Towards co-design of rehabilitation technologies: a collaborative approach to prioritize usability issues

Introduction

Early stakeholder engagement is critical to the successful development and translation of rehabilitation technologies, a pivotal step of which is usability testing with intended end-users. To this end, several methods employ end-user feedback to identify usability and implementation issues. However, the process of prioritizing identified issues seldom leverages the knowledge and expertise of the range of stakeholders who will ultimately affect the demand and supply of a device. This paper describes a novel method to prioritize end-user feedback using transdisciplinary stakeholder consultation and address it in subsequent product development. The proposed approach was demonstrated using a case study relating to the development of a novel technology for neural recovery after spinal cord injury.

Method

Feedback from five individuals with chronic spinal cord injury was collected during two-hour usability evaluation sessions with a fully functional high-fidelity system prototype. A think-aloud and semi-structured interview protocol was used with each participant to identify usability and acceptability issues relating to the system in a 3-phase approach. Phase 1 involved extracting usability issues from think-aloud and semi-structured interview data. Phase 2 involved rating the usability issues based on their significance, technical feasibility, and implementation priority by relevant internal and external stakeholders. Finally, Phase 3 involved aggregating the usability issues according to design and implementation elements to facilitate solution generation, and these solutions were then raised as action tasks for future design iterations.

Results

Sixty usability issues representing nine facets of usability were rated. Eighty percent of issues were rated to be of moderate to high significance, 83% were rated as being feasible to address, and 75% were rated as addressable using existing project resources. Fifty percent of the issues were rated to be a high priority for implementation. Evaluation of the grouped issues identified 21 tasks which were mapped to the product roadmap for integration into future design iterations.

Discussion

This paper presents a method for meaningful transdisciplinary stakeholder engagement in rehabilitation technology development that can extended to other projects. Alongside a worked example, we offer practical considerations for others seeking to co-develop rehabilitation technologies.

On the Relationship Between Oceanic Plate Speed, Tectonic Stress, and Seismic Anisotropy

Seismic radial anisotropy (the squared ratio between the speeds of horizontally and vertically polarized shear waves, ξ = V S H 2 V S V 2 ) is a powerful tool to probe the direction of mantle flow and accumulated strain. While previous studies have confirmed the dependence of azimuthal anisotropy on plate speed, the first order control on radial anisotropy is unclear. In this study, we develop 2D ridge flow models combined with mantle fabric calculations to report that faster plates generate higher tectonics stresses and strain rates which lower the dislocation creep viscosity and lead to deeper anisotropy than beneath slower plates. We apply the SGLOBE-rani tomographic filter, resulting in a flat depth-age trend and stronger anisotropy beneath faster plates, which correlates well with 3D global anisotropic mantle models. Our predictions and observations suggest that as plate speed increases from 2 to 8 cm/yr, radial anisotropy increases by ∼0.01-0.025 in the upper 100-200 km of the mantle between 10 and 60 Ma.

Age of acquisition effects in recognition without identification tasks

The Age of Acquisition (AoA) effect results in early-acquired words being processed more quickly and accurately than later-acquired words. This effect is argued to result from a gradual development of semantic representations and a changing neural network throughout development (Chang, Y.-N., Monaghan, P., & Welbourne, S., 2019). Some forms of the Recognition Without Identification (RWI) effects have been observed at a perceptual level. The present study used the RWI paradigm to examine whether the AoA effect is located at the perceptual loci. A total of 174 participants were presented a list of pictures (Experiment 1) or words (Experiment 2) followed by a list of mixed early- and late-acquired picture or word fragments that participants had to identify; half of which corresponded to studied words and half of which to unstudied words. Irrespective of whether the item was identified, participants then rated the likelihood that the item appeared in the study phase. In both experiments, results showed that studied items were recognised more accurately than unstudied items, even when they could not be identified and late-acquired items were recognised more than early-acquired items, even when they were not identified. Finally, RWI interacted with the AoA effect only in pictorial stimuli, suggesting that the RWI and AoA effects are located at the perceptual level.

Correction to: Recommendations from Two Citizens' Juries on the Surgical Management of Obesity

The spelling of the name of author K. Chalkidou was incorrect in the original article. It is correct here.

Engaging the public in healthcare decision-making: results from a Citizens' Jury on emergency care services

BACKGROUND

Policies addressing ED crowding have failed to incorporate the public's perspectives; engaging the public in such policies is needed.

OBJECTIVE

This study aimed at determining the public's recommendations related to alternative models of care intended to reduce crowding, optimising access to and provision of emergency care.

METHODS

A Citizens' Jury was convened in Queensland, Australia, to consider priority setting and resource allocation to address ED crowding. Twenty-two jurors were recruited from the electoral roll, who were interested and available to attend the jury from 15 to 17 June 2012. Juror feedback was collected via a survey immediately following the end of the jury.

RESULTS

The jury considered that all patients attending the ED should be assessed with a minority of cases diverted for assistance elsewhere. Jurors strongly supported enabling ambulance staff to treat patients in their homes without transporting them to the ED, and allowing non-medical staff to treat some patients without seeing a doctor. Jurors supported (in principle) patient choice over aspects of their treatment (when, where and type of health professional) with some support for patients paying towards treatment but unanimous opposition for patients paying to be prioritised. Most of the jurors were satisfied with their experience of the Citizens' Jury process, but some jurors perceived the time allocated for deliberations as insufficient.

CONCLUSIONS

These findings suggest that the general public may be open to flexible models of emergency care. The jury provided clear recommendations for direct public input to guide health policy to tackle ED crowding.

Magnetic resonance imaging and spectroscopy of the rat hippocampus 1 month after exposure to 56Fe-particle radiation

The response of the central nervous system to space radiation is largely unknown. The hippocampus, which is known for its critical role in learning and memory, was evaluated for its response to heavy-ion radiation. At 1 month, animals exposed to brain-only 56Fe-particle irradiation (0-4 Gy) were examined using contrast-enhanced T1 imaging (CET1), T2-weighted imaging (T2WI), diffusion weighted imaging (DWI), and (1)H-magnetic resonance spectroscopy (MRS). Correlative histology was performed after imaging. The T2WI, DWI and CET1 images revealed no overt anatomical changes after irradiation. Quantitative analysis demonstrated a significant increase in T2 at 2 Gy compared to 0 Gy. The apparent diffusion coefficient (ADC) revealed an inverse dose-dependent quantitative change in water mobility. Compared to 0 Gy, the ADC increased 122% at 1 Gy and declined to 44% above control levels at 4 Gy. MRS showed a significant increase in the N-acetylaspartate/choline ratio at 4 Gy and a lactate peak. Histology demonstrated no overt pathological changes in neuronal and astrocyte populations. However, a significant inverse dose-dependent morphological change in the microglial population was detected in irradiated animals. Our results suggest that early tissue matrix modifications induced by 56Fe-particle radiation can be detected by MRI in the absence of evident histopathology. These changes may indicate fundamental changes in the structure and function of the hippocampus.

Quercetin promotes functional recovery following acute spinal cord injury

We tested the hypothesis that quercetin, a potent Fe(2+)-chelating flavonoid, would decrease secondary damage following spinal cord trauma. MRI studies using the relaxation of the T1 proton signal caused by Fe(2+) ions and the dose-dependent reversal of this effect by addition of quercetin in aqueous solution were used to guide us to the dosage of quercetin to be used in animal experimentations. Forty-four male Wistar rats were used in two experimental series to test the hypothesis that administration of quercetin improves recovery of motor function after acute traumatic spinal cord injury. Animals were subjected to laminectomy and subjected to an extradural 40-g force clip compression for 5 sec at T7. Quercetin or saline was administered intraperitoneally 1 h after injury and then every 12 hr thereafter. Recovery of motor function was assessed using BBB scores at weekly intervals for 4 weeks. A dose of 2.5 micromoles quercetin/kg body weight did not result in significantly better functional outcome, whereas doses ranging from 5 to 100 micromoles quercetin/kg body weight resulted in a significantly better functional outcome with half or more of the animals walking, although with deficit; in contrast, no animals walked in the group of saline-treated animals. No significant differences in behavioral outcome were seen amongst the doses ranging from 5 to 100 micromol/kg, nor was there a difference if animals were treated for 4 or 10 days. Therapeutic outcome was coincident with more efficient iron clearance, suggesting that one possible mechanism whereby quercetin decreases secondary damage is through iron chelation.

Evaluation of a rural community-based disability service in Queensland, Australia

INTRODUCTION

The article outlines the evaluation framework devised for a semi-formal disability service project in central Queensland, Australia, which was implemented using a community-based, participatory model. Utilising a service framework known as Community-Based Rehabilitation and an implementation strategy adapted from Participatory Rural Appraisal, this model is presented as a potential alternative for rehabilitation and disability services in the light of concerns that such services are poorly tailored and inadequate in remote and rural areas of Australia.

METHOD

In recognition of the difficulty of evaluating such participatory and community-based initiatives, this evaluation was based on the analysis of large amounts of qualitative data from multiple sources, which were categorised against key themes drawn from the literature, using a SWOT analysis (strengths, weaknesses, opportunities and threats). It is suggested that this innovative and multifaceted evaluation methodology may have broader application.

RESULTS AND CONCLUSIONS

Findings of the service evaluation indicated positive informal, community and social outcomes. Formal structural and organisational outcomes were found to be limited with a possibility of compromising the long-term viability of the initiative. Suggestions are made regarding the process of implementing similar research initiatives. The model may have application in similar rural community-based initiatives internationally.

Developing a rural community-based disability service: (I) service framework and implementation strategy

In response to widely recognised dilemmas associated with rehabilitation and disability service provision in remote and rural areas of Australia, a community-based, participatory approach to service development was adapted for a disability service project in central Queensland. The service framework, known as Community Based Rehabilitation (CBR), fosters the involvement of community members in disability service provision. Although this framework has been described previously, few guidelines exist regarding appropriate implementation of such an approach. Consequently, the implementation strategy known as Participatory Rural Appraisal (PRA) was adopted. Participatory Rural Appraisal has been reported to foster the participation and decision-making of community members in community projects. The present article describes the application of this implementation strategy to disability service provision in a relatively under-resourced rural shire. The rationale, framework and process of the pilot are described. A subsequent publication will document the service component, detail evaluation findings and describe the long-term outcomes of this research.

Community-based service delivery in rehabilitation: the promise and the paradox

PURPOSE

According to many researchers, rehabilitation is being prevented from developing as a distinct profession due to two major problems. First, it has been claimed that rehabilitation is in need of a professional identity and a sense of cohesion if it is to emerge as a discipline. Second, it has been recognized that there is a need for a rehabilitation framework to challenge the restorative approach that continues to dominate rehabilitation, linking it back to the medical model from which it has attempted to escape. The model of community-based rehabilitation (CBR) is offered as a model that can provide the impetus for an attitudinal shift from the restorative tradition and unite rehabilitation workers through a cohesive framework.

METHOD

Unfortunately, the implementation of community-based rehabilitation in urban societies has been disappointing. The current paper is a conceptual discussion of community-based rehabilitation that explores some potential causes of this poor implementation.

RESULTS

To some extent, the implementation failure of community-based rehabilitation can be attributed to the paradoxes that are inherent in its fundamental constructs-empowerment and community inclusion. These paradoxes occur at a conceptual level, a practical level and a contextual level.

CONCLUSIONS

Some solutions are offered to enable the paradigm to be implemented more fully. In particular, it is suggested that there is a need to develop useful working definitions of these constructs, favourable attitudes among rehabilitation workers and a focus on community development.

The human family of Deafness/Dystonia peptide (DDP) related mitochondrial import proteins

The gene responsible for the human genetic neurodegenerative disorder DFN-1/MTS encodes a small protein known as deafness/dystonia peptide (DDP). It bears a strong resemblance to a recently characterized set of zinc-binding yeast proteins (Tim8p, Tim9p, Tim10p, Tim12p, and Tim13p) that are implicated in the import of a class of transmembrane carrier proteins from the cytoplasm to the mitochondrial inner membrane. We describe here the human complement of DDP/Tim-like proteins and establish the likely orthologous relationships between sequences from human, yeast, and other organisms. We also describe the expression patterns and chromosomal locations of their genes, which are candidate loci for autosomal recessive neurodegenerative disorders.

Pelizaeus-Merzbacher disease: identification of Xq22 proteolipid-protein duplications and characterization of breakpoints by interphase FISH

Pelizaeus-Merzbacher disease (PMD) is an X-linked, dysmyelinating disorder of the CNS. Duplications of the proteolipid protein (PLP) gene have been found in a proportion of patients, suggesting that, in addition to coding-region or splice-site mutations, overdosage of the gene can cause PMD. We show that the duplication can be detected by interphase FISH, using a PLP probe in five patients and their four asymptomatic carrier mothers. The extent of the duplication was analyzed in each family by interphase FISH, with probes from a 1. 7-Mb region surrounding the PLP gene between markers DXS83 and DXS94. A large duplication >=500 kb was detected, with breakpoints that differed, between families, at the proximal end. Distinct separation of the duplicated PLP signals could be seen only on metaphase chromosomes in one family, providing further evidence that different duplication events are involved. Quantitative fluorescent multiplex PCR was used to confirm the duplication in patients, by the detection of increased copy number of the PLP gene. Multiallelic markers from the duplicated region were analyzed, since the identification of two alleles in an affected boy would indicate a duplication. The majority of boys were homozygous for all four markers, compared with their mothers, who were heterozygous for one to three of the markers. These results suggest that intrachromosomal rearrangements may be a common mechanism by which duplications arise in PMD. One boy was heterozygous for the PLP marker, indicating a duplication and suggesting that interchromosomal rearrangements of maternal origin also can be involved. Since duplications are a major cause of PMD, we propose that interphase FISH is a reliable method for diagnosis and identification of female carriers.

A complete YAC contig and cosmid interval map covering the entirety of human Xq21.33 to Xq22.3 from DXS3 to DXS287

We have produced a physical map that covers the entirety of Xq21.33 to Xq22.3, from DXS3 to DXS287, approximately 15-17 Mb of the proximal long arm of the human X chromosome. This region has already been shown to contain a number of genes involved in genetic disorders, some of which have yet to be cloned. The physical map consists of a contig of 420 yeast artificial chromosome (YAC) clones ordered with respect to 142 DNA markers, approximately one probe every 110 kb. Forty-three YACs from across the contig have been used to isolate 2019 cosmids that have been mapped into 87 intervals, and 667 of these clones are positive for at least 1 single-copy marker. These YACs and cosmids have been used to confirm data from other published contigs that map to the region. The physical map described here constitutes the first step toward a complete transcriptional map of the region.

The effect of intravenous erythromycin on solid meal gastric emptying in patients with chronic symptomatic post-vagotomy-antrectomy gastroparesis

BACKGROUND

Chronic symptomatic gastroparesis occurs in 3-5% of patients following vagotomy and antrectomy. Erythromycin, a macrolide antibiotic, improves gastric emptying in patients with idiopathic and diabetic gastroparesis. Erythromycin's effect on gastric emptying in patients with post-vagotomy-antrectomy gastroparesis is unknown. The aim of this study was to determine if a single dose of intravenous erythromycin (1 mg/kg or 6 mg/kg) accelerates solid meal gastric emptying in patients with chronic symptomatic post-vagotomy-antrectomy gastroparesis.

METHODS

Six patients were entered into the study, three males and three females, with a mean age of 50 years. Four patients were randomized to receive erythromycin 6 mg/kg and two patients 1 mg/kg. The mean time since initial surgery was 9.2 years (range 1-16 years) with five patients having undergone a Roux-en-Y revision.

RESULTS

Intravenous erythromycin significantly lowered percentage gastric retention at 120 min, from a baseline of 90.5 +/- 6% (S.E.M.) to 40.1 +/- 4.8% after erythromycin (P = 0.0002). Erythromycin improved gastric emptying in each patient by at least 40%. Intravenous erythromycin significantly accelerated the rate of gastric emptying in the first 30 min after meal ingestion from a baseline rate of 0.072 +/- 0.06%/min to 0.96 +/- 0.31%/min after erythromycin (P = 0.028). For each of the subsequent 30 minute time periods, erythromycin had no significant effect on the rate of gastric emptying.

CONCLUSION

Intravenous erythromycin significantly improves the initial phase of solid meal gastric emptying in patients with chronic symptomatic post-antrectomy-vagotomy gastroparesis.

Sequence and chromosomal location of a human homologue of LRPR1, an FSH primary response gene

The rat gene Leucine-Rich Primary Response Gene-1 (LRPR1) has been proposed to encode a protein involved in the response of gonadal tissues to follicle-stimulating hormone. We have characterized a human transcript that probably encodes the orthologue of the rat protein, exhibiting 72% identity at the amino acid level. The gene from which the transcript is derived maps to human chromosomal region Xq22 and therefore becomes a potential candidate for human X-linked disorders of gonadal development.

A novel X-linked gene, DDP, shows mutations in families with deafness (DFN-1), dystonia, mental deficiency and blindness

In 1960, progressive sensorineural deafness (McKusick 304,700, DFN-1) was shown to be X-linked based on a description of a large Norwegian pedigree. More recently, it was shown that this original DFN-1 family represented a new type of recessive neurodegenerative syndrome characterized by postlingual progressive sensorineural deafness as the first presenting symptom in early childhood, followed by progressive dystonia, spasticity, dysphagia, mental deterioration, paranoia and cortical blindness. This new disorder, termed Mohr-Tranebjaerg syndrome (referred to here as DFN-1/MTS) was mapped to the Xq21.3-Xq22 region2. Using positional information from a patient with a 21-kb deletion in chromosome Xq22 and sensorineural deafness along with dystonia, we characterized a novel transcript lying within the deletion as a candidate for this complex syndrome. We now report small deletions in this candidate gene in the original DFN-1/MTS family, and in a family with deafness, dystonia and mental deficiency but not blindness. This gene, named DDP (deafness/ dystonia peptide), shows high levels of expression in fetal and adult brain. The DDP protein demonstrates striking similarity to a predicted Schizosaccharomyces pombe protein of no known function. Thus, is it likely that the DDP gene encodes an evolutionarily conserved novel polypeptide necessary for normal human neurological development.

Characterization of DRP2, a novel human dystrophin homologue

The currently recognised dystrophin protein family comprises the archetype, dystrophin, its close relative, utrophin or dystrophin-related protein (DRP), and a distantly related protein known as the 87K tyrosine kinase substrate. During the course of a phylogenetic study of sequences encoding the characteristic C-terminal domains of dystrophin-related proteins, we identified an unexpected novel class of vertebrate dystrophin-related sequences. We term this class dystrophin-related protein 2 (DRP2), and suggest that utrophin/DRP be renamed DRP1 to simplify future nomenclature. DRP2 is a relatively small protein, encoded in man by a 45 kb gene localized to Xq22. It is expressed principally in the brain and spinal cord, and is similar in overall structure to the Dp116 dystrophin isoform. The discovery of a novel relative of dystrophin substantially broadens the scope for study of this interesting group of proteins and their associated glycoprotein complexes.

Self-Diffusion Maps from Wavelet De-Noised NMR Images

A wavelet transform was used to improve the signal-to-noise in NMR microimages of Phaseolus vulgaris cotyledonary tissues. Two cases were tested: a relatively clean image and, at longer TE, a relatively noisy image. Significant improvement in the image quality of both test cases was achieved, with the most dramatic improvement noted in the noisy image. The conditions were extended to include diffusion weighting with the aim of computing diffusion maps for the tissues. Again, the wavelet procedure was effective in improving the appearance of the (diffusion-weighted) images. Finally, diffusion maps from the raw and de-noised data were computed and compared. The de-noised images produced maps with better detail and more consistent features. It is concluded that wavelet de-noising is a very useful approach for enhancing the image quality of hard-to-image tissues.

A low molecular weight peptide from snow mold with epitopic homology to the winter flounder antifreeze protein

Evidence for a small size protein (ca. 3500 kDa) exhibiting epitopic homology to the Atlantic winter flounder antifreeze protein (AFP) is found in the snow molds Coprinus psychromorbidus, Myriosclerotinia borealis, and Typhula incarnata. The protein shows strong cross-reactivity with antisera specific for the flounder AFP. Preliminary studies suggest that the protein is synthesized in response to lowering the culture temperature, and that it is membrane associated and, therefore, may function in an analogous capacity to the fish AFP. Also, the protein is shown to have antifreeze properties as determined by nuclear magnetic resonance microimaging experiments.

Characterisation of the novel gene G11 lying adjacent to the complement C4A gene in the human major histocompatibility complex

Twelve transcriptional units have now been located in a 160 kb segment of DNA that includes the genes encoding members of the serum complement system C2, Factor B (Bf) and C4 within the class III region of the human major histocompatibility complex (MHC). The common arrangement of these genes is tel-C2-Bf-RD-G11-C4A-[P450c21A-YA-XA]-C4B-[P450c21B-YB ]-+ ++TNX-cen. Characterisation of cDNA and genomic clones corresponding to the novel gene G11 has revealed that the gene spans approximately 9.1 kb of DNA and is split into 7 exons. The 5' end of the gene is associated with a CpG-island while the 3' end of the gene lies 611 bp from the transcriptional start site of the C4A gene. The approximately 1.4 kb G11 mRNA, which is expressed in a number of different cell types including monocytes, hepatocytes, epithelial cells, T and B lymphocytes, encodes protein products of 254 or 258 amino acids due to differential use of two splice sites lying 12 bp apart at the end of exon 3. These polypeptides share homology with a limited number of proteins including human cytochrome P450XIB1 and the tyrosine kinase transforming protein from fujinami virus. Duplication of the C4/P450c21 transcriptional unit occurred by a nonhomologous recombination event. Sequence analysis of a 1.5 kb segment of DNA flanking the C4B gene has revealed that 914 bp of the 3' end of the G11 gene also lies 611 bp from the transcriptional start site of the C4B gene.(ABSTRACT TRUNCATED AT 250 WORDS)

A 6.5-Mb yeast artificial chromosome contig incorporating 33 DNA markers on the human X chromosome at Xq22

The Xq22 region of the human X chromosome contains genes for a number of inherited disorders. Sixty-nine yeast artificial chromosome clones have been isolated and assembled into a 6.5-Mb contig that contains 33 DNA markers localized to this region. This contig extends distally from DXS366 to beyond DXS87 and includes the genes involved in X-linked agammaglobulinemia (btk), Fabry disease (GLA), and Pelizaeus-Merzbacher disease (PLP). The order of markers in this contig is consistent with the known genetic and physical mapping information of Xq22. This cloned material provides a source from which to isolate other genes located in this part of the X chromosome.

RFLP analysis of the MHC class III region defines unique haplotypes for the non-obese diabetic, cataract Shionogi and the non-obese non-diabetic mouse strains

The non-obese diabetic (NOD) mouse strain which spontaneously develops diabetes is a model for human Type 1 (insulin-dependent) diabetes mellitus. At least one of several genes controlling diabetes in the NOD mouse has been mapped to the MHC. Although previous experiments have implicated the MHC class II genes in the development of the disease, the existence of other MHC linked susceptibility genes has not been ruled out. In order to identify these susceptibility genes we have further characterized the MHC haplotype of the NOD mouse and two non-diabetic sister strains, the non-obese non-diabetic (NON) and cataract Shionogi (CTS). We have examined the mouse MHC class III region for the presence of homologous genes to 17 newly isolated human MHC class III region genes (G1, G2, G4, G6, G7a/valyl-tRNA synthetase, HSP70, G8, G9, G10, G12, G13, G14, G15, G16, G17 and G18). We detect unique hybridizing DNA fragments for 16 of the 17 genes in six inbred mouse strains (NOD, NON, CTS, B10, BALB/c and CBA/J) indicating that this part of the H-2 region is similar to the human MHC class III region. Using a panel of restriction enzymes we have defined RFLPs for 6 (G2, G6, HSP70, G12, G16, G18) of the 16 cross-hybridizing probes. The RFLPs demonstrate that NOD, NON and CTS mouse strains each have a distinct MHC haplotype in the MHC class III region.

Molecular analysis of the MHC class II region in DR4, DR7, and DR9 haplotypes

Within the class II region of the major histocompatibility complex (MHC) the amount of DNA in the DR-DQ interval has been shown to be haplotype dependent, with those carrying the DR4, DR7, and DR9 specificities having been reported to contain 110-160 kilobases (kb) more DNA than haplotypes carrying the DR3 specificity. Certain subtypes of haplotypes carrying particular DR specificities are more closely associated with autoimmune diseases than others. With the prospect of the DNA perhaps containing a disease susceptibility locus, we have mapped eight DR4 and two DR7 homozygous cell lines and a DR7/9 heterozygous cell line together with a control DR3 cell line using pulsed field gel electrophoresis (PFGE) with the enzymes Bss H II, Pvu I, and Not I/Nru I. Our results, however, show that the presence and amount of the extra DNA is constant irrespective of the subtype. We have also tried to narrow down the position of insertion of the extra DNA using eight further rare-cutting enzymes but, due to the polymorphic nature of sites and/or differences in methylation in this region, it was not possible to refine it further than between DRA and DQA1/B1. This polymorphic nature of the DR-DQ region is unusual, considering the uniformity of rare cutter sites that has been observed within the rest of the class II, and class III, regions. The presence of this, and other, haplotype dependent variations in the DNA content of the DR subregion may be important with respect to recombination and will be particularly interesting if the additional DNA is found to contain novel genes.

Cloning of the HLA class II region in yeast artificial chromosomes

Yeast artificial chromosomes (YACs) have been applied to clone the entire class II region of the human major histocompatibility complex (MHC), including its flanking regions, in a contig over 1.5 million base pairs (bp) long. The human DNA inserts in the YACs have a size between 60 and 1300 kbp and were isolated from two EcoRI partial digest libraries. The gaps between DRA and DRB, DRB and DQA, and DOB and DPA, which had not been cloned by other means, have been bridged with YAC clones. The contig extends through the 400 kpb of DNA between the DRA and C4 genes, thus linking the class II region with the complement gene cluster in the class III region. The cloning in YACs has been supported by a conventional cosmid walk of 290 kbp in the C4-DRA region. Restriction enzyme sites in the YAC clones were compared to the sites in the cosmid walk, to published cosmid clones, and to the already existing physical maps, leading to a detailed characterization of a region of the human genome over 1500 kbp. The YAC clones will be valuable for functional analysis of the MHC.

Human major histocompatibility complex contains a new cluster of genes between the HLA-D and complement C4 loci

A new cluster of genes has been defined in the human Major Histocompatibility Complex class III region. The seven novel genes, G12 to G18, are localised in a 160 kb segment of DNA extending from the complement gene cluster towards HLA-DR. The genes were identified by isolation of cDNA clones using cosmid genomic inserts as hybridisation probes, and by the detection of the corresponding transcripts in Northern blot analysis. Characterisation of the cosmid genomic DNA inserts, in conjunction with pulsed field gel electrophoresis analysis of uncloned DNA, for the presence of clustered sites for infrequently cutting restriction endonucleases has revealed that at least 5 of the 7 genes are associated with HTF-islands. These unmethylated CpG-rich sequences are frequently found at the 5' ends of ubiquitously expressed genes. Together with previously published data 36 genes have now been defined in a 680kb stretch of DNA within the MHC. With one gene approximately every 20kb of DNA this represents the most densely packed region of the human genome so far characterised, and is of major significance in relation to the mapping and sequence analysis of the rest of the genome.

Characterization of the class III region in different MHC haplotypes by pulsed-field gel electrophoresis

The class III region of the human major histocompatibility complex (MHC) in seven HLA haplotypes has been analyzed using pulsed-field gel electrophoresis (PFGE), restriction enzymes that cut genomic DNA infrequently, and Southern blotting. In particular, extensive mapping with the enzyme Bss HII, which generates fragments in the size range 8-280 kilobases (kb), has revealed that in the haplotypes studied the DNA content of the class III region does not appear to vary other than as previously observed at the C4 and CYP21 loci.

Transient expression of chloramphenicol acetyltransferase (CAT) gene in barley cell cultures and immature embryos through microprojectile bombardment

Transient expression of chloramphenicol acetyl transferase gene has been detected in cultured barley (Hordeum vulgare L. cv. Heartland) cells and freshly isolated immature zygotic embryos (cv. Ellice) following the introduction of the gene by microprojectile bombardment. The DNA expression vector used to introduce the CAT gene, pCaMVI1CN, is a pUC8 derivative and consisted of a CaMV35S promoter, a fragment of alcohol dehydrogenase intron1, a CAT coding region and NOS polyadenylation region. The inclusion of the Adh1 intron1 was essential for the expression of CAT activity in cultured cells as well as immature zygotic embryos. Expression of CAT activity, which was dependent upon the DNA concentration used, could be detected as early as 20 h after bombardment. The results also suggested that the recipient cells have to be in an active state of cell division in order for the introduced gene to be expressed since mature zygotic as well as somatic embryos failed to reveal any gene expression. The effect of other parameters which influence the expression of the introduced gene as well as the potential of this novel technology for cereal transformation are also discussed.