Seasonal changes of redox potential and microbial activity in two agricultural soils of tropical Australia: some implications for soil-to-plant transfer of radionuclides

Very little is known of the factors controlling soil-to-plant transfer of radionuclides in tropical environments. As part of an IAEA/FAO coordinated research project (CRP) designed to elucidate some of those factors, near-surface samples of two agricultural red-earth soils (Blain and Tippera) were collected from a study site in the Northern Territory. The climate is tropical monsoonal with crops being grown over the wet season from December to March/April. It is important to understand soil variables that may be related to this dramatic seasonality. In this investigation, soil redox state and microbial populations were assessed before and after the growing season with a view to generating hypotheses for future evaluation. The X-ray absorption near edge structure (XANES) technique was used to determine overall changes in the solid-state redox speciation of Fe and Mn in soils across the growing period. Fe speciation did not change but approximately 10% of the total Mn was oxidised from Mn(II) to Mn(III) and Mn(IV) in both soils between October 1999 and April 2000. An apparent disconnect between Fe and Mn was not unexpected given the >10 times higher concentration of Fe in the soils compared with Mn. These results have implications for the bioavailability of redox sensitive radionuclides such as Tc and Pu. Similarly, microbial population estimates were derived before and after the growing period. Total bacterial populations did not vary from 10(6) to 10(7) colonies per gram. Fungal populations increased over the growing season from 3-6 x 10(5) to 1-4 x 10(6) colonies per gram of soil. Fungi have the potential to decrease soil pH and hence increase the bioavailability of radionuclides such as Cs. In addition, fungi act to facilitate plant nutrition. This could lead to enhanced accumulation of nutrient analogues (e.g. Sr and Ra for Ca; Tc for Mn), but this effect may be masked by improved biomass production.

Multidisciplinary team interventions for delirium in patients with chronic cognitive impairment

BACKGROUND

Delirium is common in hospitalized elderly people. Delirium may affect 60% of frail elderly people in hospital. Among the cognitively impaired, 45% have been found to develop delirium and these patients have longer lengths of hospital stay and a higher rate of complications which, with other factors, increase costs of care. The management of delirium has commonly been multifaceted, the primary emphasis has to be on the diagnosis and therapy of precipitating factors, but as these may not be immediately resolved, symptomatic and supportive care are also of major importance.

OBJECTIVES

The objective of this review is to assess the available evidence for the effectiveness, if any, of multidisciplinary team interventions in the coordinated care of elderly patients with delirium superimposed on an underlying chronic cognitive impairment in comparison with usual care.

SEARCH STRATEGY

The trials were identified from a last updated search of the Specialized Register of the Cochrane Dementia and Cognitive Improvement Group on 3 July 2003 using the terms delirium and confus*. The Register is regularly updated and contains records of all major health care databases and many ongoing trial databases.

SELECTION CRITERIA

Selection for possible inclusion in this review was made on the basis of the research methodology - controlled trials whose participants are reported as having chronic cognitive impairment, and who then developed incident delirium and were randomly assigned to either coordinated multidisciplinary care or usual care.

DATA COLLECTION AND ANALYSIS

Nine controlled trials were identified for possible inclusion in the review, only one of which met the inclusion criteria. At present the data from that study cannot be analysed. We have requested additional data from the authors and are awaiting their reply.

MAIN RESULTS

No studies focused on patients with prior cognitive impairment, so management of delirium in this group could not be assessed. There is very little information on the management of delirium in the literature despite an increasing body of information about the incidence, risks and prognosis of the disorder in the elderly population.

REVIEWERS' CONCLUSIONS

The management of delirium needs to be studied in a more clearly defined way before evidence-based guidelines can be developed. Insufficient data are available for the development of evidence-based guidelines on diagnosis or management. There is scope for research in all areas - from basic pathophysiology and epidemiology to prevention and management. Though much recent research has focused on the problem of delirium, the evidence is still difficult to utilize in management programmes. Research needs to be undertaken targeting specific groups known to be at high risk of developing delirium, for example the cognitively impaired and the frail elderly. As has been highlighted by Inouye 1999, delirium has very important economic and health policy implications and is a clinical problem that can affect all aspects of care of an ill older person.Delirium, though a frequent problem in hospitalized elderly patients, is still managed empirically and there is no evidence in the literature to support change to current practice at this time.

Radionuclide applications in laboratory studies of environmental surface reactions

The advantages of using radionuclides for laboratory studies of environmental processes include the wide range of element concentrations that can be studied, the capability to simultaneously study several isotopes in a single experiment, the direct applicability to the behaviour of radioactive waste or fallout, and the ability to study the mechanisms, reversibility and kinetics of environmental reactions under controlled conditions. These attributes are demonstrated using specific examples drawn from case studies in Australia, including radionuclide fallout onto tropical soils, the association of trace metals with harbour sediments and the behaviour of uranium in natural and contaminated systems.

Coastal oceanography sets the pace of rocky intertidal community dynamics

The structure of ecological communities reflects a tension among forces that alter populations. Marine ecologists previously emphasized control by locally operating forces (predation, competition, and disturbance), but newer studies suggest that inputs from large-scale oceanographically modulated subsidies (nutrients, particulates, and propagules) can strongly influence community structure and dynamics. On New Zealand rocky shores, the magnitude of such subsidies differs profoundly between contrasting oceanographic regimes. Community structure, and particularly the pace of community dynamics, differ dramatically between intermittent upwelling regimes compared with relatively persistent down-welling regimes. We suggest that subsidy rates are a key determinant of the intensity of species interactions, and thus of structure in marine systems, and perhaps also nonmarine communities.

Does the use of low dose bupivacaine/opioid epidural infusion increase the normal delivery rate?

To investigate whether using low dose epidural infusion improves the normal delivery rate, outcome of labour was studied in women with singleton vertex presentations randomised to receive either 0.0625% bupivacaine opioid, or plain bupivacaine 0.125% for labour. The infusion rate was titrated to maintain analgesia and a sensory level to T10. Data were analysed using the unpaired t test, Mann-Whitney U test and for categorical variables chi2 test. Adjusted odds ratios for factors significantly associated with non-normal delivery were calculated using stepwise logistic regression. There were 291 women in the low dose and 296 in the plain bupivacaine group. There were no significant differences between groups in parity, race, induction of labour, use of augmentation, cervical dilatation at epidural insertion, duration of any stage of labour or duration or volume of infusion. Total dose of bupivacaine (126 +/- 47 mg versus 91 +/- 32 mg) and the proportion of women with motor block at the end of labour (45% versus 27%) were significantly greater in the plain bupivacaine than in the low dose group (P < 0.0001). The adjusted odds ratios (95% CI) for factors significantly associated with non-normal delivery were primiparity: 4.68 (2.78-7.88), older maternal age: 1.1 (1.05-1.14), longer active second stage of labour: 1.01 (1.005-1.017), total bupivacaine dose: 1.01 (1.005-1.016) and greater cervical dilatation at epidural insertion 1.22 (1.08-1.37). Treatment group and motor block at the end of labour had no significant effect. We found no increase in normal delivery rate with low dose infusions.

Combined spinal epidural analgesia is the preferred technique for labour analgesia

To justify its place as the preferred method of pain relief in labour, CSE must demonstrated a clear superiority over epidural analgesia. Looking at the relative efficacy of the two techniques failure rates appear to be equal. Speed of onset may be faster with an initial spinal injection although perhaps only clinically relevant in advanced labour where the quality of analgesia may sometimes be better. CSE would not seem to offer significant advantage in terms of mode of delivery or the ability to ambulate. The side effects of the technique are somewhat more concerning as CSE would appear to carry slightly greater risk than epidural analgesia, most notably in neurological sequelae and the effects of intrathecal opioids. Certainly CSE confers no benefit in terms of cost. What then is the place of CSE in labour analgesia? Its potential benefit makes it a reasonable option when there is a clear clinical advantage such as requests for analgesia in late labour or where maternal distress is extreme or where epidural analgesia has been ineffective. However even in such situations the slight increase in risk must be weighed against the possible advantage. Consequently the CSE cannot at the present time be recommended as the preferred option for labour analgesia.

Distal calcific uremic arteriolopathy in a hemodialysis patient responds to lowering of Ca x P product and aggressive wound care

Calcific uremic arteriolopathy (CUA; calciphylaxis), is reported in approximately 4% of patients receiving hemodialysis, and is characterized by skin lesions that may include firm plaques or subcutaneous nodules. The syndrome has been associated with the use of calcium-containing phosphate binders, high serum phosphorus levels, and elevated calcium x phosphorus (Ca x P) product. This report describes a 73-year-old white male with chronic renal failure due to diabetes mellitus and hypertension, who had been on home hemodialysis for 3 years. He developed CUA after an acute elevation in serum phosphorus (8.1 mg/dl) and Ca x P product (84.2), with painful skin lesions that rapidly progressed to become circumferentially located around the entire lower left extremity. The patient declined amputation, opting for a treatment approach that included aggressive management of phosphorus and calcium, more frequent dialysis, and rigorous wound care. All calcium-containing phosphate binders were discontinued. The patient was switched from calcitriol to paricalcitol, a less calcemic form ofvitamin D replacement therapy, from which he was slowly weaned. Dialysis dose and frequency was also increased to 4 hours, 6 times weekly. The patient was given sevelamer hydrochloride (Renagel)--a calcium-free phosphate binder--with meals at an initial dose of 6.4 g/day. After 5 months, the dose was increased to 8 g/day, with additional dietary counseling to restrict phosphorus intake. At this point, serum phosphorus decreased to 4.9 mg/dl and calcium levels had fallen to 8.5 mg/dl, compared to 9.5 - 10.4 mg/dl prior to diagnosis of CUA with an overall decline in the Ca x P product. Significant healing of the lesions was noted at 8 months following diagnosis, with near-total healing by 12 months. Our studies support that lowering of elevated serum phosphorus, calcium, and Ca x P product, together with aggressive wound care may contribute to the successful outcome of patients with CUA.

Combined spinal epidural anaesthesia for caesarean section: a randomised comparison of Oxford, lateral and sitting positions

Maternal position during induction of intrathecal anaesthesia for caesarean section influences block height and haemodynamic stability. In a randomised study of 90 women presenting for elective caesarean section using combined spinal-epidural anaesthesia, three positions were compared--the Oxford position (group O), the right lateral to supine wedged (group R) and the sitting to supine wedged (group S). Hyperbaric bupivacaine 12.5 mg with fentanyl 12.5 microg was injected intrathecally using a needle-through-needle CSE technique. Intravenous ephedrine 6 mg was given every minute that systolic blood pressure fell below 80% of baseline. Time required for block height to reach T5 as assessed by light touch, was similar in the three groups. There were no significant differences in blood pressure although ephedrine requirements were less in group R. There were no significant differences in the incidence of maternal nausea and vomiting or in neonatal outcome as assessed by Apgar scores and umbilical cord blood gas analysis. Although the study failed to show any significant differences in block height between the groups, no women in group O had a block above T2 compared with three in group R and three in group S.

p53-dependent suppression of uridine phosphorylase gene expression through direct promoter interaction

Uridine phosphorylase (UPase) is a key enzyme in the pyrimidine salvage pathway. It reversibly catalyzes the catabolism of uridine to uracil; controls the homeostatic regulation of uridine concentration in plasma and tissues; and plays a role in the intracellular activation of 5-fluorouracil. We cloned the murine UPase gene promoter, a 1703-bp fragment, and determined the transcription initiation sites located at +1 and +92 bp of the cDNA sequence. Through transient expression analysis of the 5'-flanking region of UPase gene, we have evaluated the promoter activity for a series of fragments with 5'- to 3'-deletion in murine breast cancer EMT-6 cells and immortalized murine fibroblast NIH 3T3 cells. Cotransfection of the UPase promoter constructs (from -1619 to -445) containing p53 binding motif with the wild-type p53 construct resulted in a significant reduction of luciferase activity; however, this effect disappeared with the additional deletion of the -445 to -274 sequence to suggest the existence in this promoter region of a putative p53 recognition element. Similar cotransfection in murine embryo fibroblasts p53-/- confirmed the inhibitory role of p53 on the UPase promoter activity. The specificity of the interaction is demonstrated by nuclear protein-specific binding to the putative p53 recognition sequence using gel mobility shift assay and DNase I footprinting analysis. These data indicate the UPase gene is a novel target of p53, and its expression is down-regulated by p53 at the promoter level.

Zimmer splintage: a simple effective treatment for keloids following ear-piercing

An auricular keloid occurring following ear-piercing remains a difficult condition to treat. Various treatments have been described, with different reported degrees of success. Pressure therapy has been shown to be an effective treatment for auricular keloids, although the devices used have not all been universally accepted. We assessed 30 patients, between 1989 and 1999, who had been fitted with pressure devices made from Zimmer splints. There was a 50% or greater reduction in the size of each keloid when assessed at 1 year. Zimmer splints are cheap, readily available, easily moulded to fit the patient and can be decorated so that they can be worn as earrings.

The neural representation of nouns and verbs: PET studies

Neuropsychological studies of patients with selective deficits for nouns or verbs have been taken as evidence for the neural specialization of different word classes. Noun deficits are associated with lesions in anterior temporal regions while verb deficits arise from left inferior frontal lesions. However, neuroimaging studies do not unequivocally support this account, with only some studies supporting claims for regional specialization. We carried out two PET studies to determine whether there is any regional specialization for the processing of nouns and verbs. One study used the lexical decision task and the other used a more semantically demanding task, i.e. semantic categorization. We found robust activation of a semantic network extending from left inferior frontal cortex into the inferior temporal lobe, but no differences as a function of word class. We interpret these data within the framework of cognitive accounts in which conceptual knowledge is represented within a non-differentiated distributed system.

Probing the folding landscape of the Tetrahymena ribozyme: commitment to form the native conformation is late in the folding pathway

Large, structured RNAs traverse folding landscapes in which intermediates and long-lived misfolded states are common. To obtain a comprehensive description of the folding landscape for a structured RNA, it is necessary to understand the connections between productive folding pathways and pathways to these misfolded states. The Tetrahymena group I ribozyme partitions between folding to the native state and to a long-lived misfolded conformation. Here, we show that the observed rate constant for commitment to fold to the native or misfolded states is 1.9 min(-1) (37 degrees C, 10 mM Mg(2+)), the same within error as the rate constant for overall folding to the native state. Thus, the commitment to alternative folding pathways is made late in the folding process, concomitant with or after the rate-limiting step for overall folding. The ribozyme forms much of its tertiary structure significantly faster than it reaches this commitment point and the tertiary structure is expected to be stable, suggesting that the commitment to fold along pathways to the native or misfolded states is made from a partially structured intermediate. These results allow the misfolded conformation to be incorporated into a folding framework that reconciles previous data and gives quantitative information about the energetic topology of the folding landscape for this RNA.

A comparison of bupivacaine-fentanyl-morphine with bupivacaine-fentanyl-diamorphine for caesarean section under spinal anaesthesia

In a randomised double-blind trial, postoperative analgesia and side effects of intrathecal morphine 0.1 mg and intrathecal diamorphine 0.25 mg were compared. Sixty women were randomised to receive intrathecal injection of 12.5 mg hyperbaric bupivacaine and 12.5 microg fentanyl with either morphine 0.1 mg (group M), or diamorphine 0.25 mg (group D). All women received 100 mg diclofenac rectally at the end of surgery and were given intravenous morphine via a patient controlled analgesia (PCA) system. Pain, PCA morphine usage and side effects were assessed at 2, 4, 8 and 24 h after spinal anaesthesia. The two groups were comparable for quality of intraoperative analgesia. There were no significant differences between the groups in time to first PCA demand, morphine consumption or oral analgesic use in each time period. Significantly more patients in group M were nauseated at 4 h whilst at 24 h nausea was significantly worse in group D. There was no significant difference between the groups in the number of women vomiting in the 24-h period. The two groups were comparable for pruritus and drowsiness. We conclude that 0.25 mg subarachnoid diamorphine is a suitable alternative to 0.1 mg morphine for post caesarean section analgesia.

Comparative quantification of diverse serotypes of HIV-1 in plasma from a diverse population of patients

HIV-1 is characterised by extensive genetic variability encompassing at least 10 different phylogenetically related clades within the major group of HIV-1 subtypes. Most commercially available HIV-1 RNA plasma viral load assays have been optimised with clade B viruses and may yield misleadingly low RNA levels for nonclade B viruses that are increasingly found in Europe. In this study we compare the most recent versions of the Roche Amplicor HIV Monitor and the Chiron Quantiplex for ability to detect viraemia in a population of patients infected with a range of HIV-1 subtypes. EDTA-treated plasma was obtained from 206 patients. The Amplicor and Quantiplex assays were carried out in accordance with manufacturers' instructions. Results from 53/206 (25.7%) samples differed by >0.4 log between Amplicor 1.5 and Quantiplex 3.0. A >0.5 log and 1.0 log difference was detected between Amplicor 1.5 and Quantiplex 3.0 in 37/206 (17.9%) and 7/206 (3.4%) of samples, respectively. Overall, Amplicor 1.5 gave a median value of 0.22 log higher than Quantiplex 3.0. Discordant results were detected in 53 out of 206 (25.7%) samples. Of these 22 out of 123 (17.9%) samples were of UK origin, 18 out of 43 (41.9%) African, 1 out of 8 (12.5%) South American, 1 out of 6 (16.7%) North American, 4 out of 9 (44.4%) North European, 3 out of 11 (23.7%) South European and 3 out of 7 (42.3%) Asian samples, respectively. Serotyping revealed that discordant viral load results between Amplicor 1.5 and Quantiplex 3.0 occurred within samples from all subtypes (A-E). Despite the improvements made to both the Roche Amplicor and the Chiron Quantiplex assays discordant results were detected between the two assays in 25.7% of cases. In a substantial minority of patients there were major discrepancies between the two assays that were not explained by HIV subtype differences.

Ability of anaesthetists to identify a marked lumbar interspace

Anaesthetists' ability to identify correctly a marked lumbar interspace was assessed in 100 patients undergoing spinal magnetic resonance imaging scans. Using ink, one anaesthetist marked an interspace on the lower spine and attempted to identify its level with the patient in the sitting position. A second anaesthetist attempted to identify the level with the patient in the flexed lateral position. A marker capsule was taped over the ink mark and a routine scan performed. The actual level of markers ranged from one space below to four spaces above the level at which the anaesthetist believed it to be. The marker was one space higher than assumed in 51% of cases and was identified correctly in only 29%. Accuracy was unaffected by patient position (sitting or lateral), although it was impaired by obesity (p = 0.001) and positioning of the markers high on the lower back (p < 0.001). The spinal cord terminated below L(1) in 19% of patients. This, together with the risk of accidentally selecting a higher interspace than intended for intrathecal injection, implies that spinal cord trauma is more likely when higher interspaces are selected.