Assay Validation of Cell-Free DNA Shallow Whole-Genome Sequencing to Determine Tumor Fraction in Advanced Cancers

Blood-based liquid biopsy is increasingly used in clinical care of patients with cancer, and fraction of tumor-derived DNA in circulation (tumor fraction; TFx) has demonstrated clinical validity across multiple cancer types. To determine TFx, shallow whole-genome sequencing of cell-free DNA (cfDNA) can be performed from a single blood sample, using an established computational pipeline (ichorCNA), without prior knowledge of tumor mutations, in a highly cost-effective manner. We describe assay validation of this approach to facilitate broad clinical application, including evaluation of assay sensitivity, precision, repeatability, reproducibility, pre-analytic factors, and DNA quality/quantity. Sensitivity to detect TFx of 3% (lower limit of detection) was 97.2% to 100% at 1× and 0.1× mean sequencing depth, respectively. Precision was demonstrated on distinct sequencing instruments (HiSeqX and NovaSeq) with no observable differences. The assay achieved prespecified 95% agreement of TFx across replicates of the same specimen (repeatability) and duplicate samples in different batches (reproducibility). Comparison of samples collected in EDTA and Streck tubes from single venipuncture in 23 patients demonstrated that EDTA or Streck tubes were comparable if processed within 8 hours. On the basis of a range of DNA inputs (1 to 50 ng), 20 ng cfDNA is the preferred input, with 5 ng minimum acceptable. Overall, this shallow whole-genome sequencing of cfDNA and ichorCNA approach offers sensitive, precise, and reproducible quantitation of TFx, facilitating assay application in clinical cancer care.

Increasing diversity in genomics requires investment in equitable partnerships and capacity building

Calls for diversity in genomics have motivated new global research collaborations across institutions with highly imbalanced resources. We describe practical lessons we have learned so far from designing multidisciplinary international research and capacity-building programs that prioritize equity in two intertwined programs — the NeuroGAP-Psychosis research study and GINGER training program — spanning institutions in Ethiopia, Kenya, South Africa, Uganda and the united States.

Abstract 5371: The Metastatic Breast Cancer Project: Partnering with patients to accelerate progress in cancer research

The Metastatic Breast Cancer Project (MBCproject) is a research study that directly engages patients (pts) through social media and advocacy groups, and empowers them to share samples, clinical data, and experiences. The goal is to create a publicly available database of genomic, molecular, clinical, and patient-reported data to enable research. Working with pts and advocates, a website (MBCproject.org) was developed that allows pts with metastatic breast cancer (MBC) to register. Registered pts are sent an online consent form that asks for permission to obtain and analyze their medical records and samples. Once enrolled, pts are sent a saliva kit and asked to mail back a saliva sample, which is used to extract germline DNA. We contact participants' medical providers and obtain medical records and a portion of their stored tumor biopsies. Pts may be asked to mail in a blood sample, which is used to extract cell free DNA (cfDNA). Whole-exome sequencing (WES) is performed on tumor DNA, germline DNA, and cfNDA; transcriptome sequencing is performed on tumor RNA. Clinically annotated genomic data are used to study specific pt cohorts (including outliers) and to identify mechanisms of response and resistance to therapies. All de-identified data are shared via public databases. Study updates are shared with participants regularly. From 10/2015-11/2017, 4237 MBC pts registered, representing over 1,000 institutions. 95% answered the 16-question survey about their cancer, treatments, and demographic information. 2471 (58%) completed the consent form. 2,136 saliva kits were mailed to pts and 1,523 saliva samples were sent in (71%). 408 blood kits were mailed to pts and 175 blood samples have been received for cfDNA analysis. To date, we have obtained medical records from 311 pts and 190 tumors from 127 pts. In 10/2017, all data generated so far were publicly released on cbioportal.org, including WES for 103 tumors from 78 pts linked to clinical data including pathology (22 elements), medical record abstraction including all treatments and timelines/durations (67 elements), and patient-reported data (11 elements). 81% of biopsies included in this release were from the breast and 19% from metastatic sites. 75% were obtained prior to any therapy, 24% following therapy. New data will be released 4/2018 and every six months thereafter, as they are generated. Additional patient-reported data, including treatments, side effects, quality of life, family history, pregnancies, and sites of metastasis, will also be collected and shared. In summary, a patient-driven approach enabled rapid identification of thousands of MBC pts willing to share samples and clinical data. Remote acquisition of medical records, saliva, blood, and tumor tissue for pts across the U.S. is feasible. This shared clinico-genomic database should enable research in MBC and may serve as a model for patient-driven research in other cancers.

Citation Format: Nikhil Wagle, Corrie Painter, Elana Anastasio, Michael Dunphy, Mary McGillicuddy, Rachel Stoddard, Esha Jain, Dewey Kim, Simona Di Lascio, Brett N. Tompson, Sara Balch, Beena Thomas, Priti Kumari, Shawn Johnson, Jamie Holloway, Ofir Cohen, Erik H. Knelson, Katie Larkin, Sam Pollock, Alicia Wong, Samira Bahl, Simone Maiwald, Andrew Zimmer, Esme O. Baker, Jen Hendry Lapan, Scott Sutherland, Scott Sassone, Viktor Adalsteinsson, Eric S. Lander, Todd R. Golub. The Metastatic Breast Cancer Project: Partnering with patients to accelerate progress in cancer research [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5371.

Tobacco-related-compound-induced Nitrosative Stress Injury in the Hamster Cheek Pouch

The nitric oxide radical (•NO) released from tobacco-related compounds induces DNA damage, protein modifications, and cellular toxicity through the formation of peroxynitrite (ONOO−), the reaction product of •NO and the oxygen radical, superoxide. We hypothesize that tobacco-related compounds are cytotoxic and induce quantifiable DNA single-strand breaks in immortalized hamster cheek pouch (POII) cells, and that an amino acid marker of ONOO− injury, namely, 3-nitrotyrosine (3-NT), is detectable in hamster cheek pouch tissues chronically exposed to these compounds. We observed a dose-dependent decrease in POII cell viability with increasing tobacco-related compound concentrations, as well as a dose-dependent increase in DNA strand breaks. Semi-quantitative immunohistochemistry showed intense 3-NT immunoreactivity in hamster tissues treated with tobacco-related compounds compared with controls (p < 0.005). Our results suggest that tobacco-related compounds, including nicotine, are genotoxic, and that 3-NT is a quantifiable marker of ONOO− damage in intact hamster cheek pouch tissues.

Population-based cohort study of variation in the use of emergency cholecystectomy for benign gallbladder diseases

Background

The aims of this prospective population-based cohort study were to identify the patient and hospital characteristics associated with emergency cholecystectomy, and the influences of these in determining variations between hospitals.

Methods

Data were collected for consecutive patients undergoing cholecystectomy in acute UK and Irish hospitals between 1 March and 1 May 2014. Potential explanatory variables influencing the performance of emergency cholecystectomy were analysed by means of multilevel, multivariable logistic regression modelling using a two-level hierarchical structure with patients (level 1) nested within hospitals (level 2).

Results

Data were collected on 4744 cholecystectomies from 165 hospitals. Increasing age, lower ASA fitness grade, biliary colic, the need for further imaging (magnetic retrograde cholangiopancreatography), endoscopic interventions (endoscopic retrograde cholangiopancreatography) and admission to a non-biliary centre significantly reduced the likelihood of an emergency cholecystectomy being performed. The multilevel model was used to calculate the probability of receiving an emergency cholecystectomy for a woman aged 40 years or over with an ASA grade of I or II and a BMI of at least 25·0 kg/m2, who presented with acute cholecystitis with an ultrasound scan showing a thick-walled gallbladder and a normal common bile duct. The mean predicted probability of receiving an emergency cholecystectomy was 0·52 (95 per cent c.i. 0·45 to 0·57). The predicted probabilities ranged from 0·02 to 0·95 across the 165 hospitals, demonstrating significant variation between hospitals.

Conclusion

Patients with similar characteristics presenting to different hospitals with acute gallbladder pathology do not receive comparable care.

The prognostic significance of tumour-stroma ratio in oestrogen receptor-positive breast cancer

Background:

A high percentage of stroma predicts poor survival in triple-negative breast cancers but is diminished in studies of unselected cases. We determined the prognostic significance of tumour–stroma ratio (TSR) in oestrogen receptor (ER)-positive male and female breast carcinomas.

Methods:

TSR was measured in haematoxylin and eosin-stained tissue sections (118 female and 62 male). Relationship of TSR (cutoff 49%) to overall survival (OS) and relapse-free survival (RFS) was analysed.

Results:

Tumours with ⩾49% stroma were associated with better survival in female (OS P=0.008, HR=0.2–0.7; RFS P=0.006, HR=0.1–0.6) and male breast cancer (OS P=0.005, HR=0.05–0.6; RFS P=0.01, HR=0.87–5.6), confirmed in multivariate analysis.

Conclusions:

High stromal content was related to better survival in ER-positive breast cancers across both genders, contrasting data in triple-negative breast cancer and highlighting the importance of considering ER status when interpreting the prognostic value of TSR.

WE-G-217A-03: Respiratory-Related External/Internal Motion Based MR Image Reconstruction Using Dynamic Keyhole for Real-Time Tumor Monitoring

PURPOSE

It is aim to test the hypothesis that a dynamic keyhole MRI reconstruction technique using external/internal respiratory surrogate position reduces acquisition time while retaining image quality for real-time tumor monitoring, compared to the conventional keyhole technique.

METHODS

46 thoracic MRI studies with 13 healthy human subjects have been acquired using a 3T GE MRI. Acquired MR images were reconstructed using zero-filling, conventional keyhole and the proposed respiratory motion based dynamic keyhole techniques; resultant images were then compared for image quality. Undersampled k-space rate in the phase encoding direction was determined based on the difference between the original image and the reconstructed image. The position of abdominal muscles and diaphragm were used to determine any excess data that exists in the overlaid temporal data. In addition, the feasibility of the dynamic keyhole method was applied using lung tumor MR images.

RESULTS

The result from dynamic keyhole using respiratory motion demonstrated significant improvement compared with the zero-filling and conventional keyhole methods. Firstly, the dynamic keyhole method using external respiratory motion had an overlaid average of 79.7% (204 lines) of 256 lines from 46 datasets, compared to 63.9% in zero-filling and 74.3% in conventional keyhole. Secondly, dynamic keyhole method using internal diaphragm motion had an overlaid average of 84.5% (216 lines) of 256 lines from all datasets compared to 67.1% and 77.8% or zero-filling and conventional keyhole, respectively. Lastly, dynamic keyhole has been validated with one dataset involving lung tumor MR images. Image blurring artifacts and inferior resolution were not present in the final MR images using dynamic keyhole.

CONCLUSIONS

Dynamic keyhole method using respiratory external/internal surrogate motion has been proposed to reconstruct MR images without image artifacts and with superior resolution. This method is applicable to MR images targeting lungs and other organs affected by respiratory motion for real-time tumor motion monitoring.

WE-G-213CD-07: Enhancing Respiratory Motion Prediction Accuracy Using Audiovisual (AV) Biofeedback

PURPOSE

Prediction of respiratory-related tumor motion is hampered by irregularities present in the patient breathing patterns. Audiovisual (AV) biofeedback reduces irregularities, thereby producing a less complex breathing pattern. The aim of this project is to improve respiratory motion prediction accuracy using an AV biofeedback system.

METHODS

An AV biofeedback system combined with real-time MRI was implemented in this project (4 human subjects across 5 studies (one subject had both an initial and follow-up study)). The AV biofeedback system consists of external marker positioned on the abdomen of human subjects, being tracked using an RPM system (Real-time Position Management, Varian) to guide the subject's breathing. Acquired respiratory data has been used as input for motion prediction through a dynamic multi-leaf collimator (DMLC) simulator developed by Prof. Keall. The prediction algorithm utilized was a kernel density estimation-based real-time prediction algorithm. A variety of prediction parameters were tested to determine optimum prediction performance. Prediction parameters adjusted were the delay time (DT) and training examples (TE); the parameters tested here were: DT/TE = 2500/1500, 2500/100, 1000/250, 500/250; Given that the data sampling rate was kept at 30 Hz, the resultant prediction training window lengths were 49.5, 8.25, 3.3 and 3.3seconds respectively.

RESULTS

The mean difference between measured and predicted data for free breathing was 1.98±2.32mm; and 0.65±0.65mm for when AV biofeedback was implemented (reduction of error of 67%). The most accurate prediction results were attained using the parameters: DT/TE = 500 ms/250.

CONCLUSIONS

This study demonstrates the improvement of respiratory motion prediction accuracy when AV biofeedback is implemented to produce a more regular breathing pattern.

Malignant mesothelioma presenting as a breast mass

We present a case of a male patient with a breast mass, found to be a malignant mesothelioma. We discuss the diagnostic challenges, the need for heightened awareness in suspected cases, the histological classification of mesotheliomas and the treatments available. We believe this to be the second reported case of a mesothelioma presenting as a breast mass.

Comparative Biomarker Analysis in 523 Matched Male and Female Breast Cancers

Incidence rates of male breast cancer (MBC) are rising. MBC etiology is poorly understood with most of our current knowledge regarding its biology, natural history and treatment extrapolated from our knowledge of female breast cancer (FBC). Retrospective studies on MBC have suffered from small numbers of cases available from any one centre thus a significant problem in studying this disease is accruing sufficiently large numbers to allow comparative analysis of possible prognostic markers. Using a co-ordinated multi-centre approach, the aim of this study was to conduct the first large scale study to address the relevance of the expression of recognised biomarkers in FBC in the same disease in males. Five hundred and twenty three cases were obtained retrospectively and assimilated into TMAs, including 260 MBCs and 263 cases of stage-matched FBCs. MBC comprised 21 grade 1, 121 grade 2, 68 grade 3, 50 unknown, mean age 67 (range 39-90) with 167 ductal, 4 lobular, 10 papillary, 10, mucinous, 4 DCIS, 1 mixed and 64 unknown. FBC comprised 29 grade 1, 140 grade 2, 94 grade, mean age 58 (range 27-92) with 220 ductal, 23 lobular, 14 mixed and 6 unknown. Four µm TMA sections were analysed using the following biomarkers: hormone receptors (ERα, ERβ1, ERβ2, ERβ5, total PR, PRA, PRB, AR), apoptosis markers (p53, bcl2), basal (CK5/6, CK14) and luminal epithelial markers (CK18, CK19), E-cadherin and HER2. Biomarkers were scored according to published criteria; for ERβ isoforms both nuclear and cytoplasmic immunoreactivity was determined Statistical analysis was conducted using SPSS. Luminal A (ERα+, and/or PR+, HER2-) was seen in 93% of MBC vs. 84% of FBC, Luminal B (ERα+, and/or PR+, HER2+) or HER2 subgroup (ERα-, PR-, HER2+) was not seen in MBC but found in 6% and 2% of FBC, respectively. Basal-like tumours (ERα-, PR-, HER2-, CK5/6+) were infrequent (MBC 2%, FBC 1%) and in MBC these tumours also expressed ERβ isoforms. No differences were observed in grade, stage or LN status between genders. Univariate analysis showed ERα, ERβ1, ERβ5, PRA, AR, p53 were significantly associated with FBC while cytoplasmic ERβ2, bcl2 and e-cadherin were associated with MBC (all P&lt;0.001). Although membranous HER2 was not seen in MBC, many cases displayed nuclear staining. Biomarker profile with respect to clinical outcome is on-going. This work has shown the luminal A phenotype is common in MBC and that gender-specific biomarkers are expressed. As MBC is becoming more common, this information may be useful in identifying biomarkers which might affect outcome.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2109.

Phosphorylation of Estrogen Receptor β at Serine 105 in Primary Breast Cancer

Background: Estrogen receptor (ER) α predicts response to hormonal therapy in breast carcinoma. The role of ERβ is less well understood. ER activities can be modulated by post-translational modifications including phosphorylation and phosphorylated ERα has been correlated with patient outcome. We investigated whether ERβ phosphorylated at Serine 105 (P-S105-ERβ) is expressed in breast carcinoma and assessed its potential clinical implications.Material and Methods: Tissue microarrays comprising 427 breast tumours (23% grade 1, 43% grade 2, 34% grade 3) with median follow up 118 months and 106 endocrine resistant breast tumours (15% grade 1, 41% grade 2, 44% grade 3) with median follow up 71 months were used in this study. Expression of P-S105-ERβ was studied by immunohistochemistry and analysed against clinical data. Regulation of P-S105-ERβ in vitro was assessed by immunofluorescence and Western blotting.Results: Expression of P-S105-ERβ was mainly nuclear and could be abolished by phosphatase pre-incubation, indicating specificity. In the first cohort Allred scoring ranged from 0 to 8 (median 6). Nuclear speckling was observed in 45% of cases. P-S105-ERβ correlated with ERβ1 (Allred score ≥ 3) and was associated with better overall survival (OS) and disease free survival (DFS) (p=0.028 and p=0.027, respectively). In a multivariate Cox hazard analysis, P-S105-ERβ overexpression was a significant predictor of better survival independent of tumor grade, lymph node status, size or ERα. In the endocrine resistant cohort Allred scoring ranged from 0 to 8 (median of 4) and the overexpression of P-S105-ERβ was also associated with improved OS and DFS (p=0.044 and p=0.033, respectively). Nuclear speckling was present in only 11% of cases. The difference in expression of P-S105-ERβ and association with survival outcome between the two cohorts was statistically significant. P-S105-ERβ was expressed in MCF-7 cells and in response to 17β-estradiol (E2); levels were raised within 30 min, and sustained for 24 hours. ERβ1 expression was unaffected by this treatment. Nuclear speckling was also observed and was markedly increased at 24 hours following E2 but not Tamoxifen.Conclusion: This is the first time to our knowledge that the expression of P-S105-ERβ in breast carcinoma has been investigated. Its presence in breast carcinoma and association with improved survival suggest P-S105-ERβ might be a useful additional prognostic marker in breast cancer.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 4141.

Conservation of hydrophobicity within viral envelope glycoproteins reveals a putative hepatitis C virus fusion peptide

The mechanism(s) by which hepatitis C virus (HCV) enters and infects cells remains unknown. Identifying the HCV fusion peptide(s) and understanding the early stages of infection may provide new opportunities for improved antiviral therapy. The HCV envelope glycoprotein E2 is thought to be a class II fusion protein. Class II fusion proteins are exemplified by the E protein of the tick-borne encephalitis virus (TBEV) and the E1 protein of the Semliki Forest virus (SFV). Analysis of the hydrophobicity profiles of four HCV E2 envelope glycoproteins revealed a region with a conserved three-pronged pattern of hydrophobicity, termed the tridentate (TD) region. The primary sequence of the TD region is highly conserved in all 490 HCV strains currently reported. The known fusion peptide loops of TBEV and SFV share the characteristic TD region hydrophobicity profile and significant sequence conservation in the TD region was identified in the E and E1 glycoproteins of members of the Flaviviridae and Togaviridae families, respectively. The HCV TD region peptides have membranotropic activity; in molecular dynamics (MD) simulations, the HCV TD region peptides insert into in a biomimetic bilayer in a similar manner to the TBEV fusion peptide and the peptides induce effective mixing of lipid membranes in a liposome fusion assay. Together these results indicate that the highly conserved TD region of the HCV E2 protein is a fusion peptide candidate and may be an important factor in the class II fusion mechanism.

Integrated magneto-optical traps on a chip using silicon pyramid structures

We have integrated magneto-optical traps (MOTs) into an atom chip by etching pyramids into a silicon wafer. These have been used to trap atoms on the chip, directly from a room temperature vapor of rubidium. This new atom trapping method provides a simple way to integrate several atom sources on the same chip. It represents a substantial advance in atom chip technology and offers new possibilities for atom chip applications such as integrated single atom or photon sources and molecules on a chip.

Intramolecular charge transfer assisted by conformational changes in the excited state of fluorene-dibenzothiophene-S,S-dioxide co-oligomers

The strong solvatochromism observed for two fluorene-dibenzothiophene-S,S-dioxide oligomers in polar solvents has been investigated using steady-state and time-resolved fluorescence techniques. A low-energy absorption band, attributed to a charge-transfer (CT) state, is identified by its red shift with increasing solvent polarity. In nonpolar solvents, the emission of these conjugated luminescent oligomers shows narrow and well-resolved features, suggesting that the emission comes from a local excited state (LE), by analogy to their conjugated fluorene-based polymer counterparts. However, in polar solvents, only a featureless broad emission is observed at longer wavelengths (CT emission). A linear correlation between the energy maximum of the fluorescence emission and the solvent orientation polarizability factor Deltaf (Lippert-Mataga equation) is observed through a large range of solvents. In ethanol, below 230 K, the emission spectra of both oligomers show dual fluorescence (LE-like and CT) with the observation of a red-edge excitation effect. The stabilization of the CT emissive state by solvent polarity is accompanied/followed by structural changes to adapt the molecular structure to the new electronic density distribution. In ethanol, above 220 K, the solvent reorganization occurs on a faster time scale (less than 10 ps at 290 K), and the structural relaxation of the molecule (CT(unrelaxed) --> CT(Relaxed)) can be followed independently. The magnitude of the forward rate constant, k(1)(20 degrees C) approximately 20 x 10(9) s(-1), and the reaction energy barrier, E(a) approximately 3.9 kcal mol(-1), close to the energy barrier for viscous flow in ethanol (3.54 kcal mol(-1)), show that large-amplitude molecular motions are present in the stabilization of the CT state.

Practice management skills for the nurse practitioner

The faculties of three schools of nursing involved in a collaborative family nurse practitioner (FNP) program designed a study to address issues involved in preparing the nurse practitioner for the challenges of practice management in the clinical environment. The purposes of the study were to (1) identify business concepts necessary to successfully manage a primary care practice; (2) determine which of these concepts should be incorporated into an FNP curriculum; and (3) clarify information to be taught regarding each identified concept. Fifty-four business concepts related to primary care were identified from a literature review. A survey was then developed to assess the extent to which the identified concepts were necessary for an FNP to effectively manage a practice. Seven experts and five FNP faculty responded to the survey. The Content Validity Index (CVI) defined by Lynn (1986) was applied and 20 concepts necessary for an FNP to effectively manage a practice were identified. A focus group that included nurse practitioners (both faculty and nonfaculty) from the three collaborative sites connected by interactive telecommunications determined that all 20 of the identified concepts should be included in an FNP curriculum. Additionally, the focus group clarified relevant information to be taught regarding each identified concept.

A common position-dependent mechanism controls cell-type patterning and GLABRA2 regulation in the root and hypocotyl epidermis of Arabidopsis

A position-dependent pattern of epidermal cell types is produced during root development in Arabidopsis thaliana. This pattern is reflected in the expression pattern of GLABRA2 (GL2), a homeobox gene that regulates cell differentiation in the root epidermis. GL2 promoter::GUS fusions were used to show that the TTG gene, a regulator of root epidermis development, is necessary for maximal GL2 activity but is not required for the pattern of GL2 expression. Furthermore, GL2-promoter activity is influenced by expression of the myc-like maize R gene (35S::R) in Arabidopsis but is not affected by gl2 mutations. A position-dependent pattern of cell differentiation and GL2-promoter activity was also discovered in the hypocotyl epidermis that was analogous to the pattern in the root. Non-GL2-expressing cell files in the hypocotyl epidermis located outside anticlinal cortical cell walls exhibit reduced cell length and form stomata. Like the root, the hypocotyl GL2 activity was shown to be influenced by ttg and 35S::R but not by gl2. The parallel pattern of cell differentiation in the root and hypocotyl indicates that TTG and GL2 participate in a common position-dependent mechanism to control cell-type patterning throughout the apical-basal axis of the Arabidopsis seedling.

A district stroke service

Stroke is the third most common cause of death in Britain, but despite its medical and economic importance, management of the three facets of stroke--prevention, acute care and rehabilitation--has been unstructured and poor value for money. This article considers how these issues might be more effectively addressed by a pragmatic coordinated approach to the whole problem of stroke in a health authority.

Leber's hereditary optic neuropathy plus dystonia is caused by a mitochondrial DNA point mutation

A novel point mutation in the ND6 subunit of complex I at position 14,459 of the mitochondrial DNA (MTND6*LDY T14459A) was identified as a candidate mutation for the highly tissue-specific disease. Leber's hereditary optic neuropathy plus dystonia. Since the MTND6*LDYT14459A mutation was identified in a single family, other pedigrees with the mutation are needed to confirm its association with the disease. Clinical, biochemical, and genetic characterization is reported in two additional pedigrees. Leber's hereditary optic neuropathy developed in two family members in one pedigree. The daughter had clinically silent basal ganglia lesions. In a second pedigree, a single individual presented with childhood-onset generalized dystonia and bilateral basal ganglia lesions. Patient groups that included individuals with Leigh's disease, dystonia plus complex neurodegeneration, and Leber's hereditary optic neuropathy did not harbor the MTND6*LDYT14459A mutation, suggesting that this mutation displays a high degree of tissue specificity, thus producing a narrow phenotypic range. These results confirm the association of the MTND6*LDYT14459A mutation with Leber's hereditary optic neuropathy and/or dystonia. As the first genetic abnormality that has been identified to cause generalized dystonia, this mutation suggests that nuclear DNA or mitochondrial DNA mutations in oxidative phosphorylation genes are important considerations in the pathogenesis of dystonia.

An unusual presentation of multiple sclerosis

Two male patients who presented with unusual pictures of dementia in the absence of other obvious symptoms or signs are reported. Investigations demonstrated changes highly suggestive of multiple sclerosis (MS) on magnetic resonance imaging, cerebrospinal fluid analysis and electrophysiological tests. We suggest this represents a rare presentation of multiple sclerosis.

Medical data capture and display: the importance of clinicians' workstation design

The Department of Veterans Affairs is developing, testing and evaluating the benefits of physicians' workstations as an aid to medical data capture in an outpatient clinic setting. The physician's workstation uses a graphical user interface to aid the clinician in recording encounter data. Various input devices including keyboard, mouse, pen, voice, barcode reader, and tablet are available on the workstations, and user preferences will be examined. Access to general services such as electronic mail and reference databases is also available. The workstation provides a wide variety of patient specific data from the hospital information system, including image data. The single data collection process by the clinician will also provide data for the cost recovery process.

Arabidopsis GLABROUS1 Gene Requires Downstream Sequences for Function

The Arabidopsis GLABROUS1 (GL1) gene is a myb gene homolog required for the initiation of trichome development. In situ hybridization revealed that the highest levels of GL1 transcripts were present in developing trichomes. In contrast, previous work had shown that putative promoter sequences from the 5[prime] noncoding region of the GL1 gene directed the expression of a [beta]-glucuronidase (GUS) reporter gene only in stipules. Deletion analysis of the 3[prime] noncoding region of GL1 has identified an enhancer that is essential for GL1 function. Sequences from the region containing the enhancer, in conjunction with GL1 upstream sequences, direct the expression of a GUS reporter gene in leaf primordia and developing trichomes in addition to stipules, indicating that the downstream enhancer is required for the normal expression pattern of GL1.

Acute encephalopathy due to coexistent nicotinic acid and thiamine deficiency

We report the case of an alcoholic woman with confusion, catatonia and extrapyramidal signs, who developed features of the Wernicke-Korsakoff syndrome after treatment with intravenous high potency vitamins. We emphasise that this should arouse the suspicion of nicotinic acid deficiency even in the absence of gastrointestinal symptoms or skin lesions.

Phrenic nerve injury. A prospective study

In cardiac surgery, topical iced saline solution slush has become an important adjunct in maintaining myocardial hypothermia during cardioplegic arrest. One complication of this technique is phrenic nerve injury (PNI). In an attempt to reduce the incidence of PNI, a prospective study was undertaken to evaluate the impact of phrenic nerve insulation on PNI during cardiac surgery. Seventy-six consecutive patients who underwent coronary revascularization constituted the control group (CG) and were compared with 76 patients who underwent a similar procedure with the addition of phrenic nerve insulation. In the intervention group (IG), a foam insulation pad was placed between the heart and the pericardium in an effort to reduce exposure of the phrenic nerve to iced saline solution slush. There was no difference in major demographic descriptors or operative variables between the CG and the IG, except that the internal mammary artery was used more frequently in the IG (64 percent vs 36 percent, p = 0.0006). The in-hospital mortality was similar between the groups (CG, 0.0 percent; IG, 1.3 percent; p = 1.0); however, the incidence of roentgenographically diagnosed PNI was much greater in the CG (14/76 patients [18 percent] vs 0/76 patients [0 percent]; p = 0.0006). Patients with and without PNI were similar with regard to age, gender, aortic cross clamp time, cardiopulmonary bypass time, and number of grafts (p greater than 0.05). All unilateral PNI occurred on the left. Three patients with bilateral PNI required tracheostomy and prolonged mechanical ventilation. In-hospital mortality was similar for patients with and without PNI (0 percent vs 0.7 percent), but mean postoperative hospital stay for patients with clinically diagnosed PNI was longer than for those without PNI (32 vs 11 days, p = 0.04). This prospective study demonstrates that the incidence of PNI can be significantly reduced by the routine use of phrenic nerve insulation.