Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

Bile duct clearance and cholecystectomy for choledocholithiasis: Definitive single-stage laparoscopic cholecystectomy with intraoperative endoscopic retrograde cholangiopancreatography versus staged procedures

BACKGROUND

Clinical equipoise exists regarding optimal sequencing in the definitive management of choledocholithiasis. Our current study compares sequential biliary ductal clearance and cholecystectomy at an interval to simultaneous laparoendoscopic management on index admission in a pragmatic retrospective manner.

METHODS

Records were reviewed for all patients admitted between January 2015 and December 2018 to a Swedish and an Irish university hospital. Both hospitals differ in their practice patterns for definitive management of choledocholithiasis. At the Swedish hospital, patients with choledocholithiasis underwent laparoscopic cholecystectomy with intraoperative rendezvous endoscopic retrograde cholangiopancreatography (ERCP) at index admission (one stage). In contrast, interval day-case laparoscopic cholecystectomy followed index admission ERCP (two stages) at the Irish hospital. Clinical characteristics, postprocedural complications, and inpatient duration were compared between cohorts.

RESULTS

Three hundred fifty-seven patients underwent treatment for choledocholithiasis during the study period, of whom 222 (62.2%) underwent a one-stage procedure in Sweden, while 135 (37.8%) underwent treatment in two stages in Ireland. Patients in both cohorts were closely matched in terms of age, sex, and preoperative serum total bilirubin. Patients in the one-stage group exhibited a greater inflammatory reaction on index admission (peak C-reactive protein, 136 ± 137 vs. 95 ± 102 mg/L; p = 0.024), had higher incidence of comorbidities (age-adjusted Charlson Comorbidity Index, ≥3; 37.8% vs. 20.0%; p = 0.003), and overall were less fit for surgery (American Society of Anesthesiologists, ≥3; 11.7% vs. 3.7%; p < 0.001). Despite this, a significantly shorter mean time to definitive treatment, that is, cholecystectomy (3.1 ± 2.5 vs. 40.3 ± 127 days, p = 0.017), without excess morbidity, was seen in the one-stage compared with the two-stage cohort. Patients in the one-stage cohort experienced shorter mean postprocedure length of stay (3.0 ± 4.7 vs. 5.0 ± 4.6 days, p < 0.001) and total length of hospital stay (6.5 ± 4.6 vs. 9.0 ± 7.3 days, p = 0.002). The only significant difference in postoperative complications between the cohorts was urinary retention, with a higher incidence in the one-stage cohort (19% vs. 1%, p = 0.004).

CONCLUSION

Where appropriate expertise and logistics exist within developing models of acute care surgery worldwide, consideration should be given to index-admission laparoscopic cholecystectomy with intraoperative ERCP for the treatment of choledocholithiasis. Our data suggest that this strategy significantly shortens the time to definitive treatment and decreases total hospital stay without any excess in adverse outcomes.

LEVEL OF EVIDENCE

Therapeutic/Care Management Level IV.

Does instillation of lidocaine gel following flexible cystoscopy decrease the severity of post procedure symptoms? A randomised controlled trial assessing the efficacy of lidocaine gel post flexible cystoscopy

Objective

To assess whether instillation of lidocaine gel both before and after flexible cystoscopy is more effective at reducing post procedural symptoms than instillation of lidocaine gel pre flexible cystoscopy alone. We hypothesise that inadequate urethral dwell time and dilution of lidocaine gel by the irrigation fluid during flexible cystoscopy limits its anaesthetic efficacy. Only one other study has attempted to reduce bothersome urinary symptoms through an intervention after flexible cystoscopy.

Methods

This was a randomised controlled trial in which patients were randomised 1:1 to receive lidocaine gel pre and post flexible cystoscopy (treatment) or lidocaine gel pre flexible cystoscopy only (control). Patient-reported outcome measures were used to assess symptoms and quality of life prior to cystoscopy, on day 2 and day 7 post cystoscopy.

Result

Fifty patients were divided equally between the treatment and control groups. There were no significant differences in baseline characteristics between the groups (p = 1.000). An overall symptoms variable was measured, though no significant difference was found in the distribution of responses between the groups at baseline, 2 or 7 days after the flexible cystoscopy (p = 0.423, 0.651,0.735). In the treatment group, 1 patient (4.0%) presented to a doctor for review following flexible cystoscopy, and 4 patients (16.0%) presented in the control group (p = 0.349).

Conclusion

Initial study results suggest that post-operative lidocaine does not significantly limit the exacerbation of urinary symptoms following flexible cystoscopy; however, our results are not powered to detect a small difference. We do not recommend a change in practice based on our results.

Obstructive Sleep Apnea in Obese Patients: a UK Population Analysis

Background

Obstructive sleep apnea (OSA) is an increasingly common disorder associated with increased cardiovascular disease, mortality, reduced productivity, and an increased risk of road traffic accidents. A significant proportion of patients with OSA in the UK are undiagnosed. This study aims to identify risk factors for OSA in an obese cohort.

Method

A population-based study was conducted of obese patients (BMI ≥ 30 kg/m²) from the Clinical Practice Research Datalink (CPRD). A logistic regression model was used to calculate odds ratios (ORs) for developing OSA according to other clinicopathological characteristics. Multivariate analysis was conducted of individual factors that affect the propensity to develop OSA. Statistical significance was defined as p < 0.050.

Results

From 276,600 obese patients identified during a data extraction of the CPRD in July 2017, the prevalence of OSA was 5.4%. The following risk factors were found to be independently associated with increased likelihood of OSA: male sex (OR = 3.273; p < 0.001), BMI class II (OR = 1.640; p < 0.001), BMI class III (OR = 3.768; p < 0.001), smoking (OR = 1.179; p < 0.001), COPD (OR = 1.722; p < 0.001), GERD (OR = 1.557; p < 0.001), hypothyroidism (OR = 1.311; p < 0.001), acromegaly (OR = 3.543; p < 0.001), and benzodiazepine use (OR = 1.492; p < 0.001). Bariatric surgery was associated with reduced risk of OSA amongst this obese population (OR = 0.260; p < 0.001).

Conclusions

In obese patients, there are numerous comorbidities that are associated with increased likelihood of OSA. These factors can help prompt clinicians to identify undiagnosed OSA. Bariatric surgery appears to be protective against developing OSA.

Implementation of a nurse-led lower urinary tract symptoms (LUTS) clinic reduces general urology clinic workload in a Model 4 Hospital: a pilot study in Tallaght University Hospital

Background

With among the lowest urologist per population ratios in Europe, the demand for urology specialist review in Ireland far exceeds supply. Lower urinary tract symptoms (LUTS) account for a significant number of referrals. The traditional paradigm of every patient being reviewed in a consultant-led clinic is unsustainable. New models of care with nurse-led clinics represent an opportunity to optimise limited resources.

Methods

Existing long-waiting male LUTS referrals were triaged to a specialist nurse-led LUTS clinic. After urology CNS assessment, charts were reviewed by a consultant urologist and a plan formulated. Relevant data were prospectively collected and analysed.

Results

Fifty-eight new male patients with LUTS were seen over a 6-month period with an average waiting time of 15.8 months. Patients were assessed with uroflowmetry, IPSS and DRE. Mean age was 64, IPSS 14.5, Qmax 18.3 ml/s and PVR 89 ml. Thirty patients (52%) were discharged directly with lifestyle modification and medical therapy.

Twenty-eight patients (48%) required one or more further investigations and subsequent review; 11 had flexible cystoscopy, 4 had urodynamics, 5 had prostate MRI, and 2 patients were listed for surgery (TURP and circumcision). The remaining 10 patients were for review post trial of lifestyle modifications and/or medical treatment. After review/investigations, 4 more patients were discharged. A total of 32 patients (55%) were discharged or listed for surgery after initial assessment. This total increased to 62% after a second review/investigations.

Conclusion

Introduction of a CNS-led LUTS clinic has significantly reduced the number of patients requiring follow-up in general urology clinics, representing a quality improvement in service provision.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11845-020-02428-8.

Does fluoroscopy prevent inadvertent parathyroidectomy in thyroid surgery?

INTRODUCTION

Near-infrared imaging may facilitate intraoperative identification of parathyroid glands by causing autofluorescence but its clinical value has not been established. Inadvertent parathyroidectomy occurs in 5-22% of thyroidectomies and is associated with temporary and permanent hypoparathyroidism. The aim of this study was to determine whether near-infrared imaging prevents inadvertent parathyroidectomy and early hypocalcaemia as a surrogate for permanent hypoparathyroidism.

MATERIALS AND METHODS

Near-infrared imaging was used in a prospective cohort of consecutive thyroidectomies. Thyroidectomies performed prior to the introduction of near-infrared imaging formed a control group. The thyroid bed and specimen were scanned with near-infrared imaging. Areas of autofluorescence on the specimen were examined and any parathyroid tissue found was autotransplanted. Inadvertent parathyroidectomy was therefore recorded as established intraoperatively by near-infrared imaging (allowing autotransplantation) or on subsequent histology (missed). Serum calcium and parathyroid hormone were measured on day one and at two weeks and six months postoperatively.

RESULTS

A total of 269 patients were included: 106 near-infrared imaging and 163 controls. Inadvertent parathyroidectomy was detected by near-infrared imaging in two (and autotransplantation performed) and histologically (i.e. missed by near-infrared imaging in 13, 12.3% vs 17, 10.4% controls). Neither result was statistically significant (P = 0.08, 0.89). There was no significant difference in serum calcium or parathyroid hormone between near-infrared imaging and control groups at one day, two weeks or thereafter.

DISCUSSION

Near-infrared imaging may detect inadvertent parathyroidectomy and may allow autotransplantation. It did not, however, reduce the incidence of missed inadvertent parathyroidectomy and no difference was seen in early hypocalcaemia or late hypoparathyroidism. Current near-infrared imaging technology does not appear to confer a clinical benefit sufficient to justify its use.

A critical review of thyroidectomy consent in the UK

BACKGROUND

In 2015-16, the National Health Service (NHS) Litigation Authority received 10,965 claims for clinical negligence, with surgery having the highest number of claims. Currently a sum amounting to 25% of the annual NHS budget has been ring-fenced to meet extant claims. Claims made on a basis of inadequate informed consent are increasingly seen with many achieving a successful plaintiff outcome. There are presently no UK guidelines for thyroidectomy consent.

METHOD

A prospective study was performed to investigate current consent practice among the British Association of Endocrine and Thyroid Surgeons (BAETS) membership and patients having previously undergone thyroidectomy. For surgeons, the Bolam legal test applied where surgeons declared what risks and complications they routinely consented for during their practice. A study was also undertaken in patients who had previously undergone thyroidectomy for cancer applying the rule of Montgomery.

RESULTS

Consent practice from 193 surgeons and data from 415 patients was analysed. In total thyroidectomy for cancer, 95% of surgeons consent for Recurrent Laryngeal Nerve (RLN) injury and temporary or permanent voice change. 70% specifically consent for External Laryngeal Nerve (ELN) injury, 50% for tracheostomy and 55% for general anaesthetic associated complications. Analysis of patient data showed they would like to be consented for far more risks than they are presently informed about in general medical practice. There was significant variation in the consenting practice in BAETS surgeons.

CONCLUSION

A BAETS approved consensus guideline to standardise UK consent practice would be appropriate. This may reduce complaints, litigation claims and guide expert witnesses.

Temperature and moisture are minor drivers of regional-scale soil organic carbon dynamics

Storing large amounts of organic carbon, soils are a key but uncertain component of the global carbon cycle, and accordingly, of Earth System Models (ESMs). Soil organic carbon (SOC) dynamics are regulated by a complex interplay of drivers. Climate, generally represented by temperature and moisture, is regarded as one of the fundamental controls. Here, we use 54 forest sites in Switzerland, systematically selected to span near-independent gradients in temperature and moisture, to disentangle the effects of climate, soil properties, and landform on SOC dynamics. We estimated two SOC turnover times, based on bulk soil ¹⁴C measurements (τ_14C) and on a 6-month laboratory soil incubation (τ_i). In addition, upon incubation, we measured the ¹⁴C signature of the CO₂ evolved and quantified the cumulated production of dissolved organic carbon (DOC). Our results demonstrate that τ_i and τ_14C capture the dynamics of contrasting fractions of the SOC continuum. The ¹⁴C-based τ_14C primarily reflects the dynamics of an older, stabilised pool, whereas the incubation-based τ_i mainly captures fresh readily available SOC. Mean site temperature did not raise as a critical driver of SOC dynamics, and site moisture was only significant for τ_i. However, soil pH emerged as a key control of both turnover times. The production of DOC was independent of τ_i and not driven by climate, but primarily by the content of clay and, secondarily by the slope of the site. At the regional scale, soil physicochemical properties and landform appear to override the effect of climate on SOC dynamics.

Observation of Mode-Locked Spatial Laser Solitons

A stable nonlinear wave packet, self-localized in all three dimensions, is an intriguing and much sought after object in nonlinear science in general and in nonlinear photonics in particular. We report on the experimental observation of mode-locked spatial laser solitons in a vertical-cavity surface-emitting laser with frequency-selective feedback from an external cavity. These spontaneously emerging and long-term stable spatiotemporal structures have a pulse length shorter than the cavity round-trip time and may pave the way to completely independent cavity light bullets.

Strong Quantum Coherence between Fermi Liquid Mahan Excitons

In modulation doped quantum wells, the excitons are formed as a result of the interactions of the charged holes with the electrons at the Fermi edge in the conduction band, leading to the so-called "Mahan excitons." The binding energy of Mahan excitons is expected to be greatly reduced and any quantum coherence destroyed as a result of the screening and electron-electron interactions. Surprisingly, we observe strong quantum coherence between the heavy hole and light hole excitons. Such correlations are revealed by the dominating cross-diagonal peaks in both one-quantum and two-quantum two-dimensional Fourier transform spectra. Theoretical simulations based on the optical Bloch equations where many-body effects are included phenomenologically reproduce well the experimental spectra. Time-dependent density functional theory calculations provide insight into the underlying physics and attribute the observed strong quantum coherence to a significantly reduced screening length and collective excitations of the many-electron system.

Use of a population pharmacokinetic approach for the clinical development of a fixed-dose subcutaneous formulation of trastuzumab

A new subcutaneous (s.c.) trastuzumab formulation provides savings in terms of time and is preferred by patients and health care professionals relative to standard intravenous (i.v.) administration due to simpler and more rapid administration (2-5 minutes). Selection of the s.c. dose was based on a pharmacokinetic bridging approach that aimed to achieve noninferior trastuzumab serum trough concentrations (Ctrough) vs. reference i.v. administration. Using population modeling and simulation, we showed that a fixed 600-mg trastuzumab s.c. dose, administered thrice-weekly (Q3W) without a loading dose, would provide Ctrough (predose Cycle 8) and area under the time-concentration curve (AUC0-21 days, Cycle 7) at least as high as Q3W i.v. administration. The model was retrospectively validated using observed pharmacokinetic data from an independent phase III study of (neo)adjuvant trastuzumab (HannaH). These results provide a strong pharmacokinetic rationale for the trastuzumab s.c. 600-mg fixed dose, supported by the noninferior efficacy of this regimen vs. reference i.v. administration.CPT Pharmacometrics Syst. Pharmacol. (2014) 3, e87; doi:10.1038/psp.2013.63; advance online publication 2 January 2014.

Lifestyle factors, medication use and risk for ischaemic heart disease hospitalisation: a longitudinal population-based study

Background

Lifestyle factors have been implicated in ischaemic heart disease (IHD) development however a limited number of longitudinal studies report results stratified by cardio-protective medication use.

Purpose

This study investigated the influence of self-reported lifestyle factors on hospitalisation for IHD, stratified by blood pressure and/or lipid-lowering therapy.

Methods

A population-based cohort of 14,890 participants aged 45+ years and IHD-free was identified from the Western Australian Health and wellbeing Surveillance System (2004 to 2010 inclusive), and linked with hospital administrative data. Adjusted hazard ratios for future IHD-hospitalisation were estimated using Cox regression.

Results

Current smokers remained at higher risk for IHD-hospitalisation (adjusted HR=1.57; 95% CI: 1.22-2.03) after adjustment for medication use, as did those considered overweight (BMI=25-29 kg/m²; adjusted HR=1.28; 95% CI: 1.04-1.57) or obese (BMI of ≥30kg/m²; adjusted HR=1.31; 95% CI: 1.03-1.66). Weekly leisure-time physical activity (LTPA) of 150 minutes or more and daily intake of 3 or more fruit/vegetable servings reduced risk by 21% (95% CI: 0.64-0.97) and 26% (95% CI: 0.58-0.96) respectively. Benefits of LTPA appeared greatest in those on blood pressure lowering medication (adjusted HR=0.50; 95% CI: 0.31-0.82 [for LTPA<150 mins], adjusted HR=0.64; 95% CI: 0.42-0.96 [for LTPA>=150 mins]). IHD risk in smokers was most pronounced in those taking neither medication (adjusted HR=2.00; 95% CI: 1.41-2.83).

Conclusion

This study confirms the contribution of previously reported lifestyle factors towards IHD hospitalisation, even after adjustment for antihypertensive and lipid-lowering medication use. Medication stratified results suggest that IHD risks related to LTPA and smoking may differ according to medication use.

Transplantation at the nexus of behavioral economics and health care delivery

The transplant surgeon's decision to accept and utilize an organ typically is made within a constrained time window, explicitly cognizant of numerous health-related risks and under the potential influence of considerable regulatory and institutional pressures. This decision affects the health of two distinct populations, those patients receiving organ transplants and those waiting to receive a transplant; it also influences the physician's life and their institute's productivity. The numerous, at times nonaligned, incentives established by the complex clinical and regulatory environment, have been derived specifically to influence physicians' behaviors, and though well intended, may lead to responses that are nonoptimal when considering the myriad stakeholders being influenced. This may compromise the quality of care provided to the population at risk, and has potential to influence the physician-patient relationship. A synergistic collaboration between transplant physicians and economists that is focused on this decision environment may help to alleviate these strains. This viewpoint discusses behavioral economic principles and how they might be applied to transplantation. Specifically, the previous medical decision-making literature on transplantation will be reviewed and a discussion on how a behavioral model of physician decision making can be utilized will be explored. To date this approach has not been integrated into transplantation decision making.

Development of a subcutaneous formulation for trastuzumab - nonclinical and clinical bridging approach to the approved intravenous dosing regimen

A subcutaneous (SC) formulation has been developed for the humanized monoclonal antibody (mAb) trastuzumab as an alternative to established intravenous (IV) infusion. The ready-to-use liquid SC formulation is injected as a fixed dose in approximately 5 min, which is expected to increase patient's convenience, reduce pharmacy preparation time, and administration costs overall.The trastuzumab dose as well as the dose of recombinant human hyaluronidase (rHuPH20), an enzyme that enables SC administration of volumes larger than 2 mL, was selected based on nonclinical xenograft, pharmacology, and pharmacokinetics mouse and minipig studies.The basic assumption for bridging from the IV to the SC regimen was that comparable trastuzumab serum trough concentrations would result in comparable efficacy. This hypothesis is confirmed by the results from the Phase 3 study in the neo-adjuvant/adjuvant setting. The safety profiles of the trastuzumab SC and IV formulations are comparable and consistent with the known safety profile of trastuzumab.

Adler synchronization of spatial laser solitons pinned by defects

Defects due to growth fluctuations in broad-area semiconductor lasers induce pinning and frequency shifts of spatial laser solitons. The effects of defects on the interaction of two solitons are considered in lasers with frequency-selective feedback both theoretically and experimentally. We demonstrate frequency and phase synchronization of paired laser solitons as their detuning is varied. In both theory and experiment the locking behavior is well described by the Adler model for the synchronization of coupled oscillators.

Phase I clinical study to select a novel oral formulation for ibandronate containing the excipient sodium N-[8-(2-hydroxybenzoyl) amino] caprylate (SNAC)

The aim of this study was to select a novel oral formulation for ibandronate (IBN, CAS number: 13892619). In four cohorts of 28, 21, 19 and 29 healthy volunteers, the impact of the carrier molecule sodium N-[8-(2-hydroxybenzoyl) amino] caprylate (SNAC, CAS number: 203787-91-1) on the bioavailability of IBN was investigated. Within each cohort different oral formulations with one dose of ibandronate (30 mg) and three different ratios of IBN:SNAC (1:5, 1:10 and 1:20) were compared to the approved oral IBN tablet formulations (150 and 50 mg IBN) in a 4-way cross-over design and a one week washout between the administrations. The highest mean IBN exposure was achieved with a capsule formulation containing drug-coated beadlets and an IBN:SNAC ratio of 1:5. AUC(last) and C(max) of IBN were approximately 1.3- and 2.2-fold higher compared to the reference treatment (150 mg IBN without SNAC). Increasing the post-dose fasting duration from 15 to 30 min resulted in a more than 2-fold increase in AUC(last), while superimposable IBN serum concentration-time profiles were achieved after a 30 and 60 min fast. The tolerability of the IBN/SNAC treatments in all cohorts was similar to that in the IBN reference groups and most adverse events (AEs) were of mild to moderate intensity.

Uptake and behavioural and attitudinal determinants of immunization in an expanded routine infant hepatitis B vaccination program in British Columbia

INTRODUCTION

British Columbia (BC) implemented a universal infant hepatitis B (HB) immunization program in 2001. The study objective was to evaluate HB immunization coverage among the first six-month cohort of eligible infants in the province outside of the Vancouver-Richmond health region and to assess parent/guardian behavioural and attitudinal determinants of HB immunization.

METHODS

A cross-sectional survey of HB immunization was conducted using a random sample of eligible infants born between 1 January-30 June 2001. HB immunization coverage data were obtained from the provincial Public Health Information System, and through a telephone survey of 487 of eligible infants' parents/guardians that was conducted between October 2002-January 2003. At this time, parents/guardians were also asked about behaviours and attitudes towards immunization, based on the Immunization Health Belief Model Scale.

RESULTS

HB immunization coverage with at least one dose of HB vaccine was 89% and uptake of 3 doses of HB vaccine was 78%. HB immunization was significantly associated (p<0.001) with a recommendation for HB immunization from a health care professional. The main reason for non-HB immunization was parental concern about side effects.

DISCUSSION

Seventy-eight percent of infants completed the 3-dose HB vaccination schedule. Parental behaviour regarding HB immunization of their children was strongly influenced by a supportive recommendation from either a nurse or doctor.

Gas jet as a waveguide for air-coupled ultrasound

The directional characteristics of an ultrasonic signal have been studied during propagation within an axial gas jet. The effects of nozzle shape, nozzle diameter, and variations in jet velocity, temperature and gas composition have been investigated. At high flow velocities of an air jet, divergence of the ultrasonic beam was observed. This was attributed to the effects of refraction, caused by increased acoustic velocities in the direction of the flow. An effective waveguide was also demonstrated by cooling the air jet to below ambient temperatures, so that the acoustic velocity in the air jet was lower than that in the surrounding atmosphere. This could also be achieved by using carbon dioxide mixed with air, whereas the use of helium led to increased divergence. The result is likely to be of use in air-coupled ultrasonic materials inspection.

Changes in cortical and striatal neurons predict behavioral and electrophysiological abnormalities in a transgenic murine model of Huntington's disease

Neurons in Huntington's disease exhibit selective morphological and subcellular alterations in the striatum and cortex. The link between these neuronal changes and behavioral abnormalities is unclear. We investigated relationships between essential neuronal changes that predict motor impairment and possible involvement of the corticostriatal pathway in developing behavioral phenotypes. We therefore generated heterozygote mice expressing the N-terminal one-third of huntingtin with normal (CT18) or expanded (HD46, HD100) glutamine repeats. The HD mice exhibited motor deficits between 3 and 10 months. The age of onset depended on an expanded polyglutamine length; phenotype severity correlated with increasing age. Neuronal changes in the striatum (nuclear inclusions) preceded the onset of phenotype, whereas cortical changes, especially the accumulation of huntingtin in the nucleus and cytoplasm and the appearance of dysmorphic dendrites, predicted the onset and severity of behavioral deficits. Striatal neurons in the HD mice displayed altered responses to cortical stimulation and to activation by the excitotoxic agent NMDA. Application of NMDA increased intracellular Ca(2+) levels in HD100 neurons compared with wild-type neurons. Results suggest that motor deficits in Huntington's disease arise from cumulative morphological and physiological changes in neurons that impair corticostriatal circuitry.

Dead or alive: immunogenicity of human melanoma cells when presented by dendritic cells

Uveal melanoma is an aggressive malignancy with a poor prognosis despite current therapeutic intervention. These tumors have been shown to be antigenic because they express a number of melanoma-associated antigens and are therefore attractive targets for immunotherapy. Here, we investigated the immunogenicity of uveal melanoma cells that have undergone apoptosis and compared this with their necrotic or live counter-parts. The fate of the tumor antigens in these cells largely depends on their ability to be processed and phagocytosed by dendritic cells (DCs). Flow cytometric analysis shows that human DCs form conjugates more efficiently with dead uveal melanoma cells, and consequently these are effective stimuli of lymphocyte proliferation. However, only DCs pulsed with apoptotic cells were able to induce proliferation of CD8+ cytotoxic T cells and stimulate antigen-specific T cells. This study demonstrates for the first time that DCs derived from melanoma patients process and present antigens derived from both HLA-matched or HLA-mismatched human apoptotic tumor cells stimulating both CD4+ and CD8+ T cells. This approach may be important to the development of DC-based immunotherapies for melanoma.

Huntingtin expression stimulates endosomal-lysosomal activity, endosome tubulation, and autophagy

An expansion of polyglutamines in the N terminus of huntingtin causes Huntington's disease (HD) and results in the accrual of mutant protein in the nucleus and cytoplasm of affected neurons. How mutant huntingtin causes neurons to die is unclear, but some recent observations suggest that an autophagic process may occur. We showed previously that huntingtin markedly accumulates in endosomal-lysosomal organelles of affected HD neurons and, when exogenously expressed in clonal striatal neurons, huntingtin appears in cytoplasmic vacuoles causing cells to shrink. Here we show that the huntingtin-enriched cytoplasmic vacuoles formed in vitro internalized the lysosomal enzyme cathepsin D in proportion to the polyglutamine-length in huntingtin. Huntingtin-labeled vacuoles displayed the ultrastructural features of early and late autophagosomes (autolysosomes), had little or no overlap with ubiquitin, proteasome, and heat shock protein 70/heat shock cognate 70 immunoreactivities, and altered the arrangement of Golgi membranes, mitochondria, and nuclear membranes. Neurons with excess cytoplasmic huntingtin also exhibited increased tubulation of endosomal membranes. Exogenously expressed human full-length wild-type and mutant huntingtin codistributed with endogenous mouse huntingtin in soluble and membrane fractions, whereas human N-terminal huntingtin products were found only in membrane fractions that contained lysosomal organelles. We speculate that mutant huntingtin accumulation in HD activates the endosomal-lysosomal system, which contributes to huntingtin proteolysis and to an autophagic process of cell death.

Mutant huntingtin expression in clonal striatal cells: dissociation of inclusion formation and neuronal survival by caspase inhibition

Neuronal intranuclear inclusions are found in the brains of patients with Huntington's disease and form from the polyglutamine-expanded N-terminal region of mutant huntingtin. To explore the properties of inclusions and their involvement in cell death, mouse clonal striatal cells were transiently transfected with truncated and full-length human wild-type and mutant huntingtin cDNAs. Both normal and mutant proteins localized in the cytoplasm, and infrequently, in dispersed and perinuclear vacuoles. Only mutant huntingtin formed nuclear and cytoplasmic inclusions, which increased with polyglutamine expansion and with time after transfection. Nuclear inclusions contained primarily cleaved N-terminal products, whereas cytoplasmic inclusions contained cleaved and larger intact proteins. Cells with wild-type or mutant protein had distinct apoptotic features (membrane blebbing, shrinkage, cellular fragmentation), but those with mutant huntingtin generated the most cell fragments (apoptotic bodies). The caspase inhibitor Z-VAD-FMK significantly increased cell survival but did not diminish nuclear and cytoplasmic inclusions. In contrast, Z-DEVD-FMK significantly reduced nuclear and cytoplasmic inclusions but did not increase survival. A series of N-terminal products was formed from truncated normal and mutant proteins and from full-length mutant huntingtin but not from full-length wild-type huntingtin. One prominent N-terminal product was blocked by Z-VAD-FMK. In summary, the formation of inclusions in clonal striatal cells corresponds to that seen in the HD brain and is separable from events that regulate cell death. N-terminal cleavage may be linked to mutant huntingtin's role in cell death.

Serum C-reactive protein as a marker for infection and inflammation in regular dialysis patients

Serum C-reactive protein (CRP) concentration was measured in 98 hemodialysis (HD) patients and 68 continuous ambulatory peritoneal dialysis patients (CAPD). The effect, if any, of a HD session on serum CRP level and the usefulness of CRP in diagnosing and monitoring proven inflammatory disease were studied. Seventy-five percent of CAPD patients without evidence of inflammation had CRP levels within the quoted normal range (< 10 mg/l), as compared with only 47% of HD patients also without evidence of overt inflammation (p < 0.001). No significant change in the CRP level was detected during a hemodialysis session. Twenty-four patients with overt inflammation (due mainly to infection) were studied, 22 of whom had CRP levels of > 50 mg/l. These increased CRP levels fell with treatment. A CRP level of > 50 mg/l proved highly suggestive of a significant inflammatory process and a value of < 10 mg/l always excluded it. The total period of time on the regular dialysis program was not related to the CRP level. A subclinical inflammatory response resulting in a raised CRP is very common in our hemodialysis patients and less so in CAPD patients. Possible reasons for this are discussed. However, CRP is still useful in the diagnosis and monitoring of response to treatment of inflammatory disease if the level is > 50 mg/l or serial/baseline measurements are available for comparison. Whether any relationship exists between elevation of CRP and the well-documented increased risk of cardiovascular death in dialysis patients is currently unknown.

Detection of circulating prostate-specific antigen-positive cells in patients with prostate cancer by flow cytometry and reverse transcription polymerase chain reaction

The presence of prostate-specific antigen (PSA)-positive cells has previously been demonstrated in the peripheral blood of prostate cancer patients by flow cytometry (FC), but the identity of these cells has not been established. In this study, the reverse transcriptase polymerase chain reaction (RT-PCR) was compared with analytical FC in an attempt to detect and characterise these cells. Peripheral blood was obtained from 12 patients with newly diagnosed and untreated prostate cancer and five controls. Nine of the 12 patients with prostate cancer (75%) had circulating PSA-positive cells as shown by FC. Only one of those patients (11.1%) was found to express PSA mRNA by RT-PCR. The absence of PSA mRNA in the majority of samples showing PSA-positive cells suggests that they do not represent haematogenous micrometastases. PSA-positive cells in the blood could represent monocytes that express PSA, either following binding/phagocytosis of free serum PSA or phagocytosis of tumour cells.

The effect of topical beta-blocker medications on the proliferation and viability of human Tenon's capsule fibroblasts in tissue culture

Several recent publications have suggested that the long-term use of topical antiglaucoma medications may be detrimental to the outcome of trabeculectomy. In this study we investigated the effect of topical beta-blocker medications on the proliferation and viability of human Tenon's capsule fibroblasts in tissue culture to see if there was a direct mechanism of enhanced proliferation. None of the tested medications stimulated the proliferation of fibroblasts. They were shown to have an inhibitory effect on proliferation and were toxic to cells at higher concentrations. The relevance of these findings to wound healing following trabeculectomy is discussed.

Public awareness and knowledge about the risks of drinking during pregnancy in Multnomah County, Oregon

Public awareness of the risks of drinking during pregnancy was assessed in a Northwestern metropolitan county. Ninety per cent of respondents stated spontaneously that drinking might be harmful, and one-fourth of this group felt pregnant women should customarily abstain from alcohol. The balance of those who considered drinking harmful felt an average of more than three drinks was safe for daily use. Thus awareness of risk does not necessarily result in recommendation of low-risk behavior.