In vitro sensitivity of the amphibian pathogen Batrachochytrium dendrobatidis to antifungal therapeutics.

Chytridiomycosis, a skin disease caused by Batrachochytrium dendrobatidis, has caused amphibian declines worldwide. Amphibians can be treated by percutaneous application of antimicrobials, but knowledge of in vitro susceptibility is lacking. Using a modified broth microdilution method, we describe the in vitro sensitivity of two Australian isolates of B. dendrobatidis to six antimicrobial agents. Growth inhibition was observed, by measurement of optical density, with all agents. Minimum inhibitory concentrations (µg/ml; isolate 1/2) were - voriconazole 0.016/0.008; itraconazole 0.032/0.016; terbinafine 0.063/0.063; fluconazole 0.31/0.31; chloramphenicol 12.5/12.5; amphotericin B 12.5/6.25. Killing effects on zoospores were assessed by observing motility. Amphotericin B and terbinafine killed zoospores within 5 and 30 min depending on concentration, but other antimicrobials were not effective at the highest concentrations tested (100 µg/ml). This knowledge will help in drug selection and treatment optimization. As terbinafine was potent and has rapid effects, study of its pharmacokinetics, safety and efficacy is recommended.

Anaesthetic preference and outcomes for elective inguinal hernia repair: a comparative analysis of public and private hospitals.

PURPOSE: There is paucity of data regarding patient selection criteria, anaesthetic preferences and outcomes of elective inguinal hernia repair in public and private sector in the UK. This study aimed to compare such outcomes. METHODS: Five hundred and fifty-five consecutive inguinal hernia repairs performed by one consultant surgeon in public and private sector were reviewed from a prospectively maintained database. The patient demographics, anaesthetic choice, day case rates and early and long-term morbidity were analysed. RESULTS: The median age of the study group was 59 years (range 16-96 years) with a male/female ratio of 21:1. A total of 436 (78 %) patients underwent surgery in the public sector and 119 (22 %) patients in the private sector. The patients undergoing surgery in the private sector were younger compared to public sector (55 vs. 60 years, p = 0.03). The number of patients with ASA grades III and IV was higher in public sector (28.6 %) compared to private sector (p = 0.0001). General anaesthesia was the preferred anaesthetic technique in the private sector (52 %) and local anaesthesia in the public sector (66 %) (p = 0.0002). The day case rates were higher than in the private sector compared to public sector (78 vs. 66.5 %, p = 0.01). No significant difference was noted in the incidence of post-operative complications, recurrence, groin pain and satisfaction rate between the two groups. CONCLUSION: Patients undergoing surgery in the private sector are younger, healthier, prefer general anaesthesia and have higher day case rates compared to public sector. The short- and long-term outcomes are similar between public and private sectors.

Protein quality and utilization of timothy, oat-supplemented timothy, and alfalfa at differing harvest maturities in exercised Arabian horses.

To evaluate the protein quality and postgut N utilization of full-bloom timothy hay, oat-supplemented timothy-hay diets, and alfalfa hay harvested at different maturities, apparent whole tract N digestibility, urinary N excretion, and serum AA profiles were determined in light to moderately exercised Arabian horses. Six Arabian geldings (16.0 ± 0.3 yr; 467 ± 11 kg of BW) were randomly allocated to a 6 × 6 Latin square design. Diets included full-bloom timothy grass hay (G), G + 0.2% BW oat (G1), G + 0.4% BW oat (G2), mid-bloom alfalfa (A1), early-bloom alfalfa (A2), and early-bud alfalfa hay (A3). Forages were fed at 1.6% of the BW of the horse (as-fed). Each period consisted of an 11-d adaptation period followed by total collection of feces and urine for 3 d. Blood samples were taken on d 11 for analysis of serum AA concentrations. During the 3-d collection period, urine and feces were collected every 8 h and measured and weighed, respectively. Approximately 10% of the total urine volume and fecal weight per period was retained for N analyses. Fecal DM output was less (P < 0.05) in A1, A2, or A3 compared with G, G1, or G2. Apparent whole tract N digestibility was greater (P < 0.01) in A1, A2, and A3 compared with G, G1, or G2, and was greater (P < 0.05) in G1 and G2 compared with G. Nitrogen retention was not different from zero, and there were no differences (P > 0.05) in N retention among diets. Urinary N excretion and total N excretion were greater (P < 0.05) in A1, A2, and A3 compared with G, G1, or G2. Plasma concentrations for the majority of AA increased curvilinearly in response to feeding G, A1, A2, and A3 (quadratic, P < 0.05), with values appearing to maximize 2-h postfeeding. Although alfalfa N digestibility increased with decreasing harvest maturity, N retention did not differ and urinary volume and N excretion increased, indicating that postabsorptive N utilization decreased. In contrast, inclusion of oats at either 0.2 or 0.4% of the BW of the horse to timothy hay markedly enhanced N digestibility without increasing N excretion, indicating improvement in postgut N utilization. These findings indicate that feeding oat-supplemented timothy hay is more environmentally sustainable than feeding alfalfa to the horse at maintenance or under light to moderate exercise.

The association of fatty acid deficiency symptoms (FADS) with actual essential fatty acid status in cheek cells.

Seven clinical symptoms have been utilised in several studies as a means of potentially identifying children with a deficiency in essential polyunsaturated fatty acids (PUFAs). The purpose of this study was to investigate whether there was any correlation between parental reports of the frequency of these seven 'fatty acid deficiency symptoms' (FADS) with actual levels of fatty acids in buccal cell samples of 450 children aged 8-10 years old. Additionally, the relationship between FADS and cognitive test performance, ratings of attention and behaviour and other somatic complaints were explored. The severity of reported FADS was not related to the levels of omega-6 or omega-3 in buccal cell samples. There was a relationship between parental reports of child behaviour and reported FADS; with high FADS being related to higher ratings of behaviour problems. Using FADS as a marker of PUFA deficiency may not be appropriate especially when assessing typically developing children.

A double-blind, placebo-controlled study investigating the effects of omega-3 supplementation in children aged 8-10 years from a mainstream school population.

Despite the increased interest in the effects of omega-3 supplementation on children's learning and behaviour, there are a lack of controlled studies of this kind that have utilised a typically developing population. This study investigated the effects of omega-3 supplementation in 450 children aged 8-10 years old from a mainstream school population, using a randomised, double-blind, placebo-controlled design. Participants were supplemented with either active supplements (containing docosahexaenoic acid, DHA and eicosapentaenoic acid, EPA) or a placebo for 16 weeks. Cheek cell fatty acid levels were recorded pre- and post-supplementation and a range of cognitive tests and parent and teacher questionnaires were used as outcome measures. After supplementation, changes in the relationship between omega-6 and omega-3 were significant in the active group. Despite the wide range of cognitive and behavioural outcome measures employed, only three significant differences between groups were found after 16 weeks, one of which was in favour of the placebo condition. Exploring the associations between changes in fatty acid levels and changes in test and questionnaire scores also produced equivocal results. These findings are discussed in relation to previous findings with clinical populations and future implications for research.

Childrens' learning and behaviour and the association with cheek cell polyunsaturated fatty acid levels.

Increasing interest in the role of omega-3 fatty acids in relation to neurodevelopmental disorders (e.g. ADHD, dyslexia, autism) has occurred as a consequence of some international studies highlighting this link. In particular, some studies have shown that children with ADHD may have lower concentrations of polyunsaturated fatty acids (PUFAs), particularly omega-3, in their red blood cells and plasma, and that supplementation with omega-3 fatty acids may alleviate behavioural symptoms in this population. However, in order to compare levels it seems appropriate to establish fatty acid levels in a mainstream school aged population and if levels relate to learning and behaviour. To date no study has established this. For this study, cheek cell samples from 411 typically developing school children were collected and analysed for PUFA content, in order to establish the range in this population. In addition, measures of general classroom attention and behaviour were assessed in these children by teachers and parents. Cognitive performance tests were also administered in order to explore whether an association between behaviour and/or cognitive performance and PUFA levels exists. Relationships between PUFA levels and socio-economic status were also explored. Measures of reading, spelling and intelligence did not show any association with PUFA levels, but some associations were noted with the level of omega-3 fatty acids and teacher and parental reports of behaviour, with some evidence that higher omega-3 levels were associated with decreased levels of inattention, hyperactivity, emotional and conduct difficulties and increased levels of prosocial behaviour. These findings are discussed in relation to previous findings from omega-3 supplementation studies with children.

Local anaesthetic inguinal hernia repair performed under supervision: early and long-term outcomes.

INTRODUCTION: Local anaesthetic inguinal hernia repair may be technically demanding. There are minimal data regarding the outcomes of local anaesthetic hernia repair by trainees in comparison with consultants. PATIENTS AND METHODS: All consecutive local anaesthetic repairs performed by trainees and one consultant over a 9-year period were reviewed. Operation time, volume of local anaesthetic used, early and long-term complications were assessed. A postal survey was conducted to assess chronic groin pain and satisfaction rates. RESULTS: A total of 369 repairs were reviewed of which 265 repairs were performed by the consultant and 104 by trainees. The male-to-female ratio was 25:1 and the median age of the study group was 61 years (range, 18-93 years). The volume of local anaesthetic used was significantly higher for trainees than the consultant (42 ml versus 69 ml; P = 0.03). The operative time for the consultant and the trainees was 35 min and 40 min (P = 0.8). The day-case rate was higher for the consultant than the trainees (84% versus 69%; P = 0.02). Three patients operated by trainees required conversion to a general anaesthetic repair. No difference was noted in chronic groin pain (consultant 28% versus trainees 32%; P = 0.52) on the postal survey. The median follow-up was 5 years (range, 2-7 years). CONCLUSIONS: Local anaesthetic inguinal hernia repair can be performed safely by surgical trainees under consultant supervision with minimal short- and long-term morbidity. A large volume dilute solution of Lignocaine and Marcaine is recommended when hernia repair is undertaken by trainees.

Local anesthetic hernia repair in overweight and obese patients.

BACKGROUND: Inguinal hernia repair under local anesthesia (LA) has many advantages and is associated with high patient satisfaction. However, there are concerns of exceeding the maximum safe dose of LA agents in overweight and obese patients. The aim of the present study was to establish whether inguinal hernia repair could be safely performed under LA in overweight and obese patients. METHODS: Patients who underwent elective LA hernia repair under a single consultant surgeon were studied retrospectively. Each patient received the same LA mixture developed at our hospital specifically for hernia repair. The mixture includes lignocaine and bupivocaine, both with adrenaline, made up to a volume of 100 ml with saline. Data were collected by case note review, and by postal and telephone surveys. RESULTS: A total of 125 patients who underwent LA hernia repair, in whom body mass index (BMI) was measured, were studied. Based on the World Health Organization (WHO) classification, there were 35 (28%) normal weight patients and 63 (72%) overweight (BMI>or=25<30) or obese (BMI>or=30) patients. The median BMI was 27 (range 19-38). The mean volumes of LA mixture used for each group were 58 ml and 62 ml, respectively. High day case rates of 91% and 84% were obtained for the two groups, respectively. Complications included three wound hematomas and three simple wound infections, with no significant differences between groups. One patient developed a recurrent hernia (<1%). CONCLUSIONS: Local anesthetic inguinal hernia repair in the obese is safe and well tolerated. Use of a large volume local anesthetic mixture is recommended in overweight and obese patients.

Local versus general anaesthesia with Prolene Hernia System mesh for inguinal hernia repair: early and long-term outcomes.

BACKGROUND: There are minimal data regarding the feasibility of Prolene Hernia System repair under local anaesthesia and patient acceptability. This study analyses the outcomes of Prolene Hernia System repair under different anaesthetic techniques. METHODS: A retrospective review of all Prolene Hernia System repairs over a 5-year period was performed. The outcome measures were type of anaesthesia used, early and late complications, recurrence and patient satisfaction. RESULTS: 100 repairs were analysed. Seventy repairs were performed under local anaesthesia and 30 under general anaesthesia. The number of patients with a body mass index >30 were 17 (24%) and 8 (27%), respectively, in the local- and general-anaesthesia groups (p = 0.7). Day cases were higher in the local-anaesthesia group (69 days vs. 16 days, p = 0.001). Early complications were similar in the two groups. 18 (26%) patients in the local-anaesthesia group and 6 (19%) in the general-anaesthesia group developed chronic groin pain (p = 0.6). One recurrence was noted in the local-anaesthesia group. Patient satisfaction was high with both anaesthetic techniques. CONCLUSIONS: Prolene Hernia System repair under local anaesthesia results in increased day cases with similar complication rates compared to general anaesthesia. Both anaesthetic techniques are associated with good outcomes and excellent patient satisfaction.

Mineral balance in horses fed two supplemental silicon sources.

Numerous studies suggest that silicon (Si) supplementation is beneficial for mineral metabolism and bone health. Mineral balance studies have not been performed in horses to determine how these supplements affect absorption of other minerals. The purpose of these studies was to investigate the effects of two different Si supplements on mineral absorption and retention in horses. Eight geldings were randomly placed in one of two groups: control (CO) or supplemental Si, which was provided by one of two supplements. The first, sodium aluminium silicate (SA), contains a bioavailable form of Si and is high in aluminium (Al). The second supplement contains oligomeric orthosilicic acid (OSA). All horses received textured feed and ad libitum access to hay. Supplemented horses received either 200 g of SA or 28.6 ml of OSA per day. Following a 10-day adaptation period, the horses underwent a 3-day total collection. Blood samples were taken on days 0 and 13. The two balance studies were conducted 4 months apart to reduce carryover effects. Intakes of Al and Si were greater with SA supplementation (p < 0.05). Sodium aluminium silicate increased faecal and urinary Si excretion (p < 0.05). Calcium retention and apparent digestion were increased by SA (p < 0.05). It also maintained plasma Si compared with the CO which tended to have a decrease in plasma Si (p = 0.08). Supplemental OSA increased retention of Ca and B (p < 0.05) and apparent digestion of B (p < 0.01). Orthosilicic acid tended to increase Si retention (p = 0.054), apparent digestion (p < 0.065), and also increased plasma Si. Both supplements were able to alter Ca retention and B metabolism, however, only OSA was able to alter Si retention, digestibility and plasma concentration. Orthosilicic acid, an Si supplement without substantial Al, appears to be a viable option for Si supplementation as it increased Si retention and digestibility.

Inguinal hernia repair: local or general anaesthesia?

INTRODUCTION: Specialist hernia centres and public hospitals with a dedicated hernia service (Plymouth Hernia Service) have achieved remarkable results for inguinal hernia repair with the use of local anaesthesia and set the standards for groin hernia surgery. There is minimal data in the literature as to whether such results are reproducible in the National Health Service in the UK. PATIENTS AND METHODS: A retrospective analysis of all inguinal hernia repairs performed in one district general hospital over a 9-year period was performed. The outcome measures were type of anaesthesia used, early and late postoperative complications and recurrence. A postal questionnaire survey was conducted to obtain satisfaction rates. In addition, a postal questionnaire survey of consultant surgeons in Wales was performed to determine the use of local anaesthesia and day-case rates for inguinal hernia repair. RESULTS: A total of 577 hernia repairs were performed during the study period. Of these, 369 (64%) repairs were performed under local anaesthesia (LA) and 208 (36%) under general anaesthesia (GA). Day-case repair was achieved in 70% (400) of cases. The day-case rates were significantly higher under LA compared to GA (82.6% versus 42.6%; P < 0.05). Patients operated under LA had lower postoperative analgesic requirements and lower incidence of urinary retention compared with the GA group (P < 0.05). There were 7 (1.2%) recurrences at a median follow-up of 5.1 years (range, 10.3-2.5 years). Postal questionnaire revealed higher satisfaction rates with LA compared to GA repair. Only 15% of surgeons in Wales offer the majority of their patients local anaesthetic repair. CONCLUSIONS: The use of LA results in increased day-case rates, lesser postoperative analgesic requirements and fewer micturition problems. The excellent results obtained by specialist hernia centres can be reproduced by district general hospitals by increasing the use of LA to repair inguinal hernias.

A survey of inguinal hernia repair in Wales with special emphasis on laparoscopic repair.

BACKGROUND: The National Institute of Clinical Excellence (NICE) recently published its guidance on the use of laparoscopic repair for inguinal hernias. This study aimed to assess the likely uptake of laparoscopic surgery for inguinal hernias in Wales. In addition the current practice with regards to day case surgery, use of local anaesthesia, antibiotic prophylaxis, thromboembolic prophylaxis and advice regarding convalescence was assessed. METHODS: A postal questionnaire survey of all consultant surgeons (n = 91) in Wales was performed. RESULTS: There was a 70% (n = 67) response to the questionnaire. Fifteen percent of surgeons (n = 9) perform laparoscopic inguinal hernia repair in Wales; 10% of surgeons in Wales agreed with the NICE guidance. Lichtenstein hernia repair was the most commonly used the technique to repair primary inguinal hernias in Wales (82%). No surgeon currently is using a laparoscopic repair as the technique of choice for repair of primary inguinal hernias. Eighteen percent of surgeons perform all the procedures as day cases; 15% of surgeons perform more than 90% of the procedures under local anaesthesia; 44% of surgeons do not use any form of thromboprophylaxis for elective inguinal hernia repair, while 78% of the surgeons used routine antibiotic prophylaxis. Post-operative advice regarding return to sedentary work and driving was highly variable (1-4 weeks), as was advice regarding heavy work and sport (2-12 weeks). CONCLUSIONS: The uptake of laparoscopic surgery for inguinal hernia repair in Wales is low. Only a minority of surgeons agree with the NICE guidance. Similarly the uptake of day case repair and the use of local anaesthesia are minimal. The use of antibiotic and thromboembolic prophylaxis is empirical and inconsistent. There is a need for evidence-based guidelines to standardise the antibiotic prophylaxis, TE prophylaxis and advice regarding post-operative advice.

The natural history of chronic painful peripheral neuropathy in a community diabetes population.

AIMS: To examine the natural history of chronic painful diabetic neuropathy (CPDN). METHODS: A cross-sectional study of 350 people with diabetes was performed during 1998-1999 to assess the prevalence of CPDN in the community. Fifty-six patients with CPDN were identified and were followed up an average of 5 years later. RESULTS: From the original cohort, 12 patients had died and 14 had moved away or were unable to participate in the follow-up study. Thus 30 patients with CPDN [21 male, mean (SD) age 68.6 years (9.4), mean (SD) duration of diabetes 15.4 years (8.7)] were re-assessed. Seven (23%) had been pain free for at least 12 months and 23 continued to report neuropathic pain of similar quality and severity [total McGill Pain Questionnaire Score median (interquartile range) at follow-up 22 (16-39) vs. 20 (16-33) at baseline, P = 0.3; mean (SD) visual analogue scale (VAS) score for pain over the preceding 24 h 5.3 cm (2.9) vs. 4.6 cm (2.5) at baseline, P = 0.1]. Only 65% had ever received treatment for CPDN despite 96% (22/23) reporting pain to their physician; 43.5% had received antidepressants, 17.4% anticonvulsants, 39% opiates and 30% had tried complementary therapies. CONCLUSIONS: The neuropathic pain of CPDN can resolve completely over time in a minority (23%). In those in whom painful neuropathic symptoms had persisted over 5 years, no significant improvement in pain intensity was observed. Despite the improvement in treatment modalities for chronic pain in recent years, patients with CPDN continue to be inadequately treated.

Comparison of buffered and unbuffered local anaesthesia for inguinal hernia repair: a prospective study.

Bicarbonate buffered local anaesthetic solutions are known to reduce the pain of infiltration. However, its efficacy in reducing the pain of infiltration in patients undergoing inguinal hernia repair has never been tested. This study aims to test the efficacy of bicarbonate buffered solution in reducing the pain of infiltration and pain for the total surgical procedure in a series of patients undergoing elective inguinal hernia repair. Forty consecutive male patients with unilateral, reducible inguinal hernias were studied prospectively. All patients underwent surgery under local anaesthesia, the first 20 with unbuffered solution and the next 20 using buffered solution. Pain scores were obtained for the infiltration in the anaesthetic room and for the total surgical procedure. In addition, satisfaction scores were obtained at the end of the procedure. The mean pain score for the initial infiltration of unbuffered anaesthetic was 3.00 (range 0-5), and for the buffered anaesthetic it was 1.45 (range 0-4), P=0.02. The mean pain score for the entire procedure for the unbuffered group was 3.05 (range 0-6), and for the buffered group it was 1.45 (range 0-5), P=0.02. The patient satisfaction rate was higher with the buffered solution compared to unbuffered solution (P<0.05). There were no complications reported with either solution. Buffered local anaesthetic solution significantly reduces the perceived pain of inguinal hernia repair, both during the infiltration and during the procedure itself. It is safe to administer and it results in a high rate of patient satisfaction.

Metals and metalloids in tissues of American alligators in three Florida lakes.

Concentrations of metals and selenium were examined in tissues of American alligators (Alligator mississippiensis) from three lakes in central Florida, in one of which alligators have exhibited reproductive or developmental defects. Our overall objective was to determine whether the levels of metals were sufficiently high to confound the association between chlorinated hydrocarbons, which are elevated in eggs and juvenile plasma, and reproductive impairment. The concentrations of all metals were relatively low compared to those reported for alligators from elsewhere in Florida and the southeastern United States, suggesting that reproductive impairment is not due to metals and that metals pose no health risk to the alligators. We also wanted to determine whether skin, biopsied tail muscle, or tail tip tissue, all easily collected from live alligators, could be used as surrogate measures of internal tissue loads. Concentrations of arsenic, cadmium, chromium, lead, manganese, mercury, and selenium in liver were highly correlated with at least one of the three biopsied tissues. Only tin showed no significant positive correlation. No single tissue gave a high prediction of liver levels for all metals, although skin gave the highest correlation for mercury, and tail muscle gave the best overall correlation for lead and cadmium.

The use of nonlinear dielectric spectroscopy to monitor the bioelectromagnetic effects of a weak pulsed magnetic field in real time.

Nonlinear dielectric spectroscopy (NLDS) was used to detect interaction of a pulsed magnetic field (PMF) with membrane protein dynamics in aggregating Dictyostelium discoideum amoebae. In the experiments reported here, a strong nonlinear dielectric response of Dictyostelium discoideum cells is shown, and a distinctive nonlinear dielectric response of cells previously exposed to PMF is shown. The method of NLDS is shown to be capable of monitoring and charting the dynamic frequency response of the cell to an electromagnetic field.

Estimating lung cancer mortality from residential radon using data for low exposures of miners.

Some recent estimates of lung cancer risk from exposure to radon progeny in homes have been based on models developed from a pooled analysis of 11 cohorts of underground miners exposed to radon. While some miners were exposed to over 10,000 working level months (WLM), mean exposure among exposed miners was 162 WLM, about 10 times the exposure from lifetime residence in an average house and about three times the exposure from lifetime residence at the "action level" suggested by the U.S. Environmental Protection Agency. The extrapolation of lung cancer risk from the higher exposures in the miners to the generally lower exposures in the home is a substantial source of uncertainty in the assessment of the risk of indoor radon. Using the pooled data for the miners, analyses of lung cancer risk were carried out on data restricted to lower exposures, either <50 WLM or <100 WLM. In the pooled data, there were 115 lung cancer cases among workers with no occupational WLM exposure and 2,674 among exposed miners, with 353 and 562 lung cancer cases in miners with <50 WLM and <100 WLM, respectively. Relative risks (RRs) for categories of WLM based on deciles exhibited a statistically significant increasing trend with exposure in each of the restricted data sets. In the restricted data, there was little evidence of departures from a linear excess relative risk model in cumulative exposure, although power to assess alternative exposure-response trends was limited. The general patterns of declining excess RR per WLM with attained age, time since exposure and exposure rate seen in the unrestricted data were similar to the patterns found in the restricted data. Risk models based on the unrestricted data for miners provided an excellent fit to the restricted data, suggesting substantial internal validity in the projection of risk from miners with high exposures to those with low exposures. Estimates of attributable risk for lung cancer (10-14%) in the U.S. from residential radon based on models from the unrestricted data were similar to estimates based on the data for miners receiving low exposures.

Mutation rates at the glycophorin A and HPRT loci in uranium miners exposed to radon progeny.

OBJECTIVES: To find whether a relation exists between estimated levels of exposure to radon and its progeny and mutations in hypoxanthine phosphoribosyl transferase (HPRT) and glycophorin A in a cohort of former uranium miners. METHODS: A cohort study involving a sample of miners from the Radium Hill uranium mine in South Australia, which operated from 1952 to 1961. Radiation exposures underground at Radium Hill were estimated from historical radon gas measures with a job exposure matrix. Workers from the mine who worked exclusively above ground according to mine records were selected as controls. In 1991-2 miners were interviewed and blood taken for measurement of somatic mutations. Mutation rates for HPRT and glycophorin A were estimated with standard assay techniques. RESULTS: Homozygous mutations of glycophorin A were increased in underground miners (P = 0.0027) and the mutation rate tended to rise with increasing exposure with the exception of the highest exposure (> 10 working level months). However, there was no association between place of work and either the hemizygous mutations of glycophorin A or the HPRT mutation. CONCLUSIONS: There may be an association between glycophorin A mutations and previous occupational exposure to ionising radiation. However, not enough is known at present to use these assays as biomarkers for historical exposure in underground mining cohorts.

Radon daughter exposures at the Radium Hill uranium mine and lung cancer rates among former workers, 1952-87.

The aim of this historical (retrospective) cohort study was to investigate the relation between occupational exposure to radon daughters and subsequent mortality from lung cancer. Participants were former workers from the Radium Hill uranium mine, which operated in eastern South Australia from 1952 to 1961. A total of 2,574 workers were identified from mine records. Exposures to radon daughters were estimated from historical records of radon gas concentrations in the mine and from individual job histories. Exposures of underground workers were low by comparison with other mines of that period (mean 7.0 Working Level Months [WLM], median 3.0 WLM). Thirty-six percent of the cohort could not be traced beyond the end of employment at Radium Hill. Among those traced to the end of 1987, lung cancer mortality was increased relative to the Australian national population of the period (Standardized Mortality Ratio = 194, 95 percent confidence interval [CI] = 142-245). Compared with surface workers, lung cancer mortality was markedly increased in the underground workers with radon daughter exposures greater than 40 WLM (relative risk = 5.2, CI = 1.8-15.1). From the available information, we conclude that this increase is unlikely to be due to differences in smoking habits or other confounders. Taken together with the findings from other occupational studies, these results support current moves towards more stringent radiation control in the workplace, and underline the importance of research into the possible effects of domestic radon exposures.