14 residential care homes were visited and peak water temperatures were measured in the kitchens and bathrooms. Only one private home and one residential home had water below 45 degrees C. It is recommended that water should be delivered at less than 43 degrees C. We conclude that water is dangerously hot. However, if water is stored at a temperature of less than 60 degrees C there is a risk of infection with Legionella pneumophila. Existing regulations governing the use of 'fail safe' thermostatic mixing devices must be enforced and extended to cover domestic hot water systems.
Accidents, Home↗
Acoustic analysis of the singing and speaking voice in singing students.
The singing power ratio (SPR) is an objective means of quantifying the singer's formant. SPR has been shown to differentiate trained singers from nonsingers and sung from spoken tones. This study was designed to evaluate SPR and acoustic parameters in singing students to determine if the singer-in-training has an identifiable difference between sung and spoken voices. Digital audio recordings were made of both sung and spoken vowel sounds in 55 singing students for acoustic analysis. SPR values were not significantly different between the sung and spoken samples. Shimmer and noise-to-harmonic ratio were significantly higher in spoken samples. SPR analysis may provide an objective tool for monitoring the student's progress.
Acoustics↗
Relationship between aerodynamic measures of glottal efficiency and stroboscopic findings in asymptomatic singing students.
Singing requires exquisite coordination between the respiratory and phonatory systems to efficiently control glottal airflow. Asymptomatic singing students underwent pulmonary function testing (PFT), videostrobolaryngoscopic examination, and measures of glottal efficiency (maximum phonation time [MPT], glottal flow rate [GFR], and phonation quotient [PQ]) performed in both a sung and spoken tone. Pulmonary function and glottal efficiency values were within reported normative data for professional singers. However, sung tones were made with significantly higher GFR and PQ and lower PQ than spoken tones. The mean GFR was not related to the degree of glottal closure (by videostrobolaryngoscopy) or underlying pulmonary support.
Adult↗