Digital health literacy among adults living in the community in Singapore

Background

this study aimed to determine the level of digital literacy in adult Singaporeans in the community and its association with demographic characteristics, physical activity, self-rated health and bodily pain, and to identify the health needs of frequent internet users.

Methods

a cross-sectional survey was carried out among individuals living in Punggol, Singapore on 2 June 2018. Survey data were using a 20-minute self-completion questionnaire. The questionnaire included the validated 8-item eHealth Literary Scale (eHEALS), the validated 4-item Exercise Stage of Change Questionnaire, a single item on self-reported health status and Likert scale items to assess level of bodily pain in the last 4 weeks and how much that pain interfered with normal work. The questionnaires and interviews were administered by registered nurses. Quota sampling was used to obtain sufficient numbers from different ethnic groups for analysis of the survey: the initial target was 120 Chinese, 60 Malay and 60 Indian individuals, one per household.

Results

survey data were collected from 279 individuals (49.6% female), including 197 (71.1%) Chinese, 47 (17.0%) Malay, 18 (6.5%) Indian and 15 (5.4%) others. The mean age was 35.6 (SD 11.3). The eHEALS score had a mean of 29.4 (SD 6.2) out of a maximum of 40. Self-reported health status was positively associated with pain in the last 4 weeks (Kendall’s τ = 0.141, p = 0.007), how much that pain interfered with normal work (Kendall’s τ = 0.160, p = 0.003) and the Exercise Stages of Change score (Kendall’s τ=-0.271, p < 0.001). The correlation between the two pain variables was strong (Kendall’s τ = 0.582, p < 0.001). The only one of these measures significantly related to the eHEALS score was the Exercise Stages of Change score (Kendall’s τ = 0.104, p = 0.030). From linear regression models, the only independent variables consistently associated with the eHEALS score were age (B=-0.090, p = 0.006) and having a mobile phone plan (B = 8.171, p < 0.001).

Key messages

Digital health literacy was negatively related to age and positively related to having a mobile phone plan. The study finding suggest the need to identify individual Singaporeans with poor e-health literacy and provide them with remedial education.

Chemically reprogramming the phospho-transfer reaction to crosslink protein kinases to their substrates

The proteomic mapping of enzyme-substrate interactions is challenged by their transient nature. A method to capture interacting protein kinases in complexes with a single substrate of interest would provide a new tool for mapping kinase signaling networks. Here, we describe a nucleotide-based substrate analog capable of reprogramming the wild-type phosphoryl-transfer reaction to produce a kinase-acrylamide-based thioether crosslink to mutant substrates with a cysteine nucleophile substituted at the native phosphorylation site. A previously reported ATP-based methacrylate crosslinker (ATP-MA) was capable of mediating kinase crosslinking to short peptides but not protein substrates. Exploration of structural variants of ATP-MA to enable crosslinking of protein substrates to kinases led to the discovery that an ADP-based methacrylate (ADP-MA) crosslinker was superior to the ATP scaffold at crosslinking in vitro. The improved efficiency of ADP-MA over ATP-MA is due to reduced inhibition of the second step of the kinase-substrate crosslinking reaction by the product of the first step of the reaction. The new probe, ADP-MA, demonstrated enhanced in vitro crosslinking between the Src tyrosine kinase and its substrate Cortactin in a phosphorylation site-specific manner. The kinase-substrate crosslinking reaction can be carried out in a complex mammalian cell lysate setting, although the low abundance of endogenous kinases remains a significant challenge for efficient capture.

Ubiquitin Regulation of Trk Receptor Trafficking and Degradation

The regulation of Trk receptors is critical for orchestrating multiple signalling pathways required for developing and maintaining neuronal networks. Activation of Trk receptors results in signalling, internalisation and subsequent degradation of the protein. Although ubiquitination of TrkA by Nedd4-2 has been identified as an important degradation pathway, much less is known about the pathways regulating the degradation of TrkB and TrkC. Critical to the interaction between TrkA and Nedd4-2 is a PPxY motif present within TrkA but absent in TrkB and TrkC. Given the absence of this interaction motif, it remains to be determined how TrkB and TrkC are ubiquitinated. Here we report that the adaptor protein Ndfip1 can interact with all three Trk receptors and show for TrkB the recruitment of Nedd4-2 through PPxY motifs present in Ndfip1. Ndfip1 mediates the ubiquitination of TrkB, resulting in receptor trafficking predominantly on Rab7 containing late endosomes, highlighting a pathway for TrkB degradation at the lysosome. In vitro, overexpression of Ndfip1 increased TrkB ubiquitination and decreased viability of BDNF-dependent primary neurons. In vivo, conditional genetic deletion of Ndfip1 increased TrkB in the brain and resulted in enlargement of the granular cell layer of the dentate gyrus.

Determination of ubiquitin fitness landscapes under different chemical stresses in a classroom setting

Ubiquitin is essential for eukaryotic life and varies in only 3 amino acid positions between yeast and humans. However, recent deep sequencing studies indicate that ubiquitin is highly tolerant to single mutations. We hypothesized that this tolerance would be reduced by chemically induced physiologic perturbations. To test this hypothesis, a class of first year UCSF graduate students employed deep mutational scanning to determine the fitness landscape of all possible single residue mutations in the presence of five different small molecule perturbations. These perturbations uncover 'shared sensitized positions' localized to areas around the hydrophobic patch and the C-terminus. In addition, we identified perturbation specific effects such as a sensitization of His68 in HU and a tolerance to mutation at Lys63 in DTT. Our data show how chemical stresses can reduce buffering effects in the ubiquitin proteasome system. Finally, this study demonstrates the potential of lab-based interdisciplinary graduate curriculum.

DOI:http://dx.doi.org/10.7554/eLife.15802.001

The ability of an organism to grow and reproduce, that is, it’s “fitness”, is determined by how its genes interact with the environment. Yeast is a model organism in which researchers can control the exact mutations present in the yeast’s genes (its genotype) and the conditions in which the yeast cells live (their environment). This allows researchers to measure how a yeast cell’s genotype and environment affect its fitness.

Ubiquitin is a protein that many organisms depend on to manage cell stress by acting as a tag that targets other proteins for degradation. Essential proteins such as ubiquitin often remain unchanged by mutation over long periods of time. As a result, these proteins evolve very slowly. Like all proteins, ubiquitin is built from a chain of amino acid molecules linked together, and the ubiquitin proteins of yeast and humans are made of almost identical sequences of amino acids.

Although ubiquitin has barely changed its sequence over evolution, previous studies have shown that – under normal growth conditions in the laboratory – most amino acids in ubiquitin can be mutated without any loss of cell fitness. This led Mavor et al. to hypothesize that treating the yeast cells with chemicals that cause cell stress might lead to amino acids in ubiquitin becoming more sensitive to mutation.

To test this idea, a class of graduate students at the University of California, San Francisco grew yeast cells with different ubiquitin mutations together, and with different chemicals that induce cell stress, and measured their growth rates. Sequencing the ubiquitin gene in the thousands of tested yeast cells revealed that three of the chemicals cause a shared set of amino acids in ubiquitin to become more sensitive to mutation.

This result suggests that these amino acids are important for the stress response, possibly by altering the ability of yeast cells to target certain proteins for degradation. Conversely, another chemical causes yeast to become more tolerant to changes in the ubiquitin sequence. The experiments also link changes in particular amino acids in ubiquitin to specific stress responses.

Mavor et al. show that many of ubquitin’s amino acids are sensitive to mutation under different stress conditions, while others can be mutated to form different amino acids without effecting fitness. By testing the effects of other chemicals, future experiments could further characterize how the yeast’s genotype and environment interact.

DOI:http://dx.doi.org/10.7554/eLife.15802.002

P1-05-02: Epigenetic Regulation by Alcohol Reactivates Estrogen Receptor alpha in Estrogen Receptor alpha-Negative Cells

Introduction: Alcohol consumption is an established risk factor for breast cancer development and contributes to mammary tumorigenesis through the regulation of estrogen receptor alpha (ERα) expression. Previously, we reported that alcohol consumption in the MMTV-neu ERα-negative mouse model of human breast cancer resulted in significantly increased ERα expression compared to non-alcohol consuming mice. Thus, our results indicated that alcohol consumption led to reexpression of ERα in an ERα-negative mouse model. Several lines of evidence suggest that ERα expression in ERα-negative cancer cells is inhibited through epigenetic mechanisms. In this study, we examine the role of alcohol on ERα reactivation through changes in histone modifications, DNA methylation, and recruitment of transcriptional regulation complexes on the ERα promoter, in vitro. Methods: ERα-negative MDA-MB-231 human breast cancer cells were treated with 0.1%, 0.2% and 0.5% v/v ethanol in culture media for 24 h. Chromatin immunoprecipitation (ChIP) assays were used to examine the enrichment of active and inactive markers of chromatin on the ERα promoter following alcohol treatment. DNA methylation at three ERα promoter CpG dinucleotide sites was assessed following alcohol treatment using methyl-sensitive restriction enzyme (MSRE)-qPCR. ChIP assays are used to determine the binding of the transcriptional regulation complexes, pRb2/p130-E2F4/5-HDAC1-SUV39H1-p300 and pRb2/p130-E2F4/5-HDAC1-SUV39H1-DNMT1, to the ERa promoter following alcohol treatment. MCF-7 human breast cancer cells served as an ERα-positive control.

Results: We report that histone modifications were affected by alcohol treatment in a dose-dependent manner. Enrichment levels of all five chromatin markers tested, which includes markers of active and inactive transcription, were significantly altered as a result of alcohol treatment (p<0.05). We also found significantly decreased DNA methylation at three ERα promoter CpG sites as a result of alcohol treatment (p<0.05). Experiments testing the recruitment of the transcriptional regulation complexes, pRb2/p130-E2F4/5-HDAC1-SUV39H1-p300 and pRb2/p130-E2F4/5-HDAC1-SUV39H1-DNMT1, are currently ongoing.

Discussion: ERα expression has been linked to mammary carcinogenesis and clinical outcome in breast cancer patients. However, approximately one out of three breast cancers lack ERα expression at the time of diagnosis and many breast cancers lose ERα expression during the course of tumor progression. Thus, understanding the regulation of ERα expression in breast cancer cells is critical and results from this study will facilitate the development of novel therapeutic strategies and treatment options for hormone-resistant breast cancer.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P1-05-02.

Objective measurement of motor speech characteristics in the healthy pediatric population

OBJECTIVE

To obtain objective measurements of motor speech characteristics in normal children, using a computer-based motor speech software program.

METHODS

Cross-sectional, observational design in a university-based ambulatory pediatric otolaryngology clinic. Participants included 112 subjects (54 females and 58 males) aged 4-18 years. Participants with previously diagnosed hearing loss, voice and motor disorders, and children unable to repeat a passage in English were excluded. Voice samples were recorded and analysed using the Motor Speech Profile (MSP) software (KayPENTAX, Lincoln Park, NJ). The MSP produced measures of diadochokinetics, second formant transition, intonation, and syllabic rates.

RESULTS

Demographic data, including sex, age, and cigarette smoke exposure were obtained. Normative data for several motor speech characteristics were derived for children ranging from age 4 to 18 years. A number of age-dependent changes were indentified, including an increase in average diadochokinetic rate (p<0.001) and standard syllabic duration (p<0.001) with age. There were no identified differences in motor speech characteristics between males and females across the measured age range. Variations in fundamental frequency (Fo) during speech did not change significantly with age for both males and females.

CONCLUSIONS

To our knowledge, this is the first pediatric normative database for the MSP progam. The MSP is suitable for testing children and can be used to study developmental changes in motor speech. The analysis demonstrated that males and females behave similarly and show the same relationship with age for the motor speech characteristics studied. This normative database will provide essential comparative data for future studies exploring alterations in motor speech that may occur with hearing, voice, and motor disorders and to assess the results of targeted therapies.

Sensium: an ultra-low-power wireless body sensor network platform: design & application challenges

In this paper we present a system-on-chip for wireless body sensor networks, which integrates a transceiver, hardware MAC protocol, microprocessor, IO peripherals, memories, ADC and custom sensor interfaces. Addressing the challenges in the design, this paper will continue to discuss the issues in the applications of this technology to body worn monitoring for real-time measurement of ECG, heart rate, physical activity, respiration and/or skin temperature. Two application challenges are described; the real-time measurement of energy expenditure using the LifePebble, and; the development issues surrounding the 'Digital Patch'.

Stroop interference and facilitation effects in first-episode schizophrenic patients

In the Stroop test, interference occurs in naming the print color of a word when the word is itself the name of another color. Facilitation occurs when the word is the same as the print color. Previous studies on selective attention in schizophrenia using the Stroop interference effects have yielded contradicting results. Constraints included limited sample size and the recruitment of medicated chronic patients. We studied the Stroop interference and facilitation effects in a relatively large sample of first-episode schizophrenic patients (n=56), a substantial proportion of whom were medication-naïve (n=30) at the time of initial testing. We have also carried out longitudinal follow-up assessments when patients reached a clinically stable state, as well as 4months after recovery from the episode. We found that the Stroop interference effect was not increased in first-episode schizophrenic patients, whether medication-naïve or not. This effect did not change over the follow-up period. In addition, we detected an increase in Stroop facilitation effect in medicated schizophrenic patients, but only in the initial assessment soon after they had received medication. After sustained treatment, the increase in facilitation was normalized. These observations supported previous findings of a normal Stroop interference effect amongst schizophrenic patients. The increased facilitation effect for patients in their early phase of treatment (but not later) may represent an acute effect of anti-psychotic medication. Its nature and significance require further investigation.

Surgical treatment of recalcitrant radiation-induced gastric erosions

BACKGROUND

Uncontrolled bleeding as a result of radiation gastritis in patients who have pharyngo-laryngo-esophagectomy and gastric pull-up is seldom reported. Surgical resection in the management of this condition has rarely been described.

METHOD

A 66-year-old man with hypopharyngeal cancer was treated by pharyngo-laryngo-esophagectomy and gastric transposition. He received postoperative radiotherapy and had recurrent hemorrhagic gastritis, necessitating surgical resection. The manubrium was resected to access the mediastinal part of the gastric conduit. The diseased part of the gastric conduit was removed and a free jejunal graft was interposed to replace the resected stomach.

RESULTS

Manubrial resection offered adequate access to the stomach transposed in the mediastinum, and the life-threatening bleeding gastritis was successfully controlled by surgical resection.

CONCLUSION

Surgical resection of the radiation-damaged transposed stomach through a manubrial resection approach can safely be performed. Free jejunal graft is the choice of reconstruction of the circumferential defect.

Selection of anionic dopant for quantifying desialylation reactions with MALDI-FTMS

Alkylsulfonates are examined as anion dopants for the matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS) of neutral oligosaccharides. The anion dopants allow neutral oligosaccharides to be examined in the same mixture as acidic oligosaccharides. The alkylsulfonate dopants interact strongly with the oligosaccharide to produce a quasimolecular ion composed of the oligosaccharides and the deprotonated alkylsulfonates. Compounds as small as disaccharides to large branched oligosaccharides can all be examined. The new series of alkylsulfonates works as well as HSO4- in terms of signal-to-noise ratio, sensitivity, and ease of preparation in the negative ion mode. The alkylsulfonates are used to construct a calibration curve for obtaining the relative amounts of varying neutral and acidic oligosaccharide mixtures. With the anion dopants, the MALDI-FTMS signals are shown to have a linear relationship with the molar ratios of the neutral and sialylated oligosaccharides. The method is also used to monitor the product of a desialylation reaction by acid hydrolysis.

Fragmentation reactions in the mass spectrometry analysis of neutral oligosaccharides

A method is described to obtain multicollision dissociation threshold (MCDT) values. These values provide relative reaction thresholds for dissociation in the three major gas-phase fragmentation reactions of oligosaccharides complexed to alkali metal ions. The quasimolecular ions are produced using matrix-assisted laser desorption/ionization Fourier transform mass spectrometry. The MCDTs for alkali metal ion dissociation and glycosidic bond and cross-ring cleavages were resolved from the kinetic energy dependence of collision-induced dissociation (CID) products. The relative strengths of alkali metal ion binding to N,N'-diacetylchitobiose (chitobiose) and N,N',N"-triacetylchitotriose (chitotriose) were probed using sustained off-resonance irradiation (SORI) CID. Experiments to evaluate MCDT values and the method for obtaining them were performed by studying alkali metal ion coordinated crown ethers. Molecular dynamic simulations were also performed to provide insight into the alkali metal ion binding of chitin-based oligosaccharides. The relative dissociation thresholds of glycosidic bond cleavages and cross-ring cleavages were determined for various alkali metal ion coordinated oligosaccharides. The activation barriers of glycosidic bond cleavages were found to depend on the size of the alkali metal ion. Cross-ring cleavages were found to be independent of the alkali metal ion but dependent on linkage type. The results suggest that glycosidic bond cleavages are charge-induced while cross-ring cleavages are charge-remote processes.

Anion dopant for oligosaccharides in matrix-assisted laser desorption/ionization mass spectrometry

A new anion dopant for oligosaccharides is developed for use in matrix-assisted laser desorption/ionization mass spectrometry. Two types of sulfate-attached quasimolecular ions are formed in the negative ion mode when neutral oligosaccharides are doped with dilute H2SO4 solutions. Under mild conditions, i.e., low H2SO4 concentration (approximately 10(-3) M) and threshold laser fluence, a sulfate adduct [M + HSO4]- is formed. With more concentrated H2SO4 solutions (approximately 10(-2) M) and higher laser fluence, in situ derivatization of the oligosaccharides occurs to produce an ion whose m/z corresponds to a sulfate derivative [M + HSO4 - H2O]-. Hydrogen sulfate appears to be a general anion dopant because it forms complexes with a wide variety of neutral oligosaccharides. Conversely, anionic oligosaccharides form neither the adduct nor the derivative. The combination of complex formation (with neutral oligosaccharides) and the deprotonation of acidic oligosaccharides allows simultaneous detection of the respective mixture.

Identification of Glu-540 as the catalytic nucleophile of human beta-glucuronidase using electrospray mass spectrometry

Human beta-glucuronidase is a member of the Family 2 glycosylhydrolases that cleaves beta-D-glucuronic acid residues from the nonreducing termini of glycosaminoglycans. The enzyme is shown to catalyze glycoside bond hydrolysis with net retention of anomeric configuration, presumably via a mechanism involving a covalent glucuronyl-enzyme intermediate. Incubation of human beta-glucuronidase with 2-deoxy-2-fluoro-beta-D-glucuronyl fluoride resulted in time-dependent inactivation of the enzyme through the accumulation of a covalent 2-deoxy-2-fluoro-alpha-D-glucuronyl-enzyme, as observed by electrospray mass spectrometry. Regeneration of the free enzyme by hydrolysis or transglycosylation and removal of excess inactivator demonstrated that the covalent intermediate was kinetically competent. Peptic digestion of the 2-deoxy-2-fluoro-alpha-D-glucuronyl-enzyme intermediate and subsequent analysis by liquid chromatography coupled with electrospray ionization triple quadrupole mass spectrometry indicated the presence of a 2-deoxy-2-fluoro-alpha-D-glucuronyl peptide. Sequence determination of the labeled peptide by tandem mass spectrometry in the daughter ion scan mode permitted the identification of Glu-540 as the catalytic nucleophile within the sequence SEYGAET.

Catamenial fevers associated with a uterine smooth muscle tumor of undetermined malignant potential

BACKGROUND

Pyrexia associated with solid and hematogenous neoplasms are a well-recognized clinical condition. Menstrually related (catamenial) fevers have not been reported previously.

CASE

A 52-year-old woman with a history of stage I breast cancer on adjuvant tamoxifen citrate presented with recurrent fevers associated with menses. An extensive evaluation of possible causes, including recurrent breast cancer and infectious, collagen-vascular, and drug-related sources, initially was unrevealing. A gynecologic evaluation identified a uterine tumor, which appeared to be a cellular leiomyoma on hysteroscopic biopsy. The catamenial fevers resolved immediately after hysterectomy. A uterine smooth muscle tumor of undetermined malignant potential was identified on pathology.

CONCLUSION

Smooth muscle tumors of the myometria are a rare cause of menstrual fevers.

Performance of asynchronous transfer mode (ATM) local area and wide area networks for medical imaging transmission in clinical environment

Asynchronous transfer mode (ATM) technology emerges as a leading candidate for medical image transmission in both local area network (LAN) and wide area network (WAN) applications. This paper describes the performance of an ATM LAN and WAN network at the University of California, San Francisco. The measurements were obtained using an intensive care unit (ICU) server connecting to four image workstations (WS) at four different locations of a hospital-integrated picture archiving and communication system (HI-PACS) in a daily regular clinical environment. Four types of performance were evaluated: magnetic disk-to-disk, disk-to-redundant array of inexpensive disks (RAID), RAID-to-memory, and memory-to-memory. Results demonstrate that the transmission rate between two workstations can reach 5-6 Mbytes/s from RAID-to-memory, and 8-10 Mbytes/s from memory-to-memory. When the server has to send images to all four workstations simultaneously, the transmission rate to each WS is about 4 Mbytes/s. Both situations are adequate for radiologic image communications for picture archiving and communication systems (PACS) and teleradiology applications.

Clinical experience with a second-generation hospital-integrated picture archiving and communication system

In a previous report we described a second-generation hospital-integrated picture archiving and communication system (HI-PACS) developed in-house. This HI-PACS had four unique features not found in other PAC systems. In this report, we will share some of our clinical experiences pertaining to these features during the past 12 months. We first describe the usage characteristics of two 2,000-line workstations (WSs), one in the in-patient and the second in the out-patient neuroradiology reading area. These two WSs can access neuro-images from 10 computed tomographic and magnetic resonance scanners located two medical centers through an asynchronous transfer mode network connection. The second unique feature of the system is an intensive care unit (ICU) server, which supports three WSs in the pediatric, medical surgery, and cardiac ICUs. The users' experiences and requests for refinement of the WSs are given. Another feature is physician desk-top access of PACS data. The HI-PACS provides a server connected to more than 100 Macintosh users for direct access of PACS data from their offices. The server's performance and user critiques are described. The last feature is a digital imaging and communication in medicine (DICOM) connection of the HI-PACS to a manufacturer's ultrasound PACS module. The authors then outline the interfacing process and summarize some of the difficulties encountered. Developing an in-house PACS has many advantages but also some drawbacks. Based on experience, the authors have formulated three axioms as a guide for in-house PACS development.

Design and implementation of a picture archiving and communication system: the second time

This report describes the authors' experience in the design and implementation of two large scale picture archiving and communication systems (PACS) during the past 10 years. The first system, which is in daily clinical operation was developed at University of California, Los Angeles from 1983 to 1992. The second system, which continues evolving, has been in development at University of California, San Francisco (UCSF) since 1992. The report highlights the differences between the two systems and points out the gradual change in the PACS design concept during the past 10 years from a closed architecture to an open hospital-integrated system. Both systems focus on system reliability and data integrity, with 24-hour on-line service and no loss of images. The major difference between the two systems is that the UCSF PACS infrastructure design is a completely open architecture and the system implementation uses more advanced technologies in computer software, digital communication, system interface, and stable industry standards. Such a PACS can withstand future technology changes without rendering the system obsolete, an essential criterion in any PACS design.

Asynchronous transfer mode technology for radiologic image communication

Image communication is an important component in picture archiving and communication systems (PACS) and teleradiology applications. Currently, local area networks (LANs) and wide area networks (WANs) use different technologies for image communication. Asynchronous transfer mode (ATM) is an emerging technology that can be used for both LANs and WANs. This article describes experimental results using an ATM network to transmit CT scans and digitized radiographs between the University of California, San Francisco (UCSF) and Mount Zion Hospital, an affiliated community hospital in the San Francisco Bay area. The WAN connection between the two hospitals is via an ATM main switch at Pacific Bell, a local communication carrier located in Oakland, CA, which uses single-mode optical fibers. Preliminary results show that, using the ATM Optical Carrier Level 3 (OC3) (155 Mbits/sec) specification, it takes 1.3 sec and 2.7 sec to transmit a 10-Mbyte digitized radiograph and a 20-Mbyte CT scan, respectively, between the two locations. Encouraged by these results, we have designed and implemented an ATM WAN and LAN between UCSF and Mount Zion Hospital. This is the first of a three-phase project of installing a WAN serving four hospitals and one clinic in the San Francisco Bay area.

Accessing picture archiving and communication system text and image information through personal computers

Recent advances in storage technology have made possible the archiving of tremendous amounts of text and image information within a picture archiving and communication system (PACS). However, a radiologist's access to this information typically has been limited to viewing workstations designed primarily to support clinical activities. Unfortunately, these workstations often overlook the benefits of PACS in teaching and research applications, which are of significant importance in an academic institution. To support such activities at our own institution, we have included two major objectives in our second-generation PACS development: (1) to provide access to text and image information archived within our PACS in an environment that is easily accessible to and comfortable for our radiologists, namely, their own Macintosh (Apple Computer, Cupertino, CA) personal computers; and (2) to provide this information in standard Macintosh formats, so that tools with which radiologists are already familiar can be used in frequently performed teaching activities--the production of slides and prints, the maintenance of personal teaching and research files, and specialized image analysis and processing.

Digital archive system for radiologic images

Use of a picture archiving and communication system (PACS) for clinical review requires rapid access to patient images. The authors have developed a second-generation archive system for a departmental PACS that optimizes access time for both current and historical images. The system is based on a composite staging mechanism that uses multiple storage media: magnetic disks, erasable magneto-optical disks, and write-once-read-many (WORM) disks. A two-tiered communication network composed of a standard Ethernet network and a gigabit bandwidth fiberoptic UltraNet network is used for distributing images to remote display stations. The system currently archives 1.5 Gbytes of radiologic images daily from three magnetic resonance imagers, two computed tomographic scanners, one computed radiographic system, and one laser film digitizer. The system features (a) multiple optical drives and robotic arms, which support concurrent archival and retrieval operations; (b) a stacking mechanism, which provides fast retrieval of current images; (c) a pre-fetch mechanism, which minimizes on-line image retrieval, hence relieving peak-hour workload of the optical disk library and the networks; (d) studies grouping and platter management, which optimize retrieval of a patient's images from multiple examinations; and (e) a job-prioritizing control, which minimizes waiting time for radiologists and referring physicians to review images at the display stations. This system is suitable for a large-scale PACS to serve the clinical and research staff.

Multimedia in the radiology environment: current concept

Multimedia has different meanings according to its context. Here, multimedia in the radiology environment is defined as the integration of multiple radiology and medical information systems to facilitate the practice of radiology. These information systems include the hospital information system, radiology information system, picture archiving and communication systems, voice reporting, library information systems, and electronic mail and file systems. The concept of multimedia within the context of integration of these database systems will be presented. An example is given on how to access these information systems by a radiologist's desktop personal computer.

O-linked glycosylation modifies the association of apolipoprotein A-II to high density lipoproteins

O-linked glycosylation is a common post-translational modification of apolipoproteins, but no structural or functional role for it has been identified. We examined the biosynthesis of apolipoprotein (apo) A-II in Hep G2 cells and in glycosylation-defective Chinese hamster ovary (CHO) cell mutants transfected with apoA-II cDNA. Three monomeric isoforms of apoA-II with an apparent molecular mass of 8.5, 9.8, and 11.4 kDa were synthesized by Hep G2 cells and transfected wild-type CHO cells. The 9.8- and 11.4-kDa isoforms were sialylated but not the 8.5-kDa isoform. Transfected 1dlD cells, which are defective in the biosynthesis of galactose and N-acetylgalactosamine, only produced the 8.5-kDa isoform; however, when grown in media supplemented with these sugars, ldlD cells produced all three isoforms of apoA-II. Pulse-chase analysis of ldlD cells showed that glycosylation was not necessary for secretion of apoA-II. Glycosylation did modify the association of apoA-II with nascent high density lipoprotein (HDL) secreted by Hep G2 cells. The sialylated isoforms were lipid-poor and were present in the lipoprotein-deficient density range, whereas the nonsialylated 8.5-kDa isoform was associated with LpA-I, A-II lipoprotein particles in the HDL density range. ApoA-II from transfected ldlD cells, regardless of glycosylation, were lipid-poor. When preincubated with HDL from serum, however, sialylated apoA-II from both ldlD cells and Hep G2 cells associated with lipoprotein particles within the HDL3 density, whereas nonsialylated apoA-II was found throughout the HDL density range. In summary, O-linked glycosylation is not necessary for the secretion of apoA-II but does modify the association of apoA-II to HDL and may, therefore, play an important role in the metabolism of HDL.

Implementation of a large-scale picture archiving and communication system

This paper describes the implementation of a large-scale picture archiving and communication system (PACS) in a clinical environment. The system consists of a PACS infrastructure, composed of a PACS controller, a database management system, communication networks, and optical disk archive. It connects to three MR units, four CT scanners, three computed radiography systems, and two laser film digitizers. Seven display stations are on line 24 h/day, 7 days/wk in genitourinary radiology (2K), pediatric radiology in-patient (1K and 2K) and outpatient (2K), neuroradiology (2K), pediatric ICU (1K), coronary care unit (1K), and one laser film printing station. The PACS is integrated with the hospital information system and the radiology information system. The system has been in operation since February 1992. We have integrated this PACS as a clinical component in daily radiology practice. It archives an average of 2.0-gigabyte image data per workday. A 3-mo system performance of various components are tabulated. The deployment of this large-scale PACS signifies a milestone in our PACS research and development effort. Radiologists, fellows, residents, and clinicians use it for case review, conferences, and occasionally for primary diagnosis. With this large-scale PACS in place, it will allow us to investigate the two critical issues raised when PACS research first started 10 yrs ago: system performance and cost effectiveness between a digital-based and a film-based system.

Digital archive center: implementation for a radiology department

OBJECTIVE

In this article, we describe the implementation of a digital archive center for a radiology department in a 700-bed teaching hospital.

MATERIALS AND METHODS

The archive center consists of two identical archive systems, each comprising five components: an archive server, a data-base server, an optical disk library, a stand-alone optical disk drive, and a communication network. An image management system controls the image traffic from acquisition devices to display stations. A fault-tolerant mechanism was built into the archive center to achieve a 100% uptime.

RESULTS

The center has been in operation for over 6 months. We have not experienced a single total system failure during this period. It currently archives all digital images from three MR units and four CT scanners and selected images from three computed radiographic systems and two laser film digitizers. The center archives between 1.5 and 2.0 gigabytes of images per workday.

CONCLUSION

With its built-in fault-tolerant mechanism, we believe that the implemented archive center is very reliable and is suitable for a radiology department to archive its digital images.

Subsystem throughputs of a clinical picture archiving and communications system

We measured the throughtput rates of individual picture archiving and communications system (PACS) subsystems including the acquisition, archive, display, and communication network as a basis of evaluation the overall throughput of our clinical PACS. The throughput rate of each PACS subsystem was measured in terms of average residence time of individual images in the subsystem. The residence time of an image in a PACS subsystem was determined by the total time the image was required to be processed within the subsystem. The overall throughput of the PACS was measured as the total residence time of an image in the various subsystems. We also measured throughputs of the PACS subsystems using three types of networks (Ethernet; fiber distributed data interface; and UltraNet, UltraNetwork Technologies, San Jose, CA), and the results were compared. Approximately 200 gigabytes of data transactions including magnetic resonance, computed tomography and computed radiography images from our PACS were analyzed. Results showed that PACS throughput was limited by three major factors: (1) low-speed data interface used in the radiologic imaging devices and archive devices; (2) competition for systems processing time among the PACS processes; and (3) network degradation caused by heavy network traffic. We concluded that PACS performance could be improved with a well-designed network architecture, a job prioritizing mechanism, and an image routing strategy. However, device-dependent low-speed data interface has limited PACS performance.

Trends in pulmonary embolism death rates for Canada and the United States, 1962-87

To investigate the effect of advances in the prevention and treatment of pulmonary embolism, we examined the rates of death from pulmonary embolism in Canada for 1965-87 and compared them with those for the United States for 1962-84. The direct method of age standardization was used on sex-specific and age-specific death rates, with the 1960 US population as the standard. In both countries the death rates increased then decreased, although the changes in the Canadian rates occurred later and were less pronounced than those in the US rates. Men and elderly people were at higher risk of death from pulmonary embolism than women and younger people. Prevention strategies, possibly including encouraging a more active lifestyle and targetting high-risk groups, may further reduce pulmonary embolism death rates in both countries.

Factors affecting the success of artificial insemination by frozen donor semen

The records of 227 couples who received artificial insemination by frozen donor semen in 984 treatment cycles were analysed to find out the factors affecting the pregnancy rates. The cumulative pregnancy rate at 6 months was 46.8% and the pregnancy rate per cycle was 10%. The pregnancy rates were adversely affected by (1) increase in the recipient age above 30 years, (2) irregularity of menstrual cycles, (3) the use of clomiphene citrate for induction of ovulation, and (4) low cervical mucus scores. Among our donor semen samples selected with a set of criteria, the sperm counts and initial and post-thaw motility did not affect the pregnancy rates.