Excitable systems: A new perspective on the cellular impact of elongate mineral particles

We investigate how the geometry of elongate mineral particles (EMPs) in contact with cells influences esotaxis, a recently discovered mechanism of texture sensing. Esotaxis is based on cytoskeletal waves and oscillations that are nucleated, shaped, and steered by the texture of the surroundings. We find that all EMPs studied trigger an esotactic response in macrophages, and that this response dominates cytoskeletal activity in these immune cells. In contrast, epithelial cells show little to no esotactic response to the EMPs. These results are consistent with the distinct interactions of both cell types with ridged nanotopographies of dimensions comparable to those of asbestiform EMPs. Our findings raise the question of whether narrow, asbestiform EMPs may also dominate cytoskeletal activity in other types of immune cells that exhibit similar esotactic effects. These findings, together with prior studies of esotaxis, lead us to the hypothesis that asbestiform EMPs suppress the migration of immune cells and activate immune signaling, thereby outcompeting signals that would normally stimulate the immune system in nearby tissue.

Understanding the burden of injury in children from conflict: an analysis of radiological imaging from a Role 3 hospital in Afghanistan in 2011

INTRODUCTION

There is a need for quality medical care for children injured in conflict, but a description of injuries and injury burden from blast and ballistic mechanisms is lacking. The radiology records of children imaged during the war in Afghanistan represent a valuable source of information about the patterns of paediatric conflict injuries.

METHODS

The UK military radiological database was searched for all paediatric presentations to Camp Bastion during 2011. Reports and original images were reviewed to determine location and severity of injuries sustained. Additional information was obtained from imaging request forms and the Joint Theatre Trauma Register, a database of those treated at UK medical facilities in Iraq and Afghanistan.

RESULTS

Radiology was available for 219 children. 71% underwent CT scanning. 46% suffered blast injury, 22% gunshot wounds (GSWs), and 32% disease and non-battle injuries (DNBIs). 3% had penetrating head injury, 11% penetrating abdominal trauma and 8% lower limb amputation, rates far exceeding those found in civilian practice. Compared with those with DNBI, those with blast or GSW were more likely to have serious (Abbreviated Injury Score, AIS, ≥3) injuries (median no. AIS ≥3 injuries were 1 for blast, 1 for GSW and 0 for DNBI, p<0.05) and children exposed to blast were more likely to have multiple body regions with serious injuries (OR for multiple AIS ≥3 injuries for blast vs DNBI=5.811 CI [1.877 to 17.993], p<0.05).

CONCLUSIONS

Paediatric conflict injuries are severe, and clinicians used only to civilian practice may be unprepared for the nature and severity of injuries inflicted on children in conflict. Whole-body CT for those with conflict-related injuries, especially blast, is hugely valuable. We recommend that CT is used for paediatric assessment in blast and ballistic incidents and that national imaging guidelines amend the threshold for doing so.

Identification and comparison of key criteria of feedback of funding decisions: mixed-methods analysis of funder and applicant perspectives

OBJECTIVE

This study investigated the content, quality and value of feedback given to applicants who applied to one of four research programmes in the UK funded (or jointly funded) by the National Institute for Health Research (NIHR).

METHODS

A mixed-method phased approach was conducted using document analysis and an online survey. Phase 1 examined 114 NIHR applicant feedback documents comprised written feedback from funding committees and external peer-reviewers and a conceptual framework of the key components of feedback was developed using content analysis. Phase 2 was an online survey completed by 113 NIHR applicants. Frequencies of responses to closed questions were calculated. Perceptions of quality and value of feedback were identified using content analysis of open-text responses.

RESULTS

In phase 1, a conceptual framework was developed with seven overarching categories: 'Study structure and quality'; 'Team and infrastructure'; 'Acceptability to patients and professionals'; 'Study justification and design'; 'Risks and contingencies'; 'Outputs'; 'Value for money'. A higher frequency of feedback was provided at stage 2 and for successful applications across the majority of components. In phase 2, frequency data showed that opinion on feedback was dependent on funding outcome. Content analysis revealed four main themes: 'Committee transparency'; 'Content validity and reliability'; 'Additional support'; Recognition of effort and constraints'.

CONCLUSIONS

This study provides key insights and understanding into the quality, content and value of feedback provided to NIHR applicants. The study identified key areas for improvement that can arise in NIHR funding applications, as well as in the feedback given to applicants that are applicable to other funding organisations. These findings could be used to inform funding application guidance documents to help researchers strengthen their applications and used more widely by other funders to inform their feedback processes.

Decision-making approaches used by UK and international health funding organisations for allocating research funds: A survey of current practice

Innovations in decision-making practice for allocation of funds in health research are emerging; however, it is not clear to what extent these are used. This study aims to better understand current decision-making practices for the allocation of research funding from the perspective of UK and international health funders. An online survey (active March-April 2019) was distributed by email to UK and international health and health-related funding organisations (e.g., biomedical and social), and was publicised on social media. The survey collected information about decision-making approaches for research funding allocation, and covered assessment criteria, current and past practices, and considerations for improvements or future practice. A mixed methods analysis provided descriptive statistics (frequencies and percentages of responses) and an inductive thematic framework of key experiences. Thirty-one responses were analysed, representing government-funded organisations and charities in the health sector from the UK, Europe and Australia. Four themes were extracted and provided a narrative framework. 1. The most reported decision-making approaches were external peer review, triage, and face-to-face committee meetings; 2. Key values underpinned decision-making processes. These included transparency and gaining perspectives from reviewers with different expertise (e.g., scientific, patient and public); 3. Cross-cutting challenges of the decision-making processes faced by funders included bias, burden and external limitations; 4. Evidence of variations and innovations from the most reported decision-making approaches, including proportionate peer review, number of decision-points, virtual committee meetings and sandpits (interactive workshop). Broadly similar decision-making processes were used by all funders in this survey. Findings indicated a preference for funders to adapt current decision-making processes rather than using more innovative approaches: however, there is a need for more flexibility in decision-making and support to applicants. Funders indicated the need for information and empirical evidence on innovations which would help to inform decision-making in research fund allocation.

Additive Modulation of DNA-DNA Interactions by Interstitial Ions

Quantitative understanding of biomolecular electrostatics, particularly involving multivalent ions and highly charged surfaces, remains lacking. Ion-modulated interactions between nucleic acids provide a model system in which electrostatics plays a dominant role. Using ordered DNA arrays neutralized by spherical cobalt³⁺ hexammine and Mg²⁺ ions, we investigate how the interstitial ions modulate DNA-DNA interactions. Using methods of ion counting, osmotic stress, and x-ray diffraction, we systematically determine thermodynamic quantities, including ion chemical potentials, ion partition, DNA osmotic pressure and force, and DNA-DNA spacing. Analyses of the multidimensional data provide quantitative insights into their interdependencies. The key finding of this study is that DNA-DNA forces are observed to linearly depend on the partition of interstitial ions, suggesting the dominant role of ion-DNA coupling. Further implications are discussed in light of physical theories of electrostatic interactions and like-charge attraction.

Using digital tools in the recruitment and retention in randomised controlled trials: survey of UK Clinical Trial Units and a qualitative study

BACKGROUND

Recruitment and retention of participants in randomised controlled trials (RCTs) is a key determinant of success but is challenging. Trialists and UK Clinical Research Collaboration (UKCRC) Clinical Trials Units (CTUs) are increasingly exploring the use of digital tools to identify, recruit and retain participants. The aim of this UK National Institute for Health Research (NIHR) study was to identify what digital tools are currently used by CTUs and understand the performance characteristics required to be judged useful.

METHODS

A scoping of searches (and a survey with NIHR funding staff), a survey with all 52 UKCRC CTUs and 16 qualitative interviews were conducted with five stakeholder groups including trialists within CTUs, funders and research participants. A purposive sampling approach was used to conduct the qualitative interviews during March-June 2018. Qualitative data were analysed using a content analysis and inductive approach.

RESULTS

Responses from 24 (46%) CTUs identified that database-screening tools were the most widely used digital tool for recruitment, with the majority being considered effective. The reason (and to whom) these tools were considered effective was in identifying potential participants (for both Site staff and CTU staff) and reaching recruitment target (for CTU staff/CI). Fewer retention tools were used, with short message service (SMS) or email reminders to participants being the most reported. The qualitative interviews revealed five themes across all groups: 'security and transparency'; 'inclusivity and engagement'; 'human interaction'; 'obstacles and risks'; and 'potential benefits'. There was a high level of stakeholder acceptance of the use of digital tools to support trials, despite the lack of evidence to support them over more traditional techniques. Certain differences and similarities between stakeholder groups demonstrated the complexity and challenges of using digital tools for recruiting and retaining research participants.

CONCLUSIONS

Our studies identified a range of digital tools in use in recruitment and retention of RCTs, despite the lack of high-quality evidence to support their use. Understanding the type of digital tools in use to support recruitment and retention will help to inform funders and the wider research community about their value and relevance for future RCTs. Consideration of further focused digital tool reviews and primary research will help to reduce gaps in the evidence base.

Evaluation of stakeholder views on peer review of NIHR applications for funding: a qualitative study

OBJECTIVES

Innovations resulting from research have both national and global impact, so selecting the most promising research studies to fund is crucial. Peer review of research funding applications is part of the selection process, and requires considerable resources. This study aimed to elicit stakeholder opinions about which factors contribute to and influence effective peer review of funding applications to the UK National Institute for Health Research (NIHR), and to identify possible minor improvements to current processes and any major changes or potential innovations to achieve a more efficient peer review process.

DESIGN

Qualitative interviews with 30 stakeholders involved in the peer review process.

PARTICIPANTS

Participants were drawn from three NIHR coordinating centres and represented four types of stakeholders: board members with responsibility for making funding decisions, applicants, external peer reviewers and NIHR staff.

METHODS

All interviews were conducted by telephone apart from three that were face to face with NIHR staff. Data were analysed using a thematic template method.

RESULTS

The responses from NIHR staff, board members and reviewers differed from those received from applicants. The first three groups focused on how well the process of peer review did or did not function. The applicants mentioned these points but in addition often reflected on how their personal application was assessed. Process improvements suggested included: developing a more proportionate review process; providing greater guidance, feedback, training, acknowledgement or incentives for peer reviewers; reducing the time commitment and amount of paperwork; and asking reviewers to comment on the importance, strengths and weaknesses of applications and flaws which are potentially 'fixable'.

CONCLUSIONS

Overall, participants were supportive of the need for peer review in evaluating applications for research funding. This study revealed which parts of the process are working well and are valued, and barriers, difficulties and potential areas for improvement and development.

Impact of participation in a surgical site infection surveillance network: results from a large international cohort study

BACKGROUND

Surveillance of surgical site infections (SSIs) is a core component of effective infection control practices, though its impact has not been quantified on a large scale.

AIM

To determine the time-trend of SSI rates in surveillance networks.

METHODS

SSI surveillance networks provided procedure-specific data on numbers of SSIs and operations, stratified by hospitals' year of participation in the surveillance, to capture length of participation as an exposure. Pooled and procedure-specific random-effects Poisson regression was performed to obtain yearly rate ratios (RRs) with 95% confidence intervals (CIs), and including surveillance network as random intercept.

FINDINGS

Of 36 invited networks, 17 networks from 15 high-income countries across Asia, Australia and Europe participated in the study. Aggregated data on 17 surgical procedures (cardiovascular, digestive, gynaecological-obstetrical, neurosurgical, and orthopaedic) were collected, resulting in data concerning 5,831,737 operations and 113,166 SSIs. There was a significant decrease in overall SSI rates over surveillance time, resulting in a 35% reduction at the ninth (final) included year of surveillance (RR: 0.65; 95% CI: 0.63-0.67). There were large variations across procedure-specific trends, but strong consistent decreases were observed for colorectal surgery, herniorrhaphy, caesarean section, hip prosthesis, and knee prosthesis.

CONCLUSION

In this large, international cohort study, pooled SSI rates were associated with a stable and sustainable decrease after joining an SSI surveillance network; a causal relationship is possible, although unproven. There was heterogeneity in procedure-specific trends. These findings support the pivotal role of surveillance in reducing infection rates and call for widespread implementation of hospital-based SSI surveillance in high-income countries.

Experimental platforms to study blast injury

Injuries sustained due to attacks from explosive weapons are multiple in number, complex in nature, and not well characterised. Blast may cause damage to the human body by the direct effect of overpressure, penetration by highly energised fragments, and blunt trauma by violent displacements of the body. The ability to reproduce the injuries of such insults in a well-controlled fashion is essential in order to understand fully the unique mechanism by which they occur, and design better treatment and protection strategies to alleviate the resulting poor long-term outcomes. This paper reports a range of experimental platforms that have been developed for different blast injury models, their working mechanism, and main applications. These platforms include the shock tube, split-Hopkinson bars, the gas gun, drop towers and bespoke underbody blast simulators.

Lentiviral gene rescue of a Bernard-Soulier mouse model to study platelet glycoprotein Ibβ function

Essentials A signaling role of glycoprotein (GP)Ibβ is postulated but not formally demonstrated in platelets. Lentiviral-mediated rescue in knock-out mice can be used to evaluate GPIbβ function in vivo. Transduction of the native subunit corrected the main defects associated with GPIb-IX deficiency Deletion of intracellular 159-170 segment increased thrombosis, 150-160 removal increased bleeding.

SUMMARY

Background The platelet glycoprotein (GP)Ib-V-IX complex is required for normal hemostasis and megakaryopoiesis. A role in GPIb-dependent responses has been ascribed to the less well characterized GPIbβ subunit using a specific antibody and GPIb-IX transfected cells. Objectives Our aim was to evaluate, in vivo, the role of the GPIbβ in hemostasis and thrombosis. Methods GPIbβ(null) Sca-1(+) progenitors transduced with viral particles harboring hGPIbβ were transplanted into lethally irradiated GPIbβ(-/-) recipient mice. Results hGPIbβ transplanted into the bone marrow of GPIbβ(null) mice rescued GPIb-IX expression in 97% of circulating platelets. These platelets efficiently bound von Willebrand factor (VWF) and extended filopodia on a VWF matrix, demonstrating the restoration of GPIb-dependent adhesive and signaling properties. These mice exhibited less severe macrothrombocytopenia and had normal tail bleeding times as compared with GPIbβ(null) mice. This strategy was employed to manipulate and evaluate the role of the GPIbβ intracellular domain. Removal of the membrane proximal segment (Δ(150-160) ) decreased GPIb-IX expression by 43%, confirming its involvement in receptor assembly and biosynthesis, and resulted in increased bleeding times and decreased thrombosis in a mechanical injury model in the aorta. On the other hand, deletion of the C-flanking 159-170 segment allowed normal GPIb-IX expression, VWF-dependent responses and bleeding times, but resulted in enhanced arterial thrombosis. Conclusion This pointed to a repressor role of GPIbβ in thrombus formation in vivo that was not predicted in studies of heterologous cells. These results highlight the utility of this lentiviral strategy for the structure-function evaluation of GPIb-IX in platelets.

Vergleichende Untersuchungen zu ausgewählten Kriterien des Energiestoffwechsels in Skelettmuskulatur, Plasma und Lymphozyten bei gesunden und an Congenitaler Myofibrillärer Hypoplasie erkrankten Ferkeln

Abstract. Title of the paper: Comparative investigations of selected criteria of energy metabolism in skeletal muscle, plasma and lymphocytes in healthy and in piglets with congenital myofibrillar hypoplasia Carnitine contents of skeletal muscle, plasma and lymphocytes, the capacity of ATPsynthesis in muscle mitochondria and lymphocytes, and the enzyme activity of carnitine palmitoyltransferase I (CPT I) in muscle mitochondria were determined in piglets with congenital myofibrillar hypoplasia (CMH) in comparision to their clinical healthy siblings and piglets from CMH-free litters. Tendentious differences in the relation of acylcarnitine to free carnitine in healthy piglets and piglets suffering from CMH could be detected. Healthy piglets showed in tendency superiority in the ATP-production of their lymphocytes compared with diseased animals. Depending on the applied substrate, muscle mitochondria showed tendentially differences in the ATP-production between CMH-affected and healthy litters, so that a connection between CMH and the lipid metabolism, particular the β-oxidation, is supposed. Differences in the carnitine palmitoyltransferase I-activity as a possible cause for CMH could be excluded.

Fluid restriction during running increases GI permeability

The purpose of this study was to determine gastrointestinal (GI) permeability during prolonged treadmill running (60 min at 70 % V.O2max) with and without fluid intake (3 ml/kg body mass/10 min). Twenty runners (11 males, 9 females; age = 22 +/- 3 (SD) yrs; mean V.O2max = 55.7 +/- 5.0 ml/kg/min) completed four experiments: 1) rest, 2) running with no fluid (NF), 3) running with ingestion of a 4 % glucose solution (GLU), and 4) running with ingestion of a water placebo (PLA). To determine GI permeability, subjects also drank a solution containing 5 g sucrose (S), 5 g lactulose (L), and 2 g rhamnose (R) immediately prior to each trial. Gastroduodenal permeability was determined by urinary S excretion, while small intestinal permeability was determined by the L/R excretion ratio. Percent body mass loss (i.e., dehydration) was negligible during rest, GLU and PLA, while NF resulted in a 1.5 % loss of body mass (p < 0.05). Gastroduodenal and intestinal permeability were significantly (p < 0.008) increased in NF compared to rest. There were no other differences in GI permeability. These results indicate that fluid restriction during 1 h of steady-state running increases GI permeability above resting levels.

Effect of aspirin and ibuprofen on GI permeability during exercise

This study was conducted to determine the effects of aspirin or ibuprofen on gastrointestinal permeability when combined with exercise. Eight runners completed three 60 min treadmill runs at 70 % VO(2max). For 24 hours prior to each run, subjects ingested aspirin (2 x 325 mg), ibuprofen (2 x 200 mg), or placebo capsules every 6 hours. Immediately before each run, a solution containing 5 g sucrose, 5 g lactulose, and 2 g rhamnose was ingested. Urine produced during each run, and for 4 h afterwards was collected. Urinary excretion of sucrose is an indicator of gastroduodenal permeability. The excretion ratio of lactulose-to-rhamnose assesses small intestinal permeability. Sucrose excretion (%) was greater (p < 0.017) for aspirin (0.37 [0.2 - 0.97]) compared to placebo (0.09 [0.05 - 0.30]) or ibuprofen (0.22 [0.1 - 0.39]) and sucrose excretion for ibuprofen was greater than placebo. The lactulose-to-rhamnose ratio was greater for aspirin (0.09 [0.08 - 0.30]) than placebo (0.065 [0.04 - 0.08]) however ibuprofen (0.08 [0.06 - 0.19]) was not different from aspirin or placebo. These results indicate that with prolonged running, gastroduodenal permeability is increased if aspirin or ibuprofen is used prior to such exercise. Furthermore, aspirin promotes greater gastroduodenal permeability and also increases small intestinal permeability.

Calmodulin-dependent cyclic nucleotide phosphodiesterase activity is altered by 20 microT magnetostatic fields

Absorbance measurements at 660 nm of calmodulin (CaM) dependent cyclic nucleotide phosphodiesterase activity under cell free conditions indicate that 30-min exposures to weak magnetostatic field intensities alters this activity, compared to zero magnetic field exposures. This effect depends nonlinearly on the concentration of free calcium, with maximum magnetic interaction apparently occurring at an optimal Ca(2+) concentration corresponding to 50% activation (EC(50)). If one regards Ca(2+)/CaM activation as a switching process, then increasing the magnetic field at Ca(2+) levels in excess of optimal acts to bias this switch towards lower calcium concentrations. A magnetic dependence has been previously reported by others in an homologous system, CaM dependent myosin light chain phosphorylation, implying that there may be an underlying magnetic interaction that involves the initial Ca(2+)/CaM binding process common to both enzymatic pathways. The level of magnetostatic intensity at which this effect is observed ( approximately 20 microT) implies that CaM activation may be functionally sensitive to the geomagnetic field.

Effect of creatine loading on neuromuscular fatigue threshold

The purpose of this investigation was to determine the effect of creatine (Cr) loading on the onset of neuromuscular fatigue by monitoring electromyographic fatigue curves from the vastus lateralis muscle using the physical working capacity at the fatigue threshold (PWC(FT)) test. Using a double-blind random design, 15 women athletes [mean age 19.0 +/- 2.0 (SD) yr] from the university crew team received a placebo (n = 8; 20 g glucose) or Cr (n = 7; 5 g Cr monohydrate + 20 g glucose) four times per day for 5 consecutive days. Analysis of covariance was used to analyze the data (covaried for presupplementation PWC(FT) values). The adjusted mean postsupplementation PWC(FT) value for the Cr group (mean = 186 W) was significantly (P < 0.05) higher than that of the placebo group (mean = 155 W). These findings suggest that Cr loading may delay the onset of neuromuscular fatigue.

Design and synthesis of thrombin inhibitors: analogues of MD-805 with reduced stereogenicity and improved potency

Mitsubishi's MD-805, a potent and selective inhibitor of thrombin which contains four stereogenic centers, has been the starting point for an optimization program. A systematic synthetic study resulted in thrombin inhibitors achiral at P2 and P3 but with a 10-fold increase in potency over the original lead. A number of 4-substituted piperidines were synthesized and examined as replacements for 2-carboxy-4-methylpiperidine at P2; 4-fluoroethylpiperidine (FEP) among others provided inhibitors (e.g. 45g) of increased potency. An enantioselective route was developed to 3(R)-methyl-1,2,3,4-tetrahydroquinolinesulfonyl chloride. Inhibitors containing this enantiomerically pure P3 (42d) had similar potency to the racemic material and provided support, with modeling studies, for the preparation of the gem 3,3-disubstituted compounds. A series of inhibitors containing the novel 3, 3-dimethyl-1,2,3,4-tetrahydroquinolinesulfonyl (DMTHQS) P3 (Table 5) were synthesized and showed a similar activity profile as the monomethyl series. The combination of P3-DMTHQS, P2-FEP, and P1-arginine (45g) had a K(i) of 6 nM (MD-805 K(i) = 85 nM). In animal models of both venous and arterial thrombosis, one inhibitor (42e) was shown to produce a dose-dependent inhibition of thrombus formation that in some situations was superior to that of MD-805.

Cyclosporin A/alpha interferon-induced autologous graft-versus-host disease following peripheral blood stem cell transplant for chronic myeloid leukaemia: a clinico-pathological study

Autologous GVHD was induced using CsA and alpha-IFN in a patient undergoing autologous PBSCT for accelerated phase CML. We demonstrated that the autologous mixed lymphocyte reactions were extremely sensitive and specific for the detection of the GVHD when compared to skin biopsy. The resultant autologous GVHD was associated with an in vitro GVL effect, suggesting a potential clinical benefit of this therapeutic manoeuvre. The post-PBSCT period was associated with an improvement in normal haemopoiesis and reduction in the proportion of blood cells expressing the Philadelphia chromosome.

Purchaser and provider relations in the UK: a perspective from the private sector

Gives an overview of the major features of the general changes in the UK health care system, and describes how PPP healthcare is taking advantage of those changes in developing and implementing strategies for relations with both hospitals and specialists. Notes that similar issues are faced by public sector purchasers. Points out that many of the initiatives described are being adopted, in one form or another, in health care industries across the world. Suggests that new insights or understandings may be found by seeing and considering those issues and initiatives in the context of health care economies.

Commissioning community health care: missing the point

Discusses commissioning community health care and the fact that present mechanisms do not enable commissioning to meet the needs of patients requiring community care relevant to their needs. The focus on efficiency, money and simple activity does not take into account the complex nature of community care and the need to take a variety of factors into account if commissioning is to be effective.

Effect of lipid supplements on the production and glycosylation of recombinant interferon-gamma expressed in CHO cells

The effects of lipids on the glycosylation of recombinant human interferon-gamma expressed in a Chinese Hamster Ovary cell line were investigated in batch culture. Lipids form an essential part of the N-glycosylation pathway, and have been shown to improve cell viability. In control (serum-free) medium the proportion of fully-glycosylated interferon-gamma deteriorated reproducibly with time in batch culture, but the lipoprotein supplement ExCyte was shown to minimise this trend. Partially substituting the bovine serum albumin content of the medium with a fatty-acid free preparation also improved interferon-gamma glycosylation, possibly indicating that oxidised lipids carried on Cohn fraction V albumin may damage the glycosylation process.

Specifying quality in health care

Quality should be a central issue in the commissioning and provision of health care. This requires a systematic approach to defining and monitoring quality. Such an approach should address: quality characteristics such as efficiency, accessibility, effectiveness (which may conflict with each other); the several levels at which quality may be specified, from general (across all health care) to specific (particular conditions or patient groups); and the methods of quality monitoring which include documented policies, clinical audit, inspection visits/patient surveys, and routine information returns. Shows how a matrix for quality surveillance can be devised which provides a framework for purchasers and providers to work together in developing quality in health care.

Sharing resources: choices in health care

Across the world, health care continues to consume ever-increasing amounts of nations' wealth. Different societies are grappling with the problem of how to define and constrain the burgeoning demand on their resources. The DoH has stated that there should be no blanket ban on any service; some RHAs have sought a consensus among district health authorities and many district health authorities are setting out their own conclusions. If each purchaser is free to form a distinctive view on what constitutes need in their population, the range of available services, and balances within that range, may vary from place to place. Should society accept those variations? asks Adrian Bull.

Chromosomal organization of the human VH4 gene family. Location of individual gene segments

To investigate the organization and evolution of VH gene segments, we characterized the elements belonging to the VH4 gene family from the germline of a single subject. One hundred sixty VH4-carrying lambda-phage clones were isolated from a genomic library. A combination of hybridization and sequence analysis yielded 13 distinct VH4 clones. Six of these elements had one or more nucleotide substitutions that distinguished them from previously identified VH4 genes, whereas seven elements were identical to previously described VH4 genes. In four of the six new sequences, nucleotide substitutions resulted in amino acid replacements. One pseudogene was identified. On the basis of sequence-specific hybridization using oligonucleotide probes corresponding to these sequences, each of the elements could be assigned to a specific band in a BglII digest. Since the VH4-carrying BglII bands have been mapped in genomic DNA, it was also possible to assign chromosomal locations to the specific VH4 elements. The results indicate that the majority of VH4 elements are located in a region of approximately 500 kb, extending from approximately 500 to 1000 kb 5' of the JH locus. The distribution of shared structural motifs among the VH4 elements indicates that the VH4 gene family has evolved through repeated duplication and gene conversion events.

Chromosomal organization of the human VH4 gene family. Location of individual gene segments

To investigate the organization and evolution of VH gene segments, we characterized the elements belonging to the VH4 gene family from the germline of a single subject. One hundred sixty VH4-carrying lambda-phage clones were isolated from a genomic library. A combination of hybridization and sequence analysis yielded 13 distinct VH4 clones. Six of these elements had one or more nucleotide substitutions that distinguished them from previously identified VH4 genes, whereas seven elements were identical to previously described VH4 genes. In four of the six new sequences, nucleotide substitutions resulted in amino acid replacements. One pseudogene was identified. On the basis of sequence-specific hybridization using oligonucleotide probes corresponding to these sequences, each of the elements could be assigned to a specific band in a BglII digest. Since the VH4-carrying BglII bands have been mapped in genomic DNA, it was also possible to assign chromosomal locations to the specific VH4 elements. The results indicate that the majority of VH4 elements are located in a region of approximately 500 kb, extending from approximately 500 to 1000 kb 5' of the JH locus. The distribution of shared structural motifs among the VH4 elements indicates that the VH4 gene family has evolved through repeated duplication and gene conversion events.

VH genes in tandem array comprise a repeated germline motif

In a study of human VH gene heterogeneity, we have previously used sequence-specific oligonucleotide probes to demonstrate polymorphism of 56pl and three highly homologous VH3 germline elements. We now extend these findings with VH nucleotide sequences obtained from a person who possesses restriction fragments corresponding to each of these four VH3 genes. From a lambda-phage library of genomic DNA, distinct phage clones containing putative 56pl, hv3005, 1.9III, and hv3019b9 genes were selected by screening with oligonucleotide probes. PCR amplification, subcloning, and sequencing from the respective clones 3d216, 3d24, 3d28, and 3d277, yielded exact 56p1, hv3005, 1.9III, and hv3019b9 nucleotide sequences. A panel of oligonucleotide probes was shown to hybridize to these cloned VH3 genes with exact specificity, demonstrating the ability of the probes to predict the sequence of detected target DNA. Based on their chromosomal organization and their previously determined distribution in the population, these VH3 genes represent at least three distinct loci. From each of the VH3-containing phage clones, a VH4 element was also identified and sequenced. Linked to 3d24 and 3d28, respectively, were VH4 sequences identical to hv4005 and 1.9II, corroborating previous reports. The VH4 elements linked to 3d216 and 3d277 were distinct from published VH4 sequences. Nucleotide sequence homology was 97 to 99% among the VH3 sequences, and 93 to 99% among the VH4. These findings indicate that the VH3-VH4 gene pairs we have identified are a repeated germline motif, apparently resulting from multiple duplications of tandemly arrayed VH genes.