Intravenous magnesium sulphate in suspected acute myocardial infarction: results of the second Leicester Intravenous Magnesium Intervention Trial (LIMIT-2)

The cardiovascular actions of the magnesium ion at pharmacological concentrations include coronary and systemic vasodilatation, platelet inhibition, and antiarrhythmic effects. Magnesium has also been reported to protect myocardial tissue in experimental models of ischaemia and reperfusion. Several small clinical trials in suspected acute myocardial infarction have suggested that early mortality can be reduced by intravenous infusion of magnesium salts in the acute phase, but none has been of sufficient size to be conclusive. We therefore conducted a randomised, double blind, placebo controlled study in 2316 patients with suspected acute myocardial infarction who received either intravenous magnesium sulphate (8 mmol over 5 min followed by 65 mmol over 24 h) or physiological saline. The primary outcome measure was 28-day mortality, which was ascertained in 99.3% of patients. The groups were well balanced for prognostic factors. By intention-to-treat analysis mortality from all causes was 7.8% in the magnesium group and 10.3% in the placebo group (2p = 0.04), a relative reduction of 24% (95% confidence interval 1-43%). Within the coronary care unit the incidence of left ventricular failure was reduced by 25% (7-39%) in the magnesium group (2p = 0.009). There was no significant difference between the groups in the incidence of heart block or the use of antiarrhythmic drugs, direct-current cardioversion, or temporary pacing. Myocardial infarction was confirmed in 65% of each group, with closely similar rises in cardiac enzymes. The side-effects of magnesium treatment were transient flushing, related to speed of injection of the loading dose, and an increased incidence of sinus bradycardia (2p = 0.02). Exploratory subgroup analyses of 28-day mortality did not indicate any effect modification by thrombolysis or aspirin, or by previous treatment with beta blockers, calcium antagonists, or diuretics. Intravenous magnesium sulphate is a simple, safe, and widely applicable treatment. Its efficacy in reducing early mortality of myocardial infarction is comparable to, but independent of, that of thrombolytic or antiplatelet therapy.

Antisense-induced exon skipping and synthesis of dystrophin in the mdx mouse

Duchenne muscular dystrophy (DMD) is a severe muscle wasting disease arising from defects in the dystrophin gene, typically nonsense or frameshift mutations, that preclude the synthesis of a functional protein. A milder, allelic version of the disease, Becker muscular dystrophy, generally arises from in-frame deletions that allow synthesis of a shorter but still semifunctional protein. Therapies to introduce functional dystrophin into dystrophic tissue through either cell or gene replacement have not been successful to date. We report an alternative approach where 2'-O-methyl antisense oligoribonucleotides have been used to modify processing of the dystrophin pre-mRNA in the mdx mouse model of DMD. By targeting 2'-O-methyl antisense oligoribonucleotides to block motifs involved in normal dystrophin pre-mRNA splicing, we induced excision of exon 23, and the mdx nonsense mutation, without disrupting the reading frame. Exon 23 skipping was first optimized in vitro in transfected H-2K(b)-tsA58 mdx myoblasts and then induced in vivo. Immunohistochemical staining demonstrated the synthesis and correct subsarcolemmal localization of dystrophin and gamma-sarcoglycan in the mdx mouse after intramuscular delivery of antisense oligoribonucleotide:liposome complexes. This approach should reduce the severity of DMD by allowing a dystrophic gene transcript to be modified, such that it can be translated into a Becker-dystrophin-like protein.

Clinical characteristics with inflammation profiling of long COVID and association with 1-year recovery following hospitalisation in the UK: a prospective observational study

BACKGROUND

No effective pharmacological or non-pharmacological interventions exist for patients with long COVID. We aimed to describe recovery 1 year after hospital discharge for COVID-19, identify factors associated with patient-perceived recovery, and identify potential therapeutic targets by describing the underlying inflammatory profiles of the previously described recovery clusters at 5 months after hospital discharge.

METHODS

The Post-hospitalisation COVID-19 study (PHOSP-COVID) is a prospective, longitudinal cohort study recruiting adults (aged ≥18 years) discharged from hospital with COVID-19 across the UK. Recovery was assessed using patient-reported outcome measures, physical performance, and organ function at 5 months and 1 year after hospital discharge, and stratified by both patient-perceived recovery and recovery cluster. Hierarchical logistic regression modelling was performed for patient-perceived recovery at 1 year. Cluster analysis was done using the clustering large applications k-medoids approach using clinical outcomes at 5 months. Inflammatory protein profiling was analysed from plasma at the 5-month visit. This study is registered on the ISRCTN Registry, ISRCTN10980107, and recruitment is ongoing.

FINDINGS

2320 participants discharged from hospital between March 7, 2020, and April 18, 2021, were assessed at 5 months after discharge and 807 (32·7%) participants completed both the 5-month and 1-year visits. 279 (35·6%) of these 807 patients were women and 505 (64·4%) were men, with a mean age of 58·7 (SD 12·5) years, and 224 (27·8%) had received invasive mechanical ventilation (WHO class 7-9). The proportion of patients reporting full recovery was unchanged between 5 months (501 [25·5%] of 1965) and 1 year (232 [28·9%] of 804). Factors associated with being less likely to report full recovery at 1 year were female sex (odds ratio 0·68 [95% CI 0·46-0·99]), obesity (0·50 [0·34-0·74]) and invasive mechanical ventilation (0·42 [0·23-0·76]). Cluster analysis (n=1636) corroborated the previously reported four clusters: very severe, severe, moderate with cognitive impairment, and mild, relating to the severity of physical health, mental health, and cognitive impairment at 5 months. We found increased inflammatory mediators of tissue damage and repair in both the very severe and the moderate with cognitive impairment clusters compared with the mild cluster, including IL-6 concentration, which was increased in both comparisons (n=626 participants). We found a substantial deficit in median EQ-5D-5L utility index from before COVID-19 (retrospective assessment; 0·88 [IQR 0·74-1·00]), at 5 months (0·74 [0·64-0·88]) to 1 year (0·75 [0·62-0·88]), with minimal improvements across all outcome measures at 1 year after discharge in the whole cohort and within each of the four clusters.

INTERPRETATION

The sequelae of a hospital admission with COVID-19 were substantial 1 year after discharge across a range of health domains, with the minority in our cohort feeling fully recovered. Patient-perceived health-related quality of life was reduced at 1 year compared with before hospital admission. Systematic inflammation and obesity are potential treatable traits that warrant further investigation in clinical trials.

FUNDING

UK Research and Innovation and National Institute for Health Research.

Meiotic and epigenetic defects in Dnmt3L-knockout mouse spermatogenesis

The production of mature germ cells capable of generating totipotent zygotes is a highly specialized and sexually dimorphic process. The transition from diploid primordial germ cell to haploid spermatozoa requires genome-wide reprogramming of DNA methylation, stage- and testis-specific gene expression, mitotic and meiotic division, and the histone-protamine transition, all requiring unique epigenetic control. Dnmt3L, a DNA methyltransferase regulator, is expressed during gametogenesis, and its deletion results in sterility. We found that during spermatogenesis, Dnmt3L contributes to the acquisition of DNA methylation at paternally imprinted regions, unique nonpericentric heterochromatic sequences, and interspersed repeats, including autonomous transposable elements. We observed retrotransposition of an LTR-ERV1 element in the DNA from Dnmt3L-/- germ cells, presumably as a result of hypomethylation. Later in development, in Dnmt3L-/- meiotic spermatocytes, we detected abnormalities in the status of biochemical markers of heterochromatin, implying aberrant chromatin packaging. Coincidentally, homologous chromosomes fail to align and form synaptonemal complexes, spermatogenesis arrests, and spermatocytes are lost by apoptosis and sloughing. Because Dnmt3L expression is restricted to gonocytes, the presence of defects in later stages reveals a mechanism whereby early genome reprogramming is linked inextricably to changes in chromatin structure required for completion of spermatogenesis.

Preclinical characterization of GLPG0634, a selective inhibitor of JAK1, for the treatment of inflammatory diseases

The JAKs receive continued interest as therapeutic targets for autoimmune, inflammatory, and oncological diseases. JAKs play critical roles in the development and biology of the hematopoietic system, as evidenced by mouse and human genetics. JAK1 is critical for the signal transduction of many type I and type II inflammatory cytokine receptors. In a search for JAK small molecule inhibitors, GLPG0634 was identified as a lead compound belonging to a novel class of JAK inhibitors. It displayed a JAK1/JAK2 inhibitor profile in biochemical assays, but subsequent studies in cellular and whole blood assays revealed a selectivity of ∼30-fold for JAK1- over JAK2-dependent signaling. GLPG0634 dose-dependently inhibited Th1 and Th2 differentiation and to a lesser extent the differentiation of Th17 cells in vitro. GLPG0634 was well exposed in rodents upon oral dosing, and exposure levels correlated with repression of Mx2 expression in leukocytes. Oral dosing of GLPG0634 in a therapeutic set-up in a collagen-induced arthritis model in rodents resulted in a significant dose-dependent reduction of the disease progression. Paw swelling, bone and cartilage degradation, and levels of inflammatory cytokines were reduced by GLPG0634 treatment. Efficacy of GLPG0634 in the collagen-induced arthritis models was comparable to the results obtained with etanercept. In conclusion, the JAK1 selective inhibitor GLPG0634 is a promising novel therapeutic with potential for oral treatment of rheumatoid arthritis and possibly other immune-inflammatory diseases.

Specific removal of the nonsense mutation from the mdx dystrophin mRNA using antisense oligonucleotides

The mdx mouse, which carries a nonsense mutation in exon 23 of the dystrophin gene, has been used as an animal model of Duchenne muscular dystrophy to evaluate cell or gene replacement therapies. Despite the mdx mutation, which should preclude the synthesis of a functional dystrophin protein, rare, naturally occurring dystrophin-positive fibres have been observed in mdx muscle tissue. These dystrophin-positive fibres are thought to have arisen from an exon-skipping mechanism, either somatic mutations or alternative splicing. Increasing the frequency of these fibres may offer another therapeutic approach to reduce the severity of Duchenne muscular dystrophy. Antisense oligonucleotides have been shown to block aberrant splicing in the human beta-globin gene. We wished to use a similar approach to re-direct normal processing of the dystrophin pre-mRNA and induce specific exon skipping. Antisense 2'-O-methyl-oligoribonucleotides, directed to the 3' and 5' splice sites of introns 22 and 23, respectively in the mdx pre-mRNA, were used to transfect myoblast cultures. The 5' antisense oligonucleotide appeared to efficiently displace factors normally involved in the removal of intron 23 so that exon 23 was also removed during the splicing of the dystrophin pre-mRNA. Approximately 50% of the dystrophin gene mRNAs were missing this exon 6 h after transfection of primary mdx myotubes, with all transcripts showing skipping of exon 23 after 24 h. Deletion of exon 23 does not disrupt the reading frame and should allow the synthesis of a shorter but presumably functional Becker-like dystrophin. Molecular intervention at dystrophin pre-mRNA splicing has the potential to reduce the severity of a Duchenne mutation to the milder Becker phenotype.

[3H]L-655,708, a novel ligand selective for the benzodiazepine site of GABAA receptors which contain the alpha 5 subunit

A compound (L-655,708) has been identified which has at least 50-fold selectivity for the benzodiazepine site on GABAA receptors containing an alpha 5 subunit over those containing an alpha 1, alpha 2, alpha 3 or alpha 6 subunit in combination with beta 3 and gamma 2. The compound was radiolabelled with tritium and investigated as a novel radioligand which recognizes the benzodiazepine site of GABAA receptors which contain the alpha 5 subunit. [3H]L-655,708 labels one saturable and specific population of binding sites in rat hippocampus with a Kd of 2.4 +/- 0.7 nM and a Bmax of 256 +/- 42 fmol/mg protein. The pharmacology of the binding site labelled was consistent with that of receptors present in cells transfected with alpha 5, beta 2 and gamma 2 and with receptors immunoprecipitated from rat brain with an alpha 5-selective antiserum. It is concluded that [3H]L-655,708 is the first radioligand to date which is selective for any BZ2 subtype of the GABAA receptor and should provide a valuable tool for elucidating the structure and function of the alpha 5-containing GABAA receptor subtype.

Antisense oligonucleotide-induced exon skipping restores dystrophin expression in vitro in a canine model of DMD

Manipulation of pre-mRNA splicing by antisense oligonucleotides (AOs) offers considerable potential for a number of genetic disorders. One of these is Duchenne muscular dystrophy (DMD), where mutations in the dystrophin gene typically result in premature termination of translation that causes a loss of functional protein. AOs can induce exon skipping such that the mutation is by-passed and the reading frame restored, producing an internally deleted protein similar to that found in the milder Becker muscular dystrophy. To date, this approach has been applied to the mdx mouse model in vitro and in vivo and in human myoblast cultures. Here, we report the application of AO-directed exon skipping to induce dystrophin expression in vitro in a canine model of DMD, golden retriever muscular dystrophy (GRMD). The efficacy of 2'-O-methyl phosphorothioate (2OMe), phosphorodiamidate morpholino oligomers (PMOs) and peptide-linked PMOs (PMO-Pep) to induce dystrophin expression was assessed. The 2OMe chemistry was only effective for short-term induction of corrected transcript and could not induce detectable dystrophin protein. The PMO chemistry generally induced limited exon skipping at only high concentrations; however, a low level of dystrophin protein was produced in treated cells. Use of the PMO-Pep, applied here for the first time to a DMD model, was able to induce high and sustained levels of exon skipping and induced the highest level of dystrophin expression with no apparent adverse effects upon the cells. The induction of dystrophin in the GRMD model offers the potential for further testing of AO delivery regimens in a larger animal model of DMD, in preparation for application in human clinical trials.

Older adults and withdrawal from benzodiazepine hypnotics in general practice: effects on cognitive function, sleep, mood and quality of life

BACKGROUND

Older adults are the main recipients of repeat prescriptions for benzodiazepine (BZD) hypnotics. BZDs can impair cognitive function and may not aid sleep when taken continuously for years. This study therefore aimed to determine if withdrawing from BZDs leads to changes in patients' cognitive function, quality of life, mood and sleep.

METHOD

One hundred and ninety-two long-term users of BZD hypnotics, aged > or = 65 years, were identified in 25 general practices. One hundred and four who wished to withdraw were randomly allocated to one of two groups under double-blind, placebo controlled conditions: group A's BZD dose was tapered from week 1 of the trial; group B were given their usual dose for 12 weeks and then it was tapered. An additional group (C) of 35 patients who did not wish to withdraw from BZDs participated as 'continuers'. All patients were assessed at 0, 12 and 24 weeks and 50% were reassessed at 52 weeks.

RESULTS

Sixty per cent of patients had taken BZDs continuously for > 10 years; 27% for > 20 years. Of all patients beginning the trial, 80% had successfully withdrawn 6 months later. There was little difference between groups A and B, but these groups differed from continuers (C) in that the performance of the withdrawers on several cognitive/psychomotor tasks showed relative improvements at 24 or 52 weeks. Withdrawers and continuers did not differ in sleep or BZD withdrawal symptoms.

CONCLUSIONS

These results have clear implications for clinical practice. Withdrawal from BZDs produces some subtle cognitive advantages for older people, yet little in the way of withdrawal symptoms or emergent sleep difficulties. These findings also suggest that, taken long-term, BZDs do not aid sleep.

Major threats of pollution and climate change to global coastal ecosystems and enhanced management for sustainability

Coastal zone is of great importance in the provision of various valuable ecosystem services. However, it is also sensitive and vulnerable to environmental changes due to high human populations and interactions between the land and ocean. Major threats of pollution from over enrichment of nutrients, increasing metals and persistent organic pollutants (POPs), and climate change have led to severe ecological degradation in the coastal zone, while few studies have focused on the combined impacts of pollution and climate change on the coastal ecosystems at the global level. A global overview of nutrients, metals, POPs, and major environmental changes due to climate change and their impacts on coastal ecosystems was carried out in this study. Coasts of the Eastern Atlantic and Western Pacific were hotspots of concentrations of several pollutants, and mostly affected by warming climate. These hotspots shared the same features of large populations, heavy industry and (semi-) closed sea. Estimation of coastal ocean capital, integrated management of land-ocean interaction in the coastal zone, enhancement of integrated global observation system, and coastal ecosystem-based management can play effective roles in promoting sustainable management of coastal marine ecosystems. Enhanced management from the perspective of mitigating pollution and climate change was proposed.

Long-term outcome after intravenous magnesium sulphate in suspected acute myocardial infarction: the second Leicester Intravenous Magnesium Intervention Trial (LIMIT-2)

The second Leicester Intravenous Magnesium Intervention Trial (LIMIT-2) examined the effect of an intravenous regimen of magnesium sulphate in 2316 patients with suspected acute myocardial infarction. Treatment, according to a double-blind randomised protocol, was started with a loading injection, before any thrombolytic therapy, and continued with a maintenance infusion for a further 24 h. Cause-specific mortality of randomised patients has now been examined over 1.0-5.5 (mean 2.7) years of follow-up. Mortality rate from ischaemic heart disease was reduced by 21% (95% CI 5-35%, p = 0.01) and all-cause mortality rate reduced by 16% (2-29%, p = 0.03) in magnesium-treated patients. Magnesium protects the contractile function of the myocardium from reperfusion injury ("stunning") in experimental models; this observation accords with the 25% (7-39%, p = 0.009) reduction in early left ventricular failure in the magnesium group of LIMIT-2. For such protection to occur, magnesium must be raised by the time of reperfusion since the injury is immediate. In the clinical context the timing of magnesium treatment in relation to thrombolytic therapy or spontaneous reperfusion is likely to be critical. The early benefits of this simple and safe intervention are reflected in improved long-term survival.

Evaluation and optimization of the new EBT2 radiochromic film dosimetry system for patient dose verification in radiotherapy

A new radiochromic film, the yellow Gafchromic EBT2, has been marketed as a drop-in replacement for the discontinued blue EBT film. In order to verify the manufacturer's claims prior to clinical use, EBT2 was characterized in transmission, and the less commonly used, reflection modes with an Epson Expression 10000XL A3 flatbed scanner. The red channel was confirmed to provide the greatest sensitivity and was used for all measurements. The post-irradiation darkening of the film was investigated, and the relative response was found to be dose dependent with higher doses stabilizing earlier than lower doses. After 13 h all dose levels had stabilized to within 1% of their value at 24 h. Uniformity of irradiated EBT2 films was within 0.8% and 1.2% (2SD of signal), in reflection and transmission modes, respectively. The light scattering effect, arising from the structure and thickness of EBT2, was found to give rise to an apparent scanner non-uniformity of up to 5.5% in signal. In reflection mode, differences of up to 1.2% were found between the signal obtained from a small film fragment (5 x 5 cm(2)) and the signal obtained from the same fragment bordered by extra film. Further work is needed to determine the origin of this effect, as there will be implications for reflection dosimetry of intensity modulated fields; reflection mode cannot yet be regarded as a viable alternative to transmission mode. Our results suggest that EBT2 film is a valid alternative, rather than a direct replacement for EBT film.

Bilateral retinopathy, aplastic anaemia, and central nervous system abnormalities: a new syndrome?

A male infant was found to have bilateral exudative retinopathy at 6 months of age. A month later severe aplastic anaemia was diagnosed, eventually leading to the infant's death. Additional features of this seemingly new syndrome were intrauterine growth retardation, fine sparse hair, fine reticulate skin pigmentation, ataxia because of cerebellar hypoplasia, cerebral calcifications, extensor hypertonia, and progressive psychomotor retardation.

Translation of chick aortic elastin messenger ribonucleic acid. Comparison to elastin synthesis in chick aorta organ culture

Studies were undertaken to define the molecular size of the elastin primary gene product. Translation of chick aortic messenger ribonucleic acid (mRNA) in an mRNA-dependent reticulocyte lysate resulted in the synthesis of two major proteins of 70 000 and 73 000 molecular weights. Both proteins were shown to be soluble forms of elastin by isotope incorporation, immunoprecipitation, collagenase and cyanogen bromide sensitivity, and two-dimensional gel electrophoresis. The 70 000-dalton protein behaves similarly to authentic tropoeleastin in sodium dodecyl sulfate gel electrophoresis. There was no evidence for a high molecular weight form of soluble elastin, although procollagen chains were indirectly identified among the aortic mRNA-directed translation products. The same molecular size proteins were also seen in organ cultures of chick embryonic aortas labeled with [3H]valine. However, the 73 000-dalton protein was not extractable in a neutral salt buffer but was found only if the aortas were extracted with urea in the presence of reducing and alkylating reagents. The results from these studies suggest that elastin is first synthesized as two distinct polypeptide chains which differ slightly in size and overall charge. The possibility that these two proteins may associate posttranslationally to form a dimer prior to secretion is postulated to explain the existence of a putative proelastin molecule seen in other systems.

Late intellectual and academic outcomes following traumatic brain injury sustained during early childhood

OBJECT

Although long-term neurological outcomes after traumatic brain injury (TBI) sustained early in life are generally unfavorable, the effect of TBI on the development of academic competencies is unknown. The present study characterizes intelligence quotient (IQ) and academic outcomes an average of 5.7 years after injury in children who sustained moderate to severe TBI prior to 6 years of age.

METHODS

Twenty-three children who suffered inflicted or noninflicted TBI between the ages of 4 and 71 months were enrolled in a prospective, longitudinal cohort study. Their mean age at injury was 21 months; their mean age at assessment was 89 months. The authors used general linear modeling approaches to compare IQ and standardized academic achievement test scores from the TBI group and a community comparison group (21 children). Children who sustained early TBI scored significantly lower than children in the comparison group on intelligence tests and in the reading, mathematical, and language domains of achievement tests. Forty-eight percent of the TBI group had IQs below the 10th percentile. During the approximately 5-year follow-up period, longitudinal IQ testing revealed continuing deficits and no recovery of function. Both IQ and academic achievement test scores were significantly related to the number of intracranial lesions and the lowest postresuscitation Glasgow Coma Scale score but not to age at the time of injury. Nearly 50% of the TBI group failed a school grade and/or required placement in self-contained special education classrooms; the odds of unfavorable academic performance were 18 times higher for the TBI group than the comparison group.

CONCLUSIONS

Traumatic brain injury sustained early in life has significant and persistent consequences for the development of intellectual and academic functions and deleterious effects on academic performance.

Message in a Bubble: Shuttling Small RNAs and Proteins Between Cells and Interacting Organisms Using Extracellular Vesicles

Communication between plant cells and interacting microorganisms requires the secretion and uptake of functional molecules to and from the extracellular environment and is essential for the survival of both plants and their pathogens. Extracellular vesicles (EVs) are lipid bilayer-enclosed spheres that deliver RNA, protein, and metabolite cargos from donor to recipient cells and participate in many cellular processes. Emerging evidencehas shown that both plant and microbial EVs play important roles in cross-kingdom molecular exchange between hosts and interacting microbes to modulate host immunity and pathogen virulence. Recent studies revealed that plant EVs function as a defense system by encasing and delivering small RNAs (sRNAs) into pathogens, thereby mediating cross-species and cross-kingdom RNA interference to silence virulence-related genes. This review focuses on the latest advances in our understanding of plant and microbial EVs and their roles in transporting regulatory molecules, especially sRNAs, between hosts and pathogens. EV biogenesis and secretion are also discussed, as EV function relies on these important processes.

Strokes in the elderly - higher acute and 3-month mortality - an explanation

AIM

Stroke is common in older people. The objective of the study was to determine if older stroke patients have a higher mortality and disability compared with younger patients for comparable stroke severity and pathology and whether there is an explanation for the difference.

METHODS

A prospective study was undertaken in 296 consecutive patients admitted with acute stroke. Patients were studied for neurological features, pre-stroke functional disability, severity of stroke defined by stroke syndromes and pathology of stroke on CT scans (202 patients). Post-stroke disability was defined according to the functional status within 72 h of admission. A record was made of the intercurrent illness while the patients were in acute wards and of the risk factors. Patients were dichotomized into two age groups: younger group - up to 75 years (163 patients) and older group - over 75 years (133 patients). Outcome was measured according to (1) discharge status from acute wards, i.e., dead or alive, and (2) mortality at 3 months.

RESULTS

Although there was no significant difference in severe clinical stroke syndromes (p = 0.72), CT scan features (p = 0.68) and pyrexia (0.38) between the two age groups, the older patients had significantly more disabling strokes as defined on Barthel Index (p = 0.015) and a higher mortality in the acute phase (p < 0.01) and at 3 months (p = 0.001). The older stroke patients had more severe pre-stroke disability (p < 0.001) and more severe neurological impairment for similar stroke severity and pathology. Early mortality was more influenced by pre-stroke global health than age whereas 3-month mortality was influenced by age to the exclusion of all other known prognostic factors.

CONCLUSION

The older stroke patients have more disabling stroke and an increased mortality for a similar spectrum of stroke severity and pathology. The explanation for higher mortality of the older patients is the poor pre-stroke health and higher immediate post-stroke disability.

Guidelines for the management of glucocorticoids during the peri-operative period for patients with adrenal insufficiency: Guidelines from the Association of Anaesthetists, the Royal College of Physicians and the Society for Endocrinology UK

These guidelines aim to ensure that patients with adrenal insufficiency are identified and adequately supplemented with glucocorticoids during the peri-operative period. There are two major categories of adrenal insufficiency. Primary adrenal insufficiency is due to diseases of the adrenal gland (failure of the hormone-producing gland), and secondary adrenal insufficiency is due to deficient adrenocorticotropin hormone secretion by the pituitary gland, or deficient corticotropin-releasing hormone secretion by the hypothalamus (failure of the regulatory centres). Patients taking physiological replacement doses of corticosteroids for either primary or secondary adrenal insufficiency are at significant risk of adrenal crisis and must be given stress doses of hydrocortisone during the peri-operative period. Many more patients other than those with adrenal and hypothalamic-pituitary causes of adrenal failure are receiving glucocorticoids as treatment for other medical conditions. Daily doses of prednisolone of 5 mg or greater in adults and 10-15 mg.m^-2 hydrocortisone equivalent or greater in children may result in hypothalamo-pituitary-adrenal axis suppression if administered for 1 month or more by oral, inhaled, intranasal, intra-articular or topical routes; this chronic administration of glucocorticoids is the most common cause of secondary adrenal suppression, sometimes referred to as tertiary adrenal insufficiency. A pragmatic approach to adrenal replacement during major stress is required; considering the evidence available, blanket recommendations would not be appropriate, and it is essential for the clinician to remember that adrenal replacement dosing following surgical stress or illness is in addition to usual steroid treatment. Patients with previously undiagnosed adrenal insufficiency sometimes present for the first time following the stress of surgery. Anaesthetists must be familiar with the symptoms and signs of acute adrenal insufficiency so that inadequate supplementation or undiagnosed adrenal insufficiency can be detected and treated promptly. Delays may prove fatal.

The accumulation of glutamate is necessary for optimal growth of Salmonella typhimurium in media of high osmolality but not induction of the proU operon

Synthesis of glutamate can be limited in bacterial strains carrying mutations to loss of function of glutamate synthase (2-oxoglutarate:glutamine aminotransferase) by using low concentrations of NH4+ in the growth medium. By using such gltB/D mutant strains of Salmonella typhimurium, we demonstrated that: (i) a large glutamate pool, previously observed to correlate with growth at high external osmolality, is actually required for optimal growth under these conditions; (ii) the osmoprotectant glycine betaine (N,N,N-trimethylglycine) apparently cannot substitute for glutamate; and (iii) accumulation of glutamate is not necessary for high levels of induction of the proU operon in vivo. Expression of the proU operon, which encodes a transport system for the osmoprotectants proline and glycine betaine, is induced > 100-fold in the wild-type strain under conditions of high external osmolality. Ramirez et al. (R. M. Ramirez, W. S. Prince, E. Bremer, and M. Villarejo, Proc. Natl. Acad. Sci. USA 86:1153-1157, 1989) observed and we confirmed that in vitro expression of the lacZ gene from the wild-type proU promoter is stimulated by 0.2 to 0.3 M K glutamate. However, we observed a very similar stimulation for lacZ expressed from the lacUV5 promoter and from the proU promoter when an important negative regulatory element downstream of this promoter (the silencer) was deleted. Since the lacUV5 promoter is not osmotically regulated in vivo and osmotic regulation of the proU promoter is largely lost as a result of deletion of the silencer, we conclude that stimulation of proU expression by K glutamate in vitro is not a specific osmoregulatory response but probably a manifestation of the optimization of in vitro transcription-translation at high concentrations of this solute. Our in vitro and in vivo results demonstrate that glutamate is not an obligatory component of the transcriptional regulation of the proU operon.

Directed assembly of multilayers--the case of Prussian blue

We introduce the concept of 'directed assembly' of multilayers on surfaces: the overall process involves the exposure of a surface to a series of solutions containing, alternately, adsorbable cations and adsorbable anions, and these are gradually built up into well-defined multilayer structures.