Heat-resistant, extended-spectrum ß-lactamase-producing Klebsiella pneumoniae in endoscope-mediated outbreak.

BACKGROUND: We describe an outbreak with an extended-spectrum ß-lactamase-producing Klebsiella pneumoniae strain in an intensive care unit in a secondary care hospital in Norway. The outbreak source was a fibreoptic intubation endoscope in which the outbreak strain survived despite chemothermal disinfection in a decontaminator designated for such use. The genetic marker clpK, which increases microbial heat resistance, has previously been described in K. pneumoniae outbreak strains. AIM: To investigate the role of clpK in biofilm formation and heat-shock stability in the outbreak strain. METHODS: The outbreak investigation was done by review of clinical records, screening of patients and culture from intubation endoscopes and bronchoscopes. Amplified fragment length polymorphism was used to identify the outbreak strain. clpK detection was performed by polymerase chain reaction, followed by mutant construction and heat-shock assays. FINDINGS: Five patients and one intubation endoscope contained K. pneumoniae with the same amplified fragment length polymorphism pattern. The outbreak strain contained the clpK genetic marker, which rendered the strain its increased heat resistance. The survival rate of the strain grown as biofilm following heat treatment was also strongly dependent on clpK. CONCLUSION: Although clpK has been associated with clinical isolates of K. pneumoniae in earlier outbreaks, this is the first time that a ClpK-producing strain has been isolated from an environmental outbreak source. Heat resistance of certain K. pneumoniae strains may facilitate survival in biofilms on medical equipment and hence increase the potential of those strains to persist and disperse in the hospital environment.

Systematic review of the cardiovascular effects of occupational noise.

BACKGROUND: Cross-sectional studies of occupational noise and cardiovascular effects show an association between noise and hypertension but for coronary heart disease or other cardiovascular diseases (CVDs) the evidence is not convincing. AIMS: To assess possible associations between occupational noise exposure and the risk for cardiovascular effects in follow-up studies published after 1999. METHODS: We performed a systematic critical literature review of original articles from key literature databases of associations between workplace noise and health. The studies were identified by search in Ovid Medline, Ovid Embase, Web of Science, Scopus and ProQuest Health and Safety Sciences Abstracts. We selected prospective studies of adequate quality with a measure of association between occupational noise exposure and cardiovascular health for the meta-analysis. RESULTS: Twelve papers, all prospective and mostly with high quality but with methodological shortcomings in exposure assessment, were included in the review and meta-analysis. Exposure to noise at work was consistently positively associated with hypertension [Hazard ratio (HR) = 1.68; 95% confidence interval (CI) 1.10-2.57] and CVD [relative risk (RR) = 1.34; 95% CI 1.15-1.56]. In addition, we found a trivial effect of noise exposure on CVD mortality (HR = 1.12; 95% CI 1.02-1.24). CONCLUSIONS: Occupational noise exposure is strongly associated with hypertension. For other cardiovascular effects, this meta-analysis suggests a weak association, but the evidence is limited. More longitudinal studies on the effects of occupational noise on the cardiovascular system are warranted.

Longitudinal decline in pulmonary diffusing capacity among nitrate fertilizer workers.

BACKGROUND: This study is part of a 3-year follow-up of lung function among nitrate fertilizer production workers. AIMS: To study the possible adverse effects of occupational exposure to aerosols and gases on pulmonary diffusing capacity. METHODS: A longitudinal study of a cohort of fertilizer workers who performed single-breath carbon monoxide diffusing capacity (DLco) tests and spirometry in 2007 and 2010. The workers completed a questionnaire on respiratory symptoms and smoking habits. Exposure to mineral dust, acid aerosols and inorganic gases was measured. The overall median inhalable and thoracic aerosol mass concentrations were 1.1mg/m(3) (min-max: <0.93-45) and 0.21mg/m(3) (min-max: <0.085-11), respectively. RESULTS: There were 308 participants in 2007 with 168 returning subjects in 2010. Overall, we found a statistically significant decline in the DLco of 0.068 mmol/min/kPa/year, adjusted for gender, age, height, weight, smoking status and doctor-diagnosed asthma during the 3-year follow-up (P < 0.01). The change in DLco did not vary significantly between the various job groups. Subjects with respiratory symptoms did not show a larger decline in DLco than those without symptoms. CONCLUSIONS: This study indicates a larger than expected decline in the DLco of fertilizer workers during a 3-year follow-up. However, the decline was not related to specific exposures at work, or to possible covariates of exposure.

Hearing status among Norwegian train drivers and train conductors.

BACKGROUND: There is a general perception that train drivers and conductors may be at increased risk of developing noise-induced hearing loss. AIMS: To study job-related hearing loss among train drivers and train conductors. METHODS: Audiograms from train drivers and train conductors were obtained from the medical records of the occupational health service of the major Norwegian railway company. The results were compared with audiograms from an internal control group of railway workers and an external reference group of people not occupationally exposed to noise. The monaural hearing threshold level at 4kHz, the mean binaural value at 3, 4 and 6kHz and the prevalence of audiometric notches (≥25 dB at 4kHz) were used for comparison. RESULTS: Audiograms were available for 1567 drivers, 1565 conductors, 4029 railway worker controls and 15 012 people not occupationally exposed to noise. No difference in hearing level or prevalence of audiometric notches was found between study groups after adjusting for age and gender. CONCLUSIONS: Norwegian train drivers and conductors have normal hearing threshold levels comparable with those in non-exposed groups.

Work-related post-traumatic stress disorder.

BACKGROUND: Work-related post-traumatic stress disorder (PTSD) is an important condition encountered by many occupational health practitioners. AIMS: To carry out an in-depth review of the research on occupational groups that are at particular risk of developing work-related PTSD. METHODS: A literature search was conducted in the databases OVID MEDLINE, OVID Embase, Ovid PsycINFO, ISI Web of Science and CSA Health and Safety Science Abstracts. RESULTS: Professionals such as police officers, firefighters and ambulance personnel often experience incidents that satisfy the stressor criterion for the PTSD diagnosis. Other professional groups such as health care professionals, train drivers, divers, journalists, sailors and employees in bank, post offices or in stores may also be subjected to work-related traumatic events. Work-related PTSD usually diminishes with time. CONCLUSIONS: Mental health problems prior to the traumatic event and weak social support increase the risk of PTSD. Prevention of work-related PTSD includes a sound organizational and psychosocial work environment, systematic training of employees, social support from colleagues and managers and a proper follow-up of employees after a critical event.

Respiratory function and chemical exposures among female hairdressers in Palestine.

BACKGROUND: Hairdressers are exposed to chemicals and work tasks that may cause respiratory symptoms. There is little awareness of occupational health among hairdressing salons in Palestine. AIMS: To characterize respiratory symptoms, lung function, and knowledge of exposure to hazards among female Palestinian hairdressers. METHODS: Cross-sectional study of female hairdressers and controls of female university students and staff. Working history and respiratory symptoms were collected using questionnaire. Lung function was measured. Working conditions were characterized in salons. RESULTS: A total of 170 hairdressers from 56 salons and 170 controls participated. Nineteen per cent of the hairdressers reported wheezing versus 11% in the control group. The mean forced vital capacity was 3.31 l compared with 3.42 l for controls. Adjusting for age and height, there was a forced expiratory volume in 1 s reduction of 0.093 l (95% confidence interval (CI) = 0.06-0.15) comparing hairdressers with controls. A small number of hairdressers used respiratory protective equipment, and satisfactory ventilation in salons were lacking. CONCLUSIONS: Female hairdressers had higher prevalence of reported asthma and respiratory symptoms than the controls, but these differences reduced markedly when adjusted for age, height, weight and years of education. They had lower lung function measurements than the control group. Increasing the awareness of occupational health hazards and improving the work conditions for the hairdressers in Palestine is needed. Possible bias could be present as hairdressers might have over reported symptoms or lung function measurements might be affected by differences in socioeconomic status between the two groups.

Exposure to thoracic dust, airway symptoms and lung function in cement production workers.

Cement dust exposure has previously been associated with airway symptoms and ventilatory impairment. The aim of the present study was to examine lung function and airway symptoms among employees in different jobs and at different levels of exposure to thoracic dust in the cement production industry. At the start of a 4-yr prospective cohort study in 2007, exposure to cement dust, symptoms and lung function were recorded cross-sectionally in 4,265 employees in 24 European cement plants. Bronchial exposure was assessed by 2,670 full-shift dust samples with cyclones collecting the thoracic aerosol fraction. A job exposure matrix was constructed by grouping dust concentrations according to job type and plant. Elevated odds ratios for symptoms and airflow limitation (range 1.2-2.6 in the highest quartile), but not for chronic bronchitis, were found in the higher quartiles of exposure compared with the lowest quartile. Forced expiratory volume in 1 s (FEV(1)) showed an exposure-response relationship with a 270-mL deficit of FEV(1) (95% CI 190-300 mL) in the highest compared with the lowest exposure level. The results support the hypothesis that exposure to dust in cement production may lead to respiratory symptoms and airway obstruction.

Lung function and respiratory symptoms in male Palestinian farmers.

In a cross-sectional study of 250 farmers aged 22 to 77 years, of whom 36.4% are smokers, the authors aimed at describing lung function and respiratory symptoms and to estimate associations with exposures to pesticides and dust. Lung function was measured using a spirometer. Respiratory symptoms and exposure levels were self-reported based on a modified standardized questionnaire. Mean forced vital capacity (FVC) was 4.20 L (SD = 0.93 L), 95.51% of predicted as compared to European standards. Mean forced expiratory volume in one second (FEV(1)) was 3.28 L (SD = 0.80 L), 91.05% of predicted. The authors found high symptom prevalences: 14.0% for chronic cough; 26.4% for wheeze; and 55.2% for breathlessness. There was no clear association between exposure to pesticides or dust and lung function or between such exposures and respiratory symptoms. However, a significant association was found between smoking and respiratory symptoms such as chronic cough, cough with phlegm, and wheezes. The lack of farm exposure associations could be due to improvement in farmers' awareness to pesticides hazards as well as regulations of pesticide import, or because of inherent problems with the experimental design. Farmers who kept animals and poultry seem to have less respiratory symptoms and better lung function.

The association of antiphospholipid antibodies with pregnancy-related first time venous thrombosis--a population-based case-control study.

In this population-based case-control study we explored the association of antiphospholipid antibodies with pregnancy-related venous thrombosis. From 1990 through 2003 615 pregnant women were identified at 18 hospitals in Norway with a diagnosis of first time VT. In 2006, 531 of 559 eligible cases and 1092 of 1229 eligible controls were invited for further investigations. The final study population comprised 313 cases and 353 controls, who completed a comprehensive questionnaire and donated a single blood sample, 3-16 years after index pregnancy. We report the results on lupus anticoagulant, anticardiolipin antibodies, and anti-ss(2) glycoprotein-1 antibodies alone, in combination, and with the contribution of the factor V Leiden and the prothrombin gene G20210A polymorphisms. Cut-off values for APAs were chosen according to current international consensus. 29 (9.3%) of the cases and 24 (6.8%) of the controls had at least one positive test for APAs (OR 1.4; 95% CI 0.8-2.5). Nine cases (2.8%) and no controls had more than one positive test (multi-positivity) for APAs. After excluding women with factor V Leiden or prothrombin polymorphisms, still 6 cases were multi-positive for APAs. We conclude that multi-positivity, but not single-positivity, for APAs was weakly associated with a history of ante- and postnatal VT.

A twelve-year longitudinal study of hearing thresholds among professional divers.

In this prospective study over twelve years, we have studied 30 young professional divers. The aim of the study was to see if changes in hearing thresholds were related to cumulative diving exposure. The study started at the beginning of the divers' education to become professional divers. Over the follow-up period the divers performed air-dives to shallow sea levels with a median number of 477 dives (range: 40-4458). The examination was performed by measuring air conduction thresholds in a sound treated booth. During follow-up, a significant reduction in auditory function was found at 0.25, 0.5, 2, 3 and 6 kHz for the right ear and 3, 4 and 6 kHz for the left ear. A reduction in hearing function associated with diving was found at 4 and 8 kHz (p < 0.01) both ears combined. Hearing impairment among this group of professional divers, with possible noise exposure, shows that hearing impairment is associated with their profession.

Circulating lipopolysaccharides in the blood from "bioprotein" production workers.

BACKGROUND: Workers producing bacterial single-cell protein (BSCP), "bioprotein," are exposed to organic dust containing high levels of endoxins (lipopolysaccharides, LPS). Workers in this industry have complained of episodes of fever, fatigue, chest tightness, skin dryness and rubor. The aim of the present study was to quantify LPS and inflammatory mediators in plasma among the workers and non-exposed control subjects. METHODS: We included eight non-smoking production workers, aged 32-51 (median 38), and eight non-smoking, non-exposed controls, aged 30-51 (median 39). Airborne and plasma endotoxin concentrations were measured, as well as plasma hsCRP and different cytokines, chemokines and metalloproteinases. RESULTS: The workers who did not use personal respiratory protection were exposed to varying airborne levels of endotoxin, 430 (75-15 000) EU/m3 (median, range). The level of plasma LPS was significantly elevated (p = 0.01) among the workers compared to the non-exposed controls. The workers also had elevated levels of MCP-1 (p = 0.02), MIP-1alpha (p = 0.05) and MMP-3 (p = 0.04). IL-6 and hsCRP were also elevated among the exposed group, but not significantly (p = 0.10 and p = 0.07, respectively). CONCLUSIONS: In this study, we detected LPS in plasma of individuals exposed to high levels of LPS at their workplace. This finding is supported by elevated levels of several inflammatory cytokines among the workers, significantly exceeding that of the non-exposed control group. To the best of our knowledge, this is the first time that plasma LPS, together with increased inflammatory markers in plasma, has been detected in an occupational setting.

Cross shift changes in lung function among bar and restaurant workers before and after implementation of a smoking ban.

OBJECTIVE: To study possible cross shift effects of environmental tobacco smoke (ETS) on pulmonary function among bar and restaurant employees before and after the implementation of a smoking ban in Norway. METHODS: The study included 93 subjects employed in 13 different establishments in Oslo. They were examined at the beginning and end of a workshift both while ETS exposure was present and when smoking was banned. The mean exposure level of nicotine and total dust before the ban was 28 microg/m3 (range 3-65) and 275 microg/m3 (range 81-506), respectively. Following the smoking ban, the mean level of nicotine and total dust was 0.6 mug/m3 and 77 microg/m3, respectively. Assessment of lung function included dynamic lung volumes and flows. RESULTS: The cross shift reduction in forced vital capacity (FVC) among 69 subjects participating in both examinations changed from 81 ml (SD 136) during exposure to ETS to 52 ml (SD 156) (p = 0.24) following the smoking ban. The reduction in forced expired volume in one second (FEV1) during a workshift, was borderline significantly reduced when comparing the situation before and after the intervention, by 89 ml (SD = 132) compared to 46 ml (SD = 152) (p = 0.09), respectively. The reduction in forced mid-expiratory flow rate (FEF25-75%) changed significantly from 199 ml/s (SD = 372) to 64 ml/s (SD = 307) (p = 0.01). Among 26 non-smokers and 11 asthmatics, the reduction in FEV1 and FEF25-75% was significantly larger during ETS exposure compared to after the smoking ban. There was an association between the dust concentration and decrease in FEF25-75% before the ban among non-smokers (p = 0.048). CONCLUSIONS: This first study of cross shift changes before and after the implementation of a smoking ban in restaurants and bars shows a larger cross shift decrease in lung function before compared with after the implementation of the ban.

Short term changes in lung function, leukocytosis in blood, and lachrymal fluid among bacterial single cell protein workers after an episode with high exposure to endotoxins.

AIMS: To study possible effects of endotoxin exposure among bacterial single cell protein workers on pulmonary function, blood parameters, and lachrymal fluid before and after a work shift. METHODS: The study included 23 men and five women who were examined at the start and at the end of a work shift. Most workers performed a task with unusually high exposure levels. Twelve of the workers were re-examined the day after. The workers were divided into three exposure groups: production workers with the highest assumed exposure levels (n = 18), engineers (n = 5), and clerks (n = 2). The median endotoxin level during a work shift was 34000 EU/m3 in the high exposure group (range 3300-89000 EU/m3 ), 11000 EU/m3 (range 350-27000 EU/m3) among the engineers, and 180 EU/m3 (range 60-300 EU/m3) for the clerks. The workers answered a questionnaire about work related symptoms. Assessment of lung function included dynamic lung volumes and flows. The blood analysis included cell count of leukocytes and mediators of inflammation, fibrinogen, interleukin-6 (IL-6), D-dimer, and C-reactive protein (CRP). Cells in lachrymal fluid were counted with a microscope. RESULTS: The forced vital capacity (FVC) changed significantly (p<0.05) from 5.34 l (SD 0.9) to 5.25 l (SD 0.9) and forced expired volume in one second (FEV1) from 4.15 l (SD 0.7) to 4.07 l (SD 0.7) during the work shift. The leukocytes increased significantly (p<0.05) from 6.9 10(9)/l (SD 1.2) to 7.7 10(9)/l (SD 1.5) and IL-6 from 1.5 ng/l (SD 0.6) to 3.31 ng/l (SD 2.7). Except for fibrinogen, which had a borderline increase and PEF that decreased, the parameters were normalised the day after. Four of the workers had an increase of neutrofile granulocytes in the lachrymal fluid during the shift. There was a significant association between the endotoxin concentration and decrease of FEV1 despite the use of powered respirators. CONCLUSIONS: During a work shift with unusual high levels of endotoxins at a plant manufacturing bacterial single cell protein the results show that FVC and FEV1 were reduced. Mediators of inflammation increased along with leucocytosis in blood and lachrymal fluid among the workers.

Lung function over the first 3 years of a professional diving career.

OBJECTIVES: To characterise diving exposure and pulmonary function in professional divers at the start of their formal education and during the first 3 years of their professional career. METHODS: The study included 87 men at the start of their education as professional divers. At follow up 1 and 3 years after the school 83 and 81 divers respectively were re-examined. Assessment of lung function included dynamic lung volumes and flows and transfer factor for carbon monoxide (Tl(CO)). RESULTS: 69 Divers had preschool SCUBA diving experience and had a median number of 70 dives (range 2-3000) to a median maximal depth of 40 (range 10-73) metres. During the 15 week introductory diving course, they had 44 dives (range 38-50) in the depth range 10-50 metres. The median number of dives over the follow up period was 95 (range 0-722) to a maximal median depth of 38 (range 0-98) metres. At the start of the diving course there were no differences in forced vital capacity (FVC), forced expired volume in 1 second (FEV(1)), and in Tl(CO) between the 69 pre-exposed divers and the 18 never exposed divers. The FVC was significantly larger than predicted in both groups. At follow up at 3 years there was a significant reduction in mean (SD) FEV(1) of 1.8% (6.5), in forced mid-expiratory flow rate (FEF(25-75%)) of 6.5% (11.7) and in forced expiratory flow at 75% of FVC expired (FEF(75%)) of 10.4% (16. 8). There was no change in FVC. The Tl(CO) was significantly decreased by 4.6% (8.8). No significant effects were found of cumulative diving exposure, including the number of dives, on the relative changes of any of the lung function variables. CONCLUSIONS: The results indicate that divers initially belong to a selected group with large FVC. Exposure to diving may contribute to changes in pulmonary function, mostly affecting small airways conductance.

Auditory function among young occupational divers: a 3-year follow-up study.

Auditory function was measured in a 3-year follow-up study of 54 young occupational divers divided into high-exposure (n = 23) and low-exposure (n = 31) groups. The divers performed open-sea dives with a median number of 132 dives (range 44-766) during follow-up. At the start of follow-up, hearing in the high-exposure group was reduced compared with that in the low-exposure group. During the follow-up period, the total group experienced a significantly reduced hearing ability at 4 kHz in the left ear. No difference in change between the last and the first measurement for both ears combined was found when the two groups were compared. A regression analysis of measurements at the end of follow-up shows an association between the loss of hearing in the left ear at 6 and 8 kHz and the total number of years of diving. This indicates that diving may contribute to hearing impairment.

Subacute effects of inspiratory resistive loading and head-out water immersion on pulmonary function.

Extrathoracic airways obstruction and scuba diving may induce pulmonary edema, probably because of increased hydrostatic transmural capillary pressure in the lung. This study was designed to examine the subacute pulmonary effects of the combined exposure to inspiratory resistive loading and immersion, as in scuba diving. Two groups each of eight healthy men were exposed to head-out water immersion in thermoneutral water for 40 min with or without an added inspiratory resistive load. At flows of 0.5 and 1.0 liter x s, the measured resistances were 4.4 and 9.0 hPa x s(-1) x liter(-1), respectively. Pulmonary function, including a flow-volume loop and transfer factor of the lung for carbon monoxide (Tlco, was measured before and 60 min after the end of the exposures. Body fluid balance was restored in the first 15 min after exposure, and Tlco was always corrected to a hemoglobin concentration of 146 g x liter(-1). There was a significant reduction in Tlco of 7.3+/-5.5% (P < 0.01) after the combined exposure to head-out water immersion and inspiratory resistive load. No changes in pulmonary function were seen after exposure to head-out water immersion or inspiratory resistive loading alone. The change in Tlco was normalized within 24 h. Submersion and resistance in breathing apparatus may contribute to the changes in pulmonary function seen immediately after dives. The nature of the exposure in these experiments and the time for recovery indicate that these changes are mechanically induced, and may not contribute to the long-term effects of diving on the lung.

Pulmonary and auditory function among experienced construction divers: a cross-sectional study.

We studied pulmonary and auditory function in a cross-sectional study of 26 experienced construction divers compared with 26 workshop workers matched for age, height, and smoking habits. The divers used air as breathing gas and performed open-sea bounce dives to a maximum of 50 m in sea water. The mean number of dives over a mean diving period of 20 yr (SD = 11) was 4746 (SD = 4743) (Range: 450-17000). Assessment of lung function included dynamic lung volume and flow and diffusion capacity (transfer factor) for carbon monoxide (TlCO). The auditory examination was performed measuring air conduction thresholds in a cabin. The results show a significantly higher mean forced vital capacity (FVC) of 6.01 L (SD = 0.88) in the divers compared with 5.67 L (SD = 0.84) (p = 0.045) in the controls, and an alveolar volume (VA) of 7.74 L (SD = 0.99) in the divers compared with 7.35 L (SD = 0.74) (p = 0.035) in the controls. There was a nonsignificant reduction in forced mid-expiratory flow rate (FEF25-75%) and a significant reduction in forced expiratory flow rate at 50% of FVC (FEF50%) among the divers of 4.69 L (SD = 1.41) compared with 5.76 L (SD = 2.03) among the controls of (p = 0.03). There were no differences in FEV1 and TlCO between the two groups. The divers showed reduced auditory function in their left ear compared with their right ear in the 3 kHz (p = 0.006) and 8 kHz (p = 0.022) area. No statistical difference was found in hearing thresholds of the divers compared with those of the controls. Our results indicate that exposure to diving may be associated with changes in pulmonary function and that the left ear may be more vulnerable than the right ear to hearing impairment in construction divers.

Divers' pulmonary function after open-sea bounce dives to 10 and 50 meters.

We have studied pulmonary function before and 2 h after open sea dives to 10 and 50 m and 24 h after the dive to 10 m. Nine trainee divers participated in the dive to 10 m and 17 in the dive to 50 m. Mean time in water was 53 (32-62) min for the 10-m dive and 38 (26-76) min for the 50-m dive. Assessment of lung function included dynamic lung volumes and flows and transfer factor for carbon monoxide (TlCO). There were significant reductions (P < 0.05) in forced vital capacity of 5.8% (SD = 3.9) and 1.8% (SD = 2.8), in forced expired volume in 1 s of 6.6% (SD = 3.5) and 2.7% (SD = 2.4), in forced mid-expiratory flow rate of 10.3% (SD = 7.8) and 5.2% (SD = 6.5), and in TlCO of 11.3% (SD = 7.9) and 12.8% (SD = 5.9) 2 h after the 10- and 50-m dive, respectively. Our results indicate that factors related to submersion and increased breathing resistance contribute to changes in pulmonary function in the first hours after open-sea bounce dives.

[Treatment with hyperbaric oxygen. Illustrated by the treatment of a patient with retinitis pigmentosa]. / Behandling med hyperbart oksygen. Illustret ved behandling av en pasient med retinitis pigmentosa.

A 26 year old man, who was physically fit and occupationally active but had retinitis pigmentosa and a slight hearing impairment, received hyperbaric oxygen treatment for 97 minutes at a pressure of 240 kPA for five days a week over a period of four weeks. After cessation of the treatment his lateral vision was found to be improved. The patient was examined both prior to and after the hyperbaric oxygen treatment to assess possible adverse effects. The examination consisted of a comprehensive neuropsychological test battery, audiometry and spirometry. The patient showed a reversible reduction in gas diffusion for CO (TLCO). No adverse effects on the central nervous system were found. He achieved higher scores in an intelligence test when retested. The gain was greater than usually found as a practice effect. The article discusses possible indications for hyperbaric oxygen treatment.