Outcomes of Telerehabilitation Versus In-Office Training With Magnification Devices for Low Vision: A Randomized Controlled Trial

Purpose

An evidence basis is lacking but needed to compare reading ability outcomes after magnification device training remotely via telerehabilitation versus in office.

Methods

A multicenter randomized controlled trial at academic centers and vision rehabilitation private practices randomized 61 visually impaired adults to telerehabilitation or in-office training 1 to 4 months after dispensing new portable electronic, hand-held, or stand optical magnifiers. Telerehabilitation included loaner equipment for Zoom videoconferencing with remote control access software. Using a multilevel regression model, changes in Activity Inventory responses using Rasch analysis estimated reading ability in dimensionless log odds units (logits) (0.14-logit change corresponds with ability change expected from a one-line change in visual acuity).

Results

Across 47 participants who completed the trial, reading ability with new magnifiers improved significantly by 0.61 logits on average (95% confidence interval [CI], 0.36-0.86; P < 0.001) from baseline to 1 month, and by an additional 0.44 logits on average (95% CI, 0.19-0.69; P < 0.001) from 1 to 4months (i.e., after magnifier training), with very similar significant findings for both telerehabilitation (n = 29; mean improvement = 0.44 logits; 95% CI, 0.08-0.80; P = 0.018) and in-office training (n = 18; mean improvement = 0.43 logits; 95% CI, 0.15-0.71; P = .003), and no significant difference between randomized groups across both follow-ups (95% CI, -0.43 to 0.61; P = .73). Vision, demographics, and health factors were nonsignificantly related to reading ability changes from 1 to 4 months.

Conclusions

Reading ability improved after the provision of newly dispensed magnifiers, with further improvements following additional magnifier training via either telerehabilitation or in-office usual care.

Translational Relevance

These findings provide support for the use of telerehabilitation to enhance reading ability with newly prescribed magnifiers as an alternative modality of care delivery.

Value of Handheld Optical Illuminated Magnifiers for Sustained Silent Reading by Visually Impaired Adults

SIGNIFICANCE

Vision rehabilitation providers tend to recommend handheld, illuminated optical magnifiers for short-duration spot reading tasks, but this study indicates that they are also a viable option to improve sustained, continuous text reading (e.g., books or magazines), especially for visually impaired adults who read slowly with only spectacle-based near correction.

PURPOSE

The utility of handheld optical magnifiers for sustained silent reading tasks involving normal-sized continuous text could be a valuable indication that is not recognized by vision rehabilitation providers and patients.

METHODS

Handheld, illuminated optical magnifiers were dispensed to 29 visually impaired adults who completed the sustained silent reading test by phone at baseline without the new magnifier and 1 month after using the magnifier. Reading speed in words per minute (wpm) was calculated from the time to read each page and then averaged across up to 10 pages or determined for the fastest read page (maximum).

RESULTS

From baseline without the magnifier to 1 month with the magnifier, there was a significant improvement in mean reading speed by 14 wpm (95% confidence interval [CI], 2.6 to 24; P = .02) and for maximum reading speed by 18 wpm (95% CI, 5.4 to 30; P = .005) on average across participants. Participants who had slower baseline reading speeds without the magnifier demonstrated significantly greater improvements in mean and maximum reading speeds on average with the magnifier (95% CI, 8 to 32 [ P = .003]; 95% CI, 4 to 36 [ P = .02]). A significantly greater number of pages were read with the new magnifier than without it (Wilcoxon z = -2.5; P = .01). A significantly greater number of pages were read with the magnifier by participants who read fewer pages at baseline (95% CI, 0.57 to 5.6; P = .02) or had greater improvements in mean reading speed (95% CI, 0.57 to 5.6; P = .007).

CONCLUSIONS

Many visually impaired adults read more quickly and/or read a greater number of pages after using a new magnifier for a month than compared to without it. The largest gains occurred among those with more difficulty at baseline, indicating the potential to improve reading rates with magnifiers for those with greater deficits.

Approaches to Greening Radiology

The health care sector is a resource-intensive industry, consuming significant amounts of water and energy, and producing a multitude of waste. Health care providers are increasingly implementing strategies to reduce energy use and waste. Little is currently known about existing sustainability strategies and how they may be supported by radiology practices. Here, we review concepts and ideas that minimize energy use and waste, and that can be supported or implemented by radiologists.

Acceptability of Telerehabilitation for Magnification Devices for the Visually Impaired Using Various Approaches to Facilitate Accessibility

Purpose

We examined different methods to reduce the burden of accessing technology for videoconferencing during telerehabilitation for magnification devices for the visually impaired.

Methods

During telerehabilitation studies over the past 5 years, vision rehabilitation providers assessed and gave training to visually impaired participants with newly dispensed magnification devices at home who connected to Zoom videoconferencing via loaner tablets or smartphones with assistance from (phase 1; n = 10) investigators by phone, (phase 2; n = 11) local Lions Club volunteers in participants’ homes, or (phase 3; n = 24) remote access control software in a randomized controlled trial with 13 usual care controls who received in-office training. All participants completed the same post-telerehabilitation phone survey.

Results

A significantly greater proportion of phase 3 subjects indicated they strongly or mostly agreed that the technology did not interfere with the session (96%) compared to phase 1 (60%; 95% confidence interval [CI], 1.2–12.5; P = 0.03) or phase 2 (55%; 95% CI, 1.8–188; P = 0.01). The majority indicated telerehabilitation was as accurate as in person (68%), they were comfortable with telerehabilitation (91%) and interested in a future session (83%), and their magnifier use improved (79%), with no significant differences in these responses between phases (all P > 0.10), including comparisons of participants randomized to telerehabilitation or in-office training in phase 3 who reported similar overall satisfaction levels (P = 0.84).

Conclusions

Participants across all phases reported high levels of acceptance for telerehabilitation, with least interference from technology using remote access control in phase 3.

Translational Relevance

With accommodations for accessibility to videoconferencing technology, telerehabilitation for magnification devices can be a feasible, acceptable, and valuable option in countries with resources to support the technology.

Breast Imaging and Social Media: A Model Specialty for Increasing Interest and Awareness of Radiology in Pre-Medical Students

OBJECTIVE

To assess how a virtual shadowing (VS) session on breast imaging (BI), shared through social media, can increase interest and awareness of radiology in pre-medical students.

METHODS

This study was IRB exempt. A VS slide presentation on BI mentorship, didactic lecture, and deidentified image-rich, case-based learning was created. This session was advertised and presented live through an Instagram page (Pre-Health Virtual Shadowing, @virtualshadowing) geared toward pre-health students. Students were asked to complete a two-question self-assessment using a 5-point Likert scale on which 1 was "least" and 5 was "most." Question 1 read: "Please rate your overall knowledge about radiology and what a radiologist does," and question 2 read: "Please rate your interest in possibly looking into radiology as a potential career."

RESULTS

A total of 420 participants logged into the VS session; 82% (345/420) answered the pre-session survey and 48% (202/420) answered the post-session survey. Of post-survey respondents, 84% (170/202) were female and 70% (143/202) were 22 years old or younger. There was a significant difference in mean pre-session survey responses to question 1 when compared to mean post-session survey responses (2.67 vs 3.55, P < 0.001). There was also a significant difference in mean pre-session survey responses to question 2 when compared to mean post-session survey responses (3.16 vs 3.58, P < 0.001). Our VS session remains on YouTube and has 6157 views to date.

CONCLUSION

When shared through VS on social media, breast imaging can increase interest and awareness of radiology in pre-medical students.

Fear of the Unknown: The Benefits of a Patient Educational Handout on Breast Biopsy Markers

OBJECTIVE

To determine whether providing a biopsy marker informational handout to patients improves patient knowledge and comfort with receiving a marker.

METHODS

In this IRB-exempt prospective study, a patient educational handout on breast biopsy markers was developed. A questionnaire was created with four questions asking patients to self-evaluate their knowledge of biopsy markers and their comfort level with marker placement before and after reading the handout. Technologists distributed the educational handouts to patients presenting for a percutaneous breast biopsy under any modality from December 11, 2020, to April 23, 2021. Data from the completed questionnaires were entered into a database. Statistical analyses included paired t-test and Wilcoxon analyses.

RESULTS

In total, 141 completed surveys were included in the analysis. The mean scores prior to reading the handout for knowledge and comfort were 2.59 and 3.40, respectively. After reading the handout, there was a significant increase in mean scores for knowledge and comfort (4.26 and 4.20, respectively) (P < 0.001). There was a 64% increase vs 23% increase for knowledge and comfort, respectively.

CONCLUSION

Patient-assessed knowledge of biopsy markers increased significantly after reading our educational handout. Patient-assessed comfort with biopsy marker placement also increased significantly after reading the educational handout, though to a lesser degree than knowledge. Although not included in our study, use of an educational handout may impact patient acceptance of marker placement. Future directions may include quantitatively assessing the effect of the handout on time to consent for a biopsy or influence on acceptance of marker placement.

Breast papillomas in the United States: single institution data on underrepresented minorities with a multi-institutional update on incidence

PURPOSE

To assess the percentage of papillomas from all biopsies performed, comparing differences in patient age and race at a single institution. To assess trends in biopsied papillomas at institutions throughout the United States (US).

METHODS

This is a HIPPA-compliant IRB-approved single-institution (Southern1) retrospective review to assess race and age of all-modality-biopsied non-malignant papillomas as a percentage of all biopsies (percentage papillomas calculated as papilloma biopsies/all biopsies) from January 2012 to December 2019. To assess national variation, several academic or large referral centers were contacted to provide data regarding papilloma percentages, biopsy modalities, and trends in case numbers. Trends were estimated using the method of analysis of variance (ANOVA). Comparisons of differences in trends were assessed.

RESULTS

Southern1 institution demonstrated a significant association between race and percentage of papillomas (p < 0.0001). After adjustment for multiple comparisons with Bonferroni correction at 5% type I family error, the percentage of biopsied papillomas in Black and Asian patients remained significantly higher than in White patients (p < 0.0001 and p = 0.0032, respectively) using a Chi-square test. The regional variation in percentage of papillomas was found to be 3-9%. Southern1 institution showed a 7-year significant trend of increase in percentage of papillomas. Other institutions showed a decreasing trend (p < 0.05).

CONCLUSION

Black and Asian women had significantly higher papilloma percentages compared to white patients in our single institution review. This institution also showed a statistically significant trend of increasing percentage papillomas from 2012 to 2019. Multi-institutional survey found regional variation in percentage papillomas, ranging from 3% to 9%.

Addressing Burnout in Radiologists

Burnout is a global health problem affecting physicians across all medical specialties. Radiologists, in particular, experience high rates of burn out, and this trend has only continued to worsen. The "Promoting Health and Wellness for Radiologists Task Force of the Association of University Radiologists-Radiology Research Alliance" presents a review of the prevalence, causes, and impact of burnout among radiology faculty and trainees, and a discussion on strategies for overcoming burnout and promoting overall health and well-being among radiologists.

Abstract P5-09-12: Germline mutation in TP53 gene in a cohort of 2,561 Chinese high-risk breast cancer patients using multigene panel testing

Background: Li-Fraumeni syndrome (LFS) is a rare autosomal genetic disorder with germline TP53 mutations. Patients with TP53 mutations have a higher risk of developing breast cancer than those harboring BRCA mutations. Although limited studies have shown that TP53 mutation carriers are less responsive to low dose radiation and more susceptible to induce new malignancies from radiotherapy. Moreover screening strategies allows early detection of a spectrum of cancers related to TP53 mutations. From work of BRCA mutations where over 40% novel mutations were detected in Chinese cohort, it is important to evaluate the frequency of TP53 mutation in Chinese to better understand the spectrum to guide appropriate clinical management of these high risk individuals.

Methods: TP53 gene mutation screening was performed on 2,561 high-risk breast cancer patients using multigene panel testing. The patients were accrued by Hong Kong Hereditary and High Risk Breast Cancer Program from March 2007 to May 2018. All detected pathogenic mutations were further validated by bi-directional DNA sequencing and analyzed by our in-house developed bioinformatics pipeline.

Results: Sixteen distinct pathogenic or likely pathogenic variants were identified, and 3 of them were de novo TP53 mutations (18.75%). The mean age of patients who harbored TP53 mutation was 30.44 years (range 18-44), and 50% of the tumors were bilateral breast cancer. Of sixteen different pathogenic mutations, majority of them were missense mutation (87.5%), and 2 were nonsense mutation (12.5%). Four of the sixteen TP53 mutation carriers had family history of breast cancer, while others had a family history of lung cancer (43.75%).

Conclusion: This study revealed that seven patients were found to habor TP53 mutation even when they did not meet the criteria of LFS of LFS-like phenotype, implicated the importance of using multigene panel test for probands and their relatives to offer a comprehensive surveillance programe for TP53 carriers.

Citation Format: Kwong A, Shin V, Au CH, Ho C, Slavin T, Weitzel J, Chan TL, Ma E. Germline mutation in TP53 gene in a cohort of 2,561 Chinese high-risk breast cancer patients using multigene panel testing [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-09-12.

Mutational spectrum in a worldwide study of 29,700 families with BRCA1 or BRCA2 mutations

The prevalence and spectrum of germline mutations in BRCA1 and BRCA2 have been reported in single populations, with the majority of reports focused on White in Europe and North America. The Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA) has assembled data on 18,435 families with BRCA1 mutations and 11,351 families with BRCA2 mutations ascertained from 69 centers in 49 countries on six continents. This study comprehensively describes the characteristics of the 1,650 unique BRCA1 and 1,731 unique BRCA2 deleterious (disease-associated) mutations identified in the CIMBA database. We observed substantial variation in mutation type and frequency by geographical region and race/ethnicity. In addition to known founder mutations, mutations of relatively high frequency were identified in specific racial/ethnic or geographic groups that may reflect founder mutations and which could be used in targeted (panel) first pass genotyping for specific populations. Knowledge of the population-specific mutational spectrum in BRCA1 and BRCA2 could inform efficient strategies for genetic testing and may justify a more broad-based oncogenetic testing in some populations.

Next-generation sequencing with a myeloid gene panel in core-binding factor AML showed KIT activation loop and TET2 mutations predictive of outcome

Clinical outcome and mutations of 96 core-binding factor acute myeloid leukemia (AML) patients 18–60 years old were examined. Complete remission (CR) after induction was 94.6%. There was no significant difference in CR, leukemia-free-survival (LFS) and overall survival (OS) between t(8;21) (N=67) and inv(16) patients (N=29). Univariate analysis showed hematopoietic stem cell transplantation at CR1 as the only clinical parameter associated with superior LFS. Next-generation sequencing based on a myeloid gene panel was performed in 72 patients. Mutations in genes involved in cell signaling were associated with inferior LFS and OS, whereas those in genes involved in DNA methylation were associated with inferior LFS. KIT activation loop (AL) mutations occurred in 25 patients, and were associated with inferior LFS (P=0.003) and OS (P=0.001). TET2 mutations occurred in 8 patients, and were associated with significantly shorter LFS (P=0.015) but not OS. Patients negative for KIT-AL and TET2 mutations (N=41) had significantly better LFS (P<0.001) and OS (P=0.012) than those positive for both or either mutation. Multivariate analysis showed that KIT-AL and TET2 mutations were associated with inferior LFS, whereas age ⩾40 years and marrow blast ⩾70% were associated with inferior OS. These observations provide new insights that may guide better treatment for this AML subtype.

Abstract P2-09-20: Evaluation on the mutation screening by next-generation sequencing in hereditary breast and ovarian cancer: Implementation of recurrent mutation panel

Background: Hereditary disposition accounts for 10-15% in breast cancers and 20-25% in ovarian cancers, in which 5-10% of women have genomic alteration in breast cancer predisposition genes, BRCA1 and BRCA2, while the rest are likely due to less penetrant genes. In specific ethnicities such as Ashkenazi Jewish, three founder mutations have been identified which covers 95 % of all the BRCA mutations identified in this race. These genes are screened prior to the gold standard Sanger Sequencing in order to reduce cost. Sanger Sequencing, however, still has the limitation on the necessity of laborious processing and results interpretation. Moreover, it limits the number of genes that can be analyzed in one setting. With the use of next-generation sequencing (NGS), identification of hereditary breast and ovarian cancer (HBOC) syndrome associated genes, other than BRCA, can be sequenced at the same time but yet a faster turnover time. This allows more timely targeted risk-reducing strategies and interventions to be implemented for mutation positive carriers and their family members.

Methods: In this study cohort, 948 high-risk breast/ovarian patients who met the HBOC selection criteria were recruited for mutation screening by our NGS pipeline. With the inclusion of 90 Sanger-validated known mutation cases, the performance of the NGS pipeline were proven to be comparable to Sanger sequencing. PTEN and TP53, other than BRCA1 and BRCA2, a 4 gene sequencing panel were included in the mutation screening for high-risk patients.

Results: The prevalence of BRCA1/BRCA2 germline mutations was 7.28% in our Chinese cohort and 47.8% of the mutation were recurrent mutations. Based on this finding, we further adopted a new workflow by screening the recurrent mutations including founder mutations from Chinese cohort prior to NGS for those who tested negative. In a testing cohort of 343 cases, the recurrent mutation pick-up rate was 3.5%, this implicated a more cost-effective method for mutation screening in the clinical setting. Moreover, the frequencies of PTEN and TP53 were 0.21% and 0.53% respectively in our population with breast and ovarian cases.

Conclusion: Taken together, our data demonstrated a strategic upfront screening for recurrent mutations in Chinese population which is highly applicable in most of the diagnostic laboratories. Multi-gene sequencing using the NGS technology will be the upcoming strategies for mutation screening for HBOC patients.

Citation Format: Kwong A, Shin VY, Au CH, Law FB, Ho DN, Ip BK, Wong AT, Lau SS, To RM, Choy G, Ford JM, Ma ES, Chan TL. Evaluation on the mutation screening by next-generation sequencing in hereditary breast and ovarian cancer: Implementation of recurrent mutation panel. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P2-09-20.

database.bio: a web application for interpreting human variations

Rapid advances of next-generation sequencing technology have led to the integration of genetic information with clinical care. Genetic basis of diseases and response to drugs provide new ways of disease diagnosis and safer drug usage. This integration reveals the urgent need for effective and accurate tools to analyze genetic variants. Due to the number and diversity of sources for annotation, automating variant analysis is a challenging task. Here, we present database.bio, a web application that combines variant annotation, prioritization and visualization so as to support insight into the individual genetic characteristics. It enhances annotation speed by preprocessing data on a supercomputer, and reduces database space via a unified database representation with compressed fields.

AVAILABILITY AND IMPLEMENTATION

Freely available at https://database.bio.

Equating Visual Function Scales to Facilitate Reporting of Medicare Functional G-Code Severity/Complexity Modifiers for Low-Vision Patients

OBJECTIVE

To present a method of estimating and equating scales across functional assessment instruments that appropriately represents changes in a patient's functional ability and can be meaningfully mapped to changes in Medicare G-code severity modifiers.

DESIGN

Previously published measures of patients' overall visual ability, estimated from low-vision patient responses to 7 different visual function rating scale questionnaires, are equated and mapped onto Medicare G-code severity modifiers.

SETTING

Outpatient low-vision rehabilitation clinics.

PARTICIPANTS

The analyses presented in this article were performed on raw or summarized low-vision patient ratings of visual function questionnaire (VFQ) items obtained from previously published research studies.

INTERVENTIONS

Previously published visual ability measures from Rasch analysis of low-vision patient ratings of items in different VFQs (National Eye Institute Visual Functioning Questionnaire, Index of Visual Functioning, Activities of Daily Vision Scale, Visual Activities Questionnaire) were equated with the Activity Inventory (AI) scale. The 39 items in the Self-Report Assessment of Functional Visual Performance (SRAFVP) and the 48 items in the Veterans Affairs Low Vision Visual Functioning Questionnaire (VA LV VFQ) were paired with similar items in the AI in order to equate the scales.

MAIN OUTCOME MEASURES

Tests using different observation methods and indicators cannot be directly compared on the same scale. All test results would have to be transformed to measures of the same functional ability variable on a common scale as described here, before a single measure could be estimated from the multiple measures.

RESULTS

Bivariate regression analysis was performed to linearly transform the SRAFVP and VA LV VFQ item measures to the AI item measure scale. The nonlinear relationship between person measures of visual ability on a logit scale and item response raw scores was approximated with a logistic function, and the 2 regression coefficients were estimated for each of the 7 VFQs. These coefficients can be used with the logistic function to estimate functional ability on the same interval scale for each VFQ and for transforming raw VFQ responses to Medicare's G-code severity modifier categories.

CONCLUSIONS

The principle of using equated interval scales allows for comparison across measurement instruments of low-vision functional status and outcomes, but can be applied to any area of rehabilitation.

A NSQIP risk assessment for thyroid surgery based on comorbidities

BACKGROUND

Thyroid surgery is associated with low mortality and morbidity and often is performed in an ambulatory setting. The majority of patients undergoing thyroidectomy have an uncomplicated outcome, but common comorbidities may increase mortality and morbidity. Due to low complication rates, studies using single surgeon or single institutional data to identify risk factors for adverse outcomes may be limited by inadequate patient volume.

STUDY DESIGN

This retrospective cohort study used data from the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP). The study group included all thyroidectomy patients over a 6-year period (2005 to 2010). Common patient comorbidities were identified and analyzed using logistic regression. Risk of adverse outcomes was calculated for single and multiple comorbidities. Statistical significance was set at p < 0.05.

RESULTS

The study group included 38,577 consecutive patients. Thirty-day mortality and postoperative morbidity were 0.06% and 1.49%, respectively. The risk factors independently associated with morbidity included hypertension, diabetes, advanced age greater than 70 years, COPD, dialysis, malignant thyroid disease, and surgical approach (total thyroidectomy). Substernal thyroidectomy, hypertension, diabetes, age greater than 70 years, COPD, and dialysis were significant predictors (unadjusted) of mortality. Multiple comorbidities resulted in significant cumulative risk. The presence of 3 or more comorbidities was associated with a postoperative morbidity of 5.1% (p < 0.001) and mortality as high as 12.5%.

CONCLUSIONS

Thyroid surgery is generally safe. Common comorbidities significantly increase the risk of adverse outcomes and death. Clinically applicable risk calculation based on overall health may improve patient selection, surgical management, and informed consent.

Abstract P2-07-03: High-throughput germline mutation screening for hereditary breast cancer in southern Chinese patients by massively parallel DNA sequencing

Introduction: Breast cancer is the most common malignancy and 3rd leading cause of deaths among the female population in Hong Kong. Since the establishment of The Hong Kong Hereditary Breast Cancer Family Registry in 2007, 1344 patients with breast and/or ovarian cancer who met the selection criteria were recruited for genetic testing in Hong Kong. Since 2011 we started to employ next-generation DNA sequencing (NGS) to expedite the analysis workflow and expand the panel of genes for sequencing.

Aim: To evaluate the workflow of NGS in mutation screening of BRCA1, BRCA2, TP53 and PTEN genes, and compared with the sequence data obtained by Sanger sequencing.

Methods: We sequenced BRCA1, BRCA2, TP53 and PTEN genes in peripheral blood samples of 410 patients, 53 positive controls and 107 healthy local individuals using 454 GS Junior System. Generation of barcoded amplicon libraries was streamlined by microfluidic PCR using Fluidigm Access Array System. Sequencing data were analyzed by an in-house developed fully automatic bioinformatics pipeline, which mainly consists of GS Amplicon Variant Analyzer, SAMtools and Ensembl Variant Effect Predictor. All putative mutations identified were validated by Sanger sequencing. Furthermore, the frequency of BRCA1, BRCA2 and PTEN missense variants of unknown significance (VUS) identified in the cohort were compared among 107 healthy local individuals and 1000 Genomes project samples. The VUS were also subjected to a panel of in silico prediction methods including PolyPhen and SIFT.

Results: Among 410 patients, there were 7 in BRCA1, 6 in BRCA2 and 1 in TP53 mutations found, including 1 novel recurrent BRCA2 (c.7007G&gt;T) and 1 novel founder BRCA2 (c.5164_5165delAG) mutations. Based on multiple criteria, 12 in BRCA1, 12 in BRCA2 and 1 in PTEN VUS could be prioritized for further investigation. The bioinformatics pipeline was extensively evaluated with Sanger-validated controls. The evaluation determined minimum sequencing coverage needed in this sequencing platform for accurate analysis. The pipeline accuracy was demonstrated by successful detecting mutations from 53 positive controls, including single nucleotide variants, insertions and deletions in different sequence context.

Conclusion: BRCA1, BRCA2, TP53 and PTEN mutation screening of 410 patients were expedited by high-throughput DNA sequencing. This method could detect 14 positive cases, including recurrent mutations, in a shorter period of time when compared with Sanger full gene sequencing. High-risk patients who are negative for the gene panel may need further investigation other than screening for BRCA1/2. The in-house developed bioinformatics pipeline was validated to detect various types of mutations and potentially become a conventional platform for genetic screening.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-07-03.

Genetic predisposition of white matter infarction with protein S deficiency and R355C mutation

BACKGROUND

The association between protein S deficiency (PSD) and ischemic stroke is controversial and warrants further investigation.

METHODS

We conducted a genotype and MRI correlation study in a Chinese family in which hereditary PSD cosegregated with premature ischemic strokes. Six out of 11 family members inherited PSD type III in an autosomal dominant manner.

RESULTS

Among all PSD members, a novel missense mutation 1063C→T in exon 10 of protein S alpha (PROS1) was identified, which encoded a substitution of arginine to cysteine at position 355 (R355C) in the first globular domain of laminin A of protein S. Wild-type PROS1 sequences were retained in non-PSD members. MRI detected deep white matter infarctions predominantly distributed in the borderzone regions. The infarct topography was homogeneous in all adult mutant carriers. By contrast, cerebral infarction was absent in nonmutant carriers. Extensive investigation in the family did not reveal any confounding stroke risk. Haplotype analysis with high-density single nucleotide polymorphism markers revealed a 6.1-Mb minimally rearranged region (rs12494685 to rs1598240) in 3q11.2, lod = 3.0. Among the 7 annotated genes in this region, PROS1 is known to be associated with thrombotic disorders. MRI screening in an additional 10 PSD families without R355C showed no cerebral infarction.

CONCLUSIONS

PROS1 R355C mutation cosegregated with PSD type III and premature white matter infarctions in the index family. The findings substantiate an association between PSD and stroke. Study of the mechanism underlying this association may improve our understanding of premature cryptogenic white matter infarction.

Experimental investigation on regulated and unregulated emissions of a diesel/methanol compound combustion engine with and without diesel oxidation catalyst

The use of methanol in combination with diesel fuel is an effective measure to reduce particulate matter (PM) and nitrogen oxides (NOx) emissions from in-use diesel vehicles. In this study, a diesel/methanol compound combustion (DMCC) scheme was proposed and a 4-cylinder naturally-aspirated direct-injection diesel engine modified to operate on the proposed combustion scheme. The effect of DMCC and diesel oxidation catalyst (DOC) on the regulated emissions of total hydrocarbons (THC), carbon monoxide (CO), NOx and PM was investigated based on the Japanese 13 Mode test cycle. Certain unregulated emissions, including methane, ethyne, ethene, 1,3-butadiene, BTX (benzene, toluene, xylene), unburned methanol and formaldehyde were also evaluated based on the same test cycle. In addition, the soluble organic fraction (SOF) in the particulate and the particulate number concentration and size distribution were investigated at certain selected modes of operation. The results show that the DMCC scheme can effectively reduce NOx, particulate mass and number concentrations, ethyne, ethene and 1,3-butadiene emissions but significantly increase the emissions of THC, CO, NO(2), BTX, unburned methanol, formaldehyde, and the proportion of SOF in the particles. After the DOC, the emission of THC, CO, NO(2), as well as the unregulated gaseous emissions, can be significantly reduced when the exhaust gas temperature is sufficiently high while the particulate mass concentration is further reduced due to oxidation of the SOF.

Emission reduction from diesel engine using fumigation methanol and diesel oxidation catalyst

This study is aimed to investigate the combined application of fumigation methanol and a diesel oxidation catalyst for reducing emissions of an in-use diesel engine. Experiments were performed on a 4-cylinder naturally-aspirated direct-injection diesel engine operating at a constant speed of 1800 rev/min for five engine loads. The experimental results show that at low engine loads, the brake thermal efficiency decreases with increase in fumigation methanol; but at high loads, it slightly increases with increase in fumigation methanol. The fumigation method results in a significant increase in hydrocarbon (HC), carbon monoxide (CO), and nitrogen dioxide (NO(2)) emissions, but decrease in nitrogen oxides (NO(x)), smoke opacity and the particulate mass concentration. For the submicron particles, the total number of particles decreases. In all cases, there is little change in geometrical mean diameter of the particles. After catalytic conversion, the HC, CO, NO(2), particulate mass and particulate number concentrations were significantly reduced at medium to high engine loads; while the geometrical mean diameter of the particles becomes larger. Thus, the combined use of fumigation methanol and diesel oxidation catalyst leads to a reduction of HC, CO, NO(x), particulate mass and particulate number concentrations at medium to high engine loads.

Experimental investigation on the performance, gaseous and particulate emissions of a methanol fumigated diesel engine

Experiments were conducted on a 4-cylinder direct-injection diesel engine with fumigation methanol injected into the air intake of each cylinder. The fumigation methanol was injected to top up 10%, 20% and 30% of the power output under different engine operating conditions. The effects of fumigation methanol on engine performance, gaseous emissions and particulate emission were investigated. The experimental results show that there is a decrease in the brake thermal efficiency when fumigation methanol is applied, except at the highest load of 0.67 MPa. At low loads, the brake thermal efficiency decreases with increase in fumigation methanol; but at high loads, it increases with increase in fumigation methanol. The fumigation method results in a significant increase in hydrocarbon (HC), carbon monoxide (CO), and nitrogen dioxide (NO(2)) emissions. The concentration of nitrogen oxides (NOx) is significantly reduced except at close to full load condition. There is also a reduction in the smoke opacity and the particulate matter (PM) mass concentration. For the submicron particles, the total number of particles decreases at low and medium loads but increases at high loads. In all cases, there is a shift of the particles towards smaller geometrical mean diameter, especially at high loads. The increase in nano-sized particles and the increase in NO(2) emission could have serious impact on human health.

[Experimental study on ultrafine particle characteristics exhausted from various fuelled vehicles]

The fine particle size distribution characteristics obtained from a diesel taxi, a diesel light bus, a gasoline private car and a liquefied petroleum gas (LPG) fuelled taxi were carried out on a chassis dynamometer system. The measurements were performed at different driving modes, i.e. , with low and high idling and from 10 kmxh(-1) to 70 kmxh(-1), 4 cruise operations using the instrument SMPS for collecting particles of 0.015-0.7microm diameter in range. It was found that different fuelled vehicles and different driving modes characterize considerable differences in size number and mass concentration distributions. Diesel vehicles contribute much more nuclei and accumulation mode particles of 30 - 150 nm, while LPG and gasoline fuelled vehicles exhaust much more nuclei mode particles of 15-30 nm. Overall, diesel-fuelled vehicles exhaust much more particles number and mass than gasoline and LPG fuelled vehicles; In the present study, diesel vehicles exhaust the ranges of total SMPS particle number, mass concentration with (0.3-3.6) x 10(8) number x cm(-3), 0.03 - 0.6 microg cm(- 3) respectively, and gasoline and LPG fuelled vehicles exhaust 2.3 x 10(4) - 1.2 x 10(7) number x cm(-3), 8 x 10(-5)-0.1 microgxcm(-3); 8.2 x 10(3)8.8 x 10(6) number x cm(-3), 1.7 x 10(-5) -0.09 microg x cm(-3), respectively; For all types of vehicles, the particle number and mass concentrations are small at low-idle and low-speed-driving modes, and are large at high-idle and high-speed-driving modes. They generally increase with the vehicle speed increasing from 10 to 70 kmx h(-1).

BRAF and NRAS mutations are uncommon in melanomas arising in diverse internal organs

BACKGROUND

Malignant melanoma arising from different body compartments may be associated with differing aetiological factors and clinical behaviour, and may manifest diverse molecular genetic profiles. Although many studies have focused on cutaneous melanoma, little is known of mucosal and other types of melanoma. In particular, malignant melanoma of soft parts is different from other melanomas in many respects, yet manifests a common melanocytic differentiation. Mutation of BRAF is now known to be common in cutaneous melanomas, and raises possible new therapeutic options of anti-RAF treatment for these patients. Few data are available for non-cutaneous melanomas.

AIMS

To study the incidence of BRAF and NRAS mutations in melanomas arising in diverse internal organs.

METHODS

Fifty one melanomas from various internal organs were investigated for BRAF and NRAS mutation by direct DNA sequencing.

RESULTS

BRAF and NRAS mutations were found in two and five mucosal melanomas arising from the aerodigestive and female genital tracts (n = 36). Their occurrence is mutually exclusive, giving a combined mutation incidence rate of 19.4% in mucosal melanomas. Both BRAF and NRAS mutations were absent in malignant melanoma of soft parts (n = 7). BRAF mutation was also absent in uveal melanoma (n = 6), but was seen in two of five cutaneous melanomas. The incidence of BRAF or combined BRAF/NRAS mutations in all non-cutaneous groups was significantly lower than published rates for cutaneous melanomas.

CONCLUSION

Each melanoma subtype may have a unique oncogenetic pathway of tumour development, and only a small fraction of non-cutaneous melanomas may benefit from anti-RAF treatment.

Paediatric utilization of a general emergency department in a developing country

AIM

Knowledge of the spectrum and frequencies of pediatric emergencies presenting to an emergency department (ED) of individual developing countries is vital in optimizing the quality of care delivered locally.

METHODS

A prospective 6 wk review of all pediatric (< 18 y) attendees to an urban ED was done, with patient age, presenting complaints, diagnoses, time of arrival and disposition recorded.

RESULTS

Complete data were available on 1172 patients, with an age range of 4 d to 18 y (mean +/- SD 6.9 +/- 5.6 y); 43% were aged < or = 4 y. The main presenting complaints were injuries (26.9%), fever (24%) and breathing difficulties (16.6%). The most common diagnosis was minor trauma (24.2%), with soft-tissue injuries predominating (80.6%). The other diagnoses were asthma (12.6%), upper respiratory infections (12.1%), other infections (12.1%) and gastroenteritis (11.8%). Equal proportions of patients were seen throughout the day. 25% of patients were admitted. Young age (< 1 y); presence of past medical history, general practitioner referrals, diagnosis of bronchiolitis and pneumonia were significantly associated with risk of admission.

CONCLUSION

A wide spectrum of paediatric illnesses was seen in the ED, with an overrepresentation of young children. This supports the decision to have either a separate pediatric ED or paediatric residents on the staff. The training curricula should emphasize the management of pediatric trauma, infections and asthma. Alternatively, developing guidelines for the five most common presenting complaints would account for 82% of all attendees and could be directed towards all staff on the ED.

Discrimination of an infected brain tumor from a cerebral abscess by combined MR perfusion and diffusion imaging

The aim of this study was to investigate the signal characteristics of the abscess wall and tumor wall on diffusion-weighted and perfusion-weighted images and thus to evaluate the feasibility of using combined MR diffusion and perfusion imaging to differentiate pyogenic cerebral abscess from infected brain tumor. The tumor wall of various types of cystic or necrotic brain tumor was significantly hyperintense relative to that of cerebral abscess wall on both diffusion-weighted images and regional cerebral blood volume maps. Sixteen patients who had cerebral masses with large cystic or necrotic cavities were imaged to generate diffusion-weighted images and regional cerebral blood volume maps using single-shot echoplanar imaging (EPI) pulse sequences. Apart from qualitative analysis, apparent diffusion coefficients (ADC) as well as regional cerebral blood volume (rCBV) ratios were calculated from the abscess wall and peripheral tumor wall and comparison was made by using Student's t-test. The tumor wall of various types of cystic or necrotic brain tumor had significantly lower ADCs relative to those of the abscess wall (P<0.005) and thus appeared relatively hyperintense on diffusion-weighted images. The mean rCBV ratio relative to normal white matter (2.90+/-0.62) of the peripheral tumor wall of various types of cystic or necrotic brain tumor were significantly larger than the mean rCBV ratio (0.45+/-0.11) of the pyogenic cerebral abscess wall (P<0.001) by Student's t-test. It is concluded that the combined MR diffusion and perfusion imaging might be capable of differentiating an infected brain tumor from a pyogenic cerebral abscess.

Acquired immunodeficiency syndrome presenting as childhood non-Hodgkin's lymphoma

Two children with non-Hodgkin's lymphoma (NHL) as the presenting illness of acquired immunodeficiency syndrome (AIDS) are described. There was a delay in diagnosing the underlying AIDS in both cases. In the first case, an 18-month-old boy with stage IV, high-grade,T-cell NHL, the diagnosis of underlying AIDS was suspected only when he developed recurrent and profound opportunistic infection during chemotherapy. The second case, an eight-month-old female infant presented initially with hepatosplenomegaly and thrombocytopenia of undetermined cause. She had progressive abdominal distension and swelling of her right eye one year later due to high grade B-cell NHL. She was later found to be sero-positive for HIV during pre-chemotherapy screening. As the prevalence of HIV infection continues to increase, HIV infection should be considered in the differential diagnoses of childhood hepatosplenomegaly and thrombocytopenia, and as a possible underlying cause of childhood cancer, especially NHL.

Bipolar cell diversity in the primate retina: morphologic and immunocytochemical analysis of a new world monkey, the marmoset Callithrix jacchus

The aim of this study was to identify the bipolar cell types in the retina of a New World monkey, the common marmoset, and compare them with those found in the Old World macaque monkey. Retinal whole-mounts, sections, or both, were stained by using DiI labeling and immunohistochemical methods. Semithin sections were analyzed by using quantitative methods. We show that the same morphologic types of bipolar cell as described for the Old World macaque monkey by Boycott and Wässle (Boycott and Wässle [1991] Eur. J. Neurosci. 3:1069-1088) are present in marmoset retina: two types of midget bipolar cells, six type of diffuse bipolar cells, a blue cone bipolar cell, and one type of rod bipolar cell. The pattern of staining with different immunohistochemical markers ("fingerprint") of each bipolar cell type in marmoset was also the same as described for macaque, with one exception: the flat midget bipolar cell (FMB) class is labeled by antibodies to recoverin in macaque but is labeled by antibodies to CD15 in marmoset. The labeled FMB cells in marmoset make contact with multiple cone photoreceptors throughout most of the extrafoveal retina. The spatial density of bipolar cells in marmoset is shown to be sufficient to support one-to-one connectivity of midget bipolar and ganglion cells in the fovea and to allow for parallel pathways to ganglion cells throughout the retina. Quantitative differences in the morphology and receptor connectivity between marmoset and macaque can be related to differences in cone and rod photoreceptor density between the species. We conclude that bipolar cell diversity is a preserved feature of the primate retina.

Early-onset colorectal cancer with stable microsatellite DNA and near-diploid chromosomes

Colorectal cancer has been described in terms of genetic instability selectively affecting either microsatellite sequences (MIN) or chromosome number and structure (CIN). A subgroup with apparently stable, near-diploid chromosomes and stable microsatellites (MACS) also exists. These distinctions are important, partly because of their value in highlighting different pathways of carcinogenesis, and partly because of their direct relevance to prognosis. Study of early-onset cancer has often proved a fruitful resource for the identification of the nature and function of cancer susceptibility genes. In a study of colorectal cancer with stable microsatellite DNA, we describe 22 early-onset tumours (mean age=33), compared with 16 late-onset tumours (mean age=68). Both groups contained carcinomas with the MACS phenotype, characterized by near diploid DNA content, as defined by flow cytometry, and minimal chromosome arm deletion or amplification (six or less events per genome), determined by comparative genomic hybridization (CGH). Minimal chromosome imbalance correlated strongly with diploid DNA content (P<0.001). The proportion of MACS cancers was significantly greater in early-onset as compared to late-onset tumours (64 vs 13%, P=0.005). Of the chromosome arm imbalances commonly observed in late-onset tumours, only 18q- was observed more than twice amongst the 14 early-onset MACS tumours. Seventy-nine per cent of these MACS tumours were located in the distal colon, and 69% were at advanced clinico-pathological stages (with lymph node or distant metastasis). A positive family history of colorectal or other cancers was elicited in seven patients in the MACS early-onset group, and one additional patient in this group had a metachronous ovarian cancer. The results suggest that MACS cancer may have a genetic basis different from either MIN or CIN, and further studies of these cancers may lead to discovery of new mechanisms of colorectal carcinogenesis and cancer susceptibility.

A novel germline 1.8-kb deletion of hMLH1 mimicking alternative splicing: a founder mutation in the Chinese population

We have previously reported that there is a high incidence of microsatellite instability (MSI) and germline mismatch repair gene mutation in colorectal cancer arising from young Hong Kong Chinese. Most of the germline mutations involve hMSH2, which is different from the mutation spectrum in the Western population. It is well known that alternative splicing is common in hMLH1, which complicates RNA based mutation detection methods. In contrast, large deletions in hMLH1, commonly observed in some ethnic groups, tend to escape detection by exon-by-exon direct DNA sequencing. Here we report the detection of a novel germline 1.8 kb deletion involving exon 11 of hMLH1 in a local hereditary non-polyposis colorectal cancer family. This mutation generates a mRNA transcript with deletion of exons 10-11, which is indistinguishable from one of the most common and predominant hMLH1 splice variants. A diagnostic test based on PCR of the breakpoint region led to the identification of an additional young colorectal cancer patient with this mutation. Haplotype analysis suggests that they may share a common ancestral mutation. Our results caution investigators in the interpretation of alternative splicing and have important implications for the design of hMLH1 mutation detection strategy in the Chinese population.

Immunocytochemical identification and analysis of the diffuse bipolar cell type DB6 in macaque monkey retina

The distribution and morphology of CD15-immunoreactive bipolar cells were studied in the retina of macaque monkey. Labelled cells have a large dendritic tree contacting several cones and a narrowly stratified axon terminal that ends deep in the inner plexiform layer, close to the ganglion cell layer. The morphology of the labelled cells corresponds to that of the diffuse bipolar cell type named DB6 by Boycott & Wässle (1991; Eur. J. Neurosci., 3,1069). We conclude that CD15 is a marker for DB6 bipolar cells, enabling the quantitative analysis of the distribution and connectivity of this diffuse bipolar cell type.

Reduction of radiation dose to patients undergoing barium enema by dose audit

Nowadays, new fluoroscopic machines are usually equipped with a dose-area product (DAP) meter for dose measurement. In our hospital, DAP meters have been used in the Diagnostic Radiology Department for dose audit since June 1997. Demographic patient data, name of radiologist, fluoroscopic duration and DAP readings of every case were recorded by radiographers. In early 1999, questionnaires were distributed to radiologists who had performed fluoroscopic examinations during the auditing period. 23 radiologists with varying years of experience completed the questionnaire and their practice was analysed. Since familiarization with the examination technique would affect radiologists' practice, these radiologists were divided into two groups for analysis. Radiologists with less than 3 years of experience were grouped together as junior radiologists, whilst others were grouped as senior radiologists. Results of the questionnaire indicated that radiologists generally found DAP meters useful for dose evaluation in the process of technique refinement. Radiologists aware of being under continuous surveillance of their practice showed significant reduction of doses (junior radiologists 25%, p<0.005; senior radiologists 36%, p<0.05) and fluoroscopic times (junior radiologists 36%, p<0.001; senior radiologists 18%, p<0.05) compared with radiologists who were unaware that they were under surveillance but with similar radiological experience. This effect is believed to be because of increased awareness of radiation dose through audit. In addition, this "audit effect" may also affect junior radiologists in decision-making regarding the number of radiographs (p<0.05), but no effect was found for senior radiologists (p>0.5).

Chromosomal instability and p53 inactivation are required for genesis of glioblastoma but not for colorectal cancer in patients with germline mismatch repair gene mutation

We have previously reported high-frequency microsatellite instability (MSI-H) and germ-line mismatch repair gene mutation in patients with unusually young onset of high-grade glioma. Some of these patients developed metachronous MSI-H colorectal cancer and conformed to the diagnosis of Turcot's syndrome. Frameshift mutation of TGFbetaRII was present in all the colorectal carcinomas but not in brain tumours. We further characterized the genetic pathways of tumour evolution in these metachronous gliomas and colorectal carcinomas. All MSI-H glioblastomas had inactivation of both alleles of the p53 gene and showed over-expression of the p53 protein while none of the colorectal carcinomas had p53 mutation or protein over-expression. Flow cytometry and comparative genomic hybridization revealed that all glioblastomas were chromosomal unstable with aneuploid DNA content, and with a variable number of chromosomal arm aberrations. In contrast, the colorectal carcinomas had diploid or near-diploid DNA content with few chromosomal arm aberrations. The pattern of chromosomal aberrations in the two organs was different. Loss of 9p was consistently observed in all glioblastomas but not in colorectal carcinomas. Epidermal growth factor receptor amplification was absent in all glioblastomas and colorectal carcinomas. Our results suggest that both the frequency of p53 mutation and its effects differ greatly in the two organs. Following loss of mismatch repair function, p53 inactivation and chromosomal instability are not necessary for development of colorectal carcinoma, but are required for genesis of glioblastoma. Oncogene (2000) 19, 4079 - 4083.

Distinct clinical features associated with microsatellite instability in colorectal cancers of young patients

The Hong Kong Chinese population has an unusually high incidence of colorectal cancer in the young, suggestive of hereditary susceptibility. To search for a genetic basis for this predisposition, we studied the incidence of microsatellite instability (MSI) in paraffin-embedded colectomy specimens of 124 young (<50 years old) Chinese colorectal cancer patients referred to the Hong Kong Hereditary Gastrointestinal Cancer Registry from 1995 to 1998. By medical record review and personal interview, we searched for distinct clinical features associated with the manifestation of MSI in this group of patients. For patients with MSI tumours, blood was taken for detection of germline mutation in 2 mismatch repair (MMR) genes. MSI was present in 33 tumours from 23 males and 10 females (26.6%). Ongoing mutation analysis has so far identified MMR gene mutations in 8 patients with MSI tumours. The incidence of MSI increased significantly with decreasing age at cancer diagnosis. For patients aged 30 to 49, MSI tumours were located mainly at the proximal colon. However, for exceptionally young patients (<30 years), MSI tumours tended to be at the distal large bowel. This observation suggested a differential activity of the MMR pathway in colorectal carcinogenesis in different age groups. On multivariate analysis, young age at cancer diagnosis, proximal tumour location, a strong family history of colorectal cancer, and a personal history of metachronous cancer were independent predictors for MSI status. This knowledge may have an impact on the management of young colorectal cancer patients and their families.

Effects of a saw palmetto herbal blend in men with symptomatic benign prostatic hyperplasia

PURPOSE

We tested the effects of a saw palmetto herbal blend in men with symptomatic benign prostatic hyperplasia (BPH) via a randomized, placebo controlled trial.

MATERIALS AND METHODS

We randomized 44 men 45 to 80 years old with symptomatic BPH into a trial of a saw palmetto herbal blend versus placebo. End points included routine clinical measures (symptom score, uroflowmetry and post-void residual urine volume), blood chemistry studies (prostate specific antigen, sex hormones and multiphasic analysis), prostate volumetrics by magnetic resonance imaging, and prostate biopsy for zonal tissue morphometry and semiquantitative histology studies.

RESULTS

Saw palmetto herbal blend and placebo groups had improved clinical parameters with a slight advantage in the saw palmetto group (not statistically significant). Neither prostate specific antigen nor prostate volume changed from baseline. Prostate epithelial contraction was noted, especially in the transition zone, where percent epithelium decreased from 17.8% at baseline to 10.7% after 6 months of saw palmetto herbal blend (p <0.01). Histological studies showed that the percent of atrophic glands increased from 25. 2% to 40.9% after treatment with saw palmetto herbal blend (p <0.01). The mechanism of action appeared to be nonhormonal but it was not identified by tissue studies of apoptosis, cellular proliferation, angiogenesis, growth factors or androgen receptor expression. We noted no adverse effects of saw palmetto herbal blend. When the study was no longer blinded, 41 men elected to continue therapy in an open label extension.

CONCLUSIONS

Saw palmetto herbal blend appears to be a safe, highly desirable option for men with moderately symptomatic BPH. The secondary outcome measures of clinical effect in our study were only slightly better for saw palmetto herbal blend than placebo (not statistically significant). However, saw palmetto herbal blend therapy was associated with epithelial contraction, especially in the transition zone (p <0.01), indicating a possible mechanism of action underlying the clinical significance detected in other studies.

Spatial order in short-wavelength-sensitive cone photoreceptors: a comparative study of the primate retina

We compared the spatial distribution of short-wavelength-sensitive (SWS or blue) cone photoreceptors in the retinas of eight primate species. The regularity of the SWS cone array was quantified with a statistic (packing factor) that varies between a random distribution (0) and a triangular array (1). We find wide variability among species, with packing factors varying between 0.06 and 0.3. The SWS cone array in at least two New World monkey species is indistinguishable from a random array. The SWS cone density gradient across the retina was measured in the capuchin monkey Cebus apella and the squirrel monkey Saimiri sciureus. Both species show a peak density of 5,000-8,000 cells/mm2 at the fovea and a 50-fold central-peripheral density gradient. In contrast to the wide variation in local regularity, the spatial density and the topography of SWS cones are well preserved across primates.

Frequent microsatellite instability and mismatch repair gene mutations in young Chinese patients with colorectal cancer

BACKGROUND

The incidence of colorectal cancer in persons under 46 years of age is substantially higher in Hong Kong than in Scotland and many other countries. Consequently, we examined whether there is a hereditary predisposition for colorectal cancer in this Southern Chinese population.

METHODS

We investigated the incidence of microsatellite instability (MSI) at 10 DNA sites in 117 colorectal cancer specimens from Chinese patients of various ages. Those tumors with new alleles at 40% or more of the sites investigated were identified as highly unstable MSI (MSI-H). In young patients, we also searched for germline mutations in three mismatch repair genes (hMSH2, hMLH1, and hMSH6).

RESULTS

The incidence of MSI-H varied statistically significantly with age, being observed in more than 60% of those younger than age 31 years at diagnosis and in fewer than 15% of those age 46 years or older. In 15 patients (<46 years old) whose colorectal cancers showed MSI-H, eight possessed germline mutations in either hMSH2 or hMLH1. When mutations in hMSH6 were included, more than 80% of Chinese colorectal cancer patients younger than 31 years had germline mutations in mismatch repair genes. We found a novel germline missense mutation in hMSH6 in a 29-year-old man whose tumor showed no MSI. Two patients had a 4-base-pair insertion in exon 10 causing a truncated protein; this insertion is a common polymorphism with a population allele frequency in Chinese of 5.6%.

CONCLUSIONS

Our results indicate that germline mutations in mismatch repair genes contribute substantially to the pathogenesis and high incidence of colorectal cancer in young Hong Kong Chinese. However, because young Chinese and Caucasians show similar proportions of colorectal cancers with MSI-H, despite the higher incidence in the former, additional factors may underlie the high susceptibility of young Chinese to colorectal cancer.

Germline hMSH2 and differential somatic mutations in patients with Turcot's syndrome

Turcot's syndrome is characterized clinically by the occurrence of primary brain tumor and colorectal tumor and has in previous reports been shown to be associated with germline mutations in the genes APC, hMLH1, and hPMS2. Here we describe three patients with Turcot's syndrome, each having colorectal adenocarcinoma and malignant glioma. All the colorectal and brain tumors from these patients showed replication errors in most of the microsatellite loci investigated. Search for underlying germline mutations in the nucleotide mismatch repair genes revealed three different hMSH2 mutations. All colorectal tumors showed a frameshift in the A(10) tract in the coding sequence of the transforming growth factor beta type II receptor (TGFBRII) gene, but no such change was detected in any of the brain tumors. Frameshift mutation in the BAX gene was found in one colon carcinoma and mutations in insulin-like growth factor type II receptor (IGFIIR) gene in one glioma. Our data have broadened the possible mutation spectrum of patients with Turcot's syndrome. The difference in the mutation spectrum of TGFBRII, BAX, and IGFIIR between brain and colorectal tumors in these individuals suggests that the mutator phenotype may target different pathogenic pathways in the oncogenic process of the two organs.

Microsatellite instability and mutation of DNA mismatch repair genes in gliomas

Microsatellite instability (MSI) has been identified in various human cancers, particularly those associated with the hereditary nonpolyposis colorectal cancer syndrome. Although gliomas have been reported in a few hereditary nonpolyposis colorectal cancer syndrome kindred, data on the incidence of MSI in gliomas are conflicting, and the nature of the mismatch repair (MMR) defect is not known. We established the incidence of MSI and the underlying MMR gene mutation in 22 patients ages 45 years or less with sporadic high-grade gliomas (17 glioblastomas, 3 anaplastic astrocytomas, and 2 mixed gliomas, grade III). Using five microsatellite loci, four patients (18%) had high level MSI, with at least 40% unstable loci. Germline MMR gene mutation was detected in all four patients, with inactivation of the second allele of the corresponding MMR gene or loss of protein expression in the tumor tissue. Frameshift mutation in the mononucleotide tract of insulin-like growth factor type II receptor was found in one high-level MSI glioma, but none was found in the transforming growth factor beta type II receptor and the Bax genes. There was no family history of cancer in three of the patients, and although one patient did have a family history of colorectal carcinoma, the case did not satisfy the Amsterdam criteria for hereditary nonpolyposis colorectal cancer syndrome. Three patients developed metachronous colorectal adenocarcinomas, fitting the criteria of Turcot's syndrome. Thus, MSI and germline MMR gene mutation is present in a subset of young glioma patients, and these patients and their family members are at risk of developing other hereditary nonpolyposis colorectal cancer syndrome-related tumors, in particular colorectal carcinomas. These results have important implications in the genetic testing and management of young patients with glioma and their families.

Horizontal cell connections with short wavelength-sensitive cones in the retina: a comparison between New World and Old World primates

Recent studies in the Old World macaque monkey have shown that the two horizontal cell types H1 and H2 differ with respect to their connections to short wavelength-sensitive (SWS) cones. We wanted to establish whether this pattern of connectivity is common to all primates. The connections of horizontal cells with SWS cones were studied in the retinas of two species of New World (marmoset and tamarin) and two species of Old World (orangutan and chimpanzee) primates by using a double-labelling technique. Horizontal cells were labelled with DiI and then photoconverted; SWS cones were labelled immunocytochemically. The marmoset shows a sex-linked polymorphism of colour vision: All males are dichromats, whereas most females are trichromats. In contrast, Old World primates are usually trichromats. Our results show that the horizontal cells of both New World and Old World primates have a comparable pattern of connectivity with SWS cones and thus indicate that the wiring of horizontal cells with SWS cones does not differ between dichromats and trichromats and is common to all primates. The H1 cells make no or only sparse contact with SWS cones. In marmoset, H1 cells have on average 0.8% of their dendritic terminals at SWS cones. The H2 cells contact all SWS cones in their dendritic field. In marmoset, H2 cells have on average 11.8% of their dendritic terminals at SWS cones. The axon of H2 cells contacts SWS cones but presumably also contacts other cones.

Detection of fluoroquinolones in urinary specimens from patients undergoing anti-tuberculous therapy

A paper strip impregnated with ferric chloride has been developed for visual detection of fluoroquinolones in urine based on a change of colour due to the chelation of the transition metal ion to the beta-oxo acid array in the 4-oxo-1,4-dihydropyridine-3-carboxylic acid moiety of the fluoroquinolone molecule. In urine specimens, the detection limit of the strip was 100 mg/l for pefloxacin, 200 mg/l for ciprofloxacin, fleroxacin, levofloxacin, norfloxacin, ofloxacin and sparfloxacin, and 300 mg/l for trovafloxacin. In 193 urine specimens taken from 138 patients on ofloxacin therapy and 55 controls preliminary evaluation of the strip showed that all the 55 specimens from control patients were negative, while 112 out of the 138 ofloxacin-treated patients were positive. Quantitative analysis by high-performance liquid chromatography of the 26 strip-test-negative specimens taken from patients with ofloxacin treatment indicated that these urinary specimens contained less than 200 mg/l of the antimicrobial, mostly because of poor renal function and in some occasions, non-compliance. This strip method would provide a convenient way of monitoring drug compliance in patients who receive fluoroquinolone therapy for tuberculosis.

The morphology and distribution of horizontal cells in the retina of a New World monkey, the marmoset Callithrix jacchus: a comparison with macaque monkey

The morphology and distribution of horizontal cells was studied in the retina of a New World monkey, the marmoset, Callithrix jacchus, and compared with that of the Old World macaque monkey. Horizontal cells in macaque and marmoset were either labelled with the carbocyanine dye, DiI, and then photoconverted, or were labelled by intracellular injection with Neurobiotin. The marmoset has two types of horizontal cell, H1 and H2, which have dendritic and axonal morphology similar to their counterparts in Old World monkeys and human. The dendritic-field size of both cell types increases with distance from the fovca. Both types make contact with the vast majority of the cones within their dendritic field. The dendrites of H1 cells in marmoset contact almost twice as many cones as H1 cells in macaque at an equivalent eccentricity. With increasing distance from the fovea, H1 cells make contact with more cones but have, on average, fewer terminal knobs inserted in each cone. The increase in dendritic-field area of H1 cells is balanced by a decrease in spatial density (from 4500 cells/mm2 at 25 deg eccentricity to 1000 cells/mm2 in far peripheral retina), so coverage of the retina remains fairly constant, between 5 and 8. Overall, the results show that the qualitative morphological properties, as well as quantitative population properties of horizontal cells, are common to both New World and Old World primates.

An economical piezoelectric phase modulator for fiber optic sensors

A homemade piezoelectric phase modulator for interfero-metric fiber optic sensors was fabricated using piezoelectric buzzers as strain elements. Six piezoelectric elements were embedded between the two halves of a bakelite cylinder split along its axis and secured tightly together again to form a cylinder. Single-mode optical fiber was then wound around the cylinder to complete the unit. Up to a frequency of 500 Hz, the phase shift produced by the modulator is linearly proportional to the amplitude of the applied voltage. The sensitivity of the phase modulator is about 3.6 rad/V and has a dynamic range of 1,000 rad, which is sufficient for most phase modulation purposes.

Horizontal cell connections with short-wavelength-sensitive cones in macaque monkey retina

This study describes the connectivity between horizontal cells and short-wavelength-sensitive (SWS) cones in macaque monkey retina. H1 and H2 horizontal cells were either labelled with the carbocyanine dye, DiI, or injected intracellular with Neurobiotin. The retinas were then processed with an antiserum against human SWS cone pigment, which usually stained the entire SWS cone. In these double-labelled retinas, the pattern of connectivity of H1 (n = 91) and H2 (n = 7) cells with SWS cones has been determined. About 85% of the H1 cells examined do not contact SWS cones. The dendritic terminal knobs of five H1 cells that do contact SWS cones were counted. They have, at most, 3% of their dendritic terminal knobs at SWS cones. All H2 cells examined make contact with SWS cones. The dendritic terminal knobs of one H2 cell were counted; about 11% of the dendritic terminal knobs are at the SWS cone. We conclude that horizontal cells in macaque monkey retina show specific patterns of connectivity to SWS cones.

Mechanism of induction of asthmatic attacks initiated by the inhalation of particles generated by airbag system deployment

OBJECTIVE

We have previously demonstrated that inhalation of the dust produced by dual frontal airbag deployment can result in significant bronchospasm in approximately 40% of mild to moderate asthmatics. This study was performed to determine the cause of the asthmatic response.

DESIGN

Controlled laboratory study.

MATERIALS AND METHODS

Asthmatics who were previously tested for their response to airbag effluents were exposed for twenty minutes to either 1) airbag effluents from airbag systems in which the airbag was insulated from the hot deployment module; 2) non-sulfur containing airbag effluents; 3) sodium chloride aerosol; or 4) sodium carbonate-bicarbonate aerosol (pH 10). Pre-exposure, post-exposure, and 2 hour post exposure pulmonary spirometry and mechanics were measured. Subject's filled out symptoms questionnaires before exposure, 2, 4, 8, 12, and 19 minutes into the exposure, immediately post-exposure, and 2 hours post-exposure.

MEASUREMENTS AND MAIN RESULTS

Prevention of the pyrolysis of the passenger-side bag as it rested on the hot module after deployment did not diminish the asthmatic response. Removal of sulfur-containing oxidants from the airbag pyrotechnic chemistry, which may have led to sulfite production, similarly did not alleviate the asthmatic response to the airbag effluents. Lastly, when asthmatics were exposed to sodium chloride and sodium carbonate-bicarbonate aerosols at approximately the same concentration (approximately 220 mg/m3) as the airbag aerosol concentration that occurred in the in-car tests, they had responses similar to those produced by the airbag exposures.

CONCLUSIONS

We conclude that the amount of soluble particulate contained in the aerosol discharged into the passenger compartment by dual frontal airbag deployment is largely the cause of the observed evoked asthmatic attacks. The alkaline pH of the airbag and carbonate aerosols may have added an additional degree of provocation.

Acute pulmonary response of asthmatics to aerosols and gases generated by airbag deployment

The purpose of this study was to determine whether the aerosols and gases that vent into an automobile's passenger compartment after airbag deployment pose a risk to the asthmatic population. After baseline pulmonary function measurements were taken, 24 diagnosed asthmatic subjects were placed in the rear seat of an automobile, and a driver-passenger airbag system was deployed. Subjects remained in the vehicle with the windows closed and no ventilation for 20 min or until they perceived or demonstrated signs of chest tightness and bronchoconstriction. They then exited the vehicle and were retested immediately after exposure and 2 and 4 h after exposure. Ten of the 24 subjects demonstrated clinically significant bronchoconstrictive episodes, three of which required medical intervention. These three events were quickly reversed by beta-agonist therapy. When eight of the responding subjects were reexposed at later dates to the same supplemental inflatable restraints emissions while wearing a high-efficiency particulate absolute respirator, which prevented inhalation of the particles but allowed passage of the gases, the pulmonary response was essentially eliminated. We conclude that the aerosols generated by deployment of automotive driver-passenger airbag systems can induce significant asthmatic reactions in some individuals.