Novel predictors of permanent pacemaker implantation following transcatheter aortic valve replacement

BACKGROUND

Conduction and rhythm abnormalities requiring permanent pacemakers (PPM) are short-term complications following transcatheter aortic valve replacement (TAVR), and their clinical outcomes remain conflicting. Potential novel predictors of post-TAVR PPM, like QRS duration, QTc prolongation, and supraventricular arrhythmias, have been poorly studied.

AIM

To evaluate the effects of baseline nonspecific interventricular conduction delay and supraventricular arrhythmia on post-TAVR PPM requirement and determine the impact of PPM implantation on clinical outcomes.

METHODS

A retrospective cohort study that identified patients with TAVR between January 1, 2012 to December 31, 2019. The group was dichotomized into those with post-TAVR PPM and those without PPM. Both groups were followed for one year.

RESULTS

Out of the 357 patients that met inclusion criteria, the mean age was 80 years, 188 (52.7%) were male, and 57 (16%) had a PPM implantation. Baseline demographics, valve type, and cardiovascular risk factors were similar except for type II diabetes mellitus (DM), which was more prevalent in the PPM cohort (59.6% vs 40.7%; P = 0.009). The PPM cohort had a significantly higher rate of pre-procedure right bundle branch block, prolonged QRS > 120 ms, prolonged QTc > 470 ms, and supraventricular arrhythmias. There was a consistently significant increase in the odds ratio (OR) of PPM implantation for every 20 ms increase in the QRS duration above 100 ms: QRS 101-120 [OR: 2.44; confidence intervals (CI): 1.14-5.25; P = 0.022], QRS 121-140 (OR: 3.25; CI: 1.32-7.98; P = 0.010), QRS 141-160 (OR: 6.98; CI: 3.10-15.61; P < 0.001). After model adjustment for baseline risk factors, the OR remained significant for type II DM (aOR: 2.16; CI: 1.18-3.94; P = 0.012), QRS > 120 (aOR: 2.18; CI: 1.02-4.66; P = 0.045) and marginally significant for supraventricular arrhythmias (aOR: 1.82; CI: 0.97-3.42; P = 0.062). The PPM cohort had a higher adjusted OR of heart failure (HF) hospitalization (aOR: 2.2; CI: 1.1-4.3; P = 0.022) and nonfatal myocardial infarction (MI) (aOR: 3.9; CI: 1.1-14; P = 0.031) without any difference in mortality (aOR: 1.1; CI: 0.5-2.7; P = 0.796) at one year.

CONCLUSION

Pre-TAVR type II DM and QRS duration > 120, regardless of the presence of bundle branch blocks, are predictors of post-TAVR PPM. At 1-year post-TAVR, patients with PPM have higher odds of HF hospitalization and MI.

0366 Investigating the use of STOP-BANG questionnaire in inpatient and outpatient settings in a rural healthcare system

Introduction

Obstructive Sleep Apnea (OSA) is one of the strongest modifiable risk factors for Atrial Fibrillation (AF). Although, STOP-BANG questionnaire is a well-validated screening tool for OSA, its adoption and utility to screen newly diagnosed AF has not been reported in a large rural healthcare system. Our aim was to identify the characteristics in patients with AF, which led to screening and referral for a sleep study by providers. In addition, we identified the provider specialty types that had the highest rate of screening for OSA and sleep study referral.

Methods

We conducted a retrospective multicenter study that identified newly diagnosed patients with AF from January 2018- January 2020. STOP-BANG questionnaire, patient demographics, electrocardiogram, and sleep study data were collected. A logistic regression model was used to identify patient characteristics that were associated with increased screening. Using a chi-squared test, we compared differences in provider specialty that screened for OSA and referred patients for a sleep study.

Results

Among the study cohort (N=845), 136 (16.1 %) were female and 709 (83.9 %) were male. Only 82 patients (9.7%) had confirmed OSA screening by STOP-BANG questionnaire. Among higher risk patients for OSA (at least 3 of the following: age&gt;50, male, hypertension, BMI&gt;35), the screened patients were 5.8 years younger (95% CI: 3.7-7.9, p&lt;0.001) compared to patients that were not screened. Patients who were screened for OSA had significantly higher BMI (p&lt;0.001), hypertension (p&lt;0.001), and diabetes mellitus (p&lt;0.001). Our findings revealed that OSA screening providers, were most commonly Primary Care Providers (PCP) (47.5%) followed by cardiologists (31.7). Furthermore, PCPs (48.5 %) and cardiologists (14.1%) were most likely to provide referrals for a sleep study. All of the patients, who were screened using STOP-BANG questionnaire and referred for a sleep study, were diagnosed with OSA.

Conclusion

Our findings revealed underutilization of STOP-BANG to screen for OSA in newly diagnosed AF patients. Screening pattern may be tilted towards patients with obvious and severe forms of OSA therefore missing on milder cases. This study could prompt systemic adoption of STOP-BANG questionnaire, education, and periodic evaluation of healthcare providers in a large rural healthcare system to improve outcomes in AF patients.

Support (If Any)

 

Effects of a Health Education Course on Pre-Service Teachers' Perceived Knowledge, Skills, Preparedness, and Beliefs in Teaching Health Education

BACKGROUND

In this study, we explore how a health education course may play a role in pre-service teachers' perceptions in teaching and integrating health education activities to nurture K-8 students' health literacy.

METHODS

We used mixed methods to examine the effect of a health education course in a teacher education program. Of 55 pre-service teachers, 41voluntarily participated in the study. Quantitative data were obtained through an online questionnaire administered to participants at the beginning and end of the course. We conducted 6 focus groups at the end of the course.

RESULTS

The inferential analysis from a series of analysis of variance with repeated measures revealed significant differences in health knowledge (F = 113.39, p < .01, η²  = 0.74), preparedness (F = 104.74, p < .01, η²  = 0.73), attitudes (F = 15.02, p < .01, η²  = 0.28), and beliefs (F = 8.87, p < .01, η²  = 0.19) between time points. Qualitative data led to the conclusion that where one health education course is insufficient, such a course is the first step into future curriculum development and implementation.

CONCLUSION

One health education course might be beneficial for general education teachers to increase their knowledge and preparation to teaching school health. On-going training is needed for program success.

Safety and Tolerability of Fremanezumab for the Prevention of Migraine: A Pooled Analysis of Phases 2b and 3 Clinical Trials

OBJECTIVE

Presentation of pooled analysis of safety data for fremanezumab in patients with chronic (CM) or episodic migraine (EM) from 4 placebo-controlled phase 2b and phase 3 studies.

BACKGROUND

There is a need for an effective, safe, and well-tolerated preventive therapy that specifically targets the pathophysiology of migraine to reduce the frequency and severity of migraine attacks in patients with CM or EM who experience 4 or more migraine days per month. Fremanezumab is a fully humanized monoclonal antibody that targets calcitonin gene-related peptide, a neuropeptide involved in the pathophysiology of migraine.

DESIGN/METHODS

The 4 placebo-controlled phases 2b and 3 studies included in this analysis were 16-week, multicenter, randomized, double-blind, placebo-controlled, and parallel-group studies consisting of a screening visit, a 28-day pretreatment baseline period, and a 12-week treatment period with a final evaluation 4 weeks after the final dose of the study drug. Safety endpoints included adverse events (AEs) and immunogenicity.

RESULTS

A total of 2566 patients were randomized across all studies (fremanezumab, n = 1704; placebo, n = 862), and 2563 patients were treated. Common reasons for study discontinuation were withdrawal by patient (n = 78), patient lost to follow-up (n = 60), and AE (n = 50). The mean (standard deviation) duration of exposure was 83.8 (13.6) days for the patients who received fremanezumab, with a total exposure of 390.4 patient years and maximum exposure of 181 days. AEs were mostly mild to moderate in severity and were reported among 48-69% of patients in all treatment groups, and most were injection site reactions (pain, induration, and erythema). Two deaths occurred (chronic obstructive pulmonary disease and intentional overdose of diphenhydramine), both of which were deemed unrelated to study drug by the investigators and sponsor. Cardiovascular adverse events, abnormal liver function tests, and hypersensitivity were uncommon and occurred at similar rates between the placebo and fremanezumab groups.

CONCLUSIONS

Fremanezumab is a generally safe and well-tolerated preventive therapy for migraine in adults.

Hypertrophic pulmonary osteoarthropathy: an unusual presentation

Objectives

Hypertrophic pulmonary osteoarthropathy (HPOA) is a syndrome characterized by the triad of periostitis, digital clubbing and painful arthropathy of the large joints, especially involving the lower limbs. HPOA without clubbing of the digits is considered an incomplete form of HPOA and has been rarely reported. We are presenting here a case of HPOA without clubbing in a patient with lung cancer.

Methods

A 52-year-old female active smoker presented with a complaint of multiple joint pains with associated morning stiffness, swelling and weight loss for 3 months. On examination, the patient had tenderness to palpation over the anterior shin, but no obvious clubbing was noted. X-rays of the lower extremities revealed periosteal thickening compatible with HPOA.

Results

A bone scan showed increased uptake along the periosteum and cortex of the long bones. In view of her smoking history and weight loss, a chest X-ray was done that revealed an upper lung mass. A diagnosis of lung carcinoma was made on biopsy.

Conclusion

Our case demonstrates that the unusual finding of HPOA in the absence of clubbing is a rare entity and can often be missed. Once diagnosed, a prompt search of other associated conditions should be conducted.

Time-stretch microscopy on a DVD for high-throughput imaging cell-based assay

Cell-based assay based on time-stretch imaging is recognized to be well-suited for high-throughput phenotypic screening. However, this ultrafast imaging technique has primarily been limited to suspension-cell assay, leaving a wide range of solid-substrate assay formats uncharted. Moreover, time-stretch imaging is generally restricted to intrinsic biophysical phenotyping, but lacks the biomolecular signatures of the cells. To address these challenges, we develop a spinning time-stretch imaging assay platform based on the functionalized digital versatile disc (DVD). We demonstrate that adherent cell culture and biochemically-specific cell-capture can now be assayed with time-stretch microscopy, thanks to the high-speed DVD spinning motion that naturally enables on-the-fly cellular imaging at an ultrafast line-scan rate of >10MHz. As scanning the whole DVD at such a high speed enables ultra-large field-of-view imaging, it could be favorable for scaling both the assay throughput and content as demanded in many applications, e.g. drug discovery, and rare cancer cell screening.

Developing an online health literacy curriculum for two German universities: a key stakeholder approach

Health literacy is a significant resource for daily life in society. Global evidence reveals that there are less than ideal levels of health literacy in populations. One potential straproviding them with the skills and tools that will improve their knowledge and practice as our future workforce. The purpose of this study was to articulate the need to develop an online health literacy introductory course for university students in Germany. A total of 16 students from two German universities participated in focus group interviews to collect data on the extent of student health literacy awareness and related health and education needs. Nine international stakeholders participated in an online self-guided review of a comprehensive draft course to obtain detailed feedback from experts in the education and health literacy fields. Results revealed that both focus group and international stakeholders are in support of developing an online health literacy curriculum. To build the draft curriculum, an existing Canadian health literacy online course was adapted as a blueprint for the German context. The proposed course was customized based on the findings from the focus groups and international stakeholder feedback, which is intended to help inform and determine contents, design, and delivery of such a course applicable for universities in Germany and beyond.

Spectral Analysis of Electrocardiograms in Patients with Inducible Atrial Fibrillation after Catheter Ablation Predicts Sinus Rhythm Maintenance

BACKGROUND

We aimed to develop a novel predictive marker for atrial fibrillation (AF) recurrence in patients with inducible AF after catheter ablation, based on power spectral analysis of baseline and postablation electrocardiograms.

METHODS

Twenty-five patients who had undergone their first AF ablation procedure (pulmonary vein isolation and ganglionated plexi ablation) and had inducible AF after ablation were included. A 30-second interval of AF was chosen for each patient before and after ablation, and a periodogram of the atrial activity was computed. A ratio of the power in the dominant frequency to the power in the remainder of the periodogram (DFR) was calculated.

RESULTS

Eight (32%) patients had recurrent AF at 1 year. The clinical and echocardiographic characteristics of patients with and without recurrence were similar (P > 0.05). After ablation, there was organization of atrial activity, evidenced by an increase in the DFR (0.28 ± 0.22 vs 0.53 ± 0.29; P = 0.001). The percent change in DFR before and after ablation (median [interquartile range]) was significantly higher in patients without AF recurrence (120% [30% to 344%] vs 3% [-27% to 66%]; P = 0.01). Receiver operating curve (ROC) analysis demonstrated that a less than 16% increase in DFR postablation was able to predict recurrence of AF (area under ROC curve = 0.82; P = 0.03) with 75% sensitivity and 94% specificity.

CONCLUSION

AF ablation leads to variable organization of atrial activity. Organization of atrial activity after AF ablation is associated with lower 1-year recurrence rates and may be used intraprocedurally after as a novel end point for AF ablation. Larger prospective studies are warranted.

Abstract P3-07-57: Development of a 6-gene qPCR RUO-validated assay as a predictive biomarker for response of vantictumab (OMP-18R5; anti-frizzled) in HER2- breast cancer patients

Background: We have developed a monoclonal antibody, vantictumab that blocks canonical WNT/β-catenin signaling through binding of five FZD receptors (1, 2, 5, 7, 8). This antibody inhibits the growth of several tumor types, including breast. Vantictumab reduces tumor-initiating cell frequency and exhibits synergistic activity with standard-of-care (SOC) agents (Gurney et al, 2012). To target breast cancer patients most likely to respond to vantictumab, we undertook a predictive biomarker study.

Methods: We have identified a 6-gene Wnt pathway-related signature, FBXW2, CCND2, RHOU, CTBP2, WIF1, and DKK1, based on microarray gene expression data from 8 breast cancer patient derived xenograft (PDX) models with established in vivo response to vantictumab plus SOC. This signature successfully predicted the response of 8 additional and independent PDX breast tumors. We further developed a qPCR Research Use Only (RUO) assay for the 6 genes to be used on FFPE human breast tumor samples. Multiple assays targeting different regions spanning each mRNA transcript were tested and selected based on PCR efficiency, specificity and sensitivity. We compared assay sensitivity under different cDNA synthesis and pre-amplification conditions: random vs. gene-specific priming, number of pre-amplification cycles, pre-amplification reaction volumes, and cDNA synthesis kits. A repeatability study was performed to test assay performance. The pre-amplification and PCR were repeated over three separate days and across two independent labs.

Results: Our results showed that cDNA synthesis by gene-specific priming followed by 18 cycles of pre-amplification performed the best and the assay is robust with minimal starting FFPE RNA input. The results of the repeatability study were consistent among the different days and the different labs (&lt;5% CV). Using the 6-gene qPCR RUO assay, the signature score from the microarray data was further refined using 12 PDX HER2- breast tumors with known in vivo response to vantictumab with SOC. The prevalence of the 6-gene signature was established using ∼100 HER2- breast cancer samples.

Conclusions: A robust 6-gene RUO-validated assay was developed as a predictive biomarker for vantictumab in HER2- breast cancer. The assay is currently being evaluated in a Phase 1b study of vantictumab with paclitaxel in HER2- breast cancer.

Citation Format: Zhang C, O'Young G, Wikstrom K, Davison T, Yeung P, Cattaruzza F, Yen W-C, Hoey T, Lewicki J, Rachmann R, Kerr P, Hill L, Eason R, McErlean S, Liu Y, Kapoun AM. Development of a 6-gene qPCR RUO-validated assay as a predictive biomarker for response of vantictumab (OMP-18R5; anti-frizzled) in HER2- breast cancer patients. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-07-57.

Control of intra-oesophageal pH in patients with Barrett's oesophagus on omeprazole-sodium bicarbonate therapy

BACKGROUND

Approximately 30-40% of patients with Barrett's oesophagus (BE) patients manifest abnormal oesophageal pH profiles despite proton pump inhibitor (PPI) therapy.

AIM

To determine control of oesophageal reflux using Bravo pH monitoring in patients BE on omeprazole-sodium bicarbonate oral suspension powder (Ome-NaBic) 40 mg twice daily.

METHODS

Initial pH monitoring off PPI for 1 week was performed. All patients underwent repeat pH testing on Ome-NaBic administered before breakfast and at bedtime after 21-28 days of therapy depending upon the prior PPI therapy. The goal was to enroll 30 subjects, however, the trial was terminated prematurely when the sponsor lost financing due to a change in business strategy.

RESULTS

A total of 88 patients responded to the study invitation, 27 patients signed informed consent, and 21 patients underwent pH testing of PPI. A total of 15 patients completed the protocol (13 men, 2 women). Demographic information for patients completing at least one Bravo study included a mean (±s.d.) age 62 ± 9 years; body mass index 31 ± 8 kg/m(2) (range 23-48); mean BE length of 2.6 ± 2 cm; 9 (43%) patients with long segment BE. All (100%) patients demonstrated normalisation of supine pH on both days of Ome-NaBic therapy. One patient (6%) demonstrated abnormal upright reflux on the second day of monitoring on Ome-NaBic therapy; all the other patients demonstrated normal pH scores on therapy.

CONCLUSIONS

Administration of twice daily Ome-NaBic demonstrated control of nocturnal oesophageal reflux in 100% of patients with Barrett's oesophagus, and complete control of oesophageal pH during 97% of the 24-h recording periods.

Abstract P6-15-10: Targeting Delta-Like 4 Ligand (DLL4)/Notch Signaling by a Novel Anti-DLL4 Antibody Inhibits Tumor Growth through Altering Cancer Stem Cell and Epithelial-to-Mesenchymal Transition-Associated Genes in Triple Negative Breast Cancer

Triple negative breast cancer (TNBC, ER-, PR-Her2-) accounts for 10% of all types of breast cancer and is known to be particularly aggressive and refractory to current therapies. Chemotherapeutic agents, such as taxanes, are currently the only treatment option for this type of breast cancer. However, these treatments often result in local and systemic relapse. While several promising targeted agents have improved the relapse rate in the combination with chemotherapy in patients with pathologic complete response, those who do not achieve pathologic complete response still have a poor prognosis. We previously demonstrated that interfering with Deltalike 4 ligand (DLL4)/Notch signaling by an anti-DLL4 antibody decreased tumor growth and delayed tumor recurrence following paclitaxel treatment through reducing breast cancer stem cell fraction and tumorigenicity (Proc Am Asso Cancer Res. 51:4, 2010). CD44+/CD24low cells have been demonstrated to be highly tumorigenic in breast tumors and are associated with treatment resistance (PNAS U S A, 106: 13820-13825, 2009). To gain insights into the mechanism of action of anti-DLL4-mediated TNBC growth inhibition, we evaluated the effect of anti-DLL4 on breast cancer CD44+/CD24low the expression patterns of a list of genes involved in sternness, differentiation, and key stem cell signaling pathways in TNBC xenograft tumors following paclitaxel with and without antibody treatment in vivo. Our data showed that paclitaxel treatment resulted in significant changes of gene expression patterns in the CD44+/CD24low cells in the residual tumors. We further analyzed these genes and identified several genes related to Notch signaling, stem cell maintenance and epithelial-to-mesenchymal transition that were modulated differentially by treatment with paclitaxel and/or anti-DLL4. In a metastatic TNBC orthotopic tumor model, the anti-DLL4 treatment resulted in tumor growth inhibition at the primary site and distant organs. Taken together, our findings suggest that targeting DLL4 may improve the efficacy of current treatments, delay tumor recurrence, and reduce metastatic growth in TNBC.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P6-15-10.

Performing slow vital capacity in older people with and without cognitive impairment--is it useful?

BACKGROUND

most patients with moderate cognitive impairment are unable to perform forced spirometry. It has been suggested that slow vital capacity (SVC) is easier to perform than forced vital capacity (FVC) because it requires less understanding and co-ordination. We conducted a study to determine whether that assertion is correct.

METHODS

we studied 83 inpatients, mean age 83 years (range 67-95, 51 female). They had measurements made of FVC, SVC and the Mini-Mental State Examination (MMSE). The spirometry was conducted using the European Respiratory Society/American Thoracic Society standards.

RESULTS

of the 83 subjects, 38 were able to do both FVC and SVC and 32 were unable to do either. The overall concordance was 84%. Twelve were able to do SVC but not FVC (eight due to excessive cough, two due to weakness and two had an MMSE < 24 with poor co-ordination). An inability to do neither FVC nor SVC was predicted by an MMSE < 24/30 (P < 0.0001) with a sensitivity of 88% and specificity of 67%.

CONCLUSION

SVC is not a usable substitute for FVC for elderly patients with cognitive impairment but is of some utility for those who tend to cough. An MMSE < 24/30 is predictive of inability to perform FVC and SVC.

Hyperbaric oxygen for idiopathic sudden sensorineural hearing loss and tinnitus

BACKGROUND

Idiopathic sudden sensorineural hearing loss (ISSHL) with or without tinnitus is common and presents a health problem with significant effect on quality of life. Hyperbaric oxygen therapy (HBOT) may improve oxygen supply to the inner ear and, it is postulated, may result in an improvement in hearing and/or a reduction in the intensity of tinnitus.

OBJECTIVES

To assess the benefits and harms of HBOT for treating ISSHL and/or tinnitus.

SEARCH STRATEGY

We initially searched in June 2004 and repeated the search in June 2006. Our search included the Cochrane Ear, Nose and Throat Disorders Group Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 2 2006), MEDLINE (1951 to 2006), EMBASE (1974 to 2006), CINAHL, Database of Randomised Trials in Hyperbaric Medicine (DORCTHIM), AMED, LILACS, KOREAMED, INDMED, National Research Register (NRR), CSA, ISI PROCEEDINGS and ZETOC.

SELECTION CRITERIA

Randomised studies comparing the effect on ISSHL and/or tinnitus of therapeutic regimens which include HBOT with those that exclude HBOT.

DATA COLLECTION AND ANALYSIS

Three authors independently evaluated the quality of the relevant trials using the validated Oxford-Scale (Jadad 1996) and extracted the data from the included trials.

MAIN RESULTS

Six trials contributed to this review (308 subjects). Pooled data from two trials involving 114 patients did not show any significant improvement in the chance of a 50% increase in hearing threshold on Pure Tone Average (PTA) when HBOT was used (relative risk [RR] with HBOT 1.53, 95% CI 0.85 to 2.78, P = 0.16), but did show a significantly increased chance of a 25% increase in PTA (RR 1.39, 95% CI 1.05 to 1.84, P = 0.02). There was a 22% greater chance of improvement with HBOT, and the number needed to treat (NNT) to achieve one extra good outcome was five (95% CI 3 to 20). A single trial involving 50 subjects also suggested significantly more improvement in the mean PTA threshold with HBOT, expressed as a percentage of baseline (WMD 37%, 95% CI 22% to 53%, P < 0.001). The significance of any improvement following HBOT in a subjective rating of tinnitus could not be assessed due to poor reporting. There were no significant improvements in hearing or tinnitus reported in the single study to examine chronic presentation (six months) of ISSHL and/or tinnitus.

AUTHORS' CONCLUSIONS

For people with early presentation of ISSHL, the application of HBOT significantly improved hearing loss, but the clinical significance of the level of improvement is not clear. We could not assess the effect of HBOT on tinnitus by pooled data analysis. The routine application of HBOT to these patients cannot be justified from this review. In view of the modest number of patients, methodological shortcomings and poor reporting, this result should be interpreted cautiously, and an appropriately powered trial of high methodological rigour is justified to define those patients (if any) who can be expected to derive most benefit from HBOT. There is no evidence of a beneficial effect of HBOT on chronic presentation of ISSHL and/or tinnitus and we do not recommend use of HBOT for this purpose based on the single study available.

Hyperbaric oxygen therapy for idiopathic sudden sensorineural hearing loss and tinnitus: a systematic review of randomized controlled trials

Background: Idiopathic sudden sensorineural hearing loss (ISSHL) and tinnitus are common. Hyperbaric oxygen therapy (HBOT) may improve hearing loss and/or reduce the intensity of tinnitus.

Methods: We performed a systematic search of the literature for randomized controlled trials, and made pooled analyses of pre-determined clinical outcomes where possible.

Results: Six trials contributed to this review (304 subjects). Pooled analysis suggested a significantly increased chance of a 25 per cent improvement in hearing threshold on pure tone average with HBOT (relative risk (RR) 1.39, 95 per cent confidence interval (CI) 1.05–1.84, p = 0.02; number-needed-to-treat 5, 95 per cent CI 3–20), but not a 50 per cent increase (RR 1.53, 95 per cent CI 0.85–2.78, p = 0.16). The significance of any improvement in tinnitus following HBOT could not be assessed due to poor reporting.

Conclusions: HBOT improved hearing, but the clinical significance of the level of improvement is not clear. Routine application of HBOT to patients with ISSHL is not justified by this review. More research is needed.

Hyperbaric oxygen for idiopathic sudden sensorineural hearing loss and tinnitus

BACKGROUND

Idiopathic sudden sensorineural hearing loss (ISSHL) with or without tinnitus is common and presents a health problem with significant effect on quality of life. Hyperbaric oxygen therapy (HBOT) may improve oxygen supply to the inner ear and thereby result in an improvement in hearing and/or a reduction in the intensity of tinnitus.

OBJECTIVES

To assess the benefits and harms of HBOT for treating ISSHL and tinnitus.

SEARCH STRATEGY

We searched the Cochrane ENT Specialist Register (June 2004), CENTRAL (The Cochrane Library Issue 3, 2004), MEDLINE (1966 to 2004), EMBASE (1974 to 2004), CINAHL (1982 to 2004), DORCTHIM (1996 to 2004), and reference lists of articles. Researchers in the field were contacted.

SELECTION CRITERIA

Randomised studies comparing the effect on ISSHL and/or tinnitus of therapeutic regimens which include HBOT with those that exclude HBOT.

DATA COLLECTION AND ANALYSIS

Three reviewers independently evaluated the quality of the relevant trials using the validated Jadad 1996 Oxford-Scale and extracted the data from the included trials.

MAIN RESULTS

Five trials contributed to this review (254 subjects, 133 receiving HBOT and 120 control). Pooled data from two trials involving 114 patients (45% of the total) suggested there was a trend towards, but no significant increase in, the chance of a 50% increase in hearing threshold on Pure Tone Average (PTA) over four frequencies when HBOT was used (relative risk (RR) for good outcome with HBOT 1.53, 95% confidence interval (CI) 0.85 to 2.78, P = 0.16). The chance of achieving a 25% increase with HBOT was, however, statistically significant (RR 1.39, 95% CI 1.05 to 1.84, P = 0.02). Fifty-six per cent of the control subjects achieved this outcome versus 78% of the HBOT subjects, with the number-needed-to-treat (NNT) to achieve one extra good outcome being 5 (95% CI 3 to 20). A single trial involving 50 subjects (20% of the total) also suggested a significant improvement in the mean PTA threshold expressed as a percentage of baseline (61% improvement with HBOT, 24% with control, WMD 37%, 95% CI 22% to 53%). The effect of HBOT in tinnitus could not be assessed due to poor reporting. There were no significant improvements in hearing or tinnitus reported in the single study to examine the effect of HBOT on a chronic presentation (six months) of ISSHL and/or tinnitus.

AUTHORS' CONCLUSIONS

For people with early presentation of ISSHL, the application of HBOT significantly improved hearing loss, but the clinical significance of the level of improvement is not clear. We could not assess the effect of HBOT on tinnitus by pooled analysis. The routine application of HBOT to these patients cannot be justified from this review. In view of the modest number of patients, methodological shortcomings and poor reporting, this result should be interpreted cautiously, and an appropriately powered trial of high methodological rigour is justified to define those patients (if any) who can be expected to derive most benefit from HBOT. There is no evidence of a beneficial effect of HBOT on chronic presentation of ISSHL and/or tinnitus.

Silicosis and lung cancer: a mortality study of compensated men with silicosis in New South Wales, Australia

BACKGROUND

Lung cancer mortality has been found to be in excess in several groups with silicosis, but allowance for smoking was not always possible. We investigated the lung cancer mortality in men with silicosis in New South Wales, Australia, who were compensated, making allowance for smoking habits.

METHODS

A mortality study of 1467 men with silicosis in New South Wales who were compensated was carried out comparing observed mortality with that expected from the New South Wales death rates adjusting for age and period. Their smoking habits were compared with national survey smoking rates and the expected number of lung cancer deaths adjusted for smoking. Cases were coded for occupation and industry.

RESULTS

The observed mortality was higher than expected, but the only site of cancer showing a significant excess was the lung. The group with silicosis had smoked more than the national rates. After adjusting for smoking the standardized mortality ratio for lung cancer was 1.9 (95% confidence interval 1.5-2.3). Although there were differences in lung cancer mortality between industries and occupations, these differences were not statistically significant.

CONCLUSIONS

The excess lung cancer death rate may not be entirely due to silica exposure because compensation may have been influenced by the presence of chronic obstructive respiratory disease and there is some evidence that the presence of this disease increases lung cancer risk independently of smoking.

Malignancies of the external auditory canal and temporal bone: a review

BACKGROUND

Malignancies of the external auditory canal and temporal bone are uncommon. A retrospective review was conducted of a large series treated at the Prince of Wales hospital between 1974 and 1995.

METHODS

Retrospective review of 59 cases of ear canal and temporal bone malignancies. These were analysed according to histopathology, disease extent, surgery, margin status and survival. A TNM-type staging system was applied to 51 cases and Kaplan-Meier survival analysis applied to this group.

RESULTS

The 5-year cancer-specific survival (CSS) for the series was 54%. For stages 1, 2, 3 and 4 disease, the CSS were 90, 45, 40 and 19%, respectively. Survival was significantly higher where clear surgical margins were achieved (80 vs 35%).

CONCLUSIONS

Carcinoma of the external ear canal is rare and, in Australia, is often related to recurrence of periauricular cutaneous malignancy. Surgical extirpation with clear margins provides the best survival.

An occupation-industry matrix analysis of mesothelioma cases in Australia 1980-1985

Australia has one of the highest national incidences of mesothelioma in the world and the rate is still rising. An industry-occupation matrix analysis was conducted for the 858 mesothelioma cases that were reported to the Australian Mesothelioma Surveillance Program between 1980 and 1985. Definite, probable, or possible occupational exposure had occurred in 57 percent (492/858) of the subjects. The primary asbestos production or manufacturing industry constituted the largest number of cases (137/492, 27.8%), followed by shipbuilding, repair and demolition (114/492, 23.2%), the building industry (69/492, 14.1%), and the railway locomotive construction and maintenance industry (47/492, 9.6%). Laborers constituted 14.8 percent (n = 73) of the occupations with a history of exposure to asbestos, followed by carpenters (13.0%, n = 64), boilermakers (10.6%, n = 52), and fitters/turners (8.1%, n = 40). The distribution of occupations in specific industries is presented in this article.

Distribution of mesothelioma cases in different occupational groups and industries in Australia, 1979-1995

Australia was a producer and user of asbestos and has one of the highest national incidences of mesothelioma in the world. The incidence is still rising and expected to do so for another 10-20 years. A study was conducted in 1996 to examine the past and current incidence rates of mesothelioma in a number of industries and occupations as the basis for predicting future outcomes. Occupational histories of a total of 3758 mesothelioma cases collected by two sequential national schemes--the Australian Mesothelioma Surveillance Program (1979-1985) and Australian Mesothelioma Register (1986-1995)--were reviewed and coded by the authors. The building industry contributed the largest number of cases nationwide followed by shipbuilding and repair, asbestos cement production, crocidolite mining and milling, railway locomotive construction and repair, coal-fired power stations, and other engineering operations. The mean latency between initial occupational asbestos exposure and diagnosis of the disease was 37.4 years (range = 4-66 years) for cases notified between 1979 and 1985, and 41.4 years (range = 6-84 years) for those between 1986 and 1995. Trends for each industry group have been changing considerably in the past 16 years, with the traditional primary asbestos industry cases from crocidolite mining and milling now on the decline and cases from asbestos cement production having plateaued. In contrast, more recently, more cases were observed from the asbestos user industries such as the building industry, and from occupations such as plumbers, carpenters, machinists, and car mechanics. These increases might be a reflection of the longer latency effects of the intermittent and less severe exposures in these larger occupational groups.

Voice changes and thyroid surgery: is pre-operative indirect laryngoscopy necessary?

BACKGROUND

Indirect laryngoscopy (IDL) is often performed prior to thyroid surgery to detect pre-existing vocal cord pathology.

METHODS

A retrospective chart review of 201 patients undergoing thyroid surgery at the Prince of Wales Hospital was undertaken in order to study the patterns of pre-operative and postoperative voice changes and IDL findings.

RESULTS

A total of 9% of patients had pre-operative voice symptoms, and 22% of this group had abnormalities detected on pre-operative IDL. Of 160 documented IDL, 4% revealed vocal cord pathology in asymptomatic patients, including an asymptomatic recurrent laryngeal nerve palsy.

CONCLUSIONS

Indirect laryngoscopy remains a useful but flawed pre-operative screening tool for patients with voice symptoms, but the literature suggests that more advanced phoniatric tests will provide superior diagnostic sensitivity. The role of routine pre-operative laryngoscopy for asymptomatic patients is of debatable value.

Intratubal pressure before and after transcervical catheterization of the fallopian tubes

OBJECTIVE

To assess the intratubal pressure (ITP) and patency status of the fallopian tubes before and after transcervical catheterization of the fallopian tubes (TCFT).

DESIGN

Prospective procedural assessment.

SETTING

Pope Paul VI Institute for the Study of Human Reproduction.

PATIENT(S)

Two hundred thirty-four women with either primary or secondary infertility.

INTERVENTION(S)

Patients underwent selective hysterosalpingography and, in some cases, TCFT with measurement of the ITP before and after the procedure.

MAIN OUTCOME MEASURE(S)

The ITP before and after TCFT.

RESULT(S)

The mean (+/-SD) ITP in freely patent tubes was 0.53 +/- 0.06 atm, that in partially obstructed tubes was 1.23 +/- 0.52 atm, and that in completely obstructed tubes was 2.79 +/- 1.40 atm. After TCFT, the mean (+/-SD) ITP in partially obstructed tubes decreased to 0.64 +/- 0.31 atm and that in completely obstructed tubes decreased to 1.86 +/- 1.35 atm. The ITP was normalized in 76% of partially obstructed tubes and in 29.5% of completely obstructed tubes. In all cases of complete obstruction in which surgical correction was attempted, organic pathology was identified.

CONCLUSION(S)

The procedure described is a safe and easy means of obtaining reliable and significant information on the status of the proximal fallopian tube.

An Australian study to evaluate worker exposure to chrysotile in the automotive service industry

A study was conducted in Sydney, Australia, in 1996 to investigate the current exposure levels, control technologies, and work practices in five service garages (four car and one bus), three brake bonding workshops, and one gasket processing workshop. This study formed part of the assessment of chrysotile as a priority existing chemical under the Australian National Industrial Chemicals Notification and Assessment Scheme. A total of 68 (11 personal and 57 area) air samples were collected, in accordance with the Australian standard membrane filter method. Fiber concentrations were determined by the traditional phase contrast microscopy (PCM) method and 16 selected samples were analyzed by the more powerful transmission electron microscopy (TEM). Chrysotile exposure of car mechanics measured by PCM was typically below the reportable detection limit of 0.05 f/mL, irrespective of whether disc brake, drum brake, or clutch was being serviced. These low levels can be attributed to the wet cleaning or aerosol spray methods used in recent years to replace the traditional compressed air jet cleaning. In the three brake shoe relining workshops, task-specific exposure reached up to 0.16 f/mL in the processes of cutting and radius grinding. TEM results were generally higher, due to its higher resolution power. The median diameter on samples taken from the service garages (passenger cars), as determined by TEM, was 0.5-1.0 micron; and was between 0.2-0.5 micron for the brake bonding and gasket processing workshops, while that for the bus service depot was 0.1-0.2 micron. Most of the respirable fibers (84%, mainly forsterite) from the bus service depot were below 0.2 micron in diameter which is the resolution limit of PCM. In the brake bonding and gasket cutting workshops, 34 percent and 44 percent of the chrysotile fibers were below 0.2 micron in diameter.

The Effects on Visually Impaired Children of Viewing Fluorescent Stimuli under Black-Light Conditions

In this study, 30 children with low vision (divided into a high and a low visual acuity group) were presented with stimuli under four conditions (white stimuli-white light, orange stimuli-white light, white stimuli-black light, and orange stimuli-black light) and were asked to rank their preferences for the four conditions. The goal was to determine the effects of the various combinations of stimuli and lighting on the children's visual performance. The orange stimuli viewed under black light resulted in the best performance overall, benefited the low-acuity group more than the high-acuity group, and was the most-preferred condition for both groups.

Nm23 gene expression in gastric carcinoma: an immunohistochemical study

BACKGROUND

The gene Nm23 is thought to play a role in the suppression of tumour metastasis. Reduced expression of Nm23 is seen in a number of human cancers, and is associated with increased metastasis and reduced survival, most strongly in ductal breast and colorectal carcinomas.

METHODS

Nm23 gene expression was compared in gastric carcinoma and normal gastric mucosa. Twenty-three gastric carcinomas were graded for differentiation as either well, moderately or poorly differentiated. Metastatic deposits from seven of the cases were also examined, along with 10 samples of normal gastric mucosa. Specimens were incubated with a murine monoclonal antibody against the protein product of Nm23, and examined by immunohistochemical staining. A semiquantitative immunostaining index was used.

RESULTS

All normal mucosa showed moderate to strong staining; 8 of 15 poorly differentiated carcinomas showed absent or weak staining; 1 of 6 moderately differentiated carcinomas stained weakly. Both well-differentiated carcinomas stained strongly; 1 of 7 metastatic deposits stained weakly. The difference in Nm23 expression between normal mucosa and carcinomas was statistically significant (P=0.024). However, there was no statistically significant difference between the three grades of carcinomas (P=0.51), or between primary and metastatic tumour (P=0.25, all by Chi-squared test).

CONCLUSIONS

These results suggest that Nm23 may have a role in gastric carcinoma pathogenesis, but do not show a correlation with metastasis. A larger study, involving detailed clinical staging and follow-up, may be of benefit.

Health status and exposure of workers at a pilot brown coal liquefaction plant in Australia, 1985-1991

In 1985, Brown Coal Liquefaction (Victoria) Pty Ltd (BCLV) commenced operation of a pilot plant that investigated the feasibility of producing oil from brown coal. The plant operated for five years. This study aimed to use exposure and health information routinely collected by the company to characterize various health parameters of the workforce and to investigate whether any adverse health measures were exposure-related. About 1680 persons were employed at some time or other by BCLV, and the primary study population consisted of 408 workers who had a medical examination at the end of employment and who consented to being in an epidemiological study. Reported photosensitivity was associated with higher cumulative skin exposure (RR = 1.85; 95% CI = 1.22-2.78), with an exposure-response relationship of increasing risk with increasing skin exposure being suggested. There was no consistent evidence that chemical exposure at BCLV had any negative effect on the haematological, biochemical, endocrine or lung function of workers at the plant. However, the maximum follow-up period of less than eight years limits the ability of the study to detect any emerging chronic effects.

Functional profile of the isolated uremic nephron: intrinsic adaptation of phosphate transport in the rabbit proximal tubule

The maintenance of phosphate homeostasis in uremia appears to be governed both by parathyroid hormone (PTH) and by PTH-independent adaptations in renal tubular function. The relative contributions of these two mechanisms that control phosphate excretion by the diseased kidney have been difficult to define in intact animals. The present study was designed to examine the nature of the adaptation of phosphate handling by the proximal tubule of subtotally nephrectomized, uremic rabbits in vitro. Euparathyroid and hyperparathyroid uremic rabbits were studied. Tubular sensitivity to PTH was examined in vitro. The dose-response relationship between bath PTH concentration and inhibition of lumen-to-bath phosphate flux (Jp-lb) in isolated perfused proximal straight tubules (PSTs) revealed that PTH sensitivity was increased in the euparathyroid uremic rabbits and was decreased in hyperparathyroid uremic rabbits. The dose-response to dibutyryl cAMP was the same as normal in both uremic groups. These data strongly suggest the existence of a receptor-mediated adaptation in the effects of PTH on the uremic proximal tubule. In addition to an altered PTH-sensitivity the uremic PST also exhibited an alteration in the basal rate of phosphate transport studied in the presence of normal rabbit serum. Although net volume flux across the PST increased in both uremic groups as a possible consequence of hypertrophy, net phosphate flux per unit length was unchanged. Considering the increase of luminal area in these tubules, net phosphate flux per unit reabsorptive surface area was actually decreased. This dissociation is supportive of the existence of an intrinsic tubular adaptation which is independent of the size of the tubule per se. These studies indicate that there is an intrinsic adaptation of the basal rate of phosphate transport by the uremic rabbit proximal tubule and that the sensitivity of the tubule to PTH is altered. The data are strongly suggestive of an increase in the number of PTH receptors in the proximal tubule of the euparathyroid uremic rabbit and suggest that "down regulation" or persistent occupancy of these receptors occurs when hyperparathyroidism supervenes.

Radioimmunoassay for trifluoperazine in human plasma

1 A new sensitive and rapid radioimmunoassay procedure for the determination of the plasma concentrations of the neuroleptic drug trifluoperazine is described. 2 The antiserum developed for trifluoperazine cross-reacted with N-desmethyltrifluoperazine and 7-hydroxytrifluoperazine to the extent of 26 and 24% respectively but its cross-reactivity with commonly co-administered tricyclic antidepressants and antianxiety agents tested was negligible. 3 The assay, based on the above antiserum, enabled the quantitation of 50 pg of the drug in 200 microliters of plasma with a coefficient of variation of about 2% and therefore should be applicable for singly dose pharmacokinetic and bioavailability studies. It should be applicable to therapeutic monitoring of the drug in patients.