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Biomedical subjects

G Rosén

Publications and source records attributed to G Rosén.

At least 19 recordsLinked to original sources

A review of video exposure monitoring as an occupational hygiene tool.

This study reviews use of video exposure monitoring (VEM, also known as PIMEX) as an occupational hygiene tool since its inception in the mid-1980s. VEM involves the combination of real-time monitoring instruments, usually for gases/vapours and dust, with video of the worker's activities. VEM is an established method used by practitioners in different countries. The technical aspects of these VEM systems are described, then applications of VEM are discussed, focussing on task analysis, training (risk communication), encouraging worker participation in and motivation for improvements in the workplace environment and occupational hygiene research. The experiences from these applications are used to illustrate how exposure visualization with video can act as a catalyst, initiating a change process in the workplace. Finally, the role of VEM as a workplace improvement tool, now and in the future, is discussed.

Environmental Monitoring↗

Neurophysiological processes underlying the phantom limb pain experience and the use of hypnosis in its clinical management: an intensive examination of two patients.

In a pilot study with 2 patients suffering from phantom limb pain (PLP), hypnotic suggestions were used to modify and control the experience of the phantom limb, and positron emission tomography (PET) was used to index underlying pathways and areas involved in the processing of phantom limb experience (PLE) and PLP. The patients' subjective experiences of pain were recorded in a semistructured protocol. PET results demonstrated activation in areas known to be responsible for sensory and motor processing. The reported subjective experiences of PLP and movement corresponded with predicted brain activity patterns. This work helps to clarify the central nervous system correlates of phantom limb sensations, including pain. It further suggests that hypnosis can be incorporated into treatment protocols for PLP.

Adult↗

Surface contamination to UV-curable acrylates in the furniture and parquet industry.

Surface contamination to ultraviolet radiation curable coatings (UV coatings), used increasingly in the parquet and furniture industry, is a matter of concern as a source for skin contamination. UV coatings contain chemically and biologically reactive acrylates, well known as skin contact irritants and sensitizers. Surface contamination may spread secondarily to equipment and other unexpected areas even outside the workplace. Yet, studies concerning this type of contamination are lacking due to lack of suitable sampling methods. Surface contamination of the work environment with risk for skin exposure to UV coating was measured employing a quantitative adhesive tape sampling method developed for this purpose. A pilot study was first performed at three workplaces to evaluate the contamination. In the main study, we wanted to locate and identify in detail the surface contamination of areas where problems exist, and to determine the extent of the problem. Measurements were performed at seven workplaces on two separate workdays (round 1 and 2) within a six-month period. Samples were collected from the workplaces based on the video monitoring of skin contact frequency with the surfaces and categorized into three groups to analyze risk. The pilot study indicated that surface contamination to TPGDA containing UV coatings was common, found in 76 percent of the surfaces, and varied with a maximum of 909 microg TPGDA 10 cm(-2) sampling area. In the main study TPGDA was found in 153 out of 196 collected samples (78.1%); for round one 78.1 percent (82 out of 105 samples) and for round two 78.0 percent (71 out of 91 samples). The average TPGDA mass on positive surface samples was on the first round 2,247 +/- 7,462 microg, and on the second round 2,960 +/- 4,590 microg. We conclude that surface contamination to uncured UV coatings at UV-curing lines is common and this involves a risk for harmful, unintentional skin exposure to acrylates.

Acrylates↗

Different brain areas activated during imagery of painful and non-painful 'finger movements' in a subject with an amputated arm.

The purpose of the present study was to investigate differences in brain activation with functional magnetic resonance imaging (fMRI) during imagery of painful and non-painful 'finger movements' and 'hand positioning' in a subject with an amputated arm. The subject was a right-handed man in his mid-thirties who lost his right arm just above the elbow in a car-train accident. MRI was performed with a 1.5 T Siemens Vision Plus scanner. The basic design involved four conditions: imagining 'painful finger movements', 'non-painful finger movements', 'painful hand positioning', 'non-painful hand positioning'. Imagery of finger movements uniquely activated the contralateral primary motor cortex which contains the classic 'hand area'. The lateral part of the anterior cerebellar lobe was also activated during imagery of finger movements. Imagery of pain uniquely activated the somatosensory area, and areas in the left insula and bilaterally in the ventral posterior lateral nucleus of the thalamus. It is suggested that the insula and thalamus may involve neuronal pathways that are critical for mental processing of pain-related experiences, which may relate to a better understanding of the neurobiology of phantom limb pain.

Adult↗

Common pathways in mental imagery and pain perception: an fMRI study of a subject with an amputated arm.

The present paper reviews data from two previous studies in our laboratory, as well as some additional new data, on the neuronal representation of movement and pain imagery in a subject with an amputated right arm. The subject imagined painful and non-painful finger movements in the amputated stump while being in a MRI scanner, acquiring EPI-images for fMRI analysis. In Study I (Ersland et al., 1996) the Subject alternated tapping with his intact left hand fingers and imagining "tapping" with the fingers of his amputated right arm. The results showed increased neuronal activation in the right motor cortex (precentral gyrus) when tapping with the fingers of the left hand, and a corresponding activation in the left motor cortex when imagining tapping with the fingers of the amputated right arm. Finger tappings of the intact left hand fingers also resulted in a larger activated precentral area than imagery "finger tapping" of the amputated right arm fingers. In Study II (Rosen et al., 2001 in press) the same subject imagining painful and pleasurable finger movements, and still positions of the fingers of the amputated arm. The results showed larger activations over the motor cortex for movement imagining versus imagining the hand being in a still position, and larger activations over the sensory cortex when imagining painful experiences. It can therefore be concluded that not only does imagery activate the same motor areas as real finger movements, but also that adding instructions of pain together with imaging moving the fingers intensified the activation compared with adding instructions about non-painful experiences. From these studies, it is clear that areas activated during actual motor execution to a large extent also are activated during mental imagery of the same motor commands. In this respect the present studies add to studies of visual imagery that have shown a similar correspondence in activation between actual object perception and imagery of the same object.

Adult↗

Workers' dermal exposure to UV-curable acrylates in the furniture and Parquet industry.

The use of ultraviolet radiation-curable coatings (UV-coatings) has increased rapidly in the parquet and furniture industry. Work with UV-coatings involves risk from skin exposure to chemically reactive, concentrated acrylates that are known skin contact irritants and sensitizers. Yet, the methods and tools for measuring and quantifying dermal exposure from hazardous chemicals directly on the skin are limited and methods to measure skin exposure to UV-coatings in occupational or environmental settings have been lacking. Skin exposure to UV-coatings was measured employing a quantitative tape stripping method that we have developed for this purpose. A pilot study was performed at three workplaces. In the main study, workers' skin exposure to uncured UV-coatings was measured at seven workplaces and on two separate workdays (rounds 1 and 2) within a six-month period to determine exposure variation. Skin exposure was measured at four standardized sites on the hand, 3-4 times per work shift. The forehead was sampled once. A questionnaire was carried out with the workers in both rounds to find out factors that can affect skin exposure to UV-coatings. The pilot study indicated that both skin and surface contamination to TPGDA-containing UV-coatings were common and varied up to 2110 microgram on the sampling area of 10cm(2). In the main study skin contamination due to TPGDA was found on 16 of 23 workers, at 6 out of the 7 workplaces, and from 36 (5. 4%) of the 664 samples. In round one 8.6% (n=383) of the samples contained TPGDA and in round two 1.1 % (n=281). The average TPGDA mass on all the positive samples (n=36) was 30.4+/-77.0 microgram for the first and second rounds alone this mass was 30.6+/-80 (n=33) and 28.3+/-16.5 microgram (n=3), respectively. Despite the limited sampling area and sampling sites, we could find residues of TPGDA at all sampling times, even at the beginning of the work shift. This may be due to transfer of UV-coatings through contaminated equipment, shoes and surfaces. Our study indicates that there is a risk of harmful skin exposure to UV-coatings in the furniture and parquet industry.

Acrylates↗

A method for measuring dermal exposure to multifunctional acrylates.

UV-curable acrylates are used increasingly for coating wood surfaces in the furniture industry. One of the active components, tripropylene glycol diacrylate (TPGDA), is known to be both an allergen and irritant to the skin. Methods to measure dermal exposure to skin irritants and allergens, such as acrylates, are insufficient for exposure assessment and there is none for this compound. The aim of this investigation was to develop a skin and surface sampling method, based on tape stripping, and a gas chromatographic method for quantitative analysis for assessing occupational skin exposure to multifunctional acrylates. Twelve adhesives were tested for their efficiency to remove TPGDA and UV-coating from a glass surface, the skin of guinea pigs and human volunteers employing the tape-stripping method in order to find the best performing tape. Variables that affect removal efficiency such as the applied dose and its retention time on the skin, tape adhesion time on the skin, and the number of strippings required to detect the contaminant from the skin were studied. Fixomull tape performed the best during sampling and analysis and had the most consistent removal efficiencies for the studied substances. The average removal efficiency with a single stripping at the 2 microliters TPGDA exposed skin sites was 85% (RSD = 14.1), and for UV-resin exposed sites 63% (RSD = 20.2). The results indicated that this method can be used for measuring dermal exposure to multifunctional acrylates efficiently, accurately, and economically. This method provides a sensitive and powerful tool for the assessment of dermal exposure to multifunctional acrylates both from the skin and from other contaminated surfaces in occupational field settings.

Acrylates↗

Effect of nasal lavage on nasal symptoms and physiology in wood industry workers.

Nasal complaints and impaired nasal physiology are common in various occupational environments. Saline lavage has been recommended as treatment but has not yet been sufficiently evaluated. In this cross-sectional study of 45 wood industry workers, a significant decrease in nasal symptoms (such as obstruction, posterior secretions, itching, irritation and sneezing) was seen after a 3-week treatment with Rhinomer, which contains de-ionized, sterilized, isotonic seawater. Nasal peak expiratory flow (NPEF), especially in workers with nasal complaints, and nasal mucociliary clearance also improved significantly. The treatment, according to participants, was simple to perform and there were only a few side effects.

Adult↗

Phantom limb imaginary fingertapping causes primary motor cortex activation: an fMRI study.

A conventional 1.0 T MR-scanner was used to detect signal intensity changes in blood oxygenation level dependent-sensitive acquisitions of motor cortex during real (left hand) and imaginary (right hand) fingertapping in a man who had his right arm amputated. The subject was instructed alternately to move the intact left hand fingers and to imagine tapping his 'fingers' on the amputated right hand. Activated areas were detected using a cross-correlation technique with superimposition of highly correlated voxels on to a corresponding high resolution, anatomical 3D image. Activation was observed in the right motor cortex during fingertapping with the intact left hand, and a corresponding activation in the left motor cortex for imaginary movements of the amputated right hand fingers.

Adult↗

Upper airway symptoms and function in wood surface coating industry workers.

Respiratory and ocular effects from exposure to airborne contaminants in workers employed in the manufacture of wood products using ultraviolet radiation curing (UV) or acid curing (AC) of surface coating were investigated. Surface coating line or finishing workers exclusively employed in one or both processes were compared to a control group. Symptoms of exposure were investigated by questionnaire and medical examination. Nasal, pharyngeal, and ocular symptoms of discomfort, but not lower airway, were common among all exposed groups. These symptoms were most frequent in UV line workers and finishers of UV surface-coated wood products. Mucociliary clearance was significantly slower in UV line workers. Significantly higher olfaction thresholds were observed in UV line and AC line workers and finishers of UV/AC surface-coated wood products. Low levels of organic solvents and coating dusts (composed in part of wood dust, chemical composition unknown) were measured in the workers' breathing zones. Although remarkable improvements have been made in both AC and UV surface coating, additional control measures to eliminate airborne contaminants and improved work practices are required.

Adult↗

Symptoms, airway physiology and histology of workers exposed to medium-density fiber board.

Medium-density fiber (MDF) board was recently introduced in the furniture industry. In this pilot study health complaints, physiology, and histology of the upper airways were evaluated for two groups of workers, one handling MDF board for at least one-third of their work week (MDF group) and another handling traditional fiber board. Civil servants served as a reference group. The frequency of health complaints concerning the airways was higher, the sense of smell was poorer, and the frequency of nasal obstruction measured with rhinomanometry was higher for the MDF group, while mucociliary activity was lower in the group handling traditional board. In both groups forced vital capacity was low when compared with expected values. Histological specimens from the middle turbinate of the nose showed, in a few cases, nasal epithelial dysplasia in the traditional board group, but histological changes in terms of scoring did not differ significantly between the groups.

Cross-Sectional Studies↗

[Group therapy of patients with chronic pain].

51 patients suffering chronic pain, with different diagnoses, were treated in groups as outpatients using a cognitive behavioural approach. Groups of 7-8 patients met for two hours a week for six weeks. The groups were led by a team consisting of a clinical psychologist, a physiotherapist and a doctor. The patients learned about different aspects of pain, self-exercise and relaxation by selfhypnosis. Group dynamics was used to strengthen self-esteem, facilitate learning and encourage a change of attitude towards pain. Each patient answered a questionnaire about activities, level of pain, drugs and psychological symptoms before and immediately after treatment, and at follow-up one year later. At follow-up, 43% were less depressed, 70% felt less pain and 50% were more active and used less drugs.

Ambulatory Care↗

Reduction of exposure to solvents and formaldehyde in surface-coating operations in the woodworking industry.

A 1-year study has been performed at a company which manufacturers office furniture, and can be subdivided into three phases: measurement of exposure prior to remedial measures; remedial measures whose purpose was to reduce exposure; and new measurements after remedial measures. Remedial measures concentrated on changes which would reduce exposure to solvents. These measures fall into two categories: (i) the training of employees about the way airborne pollutants spread and ways of avoiding exposure; and (ii) locating and eliminating important sources of emission. Employees were trained mainly by the PIMEX (PIcture Mix EXposure) method for showing them how exposure depended on methods of work and conditions at the workplace. The most important sources of solvent emissions were pin-pointed by the GridMap method. The results show that exposure can be greatly reduced through training, adjustment of existing equipment and minor technical measures. This is the case even when exposure is initially at a concentration which is clearly below hygienic limit values. This approach should also reduce exposure to formaldehyde, though this could not be evaluated because the raw materials used changed during the study.

Environmental Exposure↗

Video filming and pollution measurement as a teaching aid in reducing exposure to airborne pollutants.

A method called PIMEX has been developed for investigation of the causes of exposure to airborne pollutants at workplaces. The method involves measurement of the subject's exposure with a personal, direct-reading instrument. The sampling signal is transmitted by telemetry to a special video mixer. A video camera is also connected to the video mixer. The camera is used for filming the subject. The video mixer's output signal is fed to a monitor which continuously shows how the subject works and how exposure varies. The method has been used for producing two films on the causes of exposure to solvent and effective measures for reducing exposure: one deals with screen printing and the other with surface treatment at wood-processing plants. The films have been shown at a large number of workplaces at discussions about workplace conditions, proving useful tools in efforts to reduce workplace risks and giving rise to concrete measures and increased interest in the workplace environment.

Air Pollutants, Occupational↗

Concurrent video filming and measuring for visualization of exposure.

A method has been developed for simultaneous video filming and exposure measurement with a presentation of the current exposure level mixed into the picture. With the aid of special equipment, the video camera and the instruments are coupled together in such a way that the outgoing video signal will give a picture carrying superimposed information as to the current level of the exposure. It is intended to serve as an aid in the evaluation of various measures for reducing the exposure and in connection with the training of personnel performing work involving exposure. The method has been tried out for air pollutants in seven different cases where exposure to organic solvents, carbon monoxide, wood dust and fume from welding occurred. The result, in the form of a film, showed with great clarity what working operations were critical with regard to the current exposure. In one plant where the method was used in connection with spray-painting, a study was undertaken in order to see how the exposure could be reduced by simple measures. The results showed that the exposure was reduced drastically. The method is usable for air pollutants and also for other measurable environmental factors. The method is ready for use, but there are many ways in which the system could be improved. Further evaluation is also necessary.

Adhesives↗

Effects of exposure to vehicle exhaust on health.

Exposure to combustion engine exhaust and its effect on crews of roll-on roll-off ships and car ferries and on bus garage staff were studied. The peak concentrations recorded for some of the substances studied were as follows: total particulates (diesel only) 1.0 mg/m3, benzene (diesel) 0.3 mg/m3, formaldehyde (gasoline and diesel) 0.8 mg/m3, and nitrogen dioxide (diesel) 1.2 mg/m3. The highest observed concentration of benzo(a)pyrene was 30 ng/m3 from gasoline and diesel exhaust. In an experimental study volunteers were exposed to diesel exhaust diluted with air to achieve a nitrogen dioxide concentration of 3.8 mg/m3. Pulmonary function was affected during a workday of occupational exposure to engine emissions, but it normalized after a few days with no exposure. The impairment of pulmonary function was judged to have no appreciable, adverse, short-term impact on individual work capacity. In the experimental exposure study, no effect on pulmonary function was observed. Analyses of urinary mutagenicity and thioether excretion showed no sign of exposure to genotoxic compounds among the occupationally exposed workers or among the subjects in the experimental study.

Air Pollutants↗

Lung function and rhizopus antibodies in wood trimmers. A cross-sectional and longitudinal study.

Pulmonary function was studied in 66 wood trimmers exposed to organic dust (moulds) after a month of no exposure (summer vacation) and then three and 27 months later, and also during a working week. The results of forced expirometry and single breath nitrogen washout were compared with those obtained in local controls and in larger reference materials. The forced vital capacity (FVC) and forced expired volume in one second (FEV1) were reduced by an average of 0.4 and 0.31, respectively, after one month of no exposure, however, the nitrogen washout variables showed no clear changes. Repeated measurements three months later on a Monday morning after two days of no exposure showed a further reduction in FVC and FEV1 by an average of 0.21 in a sawmill with high exposure to moulds (10 colony-forming units/m3), but not in another sawmill with ten times lower exposure. Further recordings 27 months later (Monday morning before work) displayed no further worsening in any spirometric variable. No change in lung function was noted after one day of work (Monday morning to Monday evening), but a further reduction in FVC of an average of 0.31 was seen in non-smokers at the end of the week, with apparent resolution over the weekend. The impairment was more obvious at the sawmill with higher air concentrations of organic dust than at the other sawmill. It is concluded that wood trimmers may develop restrictive pulmonary dysfunction, which might be explained by an immunopathological reaction to heavy mould exposure.

Adult↗