Reducing the rate of negative ureteroscopy: predictive factors and the role of preoperative imaging

INTRODUCTION

The aim of this study was to investigate factors that may predict a negative ureteroscopy (URS) performed for ureteric calculi in prestented patients and to assess preoperative imaging in reducing the rate of negative URS.

METHODS

Data were collected on emergency stent placement for a ureteric calculus from April 2011 to February 2016 (Group A) and October 2016 to October 2019 (Group B). Data included patient demographics, indication for a stent, stone characteristics, baseline bloods, urine culture, readmission, negative URS rate and the use of pre-URS imaging. Multivariate logistic regression was used for statistical analysis.

RESULTS

Of 257 patients who underwent emergency stent insertion, 251 underwent deferred URS for a ureteric calculus and 6 avoided URS due to pre-URS imaging. Indications for stent were pain (42%), sepsis (39%) and acute kidney injury (19%). Mean stone size was 7.8mm, mean stone density was 699 Hounsfield units (HU) and the stone locations were upper (62%), mid (13%) and lower ureter (25%). The overall negative URS rate was 12%. The negative URS rate was lower in patients with pre-URS imaging compared with those with none, 6% and 14%, respectively (OR=2.33, 95% CI: 0.69-7.56, p=0.2214). Logistic regression analysis indicated stone size as the only significant predictor of a negative URS, where the greater the size of the stone the less likely URS would be negative (β=0.75, 95% CI: 0.60-0.94 p=0.011).

CONCLUSIONS

Utilising pre-URS imaging can lead to a reduction in negative URS rate. Stone size <5mm appears to be the subgroup most likely to benefit from imaging.

An effective CTL peptide vaccine for Ebola Zaire Based on Survivors' CD8+ targeting of a particular nucleocapsid protein epitope with potential implications for COVID-19 vaccine design

The 2013-2016 West Africa EBOV epidemic was the biggest EBOV outbreak to date. An analysis of virus-specific CD8+ T-cell immunity in 30 survivors showed that 26 of those individuals had a CD8+ response to at least one EBOV protein. The dominant response (25/26 subjects) was specific to the EBOV nucleocapsid protein (NP). It has been suggested that epitopes on the EBOV NP could form an important part of an effective T-cell vaccine for Ebola Zaire. We show that a 9-amino-acid peptide NP44-52 (YQVNNLEEI) located in a conserved region of EBOV NP provides protection against morbidity and mortality after mouse adapted EBOV challenge. A single vaccination in a C57BL/6 mouse using an adjuvanted microsphere peptide vaccine formulation containing NP44-52 is enough to confer immunity in mice. Our work suggests that a peptide vaccine based on CD8+ T-cell immunity in EBOV survivors is conceptually sound and feasible. Nucleocapsid proteins within SARS-CoV-2 contain multiple Class I epitopes with predicted HLA restrictions consistent with broad population coverage. A similar approach to a CTL vaccine design may be possible for that virus.

Pause Measures during Reading and Recall in Serial List Learning

An investigation is reported into pausing and grouping during the serial learning of letter strings, when presented randomly by length and when presented in ascending order. Mean pause times for the reading and recall of longer lists were significantly greater than for lists of shorter span due to extended pausing at specific list positions. In general, reading rhythms were duplicated during recall. Subjects were highly consistent in maintaining their level of pause duration across lists and responded to additions in list length by increasing their number of groups, not by increasing group size. Triadic sequences were the most popular form of spontaneous organization. Pausing measures are discussed as indices of organizational strategies.

Axillary tumour burden in women with a fine-needle aspiration/core biopsy-proven positive node on ultrasonography compared to women with a positive sentinel node

Background

The sensitivity of axillary ultrasonography (AUS) has increased in recent years, enabling detection of even low-volume axillary nodal metastases. The aim here was to evaluate the axillary tumour burden in women with a fine-needle aspiration/core biopsy-proven positive node on AUS and in those with a positive sentinel node biopsy (SNB).

Methods

This retrospective cohort study included all patients with early breast cancer who had AUS and axillary lymph node dissection (ALND) between 2011 and 2014.

Results

A total of 332 patients who had ALND were eligible for the study, 191 (57·5 per cent) in the AUS-positive group and 141 (42·5 per cent) in the SNB-positive group. Patients in the AUS-positive group were older at diagnosis (P = 0·018), more likely to have larger tumours (P = 0·002), higher tumour grade (P = 0·005), positive human epidermal growth factor 2 status (P = 0·015), and negative oestrogen receptor status (P &lt; 0·001). The AUS-positive group also had a larger number of lymph nodes with macrometastases (P &lt; 0·001) and were more likely to have extranodal invasion (P &lt; 0·001). In the AUS-positive group, 40·3 per cent of patients (77 of 191) had only one or two nodes with macrometastases identified at histology after ALND. Tumour size no larger than 20 mm, invasive ductal or lobular histology and breast-conserving surgery were associated with the presence of two or fewer macrometastases at ALND. Only tumour size and tumour histology remained significant in multiple logistic regression analysis.

Conclusion

Patients with AUS-detected metastases had a higher axillary tumour burden than those with SNB-detected metastases. Around 40 per cent of patients with AUS-detected nodal disease had one or two nodes with macrometastases and were thus overtreated by ALND.

Secukinumab, a fully human anti-interleukin-17A monoclonal antibody, exhibits minimal immunogenicity in patients with moderate-to-severe plaque psoriasis

BACKGROUND

The proinflammatory cytokine interleukin (IL)-17A plays a pivotal role in psoriasis pathogenesis. Secukinumab, a fully human monoclonal antibody (mAb) that selectively targets IL-17A, has been demonstrated to be highly efficacious for the treatment of moderate-to-severe psoriasis, starting at early time points, with a sustained effect and a favourable safety profile. mAb therapies may be associated with production of antidrug antibodies (ADAs) that can affect drug pharmacokinetics, diminish response or cause hypersensitivity reactions.

OBJECTIVES

To investigate the immunogenicity of secukinumab across six phase III clinical trials in which patients with plaque psoriasis were treated with secukinumab for up to 52 weeks and additionally followed up at week 60.

METHODS

Immunogenicity in patients with plaque psoriasis exposed to secukinumab was evaluated at baseline and at weeks 12, 24, 52 and 60. Treatment-emergent (TE)-ADAs were defined as a positive ADA signal detected in post-treatment samples from patients with a negative baseline signal. Confirmed positive samples were further analysed for their drug-neutralizing potential.

RESULTS

Among 2842 patients receiving secukinumab and evaluated for ADAs, 11 (0·4%) developed TE-ADAs. Associations between TE-ADAs and secukinumab dose, frequency or mode of administration were not observed. Neutralizing antibodies were detected in three of nine evaluable patients with TE-ADAs.

CONCLUSIONS

Secukinumab immunogenicity was low, as shown by TE-ADA detection in only 11 of 2842 (0·4%) patients with moderate-to-severe plaque psoriasis treated with secukinumab. All but one of the patients with TE-ADAs were biologic naive. Neither TE-ADAs nor neutralizing antibodies were associated with loss of secukinumab efficacy or issues of clinical concern.

Integrated pharmacokinetic, pharmacodynamic and immunogenicity profiling of an anti-CCL21 monoclonal antibody in cynomolgus monkeys

QBP359 is an IgG1 human monoclonal antibody that binds with high affinity to human CCL21, a chemokine hypothesized to play a role in inflammatory disease conditions through activation of resident CCR7-expressing fibroblasts/myofibroblasts. The pharmacokinetics (PK) and pharmacodynamics (PD) of QBP359 in non-human primates were characterized through an integrated approach, combining PK, PD, immunogenicity, immunohistochemistry (IHC) and tissue profiling data from single- and multiple-dose experiments in cynomolgus monkeys. When compared with regular immunoglobulin typical kinetics, faster drug clearance was observed in serum following intravenous administration of 10 mg/kg and 50 mg/kg of QBP359. We have shown by means of PK/PD modeling that clearance of mAb-ligand complex is the most likely explanation for the rapid clearance of QBP359 in cynomolgus monkey. IHC and liquid chromatography mass spectrometry data suggested a high turnover and synthesis rate of CCL21 in tissues. Although lymphoid tissue was expected to accumulate drug due to the high levels of CCL21 present, bioavailability following subcutaneous administration in monkeys was 52%. In human disease states, where CCL21 expression is believed to be expressed at 10-fold higher concentrations compared with cynomolgus monkeys, the PK/PD model of QBP359 and its binding to CCL21 suggested that very large doses requiring frequent administration of mAb would be required to maintain suppression of CCL21 in the clinical setting. This highlights the difficulty in targeting soluble proteins with high synthesis rates.

Impact of climate change and population growth on a risk assessment for endocrine disruption in fish due to steroid estrogens in England and Wales

In England and Wales, steroid estrogens: estrone, estradiol and ethinylestradiol have previously been identified as the main chemicals causing endocrine disruption in male fish. A national risk assessment is already available for intersex in fish arising from estrogens under current flow conditions. This study presents, to our knowledge, the first set of national catchment-based risk assessments for steroid estrogen under future scenarios. The river flows and temperatures were perturbed using three climate change scenarios (ranging from relatively dry to wet). The effects of demographic changes on estrogen consumption and human population served by sewage treatment works were also included. Compared to the current situation, the results indicated increased future risk:the percentage of high risk category sites, where endocrine disruption is more likely to occur, increased. These increases were mainly caused by changes in human population. This study provides regulators with valuable information to prepare for this potential increased risk.

Targeted trapping surveys shed new light on the distribution and habitat characteristics of the Carpentarian pseudantechinus (Pseudantechinus mimulus), a threatened dasyurid marsupial

Through a targeted trapping survey we provide important new records and habitat descriptions for the Carpentarian pseudantechinus (Pseudantechinus mimulus) on mainland Australia, including the first records from landscapes dominated by rocks other than sandstone. We hypothesise that continued invasion by an introduced pasture grass may constitute an emerging threatening process to this rare species.

Microgeographic socio-genetic structure of an African cooperative breeding passerine revealed: integrating behavioural and genetic data

Dispersal can be motivated by multiple factors including sociality. Dispersal behaviour affects population genetic structure that in turn reinforces social organization. We combined observational information with individual-based genetic data in the Karoo scrub-robin, a facultative cooperatively breeding bird, to understand how social bonds within familial groups affect mating patterns, cause sex asymmetry in dispersal behaviour and ultimately influence the evolution of dispersal. Our results revealed that males and females do not have symmetrical roles in structuring the population. Males are extremely philopatric and tend to delay dispersal until they gain a breeding position within a radius of two territories around the natal site. By contrast, females dispersed over larger distances, as soon as they reach independence. This resulted in male neighbourhoods characterized by high genetic relatedness. The long-distance dispersal strategy of females ensured that Karoo scrub-robins do not pair with relatives thereby compensating for male philopatry caused by cooperation. The observed female-biased strategy seems to be the most prominent mechanism to reduce the risk of inbreeding that characterizes social breeding system. This study demonstrates that tying together ecological data, such as breeding status, determining social relationships with genetic data, such as kinship, provides valuable insights into the proximate causes of dispersal, which are central to any evolutionary interpretation.

Pharmacokinetics of the monohydroxy derivative of oxcarbazepine and its enantiomers after a single intravenous dose given as racemate compared with a single oral dose of oxcarbazepine

Oxcarbazepine (OXC) is an antiepileptic drug. In humans, OXC is metabolized via reduction and conjugation. Monohydroxy derivative of OXC (MHD) is the major pharmacologically active component after OXC ingestion. This study was performed to characterize the disposition of the two enantiomers of MHD after oral and intravenous administration and to estimate the bioavailability of MHD after a single oral dose administration of OXC compared to a single intravenous administration of MHD. The study was performed in two parts. In a first pilot study, three intravenous doses were given in an ascending manner (150, 200, and 250 mg of MHD; one subject per dose level) to assess the safety, tolerability, and basic pharmacokinetics. Part two was an open, single-center, randomized, two-way crossover, single-dose trial in 12 healthy adult subjects (n = 6 males and n = 6 females) given OXC orally (one film-coated 300-mg tablet of OXC) and MHD intravenously (250 mg infused over 30 min). Concentrations of OXC and its metabolites were measured by means of high-performance liquid chromatography methods. OXC given as a tablet is completely absorbed in man under fasting conditions. When MHD is given intravenously, (S)-MHD predominates as free compound in plasma. When OXC is administered orally, the ratio of the area-under-the-curve values of (S)-MHD over (R)-MHD equals 3.8, indicating an enantioselective reduction of the prochiral carbonyl group of OXC.

Potency values from the local lymph node assay: application to classification, labelling and risk assessment

Hundreds of chemicals are contact allergens but there remains a need to identify and characterise accurately skin sensitising hazards. The purpose of this review was fourfold. First, when using the local lymph node assay (LLNA), consider whether an exposure concentration (EC3 value) lower than 100% can be defined and used as a threshold criterion for classification and labelling. Second, is there any reason to revise the recommendation of a previous ECETOC Task Force regarding specific EC3 values used for sub-categorisation of substances based upon potency? Third, what recommendations can be made regarding classification and labelling of preparations under GHS? Finally, consider how to integrate LLNA data into risk assessment and provide a rationale for using concentration responses and corresponding no-effect concentrations. Although skin sensitising chemicals having high EC3 values may represent only relatively low risks to humans, it is not possible currently to define an EC3 value below 100% that would serve as an appropriate threshold for classification and labelling. The conclusion drawn from reviewing the use of distinct categories for characterising contact allergens was that the most appropriate, science-based classification of contact allergens according to potency is one in which four sub-categories are identified: 'extreme', 'strong', 'moderate' and 'weak'. Since draining lymph node cell proliferation is related causally and quantitatively to potency, LLNA EC3 values are recommended for determination of a no expected sensitisation induction level that represents the first step in quantitative risk assessment.

T helper 2 biased de novo immune response to Keyhole Limpet Hemocyanin in humans

BACKGROUND

Allergen-specific T helper 2 (Th2) cells play an important role in the pathogenesis of atopic disorders. To date, no model system exists in humans that would allow the monitoring of a developing de novo Th2 immune response in vivo.

OBJECTIVE

The aim of the experiment was to establish an immunization protocol inducing a de novo Th2 response in humans using Keyhole Limpet Hemocyanin (KLH) as neo-antigen.

METHODS

The double-blind placebo-controlled, parallel-group study was conducted in two groups of subjects (16 healthy volunteers and 16 patients with allergic rhinitis). Subjects received three i.m. injections of 100 microg KLH adsorbed to aluminium hydroxide or matching placebo (alum alone) in intervals of 2 weeks. On day 43, KLH alone (10 microg) was given intra-dermally (i.d.) to all subjects to assess immediate and late-phase skin responses.

RESULTS

The immunization protocol was well tolerated, highly specific and efficient. Antigen-specific production of Th2-cytokines (mainly IL-5 and IL-13) by PBMCs suggested a Th2 pattern, as did the presence of KLH-specific IgG4 in sera. Intra-dermal KLH challenge induced an immediate-type of response predominantly in atopic subjects followed by a late-phase skin reaction. The latter was accompanied by the presence of IgE(+) cells, eosinophils and a strong up-regulation of IL-4 and IL-13 along with the absence of Th1 transcripts in biopsies taken from the site of antigen challenge. IL-17 and IL-22 transcripts were detected only in healthy subjects skin following KLH challenge, while IL-1beta and IL-33 expression did not differ between the healthy and the atopics.

CONCLUSIONS

The immunization protocol resulted in the elicitation of a local and peripheral Th2 immune response in both healthy and atopic individuals. This may permit the investigation and monitoring of novel immunomodulatory strategies aiming to interfere with Th2 responses in man. The relevance of lack of Th17 cells in atopic skin in this model remains to be determined.

Using quantitative acid-base analysis in the ICU

The quantitative acid-base 'Strong Ion' calculator is a practical application of quantitative acid-base chemistry, as developed by Peter Stewart and Peter Constable. It quantifies the three independent factors that control acidity, calculates the concentration and charge of unmeasured ions, produces a report based on these calculations and displays a Gamblegram depicting measured ionic species. Used together with the medical history, quantitative acid-base analysis has advantages over traditional approaches.

Life-history and ecological correlates of geographic variation in egg and clutch mass among passerine species

Broad geographic patterns in egg and clutch mass are poorly described, and potential causes of variation remain largely unexamined. We describe interspecific variation in avian egg and clutch mass within and among diverse geographic regions and explore hypotheses related to allometry, clutch size, nest predation, adult mortality, and parental care as correlates and possible explanations of variation. We studied 74 species of Passeriformes at four latitudes on three continents: the north temperate United States, tropical Venezuela, subtropical Argentina, and south temperate South Africa. Egg and clutch mass increased with adult body mass in all locations, but differed among locations for the same body mass, demonstrating that egg and clutch mass have evolved to some extent independent of body mass among regions. A major portion of egg mass variation was explained by an inverse relationship with clutch size within and among regions, as predicted by life-history theory. However, clutch size did not explain all geographic differences in egg mass; eggs were smallest in South Africa despite small clutch sizes. These small eggs might be explained by high nest predation rates in South Africa; life-history theory predicts reduced reproductive effort under high risk of offspring mortality. This prediction was supported for clutch mass, which was inversely related to nest predation but not for egg mass. Nevertheless, clutch mass variation was not fully explained by nest predation, possibly reflecting interacting effects of adult mortality. Tests of the possible effects of nest predation on egg mass were compromised by limited power and by counterposing direct and indirect effects. Finally, components of parental investment, defined as effort per offspring, might be expected to positively coevolve. Indeed, egg mass, but not clutch mass, was greater in species that shared incubation by males and females compared with species in which only females incubate eggs. However, egg and clutch mass were not related to effort of parental care as measured by incubation attentiveness. Ecological and life-history correlates of egg and clutch mass variation found here follow from theory, but possible evolutionary causes deserve further study.

Strong ion calculator--a practical bedside application of modern quantitative acid-base physiology

OBJECTIVE

To review acid-base balance by considering the physical effects of ions in solution and describe the use of a calculator to derive the strong ion difference and Atot and strong ion gap.

DATA SOURCES

A review of articles reporting on the use of strong ion difference and Atot in the interpretation of acid base balance.

SUMMARY OF REVIEW

Tremendous progress has been made in the last decade in our understanding of acid-base physiology. We now have a quantitative understanding of the mechanisms underlying the acidity of an aqueous solution. We can now predict the acidity given information about the concentration of the various ion-forming species within it. We can predict changes in acid-base status caused by disturbance of these factors, and finally, we can detect unmeasured anions with greater sensitivity than was previously possible with the anion gap, using either arterial or venous blood sampling. Acid-base interpretation has ceased to be an intuitive and arcane art. Much of it is now an exact computation that can be automated and incorporated into an online hospital laboratory information system.

CONCLUSIONS

All diseases and all therapies can affect a patient's acid-base status only through the final common pathway of one or more of the three independent factors. With Constable's equations we can now accurately predict the acidity of plasma. When there is a discrepancy between the observed and predicted acidity we can deduce the net concentration of unmeasured ions to account for the difference.

The Listening Skills Test--a new instrument to assess children's pragmatic ability

Research has established that the development of autonomous (as opposed to collaborative) communication skills, using referential communication speaker and listener tasks, develops only slowly during the primary school years. Such a finding has implications for the classroom which puts a premium on independent language processing. Although the importance of oral language is recognised in the National Curriculum, there has been little attempt to assess the ability formally. The Listening Skills Test is a standardised pragmatic instrument focusing on the 3 1/2-7 years age group. The test is in four parts and assesses the ability to make judgements about the efficacy of verbal messages or instructions. Tasks include relating messages to arrays of pictorial items, making judgements about statements that refer to one complex picture, marking routes on a street plan in response to an extended set of instructions, and the ability to evaluate purely verbal utterances. The overall aim of the test is to assess children's ability to make sense on their own of verbal information in a decontextualised situation thought to represent the nature of much transactional communication in the classroom. Suggestions for remediation that have arisen from research conducted by the authors are also discussed.

Empowerment and the performance of health services

Addresses the issue of empowerment and its possible role in promoting the effectiveness of health services. Empowerment represents the ability of people within organisations to use their own initiative to further organisational interests. However, despite its apparent simplicity, the concept turns out to be quite complex and to have unanticipated implications. We explore some of these implications in health service organisations, and their consequences for health policy. Our conclusion is that many health policies may well act to degrade the empowerment of health service workers, and hence the performance of health service organisations.

Comparison of in vitro and in vivo efficiencies of a novel unit-dose liquid aerosol generator and a pressurized metered dose inhaler

Gamma scintigraphic imaging was employed in 10 healthy volunteers to compare the total and regional lung deposition of aerosols generated by two delivery platforms that permitted microprocessor-controlled actuation at an optimal point during inhalation. An aqueous solution containing 99mTc-DTPA was used to assess the deposition of aerosols delivered by inhalation from two successive unit-dosage forms (44 microl volume) using a prototype of a novel liquid aerosol system (AERx Pulmonary Delivery System). This was compared with aerosol deposition after inhalation of two 50 microl puffs of a 99mTc-HMPAO-labeled solution formulation from a pressurized metered dose inhaler (MDI). The in vitro size characteristics of the radiolabeled aerosols were determined by cascade impaction. For the AERx system, the predicted lung delivery efficiency based on the product of emitted dose (60.8%, coefficient of variation (CV)=12%) and fine particle fraction (% by mass of aerosol particles <5.7 microm in diameter) was 53.3% (CV=13%). For the solution MDI, the emitted dose was 62.9% (CV=13%) and the predicted lung dose was 44. 9% (CV=15%). The AERx system demonstrated efficient and reproducible dosing characteristics in vivo. Of the dose loaded into the device, the mean percent reaching the lungs was 53.3% (CV=10%), with only 6. 9% located in the oropharynx/stomach. In contrast, the lung deposition from the solution MDI was significantly less (21.7%) and more variable (CV=31%), with 42.0% of the radiolabel detected in the oropharynx/stomach. Analysis of the regional deposition of the radioaerosol indicated a homogeneous pattern of deposition after delivery from the AERx system. A predominantly central pattern of distribution occurred after MDI delivery, where the pattern of deposition was biased towards a central zone depicting the conducting airways. The AERx system, in contrast to MDIs, seems highly suited to the delivery of systemically active agents via pulmonary administration.

Lamivudine/zidovudine as a combined formulation tablet: bioequivalence compared with lamivudine and zidovudine administered concurrently and the effect of food on absorption

A single-center, open-label, three-way crossover study was conducted in 24 healthy subjects to assess (1) the bioequivalence of a combined lamivudine 150 mg/zidovudine 300 mg tablet relative to the separate brand-name components administered concurrently and (2) the effect of food on the bioavailability of the drugs from the combination tablet. The subjects were randomly assigned to receive each of the following three treatments, separated by a 5- to 7-day washout period: one lamivudine/zidovudine combination tablet after an overnight fast, one lamivudine 150 mg tablet and one zidovudine 300 mg tablet simultaneously after an overnight fast, or one lamivudine/zidovudine combination tablet 5 minutes after completing a standardized high-fat breakfast (67 g fat, 58 g carbohydrate, and 33 g protein). Serial blood samples were collected up to 24 hours postdose for the determination of lamivudine and zidovudine plasma concentrations. Standard pharmacokinetic parameters were estimated. Treatments were considered bioequivalent if 90% confidence intervals for the ratio of least squares (LS) means for the lamivudine and zidovudine area under the plasma concentration-time curve (AUC infinity) and maximum observed plasma concentration (Cmax) fell entirely within 0.80 to 1.25 for log-transformed parameters. The combined lamivudine/zidovudine tablet was bioequivalent in the extent (AUC infinity) and rate of absorption (Cmax and time of Cmax [tmax]) to the individual brand-name drug components administered concurrently under fasted conditions. Geometric LS mean ratios and 90% confidence intervals for AUC infinity and Cmax were 0.97 (0.92, 1.03) and 0.94 (0.84, 1.06), respectively, for lamivudine and 0.99 (0.91, 1.07) and 0.97 (0.82, 1.15), respectively, for zidovudine. The extent of absorption of lamivudine and zidovudine from the combination tablet was not altered by administration with meals, indicating that this formulation may be administered with or without food. However, food slowed the rate of absorption, delayed the tmax, and reduced the Cmax of lamivudine and zidovudine. These changes were not considered clinically important. All formulations were well tolerated under fasted and fed conditions.

Macaques infected with cloned simian immunodeficiency virus show recurring nef gene alterations

We compared nef gene sequences isolated by polymerase chain reaction from peripheral blood lymphocyte DNA of macaques that had been inoculated with either biologically (E11S) or molecularly (clone 8) cloned SIV/Mne. Two samples from each animal obtained either early (weeks 2-8) or late (weeks 21-137) after infection were analyzed. Three substitutions in the predicted Nef amino acid sequence were seen in all animals at the late time point, and two other substitutions were seen in all except one. Two of the common exchanges are located approximately 40 residues apart in the Nef core sequence but are juxtaposed on the tertiary structure as judged by computer modeling using the structure of the HIV Nef core protein as a guide. Most recurrent in vivo changes replaced a residue found in the cloned Nef sequence with one present in a consensus derived by aligning the Nef sequences of the SIV/Sm clade. Recombinant virus containing a macaque-adapted (MA nef) nef on the clone 8 backbone was 3-fold more infectious on SMAGI cells than the original virus. A lymphocyte line infected with SIV-clone 8-MAnef contained a large proportion of cells carrying provirus with defective nef genes. These findings suggest that the nef gene of the cloned SIV/Mne had undergone attenuating mutations during propagation in tissue culture that were "corrected" in vivo.

Communications. Off message

More than half of NHS organisations now have a communications post. Almost half of all communications managers are working single-handed. Most earn 30,000 Pounds or less. The typical NHS organisation spends less than 75,000 Pounds a year on communications, notably less than many local authorities. The present level of investment in communications is woefully inadequate to deliver the new NHS envisaged by the government.