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.

Glyceryl trinitrate vs. lateral sphincterotomy for chronic anal fissure: prospective, randomized trial

INTRODUCTION

Glyceryl trinitrate has been shown to be an effective treatment for chronic anal fissure. It decreases anal tone and ultimately heals anal fissures. The aim of this trial was to compare glyceryl trinitrate with lateral sphincterotomy (current standard treatment) as definitive management for chronic anal fissure.

METHODS

All patients with symptoms of chronic anal fissure were randomly assigned to one of two treatment arms. The glyceryl trinitrate group applied 0.2 percent paste to the perianal area three times a day for eight weeks. Patients in the lateral sphincterotomy group underwent surgery on the next available operating list. Patients were reviewed at two weekly intervals until the fissure healed.

RESULTS

Sixty-five patients were enrolled in the trial, with 31 in the lateral sphincterotomy group and 34 in the glyceryl trinitrate group. Five patients were excluded after randomization. Twenty of 33 (60.6 percent) glyceryl trinitrate patients had healed fissures in eight weeks compared with 26 of 27 (97 percent) in the sphincterotomy group (P = 0.001). Twelve patients in the glyceryl trinitrate group had little improvement in their symptoms and underwent lateral sphincterotomy. Poor tolerance and poor compliance with treatment were important factors in patients whose fissures did not heal with glyceryl trinitrate. Fissures healed significantly faster after sphincterotomy compared with glyceryl trinitrate treatment (P = 0.0001). Nine of the 20 patients whose fissures healed with glyceryl trinitrate paste subsequently had a recurrence of their fissures. There were no long-term complications from lateral sphincterotomy.

CONCLUSION

Glyceryl trinitrate paste heals the majority of chronic anal fissures. However, a significant minority have little improvement or develop side effects and require conventional surgical treatment. Poor compliance with prescribed treatment often contributes to nonhealing. In addition, some fissures which initially heal with glyceryl trinitrate paste recur and require further treatment. Glyceryl trinitrate treatment is labor intensive for patients and physicians and has not been shown to be superior to lateral sphincterotomy.

An investigation of the molecular basis for the synergistic interaction of tirapazamine and cisplatin

PURPOSE

To determine if the observed tirapazamine (TPZ)-cisplatin synergistic cell kill was mediated at the cellular level by impairment of upregulation of key proteins involved in repair of DNA interstrand crosslinks. Cisplatin sensitivity has been shown to be dependent on the expression of the two DNA repair proteins ERCC1 and XPA. ERCC1 expression has also been shown to be upregulated by cisplatin exposure. Therefore, these studies were undertaken to determine if hypoxia-activated TPZ pretreatment inhibited the cells' normal protective response to cisplatin via inhibiting the upregulation of ERCC1 and/or XPA expression.

METHODS AND MATERIALS

Two different cell lines, one cisplatin sensitive and one cisplatin resistant, were treated with TPZ, cisplatin, both drugs together (which results in additive cytotoxicity), or TPZ followed by cisplatin (which results in synergistic cytotoxicity). All cells were exposed to 1 h of hypoxia to bioactivate the TPZ. Expression of ERCC1 and XPA were evaluated at the mRNA and protein level at 24 or 48 h after drug exposure.

RESULTS

In the cisplatin-sensitive non-small-cell lung cancer cell line, ERCC1 expression at the mRNA or protein level was not significantly altered in any of the treatment groups. In the cisplatin-resistant ovarian cancer cell line, ERCC1 expression was upregulated by TPZ, but not by cisplatin alone. The change in protein expression was less pronounced than the change in mRNA level. XPA expression was not significantly changed from baseline in either cell line at the mRNA or protein level.

CONCLUSION

In contrast to reports in the literature, this study did not demonstrate cisplatin inducing its own repair by upregulating the DNA crosslink repair proteins ERCC1 or XPA. Therefore, the TPZ-cisplatin synergism cannot be mediated through hypoxia-activated TPZ inhibiting this cellular protective response. TPZ alone, however, was able to alter repair protein expression, which may play a role in mediating its cytotoxicity.

Net nitrogen balances for cool-season grain legume crops and contributions to wheat nitrogen uptake: a review

The removal of nitrogen (N) in grain cereal and canola crops in Australia exceeds 0.3 million t N/year and is increasing with improvements in average crop yields. Although N fertiliser applications to cereals are also rising, N2-fixing legumes still play a pivotal role through inputs of biologically fixed N in crop and pasture systems. This review collates Australian data on the effects of grain legume N2 fixation, the net N balance of legume cropping, summarises trends in the soil N balance in grain legume–cereal rotations, and evaluates the direct contribution of grain legume stubble and root N to wheat production in southern Australia. The net effect of grain legume N2 fixation on the soil N balance, i.e. the difference between fixed N and N harvested in legume grain (Nadd) ranges widely, viz. lupin –29–247 kg N/ha (mean 80), pea –46–181 kg N/ha (mean 40), chickpea –67–102 kg N/ha (mean 6), and faba bean 8–271 kg N/ha (mean 113). Nadd is found to be related to the amount (Nfix) and proportion (Pfix) of crop N derived from N2 fixation, but not to legume grain yield (GY). When Nfix exceeded 30 (lupin), 39 (pea) and 49 (chickpea) kg N/ha the N balance was frequently positive, averaging 0.60 kg N/kg of N fixed. Since Nfix increased with shoot dry matter (SDM) (21 kg N fixed/t SDM; pea and lupin) and Pfix (pea, lupin and chickpea), increases in SDM and Pfix usually increased the legume’s effect on soil N balance. Additive effects of SDM, Pfix and GY explained most (R2 = 0.87) of the variation in Nadd. Using crop-specific models based on these parameters the average effects of grain legumes on soil N balance across Australia were estimated to be 88 (lupin), 44 (pea) and 18 (chickpea) kg N/ha. Values of Nadd for the combined legumes were 47 kg N/ha in south-eastern Australia and 90 kg N/ha in south-western Australia. The average net N input from lupin crops was estimated to increase from 61 to 79 kg N/ha as annual rainfall rose from 445 to 627 mm across 3 shires in the south-east. The comparative average input from pea was 37 to 47 kg N/ha with least input in the higher rainfall shires. When the effects of legumes on soil N balance in south-eastern Australia were compared with average amounts of N removed in wheat grain, pea–wheat (1:1) sequences were considered less sustainable for N than lupin–wheat (1:1) sequences, while in south-western Australia the latter were considered sustainable. Nitrogen mineralised from lupin residues was estimated to contribute 40% of the N in the average grain yield of a following wheat crop, and that from pea residues, 15–30%; respectively, about 25 and 15 kg N/ha. Therefore, it was concluded that the majority of wheat N must be obtained from pre-existing soil sources. As the amounts above represented only 25–35% of the total N added to soil by grain legumes, the residual amount of N in legume residues is likely to be important in sustaining those pre-existing soil sources of N.

Effectiveness of beta-glucan collagen for treatment of partial-thickness burns in children

BACKGROUND/PURPOSE

Beta glucan collagen matrix (BGC), which combines the carbohydrate beta-glucan with collagen, has been used as a temporary coverage for adult partial thickness burns with reported good results. Observed advantages of BGC coverage include reduction of pain, improved healing, and better scar appearance. Potentially even more important in children is the elimination of painful daily dressing changes to the burned epithelial surface, as well as decreased fluid loss. This report details the authors' 2-year experience with BGC in a pediatric burn center.

METHODS

Retrospective chart review of 225 consecutive pediatric patients treated at our institution between 1997 and 1999 identified 43 patients (19%) with suspected partial thickness burns treated with BGC as the primary wound dressing. BGC was applied to a debrided burn wound and secured with steri-strips, kerlix, and an ace wrap. After 24 hours, adherence of the BGC was confirmed and then left open to air.

RESULTS

The most common cause of burn injury was scald (61%), followed by flame (37%), and contact (2%). The average age of patients was 5.5 years (range, 6 weeks to 16 years) and mean percent total body surface area burned was 9.3% (1% to 35%). Thirty-four patients (79%) had the BGC remain intact while the wound healed underneath, with excellent cosmetic results, minimal analgesic requirements, and no need for repetitive dressing changes. Nine patients (21%) had the BGC removed before wound healing: 6 patients lost the BGC because of progression of the burn to full thickness, 2 had BGC nonadherence over a joint, and 1 had an unexplained nonadherence.

CONCLUSIONS

Partial-thickness burns in children can be effectively treated with BGC with good results, even in infants and toddlers. BGC markedly simplifies wound care for the patient and family and seems to significantly decrease postinjury pain.

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.

The health of students in institutes of higher education: an important and neglected public health problem?

BACKGROUND

A survey of students in three UK higher education establishments was undertaken to obtain information about students' physical and emotional well-being, their attitudes to, and beliefs about health, and the prevalence of risk factors for future ill health.

METHODS

Health was measured by the prevalence of longstanding illness and by the SF-36 health status measurement tool. Survey results were compared with equivalent data for 18- to 34-year-olds in the local population. The prevalence of long-standing illness was also compared with two national surveys.

RESULTS

The survey achieved a 49 per cent response rate. More than one-third of respondents reported a long-standing illness, a higher prevalence than in all comparison surveys. Students scored significantly worse than their peers in the local population on all eight SF-36 dimensions. The greatest difference was for role limitations as a result of emotional problems. The main sources of emotional distress were study or work problems and money.

CONCLUSION

The poor response rate in this survey dictates the need for caution in interpretation of the results. However, they suggest that the health of students is poor relative to that of their peers, and that their emotional health is more of a problem than their physical health. Public health practitioners might want to pay more attention to the health of this important and relatively neglected group. Worries about studies and money appear to be affecting students' academic work, and this should be of concern to higher education establishments.

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.

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.

Impulsiveness, serotonin genes and repetition of deliberate self-harm (DSH)

BACKGROUND

Few studies have investigated independent associations of psychological, biological and social variables with repeated deliberate self-harm (DSH). Serotonin function has been linked to impulsive and suicidal behaviour and genetic polymorphisms have been identified within the serotonin system that could account for this link. This study tested hypotheses linking impulsiveness, genetic polymorphisms of tryptophan hydroxylase (TPH) and the 5-HT2c receptor and repeated DSH.

METHODS

Individuals presenting after DSH were interviewed, completed personality questionnaires and gave venous blood samples. Genotypes were determined for TPH intron7 and 5-HT2c (cys-ser) polymorphisms. Follow-up to identify repetition of DSH was for 1 year.

RESULTS

Males with the 5-HT2c serine variant were more impulsive than those with the cysteine variant (039 standardized units, P = 0.041, 95% CI 0.017 to 0.076). There was no association between impulsiveness and the TPH intron7 polymorphism overall but a weak association with the L allele in men (0.41 standardized units, P = 0.05, 95 % CI 0.001 to 0.82). Impulsiveness, although high in the group as a whole, did not distinguish those who repeated DSH.

CONCLUSIONS

The personality trait of impulsiveness may in part be related to genotypes of the 5-HT2c receptor and TPH gene in men. Impulsiveness does not differ between those who do and do not repeat DSH.

Ultrasound-guided percutaneous thrombin injection for femoral artery pseudoaneurysms

We reviewed 13 cases of ultrasound-guided thrombin injection of femoral pseudoaneurysms. All cases occurred within a 17-month period from January 1998 through May 1999 and were complications of femoral artery puncture. Immediate total thrombosis occurred in nine of 13 patients. Twenty-four-hour follow-up ultrasound in seven patients revealed no recurrence of pseudoaneurysm. Two of 13 patients required operative repair. One pseudoaneurysm thrombosed with 15 minutes of compression after injection and one case required a second injection. No cases of arterial thrombosis were noted. Ultrasound-guided thrombin injection for femoral artery pseudoaneurysm represents a safe and effective alternative to operative repair.

An interface of chlamydia testing by community family planning clinics and referral to hospital genitourinary medicine clinics

OBJECTIVES

To assess compliance with the protocol for the management of women with Chlamydia trachomatis diagnosed in community family planning (FP) clinics; to assess the rate of attendance at genitourinary medicine (GUM) clinics by these women; to assess the rate of adequate treatment and to assess the level of communication between GUM clinics and FP clinics.

METHOD

Retrospective review of FP clinic records and case notes to identify all women with positive or equivocal Chlamydia results during a 6 month period, and a retrospective review of records from five local GUM clinics.

RESULTS

One hundred and twelve women were identified from FP clinic records with positive or equivocal Chlamydia results. Eighty-nine (79.5%) were referred to a GUM clinic. Twelve out of 14 women not referred had equivocal results. The median delay from the test being taken to the results being seen by a doctor was 9 days, and to the woman being referred was 10 days. Fifty-eight (51.7%, n = l12) women definitely attended a local GUM clinic. The FP clinics provided a letter of referral in 76 (85.4%, n = 89) women and the GUM clinics provided a letter of reply in 21 (48.8%, n = 43) women who attended with a referral letter. Three months after testing, only 54 (48.2%) of the 112 women with positive or equivocal Chlamydia tests were known by the referring FP clinic to have been treated.

CONCLUSIONS

The majority of women with positive or equivocal Chlamydia results were referred to a GUM clinic according to the protocol. Attendance at GUM clinics was disappointing, as only 51.7% of the 112 women with positive or equivocal results had documented evidence of having attended. This raises the question not whether community clinics should be testing, but whether they should be initiating treatment and partner notification. Collaborative work between GUM clinics and community clinics around partner notification is needed, as well as funding for training and additional pharmacy costs. Further collaborative work between GUM and FP and reproductive healthcare (RHC) to evaluate the role of community clinics in the diagnosis and management of chlamydial infection and other sexually transmitted infections (STIs) is needed.

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.

Proton affinities of saturated aliphatic methyl esters

The kinetic method was used to determine the proton affinities of methyl esters of several saturated fatty acids. Decompositions of the proton-bound dimers of the methyl esters, AHB+, were observed under different conditions with two instruments. The proton affinities (PAs) of the methyl esters increase continually with increasing carbon number in the acid. Equilibrium and initial rate experiments were performed with a Fourier transform ion cyclotron resonance mass spectrometer on the methyl ester of the C22 saturated acid (methyl behenate). These experiments give values for PA (methyl behenate) that are perhaps slightly lower than those obtained with the kinetic method. The PAs of the methyl esters of the fatty acids could be correlated with the equation: PA (ester) = (40.0 +/- 2.5)*log(n) + (784.7 +/- 3.9) kJ/mol or PA (ester) = (864 +/- 2) - (479 +/- 41)/n, where n = number of atoms in the molecule. Proton affinities of smaller sets of 1-alkylamines and 1-alkanols can be fit to similar equations.

An epidemiological study of the relative importance of damp housing in relation to adult health

STUDY OBJECTIVE

To examine the association between damp housing and adult health, taking into account a wide range of other factors that may influence health and could confound this relation.

PARTICIPANTS AND SETTING

A general population sample of adults, aged 18-64, from Oxfordshire, Buckinghamshire, Berkshire and Northamptonshire.

DESIGN

Secondary analysis of responses to a postal questionnaire survey carried out in 1997 with a 64% response rate (8889 of 13 800). Housing dampness was assessed by self report. Health was measured by responses to a series of questions including presence of asthma and longstanding illness generally, use of health services and perceived health status (the SF-36). The effect of damp was examined using the chi(2) test and one way analysis of variance. Significant associations with the various health outcomes were further explored taking into account 35 other housing, demographic, psychosocial and lifestyle variables using stepwise logistic and linear regression.

MAIN RESULTS

Bivariate analyses indicated that damp was associated with the majority of health outcomes. Regression modelling however, found that being unable to keep the home warm enough in winter was a more important explanatory variable. Worry about pressure at work and to a lesser extent about money, showed an independent association with perceived health status equal to or greater than that of the housing environment, including cold housing, and that of health related lifestyles.

CONCLUSIONS

This study shows that being unable to keep the home warm enough in winter is more strongly associated with health outcomes than is damp housing. However, as cold and damp housing are closely related, it is likely that their combined effects are shown in these results. The importance of worry as an independent predictor of health status needs testing in other studies. Its prevalence and relative importance suggest that it may be a significant determinant of public health.

Injury risk assessment of wheelchair occupant restraint systems in a frontal crash: a case for integrated restraints

Obtaining proper occupant restraint fit when using a wheelchair as a motor vehicle seat is often difficult to attain with vehicle-mounted restraint systems. The comprehensive evaluation conducted in this study illustrates the occupant crash protection benefits of wheelchair-integrated restraint systems, as compared to vehicle-mounted restraint systems. Using computer crash simulation, occupant kinematic and biomechanical measures associated with a 20g/30mph frontal impact were evaluated and compared to injury criteria and SAE J2249 WTORS kinematic limits. These measures were also used to compile a Motion Criteria (MC) index and Combined Injury Criteria (CIC) index for each evaluated restraint scenario. These indices provide a composite method for comparing various crash scenarios. With the exception of an unsafe 36-inch height off-shoulder shoulder belt anchor scenario, the MC index was minimized for the integrated restraint scenario. Similarly, the CIC index was also minimized for the wheelchair-integrated restraint scenario. This preliminary study emphasizes the need for transfer of integrated restraint technology to the wheelchair transportation industry.

Are triglyceride breast implants really biocompatible?

A case of augmentation mammaplasty with triglyceride implants is presented. Histological examination of the capsules 3 years postimplantation showed retained, irregular, refractile yellow-brown fragments embedded in granulomatous tissue.

Lyme disease

Lyme disease (LD) is the most common tick-borne disease in the US. The overall trend has been an average annual increase in cases since surveillance was initiated by the Centers for Disease Control and Prevention in 1982. To date, 10 different Borrelia species have been described within the Borrelia burgdorferi sensu lato complex, although only Borrelia burgdorferi sensu strico, Borrelia garinii, and Borrelia afzelii have been associated with human disease. Ixodes ticks often carry more than one potential pathogen, and co-infection with B. burgdorferi and other organisms have been reported. Recent findings suggested that maintenance cycles of other tick-borne pathogens may be different than those for B. burgdorferi. A better understanding of the pathogenesis of Lyme arthritis has provided clues about the mechanisms responsible for variation in clinical expression of the disease. Results of therapeutic trials in Lyme neuroborreliosis are likely to have an impact upon treatment recommendations. A long term follow-up study of children treated for LD indicated that the prognosis is excellent in most cases. A safe vaccine for the prevention of LD has been approved in adults. Preliminary data suggested that the vaccine is safe and immunogenic in children.