Nano/microfluidic device for high-throughput passive trapping of nanoparticles

We present a design and a fabrication method for devices designed for rapid collection of nanoparticles in a fluid. The design uses nanofluidic channels as a passive size-based barrier trap to isolate particles near a central point in the channel, which is also covered by a thin membrane. Particles that enter the collection region are trapped with 100% efficiency within a 6-12 μ m radius from a central point. Flow rates for particle-free fluid range from 1.88 to 3.69 nl/s for the pressure and geometries tested. Particle trapping tests show that high trapped particle counts significantly impact flow rates. For suspensions as dilute as 30-300 aM (20-200 particles/μ l), 8-80 particles are captured within 500 s.

Transcranial Magnetic Stimulation in Bipolar II Disorder Treatment: A Case Report

The objective of this case report is to describe and document the use of transcranial magnetic stimulation (TMS) to aid in the treatment of bipolar II disorder. A 35-year-old male with a past medical history of attention-deficit/hyperactivity disorder (ADHD), post-traumatic stress disorder (PTSD), severe depression, and bipolar II disorder was presented to an outpatient psychiatric clinic 1.5 years after his initial TMS treatment for TMS maintenance therapy. He reported feeling depressed, brain fogginess, loss of concentration, fatigue, and constant changes in moods. He had tried multiple antidepressants and antipsychotics, seen several therapists, and underwent electroconvulsive therapy in 2014 with no improvement. In August 2021, he underwent the standard TMS protocol with 36 treatments and noticed significant improvement in his symptoms. He followed up with his psychiatrist who placed him on quetiapine 400 mg, lurasidone 120 mg, topiramate 100 mg, Adderall 20 mg, Wellbutrin 150 mg, propranolol 20 mg, and Klonopin 0.5 mg for management. However, after starting these medications, he noticed a loss of concentration, not being able to think straight, fatigue, depression, and a change in moods. In January 2023, the patient underwent maintenance TMS treatment with theta bursts (TBS). The treatment protocol consisted of 10 sessions for 3 ½ minutes each, 20 trains, 10 bursts, and eight seconds between intervals. He completed his treatment and reported feeling great and like himself again. Two weeks following treatment, he reported that his brain fog had resolved, hypomanic episodes had lessened, and depressive moods had been occurring less often. Due to improvement, topiramate and lurasidone were discontinued and the patient will continue with monthly follow-ups to monitor his progress. TMS appears to be a promising treatment option for bipolar disorder.

Cold Spray: Over 30 Years of Development Toward a Hot Future

Cold Spray (CS) is a deposition process, part of the thermal spray family. In this method, powder particles are accelerated at supersonic speed within a nozzle; impacts against a substrate material triggers a complex process, ultimately leading to consolidation and bonding. CS, in its modern form, has been around for approximately 30 years and has undergone through exciting and unprecedented developmental steps. In this article, we have summarized the key inventions and sub-inventions which pioneered the innovation aspect to the process that is known today, and the key breakthroughs related to the processing of materials CS is currently mastering. CS has not followed a liner path since its invention, but an evolution more similar to a hype cycle: high initial growth of expectations, followed by a decrease in interest and a renewed thrust pushed by a number of demonstrated industrial applications. The process interest is expected to continue (gently) to grow, alongside with further development of equipment and feedstock materials specific for CS processing. A number of current applications have been identified the areas that the process is likely to be the most disruptive in the medium-long term future have been laid down.

Recent advances in integrated solid-state nanopore sensors

The advent of single-molecule probing techniques has revolutionized the biomedical and life science fields and has spurred the development of a new class of labs-on-chip based on powerful biosensors. Nanopores represent one of the most recent and most promising single molecule sensing paradigms that is seeing increased chip-scale integration for improved convenience and performance. Due to their physical structure, nanopores are highly sensitive, require low sample volume, and offer label-free, amplification-free, high-throughput real-time detection and identification of biomolecules. Over the last 25 years, nanopores have been extensively employed to detect a variety of biomolecules with a growing range of applicatons ranging from nucleic acid sequencing to ultrasensitive diagnostics to single-molecule biophysics. Nanopores, in particular those in solid-state membranes, also have the potential for integration with other technologies such as optics, plasmonics, microfluidics, and optofluidics to perform more complex tasks for an ever-expanding demand. A number of breakthrough results using integrated nanopore platforms have already been reported, and more can be expected as nanopores remain the focus of innovative research and are finding their way into commercial instruments. This review provides an overview of different aspects and challenges of nanopore technology with a focus on chip-scale integration of solid-state nanopores for biosensing and bioanalytical applications.

Solid-state membranes formed on natural menisci

We present a method to create robust, nanoscale solid-state membranes using the natural shape of a liquid meniscus as a template. A narrow, open channel is etched into a silicon substrate and then a photoresist polymer is introduced into the channel through spontaneous capillary action. The natural concave meniscus formed by the polymer is then covered by a thin chemical vapor deposited membrane. The polymer is removed by sacrificial etching, leaving behind a suspended membrane. Membranes as large as 20 μm by 9 mm can be fabricated with a thickness as low as 50 nm.

Society of pediatric liver transplantation: Current registry status 2011-2018

BACKGROUND

SPLIT was founded in 1995 in order to collect comprehensive prospective data on pediatric liver transplantation, including waiting list data, transplant, and early and late outcomes. Since 2011, data collection of the current registry has been refined to focus on prospective data and outcomes only after transplant to serve as a foundation for the future development of targeted clinical studies.

OBJECTIVE

To report the outcomes of the SPLIT registry from 2011 to 2018.

METHODS

This is a multicenter, cross-sectional analysis characterizing patients transplanted and enrolled in the SPLIT registry between 2011 and 2018. All patients, <18 years of age, received a first liver-only, a combined liver-kidney, or a combined liver-pancreas transplant during this study period.

RESULTS

A total of 1911 recipients from 39 participating centers in North America were registered. Indications included biliary atresia (38.5%), metabolic disease (19.1%), tumors (11.7%), and fulminant liver failure (11.5%). Greater than 50% of recipients were transplanted as either Status 1A/1B or with a MELD/PELD exception score. Incompatible transplants were performed in 4.1%. Kaplan-Meier estimates of 1-year patient and graft survival were 97.3% and 96.6%. First 30 days of surgical complications included reoperation (31.7%), hepatic artery thrombosis (6.3%), and portal vein thrombosis (3.2%). In the first 90 days, biliary tract complications were reported in 13.6%. Acute cellular rejection during first year was 34.7%. At 1 and 2 years of follow-up, 39.2% and 50.6% had normal liver tests on monotherapy (tacrolimus or sirolimus). Further surgical, survival, allograft function, and complications are detailed.

Characterizing grassland fire activity in the Flint Hills region and air quality using satellite and routine surface monitor data

Prescribed grassland fires in the Flint Hills region of central Kansas and northern Oklahoma are a common tool for land management. Local to regional scale impacts on air quality from grassland fires in this region are not well understood, which is important as these types of prescribed fires may increase in the future to preserve broader areas of native grasses in the central U.S. Routine air quality and deposition measurements from sites in and near the Flint Hills were examined for coincident increases during periods of increased prescribed grassland fires. Prescribed fire activity in this region was quantified using satellite detections and multiple publicly available data products of area burned information. March and April comprise over half (41 to 93%) of all annual fire detections in the Flint Hills region seen from satellites between 2007 and 2018 excluding drought years. Annual total fire detections in this region range between 1 and 12 thousand and account for approximately 3% of all fire detections in the contiguous U.S. Annual acres burned ranged from 0.2 to 2 million acres based on U.S. EPA's National Emission Inventory, which accounts for 4 to 38% of grasslands in the area. A comparison of weekly standardized anomalies suggests a relationship between periods of increased grassland fire activity and elevated levels of PM_2.5 organic carbon, elemental carbon, and potassium. Daily 1-hr maximum ozone (O₃), ammonia (NH₃), sulfur dioxide (SO₂), and oxidized nitrogen gases measured at Konza Prairie also had increased levels when prescribed grassland fire activity was highest. This detailed characterization of prescribed fire activity in the Flint Hills and associated air quality impacts will benefit future efforts to understand changes in atmospheric composition due to changing land management practices.

Antireflective light-blocking layers using a liquid top matte coating

Methods exist for the creation of antireflective thin film layers; however, many of these methods depend on the use of high temperatures, harsh chemical etches, or are made with difficult pattern materials, rendering them unusable for many applications. In addition, most methods of light blocking are specifically designed to increase light coupling and absorption in the substrate, making them incompatible with some appli-cations that also require blocking transmission of light. A method of forming a simple, patternable light-blocking layer that drastically reduces both transmission and reflection of light without dependence on processes that could damage underlying structures using a light scattering matte coating over a partially antireflective thin film light-blocking layer is presented.

Scalable Spatial-Spectral Multiplexing of Single-Virus Detection Using Multimode Interference Waveguides

Simultaneous detection of multiple pathogens and samples (multiplexing) is one of the key requirements for diagnostic tests in order to enable fast, accurate and differentiated diagnoses. Here, we introduce a novel, highly scalable, photonic approach to multiplex analysis with single virus sensitivity. A solid-core multimode interference (MMI) waveguide crosses multiple fluidic waveguide channels on an optofluidic chip to create multi-spot excitation patterns that depend on both the wavelength and location of the channel along the length of the MMI waveguide. In this way, joint spectral and spatial multiplexing is implemented that encodes both spatial and spectral information in the time dependent fluorescence signal. We demonstrate this principle by using two excitation wavelengths and three fluidic channels to implement a 6x multiplex assay with single virus sensitivity. High fidelity detection and identification of six different viruses from a standard influenza panel is reported. This multimodal multiplexing strategy scales favorably to large numbers of targets or large numbers of clinical samples. Further, since single particles are detected unbound in flow, the technique can be broadly applied to direct detection of any fluorescent target, including nucleic acids and proteins.

Risk and protective factors for falls on stairs in young children: multicentre case-control study

AIM

To investigate risk and protective factors for stair falls in children aged <5 years.

METHODS

Multicentre case-control study at hospitals, minor injury units and general practices in and around four UK study centres. Cases were children with medically attended stair fall injuries. Controls were matched on age, sex, calendar time and study centre. A total of 610 cases and 2658 controls participated.

RESULTS

Cases' most common injuries were bangs on the head (66%), cuts/grazes not requiring stitches (14%) and fractures (12%). Parents of cases were significantly more likely not to have stair gates (adjusted OR (AOR) 2.50, 95% CI 1.90 to 3.29; population attributable fraction (PAF) 21%) or to leave stair gates open (AOR 3.09, 95% CI 2.39 to 4.00; PAF 24%) both compared with having closed stair gates. They were more likely not to have carpeted stairs (AOR 1.52, 95% CI 1.09 to 2.10; PAF 5%) and not to have a landing part-way up their stairs (AOR 1.34, 95% CI 1.08 to 1.65; PAF 18%). They were more likely to consider their stairs unsafe to use (AOR 1.46, 95% CI 1.07 to 1.99; PAF 5%) or to be in need of repair (AOR 1.71, 95% CI 1.16 to 2.50; PAF 5%).

CONCLUSION

Structural factors including having landings part-way up the stairs and keeping stairs in good repair were associated with reduced stair fall injury risk. Family factors including having stair gates, not leaving gates open and having stair carpets were associated with reduced injury risk. If these associations are causal, addressing these factors in housing policy and routine child health promotion could reduce stair fall injuries.

Use of high-fidelity simulation to improve communication skills regarding death and dying: a qualitative study

OBJECTIVES

The objectives of this study were to explore medical students' experiences of communicating with patients and their carers about death and dying, and to assess whether using high-fidelity simulation improved students' confidence in discussing cardiopulmonary resuscitation.

METHODS

This qualitative study was carried out at a hospital in the south of England. Participants were 7 final-year medical students. Tutorials were developed using high-fidelity simulation to teach communication skills regarding discussion of cardiopulmonary resuscitation with patients and carers. Scenarios involved a simulated ward environment, a high-fidelity simulation mannequin and actor playing the role of a carer. Data were collected through joint interviews carried out by one researcher which were audio recorded and transcribed verbatim. The same researcher analysed the data using framework analysis.

RESULTS

Students reported a lack of experience observing conversations with patients and carers about death and dying. They also reported a lack of opportunities to interact with dying patients during their training. Barriers reported by students included healthcare professionals' and patients' attitudes. Students reported a lack of confidence and preparedness to have consultations with patients and carers about death, dying and cardiopulmonary resuscitation as junior doctors. They perceived role-play scenarios observed by their peers to be stressful, and this detracted from the learning experience. Students reported that the high-fidelity simulation scenarios were more realistic than low-fidelity ('role-play') scenarios. This improved the learning gained from the sessions and improved confidence among some students.

CONCLUSIONS

This study has suggested that high-fidelity simulation may be a useful adjunct for undergraduate communication skills training in palliative medicine. Further research is required to assess whether improvements in confidence described by students in this study translate to discernible improvements in competence, and whether using high-fidelity simulation in this setting is cost-effective.

Perforated hollow-core optical waveguides for on-chip atomic spectroscopy and gas sensing

A hollow-core waveguide structure for on-chip atomic spectroscopy is presented. The devices are based on Anti-Resonant Reflecting Optical Waveguides and may be used for a wide variety of applications which rely on the interaction of light with gases and vapors. The designs presented here feature short delivery paths of the atomic vapor into the hollow waveguide. They also have excellent environmental stability by incorporating buried solid-core waveguides to deliver light to the hollow cores. Completed chips were packaged with an Rb source and the F = 3 ≥ F' = 2, 3, 4 transitions of the D2 line in ⁸⁵Rb were monitored for optical absorption. Maximum absorption peak depths of 9% were measured.

Brain natriuretic peptide and NT-proBNP levels reflect pulmonary artery systolic pressure in trekkers at high altitude

Our objective was to evaluate the utility of the natriuretic peptides BNP (brain natriuretic peptide) and NT-proBNP as markers of pulmonary artery systolic pressure (PASP) in trekkers ascending to high altitude (HA). 20 participants had BNP and NT-proBNP assayed and simultaneous echocardiographic assessment of PASP performed during a trek to 5150 m. PASP increased significantly (p=0.006) with ascent from 24+/-4 to 39+/-11 mm Hg at 5150 m. At 5150 m those with a PASP>/=40 mm Hg (n=8) (versus those with PASP<40 mm Hg) had higher post-exercise BNP (pg/ml): 54.5+/-36 vs. 13.4+/-17 (p=0.012). Their resting BNP at 5150 m was also higher: 57.3+/-43.4 vs. 12.6+/-13 (p=0.017). In those with a pathological (>/=400 pg/ml) rise in NT-proBNP at 5150 m (n=4) PASP was significantly higher: 45.9+/-7.5 vs. 32.2+/-6.2 mm Hg (p=0.015). BNP and NT-proBNP may reflect elevated PASP, a central feature of high altitude pulmonary oedema, at HA.

Reducing the cost of dietary assessment: self-completed recall and analysis of nutrition for use with children (SCRAN24)

BACKGROUND

Self-Completed Recall and Analysis of Nutrition (scran24) is a prototype computerised 24-h recall system for use with 11-16 year olds. It is based on the Multiple Pass 24-h Recall method and includes prompts and checks throughout the system for forgotten food items.

METHODS AND RESULTS

The development of scran24 was informed by an extensive literature review, a series of focus groups and usability testing. The first stage of the recall is a quick list where the user is asked to input all the foods and drinks they remember consuming the previous day. The quick list is structured into meals and snacks. Once the quick list is complete, additional information is collected on each food to determine food type and to obtain an estimate of portion size using digital images of food. Foods are located within the system using a free text search, which is linked to the information entered into the quick list. A time is assigned to each eating occasion using drag and drop onto a timeline. The system prompts the user if no foods or drinks have been consumed within a 3-h time frame, or if fewer than three drinks have been consumed throughout the day. The food composition code and weight (g) of all items selected are automatically allocated and stored. Nutritional information can be generated automatically via the scran24 companion Access database.

CONCLUSIONS

scran24 was very well received by young people and was relatively quick to complete. The accuracy and precision was close to that of similar computer-based systems currently used in dietary studies.

Severe acute mountain sickness, brain natriuretic peptide and NT-proBNP in humans

AIM

To examine the response of brain natriuretic peptide (BNP) and NT-proBNP to high altitude (HA) both at rest and following exercise.

METHODS

We measured NT-proBNP and BNP and Lake Louise (LL) acute mountain sickness (AMS) scores in 20 subjects at rest in Kathmandu (Kat; 1300 m), following exercise and at rest at 4270 and 5150 m.

RESULTS

BNP and NT-proBNP (pg ml(-1) , mean ± SEM) rose significantly from Kat (9.2 ± 2 and 36.9 ± 6.6, respectively) to arrival at 4270 m after exercise (16.6 ± 4 and 152 ± 56.1, P=0.008 and P<0.001, respectively) and remained elevated the next morning at rest (28.9 ± 9 and 207.4 ± 65.1, P = 0.004 and P<0.001 respectively). At 5150, immediately following ascent/descent to 5643 m, BNP and NT-proBNP were 32.3 ± 8.8 and 301.1 ± 96.3 (P=0.003 and P<0.001 vs. Kat, respectively) and at rest the following morning were 33.3 ± 9.7 and 258.9 ± 89.5 (P=0.008 and P=0.001 vs. Kat respectively). NT-proBNP and BNP correlated strongly at 5150 m (ρ 0.905, P<0.001 and ρ 0.914, P<0.001 for resting and post-exercise samples respectively). At 5150 m, BNP levels were significantly higher among the four subjects with severe (LL score>6) AMS (58.4 ± 18.7) compared with those without (BNP 22.7 ± 8.6, P=0.048). There were significant correlations between change in body water from baseline to 5150 m with both BNP and NT-proBNP (ρ 0.77, P=0.001, ρ 0.745, P=0.002 respectively).

CONCLUSION

In conclusion, these data suggest that BNP and NT-proBNP increase with ascent to HA both after exercise and at rest. We also report the novel finding that BNP is significantly greater in those with severe AMS at 5150 m.

Optimized piranha etching process for SU8-based MEMS and MOEMS construction

We demonstrate the optimization of the concentration, temperature and cycling of a piranha (H(2)O(2):H(2)SO(4)) mixture that produces high yields while quickly etching hollow structures made using a highly crosslinked SU8 polymer sacrificial core. The effects of the piranha mixture on the thickness, refractive index and roughness of common micro-electromechanical systems and micro-opto-electromechanical systems fabrication materials (SiN, SiO(2) and Si) were determined. The effectiveness of the optimal piranha mixture was demonstrated in the construction of hollow anti-resonant reflecting optical waveguides.

Modelling for scanning impedance imaging

Scanning electrical impedance imaging (SII) is a previously-introduced high resolution imaging modality with the potential of imaging the electrical activities of biological tissues. In this paper, a detailed complex electrostatic model is derived to describe the physical phenomena of the SII system. This model reveals the relationship between the voltage measurement and impedance distribution and also shows how system parameters such as height affect the resolution of the impedance image. A numerical solution is developed for this model based on the finite difference method (FDM). A variation of classical FDM is used to solve the complicated boundary conditions introduced by the combination of the electrostatic field and the peripheral circuit. Good correspondence can be observed when comparing the model simulation with experimental data acquired during a line-scan. It can be seen that the model provides a good explanation for the experimental results and can assist in the design of the special dual-conductor impedance probe used in the SII system. A two-source improvement for the SII system which is motivated by the modelling work is implemented and the corresponding physical analysis is obtained. It can help the reduction of the current contribution from the shield to the tip so that higher resolution can be achieved.

Non-contact scanning electrical impedance imaging

We are interested in applying electrical impedance imaging to a single cell because it has potential to reveal both cell anatomy and cell function. Unfortunately, classic impedance imaging techniques are not applicable to this small scale measurement due to their low resolution. In this paper, a different method of impedance imaging is developed based on a non-contact scanning system. In this system, the imaging sample is immersed in an aqueous solution allowing for the use of various probe designs. Among those designs, we discuss a novel shield-probe design that has the advantage of better signal-to-noise ratio with higher resolution compared to other probes. Images showing the magnitude of current for each scanned point were obtained using this configuration. A low-frequency linear physical model helps to relate the current to the conductivity at each point. Line-scan data of high impedance contrast structures can be shown to be a good fit to this model. The first two-dimensional impedance image of biological tissues generated by this technique is shown with resolution on the order of 100 mum. The image reveals details not present in the optical image.

Noncontact scanning electrical impedance imaging

We are interested in applying electrical impedance imaging to a single cell because it has potential to reveal both cell anatomy and cell function. Unfortunately, classic impedance imaging techniques are not applicable to this small scale measurement due to their low resolution. In this paper, a different method of impedance imaging is developed based on a noncontact scanning system. In this system, the imaging sample is immersed in an aqueous solution allowing for the use of various probe designs. Among those designs, we discuss a novel shield-probe design that has the advantage of better signal-to-noise ratio with higher resolution compared to other probes. Images showing the magnitude of current for each scanned point were obtained using this configuration. A low-frequency linear physical model helps to relate the current to the conductivity at each point. Line-scan data of high impedance contrast structures can be shown to be a good fit to this model. The first two-dimensional impedance image of biological tissues generated by this technique is shown with resolution on the order of 100 mum. The image reveals details not present in the optical image.

Waveguide loss optimization in hollow-core ARROW waveguides

We discuss optimization of the optical properties of hollow-core antiresonant reflecting optical waveguides (ARROWs). We demonstrate significant reduction of waveguide loss to 2.6/cm for a 10.4microm(2) mode area after adding an initial etching step of the substrate material. The effect of differences in confinement layer thickness is quantified and an optimized design is presented. The polarization dependence of the waveguide loss is measured and the implications for applications are discussed.

Surface structure silicon based impact-ionization multiplier for optical detection

This paper presents an innovative solid-state current amplifier based on impact ionization. The operation principle, fabrication, and test results for this device are reported. This amplifier was built on a silicon surface using standard microelectronics processes including ion implantation. Testing was performed by connecting the device to both silicon and indium-gallium-arsenide photodiodes to demonstrate its compatibility with arbitrary current sources. Current gains above 100 along with pre-amplified leakage currents of less than 10 nA were measured.

Improvement to reflective dielectric film color pictures

This paper presents methods used to improve reflective dielectric film color pictures. These changes include improvements in color purity, increased brightness, and elimination of any light absorption within the film layers. The color picture is fabricated by varying the silicon dioxide film thicknesses across a silicon wafer and coating the entire wafer with a thin layer of silicon nitride. In addition to the demonstration of fabricated color pictures, we also present more detailed calculation of basis colors and provide details of the fabrication process.

Integrated ARROW waveguides with hollow cores

We report the design, fabrication, and demonstration of antiresonant reflecting optical (ARROW) waveguides with hollow cores. We describe the design principles to achieve low waveguide loss in both transverse and lateral directions. A novel fabrication process using silicon dioxide and silicon nitride layers as well as sacrificial polyimide core layers was developed. Optical characterization of 3.5mum thick waveguides with air cores was carried out. We demonstrate single-mode propagation through these hollow ARROW waveguides with propagation loss as low as 6.5cm-1 and mode cross sections down to 6.7mum2. Applications of these waveguides to sensing and quantum communication are discussed.

Electronic color charts for dielectric films on silicon

This paper presents the calculation of the perceived color of dielectric films on silicon. A procedure is shown for computing the perceived color for an arbitrary light source, light incident angle, and film thickness. The calculated color is converted into RGB parameters that can be displayed on a color monitor, resulting in the generation of electronic color charts for dielectric films. This paper shows generated electronic color charts for both silicon dioxide and silicon nitride films on silicon.

A distinctive pediatric renal neoplasm characterized by epithelioid morphology, basement membrane production, focal HMB45 immunoreactivity, and t(6;11)(p21.1;q12) chromosome translocation

We report two cases of a hitherto undescribed pediatric renal neoplasm that is distinctive at the morphological, immunohistochemical, ultrastructural, and cytogenetic levels. On light microscopy, the tumors are composed of nests of polygonal, clear to eosinophilic cells associated with a subpopulation of smaller cells that surround hyaline material. Despite their epithelioid morphology, these tumors do not label immunohistochemically for epithelial markers but instead label focally for melanocytic markers HMB45 and Melan A. The hyaline material is positive with periodic acid-Schiff and methenamine-silver histochemical stains, and labels immunohistochemically for type 4 collagen. Ultrastructural examination confirms that it represents basement membrane material. Cytogenetic analysis reveals the identical t(6;11)(p21.1;q12) chromosome translocation as the sole abnormality in these two tumors, confirming their identity and distinctive nature.

Comparison of contrast sensitivity, visual acuity, and Humphrey visual field testing in patients with glaucoma

PURPOSE

To investigate the relationship between large-letter contrast sensitivity, high-contrast visual acuity, and visual field defects in patients with glaucoma.

METHODS

Patients with a diagnosis of glaucoma, glaucoma suspect, or ocular hypertension whose visual acuity was 20/40 (logMAR = 0.3) on better were included in the study. Visual acuity was measured using the Lighthouse visual acuity charts. Contrast sensitivity was measured using the Pell-Robson (PR) chart. The mean depression (MD) score from the most recent Humphrey visual field was used to quantify the visual field defect.

RESULTS

A total of 120 eyes were studied. The PR contrast sensitivity score correlated more strongly with the MD of the visual field (r = .589, P < .001) than did the logMAR visual acuity (r = .193, P = .035). When just the eyes with open-angle glaucoma were considered (N = 54), the correlation was even greater for the PR score (r = .638). In ocular hypertensive eyes (N = 25), the correlations to PR and logMAR were not that different (r = .394 for PR, r = .303 for logMAR). Pseudophakic eyes did not show as strong a correlation (r = .335) as did phakic eyes (r = .591).

CONCLUSION

For glaucomatous eyes with visual acuity of 20/40 or better, a decrease in the contrast sensitivity correlates with increased visual field loss. We speculate that this decrease in contrast sensitivity in glaucoma patients may account for their complaints of poor vision despite normal or near normal visual acuity.

Pathology in the Hundred Acre Wood: a neurodevelopmental perspective on A.A. Milne

Abstract

Somewhere at the top of the Hundred Acre Wood a little boy and his bear play. On the surface it is an innocent world, but on closer examination by our group of experts we find a forest where neurodevelopmental and psychosocial problems go unrecognized and untreated.

Trochanteric non-union in revision total hip arthroplasty: does it matter?

The aims of this study were to assess whether trochanteric non-union is an important factor in revision total hip arthroplasty in terms of postoperative morbidity. We studied prospectively 97 consecutive patients undergoing revision total hip arthroplasty in the years 1992-1996. All operations were performed by one surgeon through a Charnley trans-trochanteric approach. The patients were followed-up over a period of 1-4 years and at 12 months postsurgery were assessed using a modified scoring system devised by D'Aubigne. Anatomical union of the greater trochanter was assessed by an anterior-posterior pelvic radiograph at 12 months to decide if the greater trochanter was united in the correct anatomical position. The trochanteric non-union rate was 18.5% (18 out of 97 patients). There was no significant difference between the patients in terms of pain, function and satisfaction scores at one year between those with trochanteric union and those without. This study suggests that trochanteric non-union post revision total hip arthroplasty is not a cause of increased morbidity.

Health care coverage of high school athletics in South Carolina: does school size make a difference?

Despite an apparently high injury rate, medical coverage available to these high school athletes is often not immediately present during practice and games. The purpose of the present study was to examine the current conditions of health care coverage and delivery to the football program and associated athletic departments in the public and private high schools in South Carolina. Additionally, the relationship between student enrollment and medical coverage was examined. A survey, based upon previously utilized instruments, was sent to the athletic directors at the public and private high schools with interscholastic football programs in South Carolina. The survey included questions pertaining to the medical coverage, including personnel, equipment, and record systems, for football practices and games. Based upon the results of the survey, a majority of high schools in South Carolina appear to have adequate sports medicine coverage and compare favorably with the results of similar data from other states. The medical coverage does significantly vary depending upon the enrollment size of the high school. In spite of this finding, the health care provided high school athletes is often inconsistent and training and equipment required for basic first aid is often absent.

Genotype dependence of hepatitis C virus load measurement in commercially available quantitative assays

Standardization and genotype independence of methods used to quantify hepatitis C virus (HCV) RNA in clinical specimens are necessary for accurate assessment of the role of HCV quantitation as a prognostic marker for HCV infection and monitoring of the response to antiviral treatment. Commercially available methods used to measure HCV loads include PCR-based (Roche Monitor) and hybridization-based (Quantiplex bDNA-2) methods. Recently, a new version of the Roche Monitor assay (version 2.0) has become available; it has been modified to achieve more equal quantitation of different HCV genotypes. Consistent with previous reports, Roche Monitor version 1.0 substantially underestimated concentrations of RNA transcripts of types 2b, 3a, 4a, 5a, and 6a and virus loads in individuals infected with genotypes 2 to 6 relative to reference tests. However, version 2.0 achieved equivalent quantitation of each genotype over a narrow quantitative range (10(3) to 5 x 10(5) copies of RNA/ml) but significantly underestimated RNA concentrations above this range. The assay showed an equivalent inability to quantify high levels of HCV RNA in plasma samples, and this was responsible for the falsely narrow range of virus loads detected in HCV-infected individuals. In contrast, the Chiron bDNA-2 assay could only measure RNA concentrations in the upper quantitative range (2 x 10(5) to 5 x 10(7) copies of RNA/ml) but showed equivalent sensitivity for genotypes 1 to 5; however, concentrations of type 6a RNA transcripts and virus loads in clinical specimens from individuals infected with type 6a were underestimated by a factor of 2 to 4. Differences were observed between PCR- and hybridization-based assays in their relative quantitation of HCV RNA transcripts and HCV genomic RNA, which may cause problems with the use of transcripts for interassay calibration.

An evaluation of the nurse practitioner role in a major rural emergency department

The purpose of this pilot study was to investigate whether nurse practitioners are able to provide a level of primary health service applicable to remote/isolated settings in wound management and treatment of blunt limb trauma. It was hypothesized that there would be no significant difference in the quality of care, or the level of client satisfaction, provided by the medical officers and the nurse practitioners in the study. Two groups participated in the study, nurse practitioners and medical officers. The study used a randomized trial design. Data were collected using quantitative and qualitative methods. Two hundred and thirty-two clients participated in the study. Of this number 63 were supervised cases in the pilot trial. In the randomized trial participants were distributed between nurse practitioners and medical officers (n = 169), of which 91 were randomized to medical officers and 78 to nurse practitioners. Telephone interviews were conducted to evaluate client satisfaction. The majority of study participants were surveyed for client satisfaction (n = 132). This represents approximately 78% of the randomized sample and multivariate analysis was carried out on the data. Study results indicate that there were no significant differences between the two groups in relation to client satisfaction. Very positive outcomes of treatment were consistent across groups in the study. The study also found that there was strong support for the role of the nurse practitioner in the rural emergency setting. Recommendations include further research to measure the efficacy of nurse practitioners utilizing the selected competencies in remote/isolated settings.

cDNA cloning, in vitro expression, and biochemical characterization of cholinesterase 1 and cholinesterase 2 from amphioxus--comparison with cholinesterase 1 and cholinesterase 2 produced in vivo

We have isolated cDNAs coding for the complete amino acid sequences of cholinesterase 1 (ChE1) and cholinesterase 2 (ChE2) from amphioxus. Both ChE transcripts have the characteristics of H-type catalytic subunits, which are inserted in the membrane via an ethanolamine-glycan-phosphatidylinositol anchor. The members of the catalytic triad of ChEs, the three pairs of cysteine residues involved in intrachain disulfide bonding, a cysteine near the carboxy terminal of both sequences, which could mediate interchain disulfide bonding, and 11 of the 14 aromatic amino acids that line the catalytic gorge of AChE are conserved. A remarkable difference between the two enzymes is in the region of the acyl-binding pocket, which plays an important role in determining substrate specificity in cholinesterases. ChE2 contains a sequence that resembles the acyl pocket of invertebrate ChE, while the acyl-binding site of ChE1 is novel. There are also differences between the two enzymes in the peripheral anionic site, which mediates inhibition by certain ligands. In vitro expression in COS-7 cells demonstrates that ChE2 hydrolyzes acetylthiocholine almost exclusively, while ChE1 hydrolyzes both acetylthiocholine and butyrylthiocholine. Both enzymes are inhibited comparably by BW284c51, but ChE1 is considerably more resistant to inhibition by propidium, ethopropazine, and eserine than is ChE2. Velocity sedimentation indicates that ChE1 and ChE2 are present as amphiphilic and nonamphiphilic G2 forms in vivo and in vitro. Another molecular form, which sediments at 17 S, is also present in vivo. Nondenaturing gel electrophoresis in conjunction with digestion by phosphatidylinositol-specific phospholipase C demonstrates that the vast majority of ChE1 and ChE2 is present as ethanolamine-glycan-phosphatidylinositol-anchored G2 forms in vivo. ChE1 also possesses an ethanolamine-glycan-phosphatidylinositol-anchor in vitro; however, ChE2 produced in vitro could not be detected on nondenaturing gels.

Rupture of pectoralis major during parallel bar dips: case report and review

Rupture of the pectoralis major muscle is an uncommon athletic injury that can result in both functional and cosmetic deficiency. To date, most ruptures occurring in athletes have occurred while performing bench press or overhead lifting maneuvers. We describe a case of a pectoralis major rupture occurring while performing weighted parallel bar dips. Despite the popularity of this exercise, injuries associated with this exercise are infrequently reported. This injury can be easily detected by having the patient perform specific maneuvers on physical examination to accentuate any defect that may be present. In most cases, this injury is surgically repaired, although conservative treatment can be a successful option. Treatment options are discussed and recommendations given. A partial or complete tear of the pectoralis major muscle is a rare event and is often not easily detected on physical examination. Surgical repair is currently recommended to restore previous levels of strength and to correct the resulting cosmetic defect. Repair is rarely necessary to perform the normal activities of daily living.

The effect of treatment with alpha-interferon on hepatitis G/GBV-C viraemia. The CONSTRUCT Group

BACKGROUND

Hepatitis G virus (HGV) or GBV-C is frequently detected in patients co-infected with hepatitis C virus (HCV). This study investigated host and virologic factors influencing the response to HGV/GBV-C to alpha-interferon treatment.

METHODS

HGV/GBV-C was detected and quantified by nested polymerase chain reaction. The influence of variables such as liver biopsy appearance, liver function abnormalities, and response of HCV to interferon treatment was monitored.

RESULTS

Fourteen of the 25 HGV/GBV-C-infected patients treated with interferon (3-6 MIU three times a week for 6 months) became non-viraemic during treatment, although all relapsed after treatment withdrawal at 6 months, with no net change in virus load between 0 and 12 months.

CONCLUSIONS

Predictive factors for clearance of HGV/GBV-C viraemia by interferon were pre-treatment severity of liver disease (median Knodell score of 4, compared with 7 for non-responders; P = 0.030) and alanine aminotransferase levels (median, 114, 182 for non-responders; P = 0.039). Clearance was associated with the treatment response of HCV. Nine of 13 who cleared HGV/GBV-C also cleared HCV, compared with 3 of 11 HGV/GBV-C non-responders; P = 0.05). The shared susceptibility of HGV/GBV-C and HCV to interferon treatment suggests a link between the mechanism of clearance of the two viruses.