Using body cameras to quantify the duration of a Code Stroke and identify workflow issues: a continuous observation workflow time study

OBJECTIVE

'Code Stroke' (Code) is used in health services to streamline hyperacute assessment and treatment delivery for patients with ischaemic stroke. However, there are few studies that detail the time spent on individual components performed during a Code. We sought to quantify the time taken for each process during a Code and investigate associations with modifiable and non-modifiable factors.

DESIGN

Continuous observation workflow time study.

SETTING AND PARTICIPANTS

Recordings of 100 Codes were performed at a high-volume primary stroke centre in Melbourne, Australia, between January and June 2020 using a body camera worn by a member of the stroke team.

MAIN OUTCOME MEASURES

The main measures included the overall duration of Codes and the individual processes within the Code workflow. Associations between variables of interest and process times were explored using linear regression models.

RESULTS

100 Codes were captured, representing 19.2% of all Codes over the 6 months. The median duration of a complete Code was 54.2 min (IQR 39.1-74.7). Administrative work performed after treatment is completed (median 21.0 min (IQR 9.8-31.4)); multimodal CT imaging (median 13.0 min (IQR 11.5-15.7)), and time between decision and thrombolysis administration (median 8.1 min (IQR 6.1-10.8)) were the longest components of a Code. Tenecteplase was able to be prepared faster than alteplase (median 1.8 vs 4.9 min, p=0.02). The presence of a second junior doctor was associated with shorter administrative work time (median 10.3 vs 25.1 min, p<0.01). No specific modifiable factors were found to be associated with shorter overall Code duration.

CONCLUSIONS

Codes are time intensive. Time spent on decision-making was a relatively small component of the overall Code duration. Data from body cameras can provide granular data on all aspects of Code workflow to inform potential areas for improvement at individual centres.

Practical utility of the ACT-FAST triage algorithm from a primary stroke centre perspective

Background: Rapid reperfusion in ischaemic stroke with emergent large vessel occlusion (ELVO) reduces morbidity and mortality. Limited distribution of endovascular clot retrieval (ECR) capable comprehensive stroke centres (CSCs) necessitates development of pre-hospital models of care to provide equitable and economical access to reperfusion therapy. We examine the time metrics of the traditional secondary transfer strategy in comparison to the direct bypass strategy and the potential utility of the ACT-FAST prehospital triage algorithm on a large volume Melbourne primary stroke centre (PSC).

Method: Retrospective analysis of consecutive patients presenting to a PSC from 1 January 2020 to 31 December 2020. Clinical records were interrogated for ACT-FAST positive patients. Time metrics were established using Google Maps traffic modelling and local/published door-to-needle, door-in-door out and door-to-groin data.

Results: 88 patients during the study period were ACT-FAST positive. Of these, 49/88 (56%) cases had ELVO ischaemic strokes, 24/88 (27%) cases had intracranial haemorrhages and the remaining 15/88 (17%) had non ELVO ischaemic strokes or mimics (seizure, complex migraine, etc). 28/88 (32%) cases met indication for and were subsequently transferred to a CSC for consideration of ECR. The modelled median scene to groin time for the direct bypass strategy is 94 min whereas the median scene to groin time for the secondary transfer strategy is 109 min, giving a difference of 15 min.

Conclusion: Time savings to groin puncture for the direct bypass strategy is substantially less than previous estimates and suggests that the secondary transfer strategy continues to be a viable pathway for a high efficiency PSC.

Experimental verification of principal losses in a regulatory particulate matter emissions sampling system for aircraft turbine engines

A sampling system for measuring emissions of nonvolatile particulate matter (nvPM) from aircraft gas turbine engines has been developed to replace the use of smoke number and is used for international regulatory purposes. This sampling system can be up to 35 m in length. The sampling system length in addition to the volatile particle remover (VPR) and other sampling system components lead to substantial particle losses, which are a function of the particle size distribution, ranging from 50 to 90% for particle number concentrations and 10-50% for particle mass concentrations. The particle size distribution is dependent on engine technology, operating point, and fuel composition. Any nvPM emissions measurement bias caused by the sampling system will lead to unrepresentative emissions measurements which limit the method as a universal metric. Hence, a method to estimate size dependent sampling system losses using the system parameters and the measured mass and number concentrations was also developed (SAE 2017; SAE 2019). An assessment of the particle losses in two principal components used in ARP6481 (SAE 2019) was conducted during the VAriable Response In Aircraft nvPM Testing (VARIAnT) 2 campaign. Measurements were made on the 25-meter sample line portion of the system using multiple, well characterized particle sizing instruments to obtain the penetration efficiencies. An agreement of ± 15% was obtained between the measured and the ARP6481 method penetrations for the 25-meter sample line portion of the system. Measurements of VPR penetration efficiency were also made to verify its performance for aviation nvPM number. The research also demonstrated the difficulty of making system loss measurements and substantiates the E-31 decision to predict rather than measure system losses.

The Vaginal Microbiome of Transgender Men

BACKGROUND

Hormonal changes influence the composition of vaginal flora, which is directly related to the health of an individual. Transgender men prescribed testosterone experience a vaginal hormone composition that differs from cisgender women. To the author's knowledge, there are no clinical studies evaluating the influence that testosterone administration has on the vaginal microbiome.

METHODS

Vaginal swabs were self-collected by a cohort of self-identified healthy transgender men prescribed testosterone for at least 1 year (n = 28) and from cisgender women who were used as the comparator (n = 8). Participants completed a questionnaire to indicate the mode and dose of testosterone administration, sexual history, and vaginal health. Serum was collected for hormone analysis. Bacterial community profiles were assessed with broad-range PCR primers targeting the V3-V4 hypervariable region of the 16S bacterial rRNA, next-generation sequencing, and analysis by phylogenetic placement.

RESULTS

Compared to cisgender women, the vaginal floras of transgender men were less likely to have Lactobacillus as their primary genus. Intravaginal estrogen administration was positively associated with the presence of Lactobacillus in transgender men (P = 0.045). Transgender men had a significantly increased relative abundance of >30 species and a significantly higher α diversity (P = 0.0003). The presence of Lactobacillus was significantly associated with a lower α diversity index (P = 0.017).

CONCLUSIONS

The vaginal microbiome of transgender men who were assigned a female sex at birth and use testosterone may differ from that of cisgender women. Intravaginal estrogen administration may reduce these differences by promoting colonization with Lactobacillus species and decreasing α diversity.

User-Informed Medical Device Development: A Case Study for Pediatric Malnutrition Assessment

Background. Mid-upper arm circumference (MUAC) has been extensively used to classify pediatric malnutrition. Recently, MUAC z score was recommended; however, the logistics of implementation were not addressed. This study examines the usability of a device that provides MUAC and corresponding z score range in a single device. Methods. This was a single-center study of nutrition services providers. The device was applied to children aged 2 months to 18 years admitted as inpatients or seen as outpatients. Surveys incorporated benchmarking questions, assessed the ease with which respondents could perform 6 critical tasks, and provided an open-ended question to elicit feedback. Users were surveyed monthly until saturation was reached. Survey data were analyzed in aggregate and cross-tabulated by the respondents’ experience with the device. Thematic analysis of the open-ended responses followed a structured approach. Results. Sixty device users responded to the survey 280 times. Respondents were female (100%) with a mean age of 45.2 ± 13.2 years and 9.6 ± 8.0 years in practice. Increasing device use was accompanied by significantly shortened measuring times (P < .001) and shifts in ease of performance for 5 of 6 critical tasks (P < .05). Open-ended response themes related largely to design and materials. These were used to iteratively refine the device. Conclusions. The active engagement of end users in the real-world testing of our nutritional assessment device allowed us to refine the innovation with special attention paid to the needs of dietitians. The result is a device the majority of dietitians found easy to use, efficient, convenient, and preferable to alternative measurement options.

Examining Mid-Upper Arm Circumference Malnutrition z-Score Thresholds

BACKGROUND

Anthropometric z-scores used commonly for diagnosis and determining degree of malnutrition, specifically body mass index (BMIz), weight-for-length (WLz), and mid-upper arm circumference (MUACz), are not wholly concordant, yet the proposed thresholds for classification are identical. This study was designed to critically examine MUACz thresholds and their ability to correctly classify nutrition status.

METHODS

This was a 2-year, prospective single-center study of children ≤18 years seen by registered dietitians within a large pediatric institution. The sensitivity, specificity, and predictive performance of the malnutrition classification thresholds were estimated against clinician-based classification.

RESULTS

Sixty-one dietitians enrolled 10,401 patients with distributions of z-scores for weight (-0.5 ± 1.9), length (-0.8 ± 1.6), BMI or WL (-0.1 ± 1.8), and MUAC (-0.4 ± 1.5), suggesting participants were smaller and shorter than the reference U.S.

POPULATION

Distributions of MUACz were broad and overlapped between nutrition classification groups, an observation that extended to BMIz and WLz as well. Consequently, existing thresholds do not accurately classify 100% of children. Misclassification rates increase, with increasing severity ranging from 8% in children with no malnutrition to 71% in children with severe malnutrition. Algorithm- and manually-based refinement of thresholds result in mixed improvements and can be explored by the reader with the associated supplement.

CONCLUSION

The sensitivity of proposed MUACz thresholds systematically decreases with increasing severity of malnutrition and will require optimization if we aim to limit the number of children at risk of misclassification. Indicators for overnutrition remain to be addressed but are explored herein.

Rhodococcus fascians infection after haematopoietic cell transplantation: not just a plant pathogen?

Introduction:

Rhodococcus spp. have been implicated in a variety of infections in immunocompromised and immunocompetent hosts. Rhodococcus equi is responsible for the majority of reported cases, but Rhodococcus erythropolis, Rhodococcusgordoniae and Rhodococcusruber infections have been described. There are no prior reports of human infection with Rhodococcus fascians.

Case presentation:

We describe the unexpected finding of R. fascians in liver lesions incidentally noted at autopsy in an immunosuppressed patient status after bone-marrow transplant for acute lymphoblastic leukaemia who died of unrelated causes (septic shock due to Clostridium difficile colitis). At autopsy, an otherwise unremarkable liver contained several dozen well-demarcated sclerotic-appearing lesions measuring 0.1–0.3 cm in size. The absence of other bacterial or fungal DNA in the setting of histologically visible organisms argues against its presence as a contaminant and raises the consideration that R. fascians represents a human pathogen for the immunocompromised.

Conclusion:

Whether it represents the sole infectious agent responsible for the miliary lesions or a partially treated co-infection is impossible to determine, but our finding continues to reinforce the importance of molecular techniques in associating organisms with sites of infection and optimizing treatment of infectious diseases.

Mycobacterium llatzerense lung infection in a liver transplant recipient: case report and review of the literature

Nontuberculous mycobacteria are increasingly encountered pathogens in organ transplant recipients. We report the first case of human disease attributed to Mycobacterium llatzerense that occurred in a liver transplant recipient in the midwestern United States who developed pneumonia and describe the treatment of this patient.

Payment for obesity services: examples and recommendations for stage 3 comprehensive multidisciplinary intervention programs for children and adolescents

OBJECTIVE

The Reimbursement and Payment Subcommittee of the National Association of Children's Hospitals and Related Institutions FOCUS on a Fitter Future group sought to guide medical providers, patients, and payers to better serve obese children and adolescents to enable optimum health. Recommendations are provided for the essential components of a stage 3 comprehensive multidisciplinary intervention program as defined by the 2007 Expert Committee recommendations. In addition, suggestions are offered for a stepwise approach to implement these recommendations.

METHODS

In 2009, key informant interviews were conducted with 15 children's hospitals participating in FOCUS on a Fitter Future and 1 nonparticipating hospital. Interview transcripts identified 5 financially sustainable stage 3 programs, each funded differently.

RESULTS

The stage 3 programs interviewed ranged from being nascent to 21 years old (27%, <2 years; 47%, 2-6 years; 27%, >6 years). All of them had multidisciplinary teams that delivered services through 1 of 3 institutional structures: 60% freestanding; 7% specialty; and 33% hospital within a hospital. One-third of them had 1 to 2 funding sources, and 67% had ≥ 3 sources.

CONCLUSIONS

The stage 3 programs in this review shared some common strategies for achieving financial stability. All of them followed key strategies of the chronic care model, the details of which led to the following recommendation: stage 3 programs should include a health care team with a medical provider, registered dietitian, physical activity specialist, mental health specialist, and coordinator who, as a team, provide service to overweight and obese children at no less than moderate intensity (26-75 hours).

Plexiform-like neurofibromas develop in the mouse by intraneural xenograft of an NF1 tumor-derived Schwann cell line

Plexiform neurofibromas are peripheral nerve sheath tumors that arise frequently in neurofibromatosis type 1 (NF1) and have a risk of malignant progression. Past efforts to establish xenograft models for neurofibroma involved the implantation of tumor fragments or heterogeneous primary cultures, which rarely achieved significant tumor growth. We report a practical and reproducible animal model of plexiform-like neurofibroma by xenograft of an immortal human NF1 tumor-derived Schwann cell line into the peripheral nerve of scid mice. The S100 and p75 positive sNF94.3 cell line was shown to possess a normal karyotype and have apparent full-length neurofibromin by Western blot. These cells were shown to have a constitutional NF1 microdeletion and elevated Ras-GTP activity, however, suggesting loss of normal neurofibromin function. Localized intraneural injection of the cell line sNF94.3 produced consistent and slow growing tumors that infiltrated and disrupted the host nerve. The xenograft tumors resembled plexiform neurofibromas with a low rate of proliferation, abundant extracellular matrix (hypocellularity), basal laminae, high vascularity, and mast cell infiltration. The histologic features of the developed tumors were particularly consistent with those of human plexiform neurofibroma as well. Intraneural xenograft of sNF94.3 cells enables the precise initiation of intraneural, plexiform-like tumors and provides a highly reproducible model for the study of plexiform neurofibroma tumorigenesis. This model facilitates testing of potential therapeutic interventions, including angiogenesis inhibitors, in a relevant cellular environment.

Conservation of hotspots for recombination in low-copy repeats associated with the NF1 microdeletion

Several large-scale studies of human genetic variation have provided insights into processes such as recombination that have shaped human diversity. However, regions such as low-copy repeats (LCRs) have proven difficult to characterize, hindering efforts to understand the processes operating in these regions. We present a detailed study of genetic variation and underlying recombination processes in two copies of an LCR (NF1REPa and NF1REPc) on chromosome 17 involved in the generation of NF1 microdeletions and in a third copy (REP19) on chromosome 19 from which the others originated over 6.7 million years ago. We find evidence for shared hotspots of recombination among the LCRs. REP19 seems to contain hotspots in the same place as the nonallelic recombination hotspots in NF1REPa and NF1REPc. This apparent conservation of patterns of recombination hotspots in moderately diverged paralogous regions contrasts with recent evidence that these patterns are not conserved in less-diverged orthologous regions of chimpanzees.

Interstitial uniparental isodisomy at clustered breakpoint intervals is a frequent mechanism of NF1 inactivation in myeloid malignancies

To identify the mechanism of loss of heterozygosity (LOH) and potential modifier gene(s), we investigated the molecular basis of somatic NF1 inactivation in myeloid malignancies from 10 children with neurofibromatosis type 1. Loci across a minimal 50-Mb region of primarily the long arm of chromosome 17 showed LOH in 8 cases, whereas a less than 9-Mb region of loci flanking NF1 had LOH in the remaining 2 cases. Two complementary techniques, quantitative polymerase chain reaction (PCR) and fluorescence in situ hybridization (FISH), were used to determine whether the copy number at loci that showed LOH was 1 or 2 (ie, deleted or isodisomic). The 2 cases with LOH limited to less than 9 Mb were intrachromosomal deletions. Among the 8 leukemias with 50-Mb LOH segments, 4 had partial uniparental isodisomy and 4 had interstitial uniparental isodisomy. These isodisomic cases showed clustering of the centromeric and telomeric LOH breakpoints. This suggests that the cases with interstitial uniparental isodisomy arose in a leukemia-initiating cell by double-homologous recombination events at intervals of preferred mitotic recombination. Homozygous inactivation of NF1 favored outgrowth of the leukemia-initiating cell. Our studies demonstrate that LOH analyses of loci distributed along the chromosomal length along with copy-number analysis can reveal novel mechanisms of LOH that may potentially identify regions harboring "cryptic" tumor suppressor or modifier genes whose inactivation contributes to tumorigenesis.

Communication skills training in postgraduate medicine: the development of a new course

It has long been accepted that communication is of central importance in healthcare, and a core aspect of clinical competence. Many educational institutions and Royal Colleges now reflect this and consider communication skills a priority in postgraduate examination. The new examination "Practical Assessment of Clinical and Examination Skills" has replaced the Royal College of Physicians MRCP part 2 clinical and oral examination. This examination now consists of five clinical stations, two of which focus on communication skills. A short course for postgraduate trainees has been designed to address the communication skills requirements of the part 2 clinical examination. The aims, development, and content of the course are described. Emphasis is placed on candidates practising skills with patients and receiving feedback during the course. Evidence suggests that practice with feedback is an essential ingredient of communication skills courses, and is more effective than other methods such as observing experts or video examples, or simply discussing issues in communication. Results of a preliminary evaluation indicate that the course was perceived as valuable by candidates and that the aims, format, and content were appropriate. Although the preliminary evaluation was largely positive, it could be argued that the acid test of the effectiveness of a course is an objective evaluation of skills, observed before and after the course, a development that is being considered for future evaluation of the course. Recommendations for applying this type of training to postgraduate trainees in any branch of medicine are given.

Team approach to teaching participatory group process involving natural resources and agriculture

Contemporary issues are defined by people who share diverse and often strongly defended views about the topic. In Oregon, citizens are increasingly being asked or expected to participate in complex decisions that require a consensus. Rather than teach one professor's synthesis of a contemporary natural resource issue, faculty from six disciplines coach group process, interactive learning skills, and systems thinking as a way to address complex issues from multiple perspectives. Students learn by grappling with a natural resource issue of their choice within groups based on a diversity among majors, degree status, and gender. Students define situation (S), brainstorm new or different targets (T), and analyze two or more pathways (P), using an STP learning and action process. Exploring potential pathways involves defining possible consequences, stakeholder views, feasibility (ecological, social, economic, and political), and planning that includes expected behavior of the improved system over time. Students present their topics and improvements showing systemic relationships, systematic analysis, and integration of scientific facts and secondary data at midterm and during finals. Reflective learning is fostered throughout the course with prompted questions in a journal notebook. Grading criteria promote meaningful inquiry and participation in group process combined with integration of scientific facts and reflective learning.

Genomic context of paralogous recombination hotspots mediating recurrent NF1 region microdeletion

Recombination between paralogs that flank the NF1 gene at 17q11.2 typically results in a 1.5-Mb microdeletion that includes NF1 and at least 13 other genes. We show that the principal sequences responsible are two 51-kb blocks with 97.5% sequence identity (NF1REP-P1-51 and NF1REP-M-51). These blocks belong to a complex group of paralogs with three components on 17q11.2 and another on 19p13.13. Breakpoint sequencing of deleted chromosomes from multiple patients revealed two paralogous recombination hot spots within the 51-kb blocks. Lack of sequence similarity between these sites failed to suggest or corroborate any putative cis-acting recombinogenic motifs. However, the NF1 REPs showed relatively high alignment mismatch between recombining paralogs, and we note that the NF1REP hot spots were regions of good alignment bordered by relatively large alignment gaps. Statistical tests for gene conversion detected a single significant tract of perfect match between the NF1REPs that was 700 bp long and coincided with PRS2, the predominant recombination hot spot. Tracts of perfect match occurring by chance may contribute to breakpoint localization, but our result suggests that perfect tracts at recombination hot spots may be a result of gene conversion at sites at which preferential pairing occurs for other, as-yet-unknown reasons.

Applications of eTag™ assay platform to systems biology approaches in molecular oncology and toxicology studies

We have developed a universal eTag trade mark multiplex assay platform that can be uniquely applied to survey the molecule profiles of biologic systems in sub-global large-scale analyses. The effectiveness of eTag trade mark assays when applied to focused system biology studies in molecular oncology and predictive toxicology is herein described while reviewing the current methods commonly used. The multi-analyte and multi-parameter assay approach for parallel analysis will form the basis of an emerging paradigm of multiplexed molecular profiling for signaling pathway networks and various aspects of drug development processes.

Genetics of Neurofibromatosis 1-Associated Peripheral Nerve Sheath Tumors

Neurofibromatosis 1, an inherited disorder that affects 1/3500 individuals worldwide, predisposes to the development of benign and malignant peripheral nerve sheath tumors. The disorder results from inactivation of one of the NFI genes. The second NFI gene is typically inactivated in Schwann cells during tumor formation. This article reviews the different types of genetic alterations in NFI in both constitutional and tumor tissues and genetic alterations of other genes that may affect tumorigenesis. These studies have provided insight into the genetic basis of both the variable expression of the disorder and of benign and malignant peripheral nerve sheath tumorigenesis.

The human cystatin M/E gene (CST6): exclusion candidate gene for harlequin ichthyosis

Cystatin M/E is a recently discovered cysteine proteinase inhibitor whose expression is largely confined to cutaneous epithelia. In human skin it is expressed in sweat glands, hair follicles, and stratum granulosum of the epidermis where it presumably acts as a substrate for transglutaminase. Very recently we reported that a null mutation in the mouse cystatin M/E gene (Cst6) causes the murine ichq phenotype, which is characterized by abnormalities in cornification and desquamation, demonstrating an essential role for cystatin M/E in the final stages of epidermal differentiation. We here obtained the complete sequence of the human cystatin M/E gene (CST6), which provides a tool to investigate CST6 as a candidate gene in skin diseases characterized by abnormal cornification. The involvement of CST6 in harlequin ichthyosis in humans was evaluated by sequencing the entire coding region and intron-exon boundaries for mutations in 11 sporadic harlequin ichthyosis patients. No CST6 mutations were detected in this group, which comprised type 1 and type 2 harlequin ichthyosis patients. Disturbed transcription/translation due to mutations in regulatory and noncoding regions of cystatin M/E was unlikely because cystatin M/E protein expression was observed in all patients examined, as assessed by immunohistochemistry. Although our results indicate that CST6 is not a major gene contributing to type 1 and 2 harlequin ichthyosis, these data may facilitate further analysis of the role of cystatin M/E in normal human skin and other genetic disorders of cornification.

The ichq mutant mouse, a model for the human skin disorder harlequin ichthyosis: mapping, keratinocyte culture, and consideration of candidate genes involved in epidermal growth regulation

Harlequin ichthyosis (HI) is a rare and usually fatal scaling skin disorder. The HI mutant mouse (ichq/ichq) has many similarities to the human disorder and provides an important model to identify candidate genes. In this study, we report refined mapping of the mouse ichq locus and consideration of the candidate genes: calpain 1 (Capn1), phospholipase C beta 3 (Plcb3), and Rela and Ikka/Chuk that encode components of the nuclear factor-kappa B (NF-kappaB) pathway. Each are strong candidates because of epidermal expression and/or changes in expression in human HI. All candidates are linked to the ichq locus on mouse Chromosome 19, although Ikka is located more distally. Genetic mapping in mouse has narrowed the ichq critical region to 4 cM. Keratinocytes from skin of +/+, +/ichq and ichq/ichq mice were cultured; all genotypes had similar expression of epidermal differentiation markers. RT-PCR amplification and sequence analysis of each candidate gene did not reveal any mutations in the ichq mouse. Mutational screening of CAPN1 cDNA from different human HI cases revealed a R433P change, but analysis of 50 normal samples demonstrated that this was an apparent polymorphism. Sequence of RELA in five unrelated human HI cases was normal. The results provide compelling evidence that none of these genes are the primary defect in the ichq mouse and that CAPN1 and RELA are not mutated in the human disorder.

Complete physical map and gene content of the human NF1 tumor suppressor region in human and mouse

Duplicon-mediated microdeletions around the NF1 gene are frequently associated with a severe form of neurofibromatosis type I in a subgroup of patients who show an earlier onset of cutaneous neurofibromas, dysmorphic facial features, and lower IQ values. To clarify the discrepancies between published maps of the NF1 tumor-suppressor gene region as well as the length of gaps in these assemblies and to validate the recently described tandem duplication of the human NF1 locus, we assembled a contiguous high-density map of BAC and PAC clones from different genomic libraries. Although two WI-12393-derived low-copy fragments are known to occur at the proximal and distal boundaries of the 1.5-Mb segment that is usually deleted in NF1 microdeletion patients, we identified an additional WI-12393-related segment between the MGC13061 and the NF1 gene, which appears to trigger interstitial deletions of smaller size as observed in two patients. Moreover, we completed the genomic organization and cDNA structure of all functional genes, CYTOR4, FLJ12735, FLJ22729, CENTA2, MGC13061, NF1, OMG, EVI2B, EVI2A, KIAA1821, MGC11316, HCA66, KIAA0160, and WI-12393, from this region. A comparison of the human map to the orthologous region on mouse chromosome 11 revealed significant differences in the number and arrangement of genes, indicating that many chromosomal breaks with partial duplications, inversions, and deletions occurred predominantly in the primate lineage.

Diagnosis of five spinocerebellar ataxia disorders by multiplex amplification and capillary electrophoresis

The autosomal-dominant spinocerebellar ataxias (ADCA) are a heterogeneous group of neurodegenerative disorders with variable expression and phenotypic overlap. An accurate diagnosis relies on detection of a mutation in a specific causative gene, which is typically an abnormal number of CAG trinucleotide repeats. To streamline testing in a clinical setting, we converted our current panel of tests for the spinocerebellar ataxias (SCA) types SCA1, SCA2, SCA3, SCA6, and SCA7 from five independent amplification reactions analyzed by polyacrylamide gel electrophoresis (PAGE) to a single multiplex amplification reaction analyzed by capillary electrophoresis (CE). Multiplex amplification was facilitated by the use of chimeric primers; different lengths and fluorochromes distinguished the amplicons. During CE with commercially available molecular weight standards, the SCA amplicons migrated faster than predicted, thereby underestimating their length compared to that determined previously by PAGE. This was observed to varying degrees for each of the five loci, with the greatest size differential occurring in amplicons with greater (CAG)(n). To determine accurate amplicon length, and therefore an accurate number of CAG repeats, a size correction formula was calculated for each locus. This multiplex semi-automated assay has been reliable during 1 year of use in a clinical setting during which 57 samples were tested and five positive samples were detected.

Recombination hotspot in NF1 microdeletion patients

Neurofibromatosis type 1 (NF1) patients that are heterozygous for an NF1 microdeletion are remarkable for an early age at onset and an excessive burden of dermal neurofibromas. Microdeletions are predominantly maternal in origin and arise by unequal crossover between misaligned NF1REP paralogous sequence blocks which flank the NF1 gene. We mapped and sequenced the breakpoints in several patients and designed primers within each paralog to specifically amplify a 3.4 kb deletion junction fragment. This assay amplified a deletion junction fragment from 25 of the 54 unrelated NF1 microdeletion patients screened. Sequence analysis demonstrated that each of the 25 recombination events occurred in a discrete 2 kb recombination hotspot within each of the flanking NF1REPs. Two recombination events were accompanied by apparent gene conversion. A search for recombination-prone motifs revealed a chi-like sequence; however, it is unknown whether this element stimulates recombination to occur at the hotspot. The deletion-junction assay will facilitate the prospective identification of patients with NF1 microdeletion at this hotspot for genotype-phenotype correlation studies and diagnostic evaluation.

Expression of a truncated keratin 5 may contribute to severe palmar--plantar hyperkeratosis in epidermolysis bullosa simplex patients

Epidermolysis bullosa simplex are dominant disorders of skin fragility characterized by intraepidermal blistering upon mild mechanical trauma. Skin fragility is caused by expression of either an abnormal keratin 5 or an abnormal keratin 14 protein, which compromises the structure and function of the keratin cytoskeleton of basal cells. We report an epidermolysis bullosa simplex patient with a novel single base substitution (A-->T1414) that changes the lysine residue at amino acid 472 to a non-sense codon (K472X). This change predicts the synthesis of a truncated keratin 5, missing 119 amino acids, including the entire tail domain and the highly conserved KLLEGE motif at the carboxy terminus of the 2B domain of the central rod. Expression of an altered keratin 5, of predicted mass and pI for the product of the K472X allele, was documented by one- and two-dimensional western blots of protein extracts from patient skin. Ultrastructural analysis of the patient's nonhyperkeratotic skin was remarkable for basal keratinocytes with dense and irregular keratin filaments proximal to the basement membrane. Keratinocytes, transfected with a cDNA carrying the A-->T1414 non-sense mutation, overexpressed a truncated keratin 5, and showed a disorganized and collapsed keratin filament cytoskeleton. This is the second epidermolysis bullosa simplex patient reported with a premature termination mutation in the KLLEGE motif. The remarkable occurrence of severe palmar--plantar hyperkeratosis in both patients suggests that the keratin 5 tail domain may have unrecognized, but important, normal functions in palmar-plantar tissues.

Evidence that juvenile myelomonocytic leukemia can arise from a pluripotential stem cell

Children with neurofibromatosis type 1 (NF1) carry germline mutations in one allele of the NF1 gene and are predisposed to myeloid malignancies, particularly juvenile myelomonocytic leukemia (JMML). Disruption of the remaining NF1 allele can be found in malignant cells. Flow cytometric cell sorting techniques to isolate the malignant cell populations and molecular genetic methods to assay for somatic loss of the normal NF1 allele were used to study an unusual child with NF1 and JMML who subsequently had T-cell lymphoma. The data show that malignant JMML and lymphoma cells share a common loss of genetic material involving the normal NF1 gene and approximately 50 Mb of flanking sequence, suggesting that the abnormal T-lymphoid and myeloid populations were derived from a common precursor cell. These data support the hypothesis that JMML can arise in a pluripotent hematopoietic cell.

Formula for surgical practice resuscitation in an academic medical center

BACKGROUND

Managing patient referrals for surgical consultation in an academic practice has traditionally emphasized clinical rather than service expertise. However, assuring both efficiency and accuracy in the initial consultation have become critical early measures of quality care.

METHODS

In partnership with the academic medical center administration, current practice was analyzed. Performance and communication standards were established around an ideal patient experience. A new ambulatory consultation process was developed; and flowcharting methods for resource allocation, statistical process control, and pre-visit data collection were used to reduce patient administrative time. Automated referral reports engaged referring physicians throughout the consultation.

RESULTS

Accurate insurance and referral authorization have been provided for all patients, including the 4% who are underinsured. Patient, provider, and referring physician satisfaction has increased significantly. Staff time investment has progressively declined from 52 +/- 11 (95% confidence) minutes to 34 +/- 10 minutes for most patients. Realignment of tasks has reduced the administrative time spent by the patient by 32% without compromising clinical time. New patient volume increased by 29% per year, maintaining regional market share.

CONCLUSIONS

Expertise in the process of consultation delivery is feasible and will be increasingly critical to the survival of academic surgical practice in a competitive market.

NF1 microdeletion breakpoints are clustered at flanking repetitive sequences

Neurofibromatosis type 1 patients with a submicroscopic deletion spanning the NF1 tumor suppressor gene are remarkable for an early age at onset of cutaneous neurofibromas, suggesting the deletion of an additional locus that potentiates neurofibromagenesis. Construction of a 3.5 Mb BAC/PAC/YAC contig at chromosome 17q11.2 and analysis of somatic cell hybrids from microdeletion patients showed that 14 of 17 cases had deletions of 1.5 Mb in length. The deletions encompassed the entire 350 kb NF1 gene, three additional genes, one pseudogene and 16 expressed sequence tags (ESTs). In these cases, both proximal and distal breakpoints mapped at chromosomal regions of high identity, termed NF1REPs. These REPs, or clusters of paralogous loci, are 15-100 kb and harbor at least four ESTs and an expressed SH3GL pseudogene. The remaining three patients had at least one breakpoint outside an NF1REP element; one had a smaller deletion thereby narrowing the critical region harboring the putative locus that exacerbates neurofibroma development to 1 Mb. These data show that the likely mechanism of NF1 microdeletion is homologous recombination between NF1REPs on sister chromatids. NF1 microdeletion is the first REP-mediated rearrangement identified that results in loss of a tumor suppressor gene. Therefore, in addition to the germline rearrangements reported here, NF1REP-mediated somatic recombination could be an important mechanism for the loss of heterozygosity at NF1 in tumors of NF1 patients.

Refined mapping of the human serotonin transporter (SLC6A4) gene within 17q11 adjacent to the CPD and NF1 genes

The SLC6A4 gene encodes the serotonin transporter, the target of an important class of antidepressant drugs (serotonin selective reuptake inhibitors). Polymorphisms in the SLC6A4 gene have been reported to be associated with susceptibility to depression and other psychiatric disorders. We have constructed a 1 Mb YAC and PAC contig which harbours both the SLC6A4 and the carboxypeptidase D (CPD) genes. The order of loci within the contig was cen-D17S975-D17S1549-24R-D17S1294-SLC6A4-28L+ ++-(CPD, D17S2009, D17S2004)-D17S2120-ter. Both genes were deleted in one of 17 neurofibromatosis type 1 (NF1) patients carrying submicroscopic NF1 contiguous gene deletions.