Reaction force exposure for tightening tool users: A psychophysical based experimental study of electric right-angle nutrunners

Reaction forces from nutrunner tools constitute a risk of developing MSDs. However, recommendations for sustainable reaction force levels are lacking. The aim of this study was to inform recommendations regarding reaction load exposures from right-angle nutrunners. Through a psychophysics approach, experienced assembly workers subjectively assessed reaction loads when using a nutrunner in six combinations of tool tightening strategy, work-pace and screw-joint stiffness. Electromyography, tool and joint parameters were measured. Regardless of tightening strategy, joint stiffness and work-pace combinations, no large differences in acceptable tightening torque, peak reaction force, and handle displacement were observed. However, acceptable jerk and impulse differed substantially between the TurboTight® (high-acceleration) and QuickStep® (conventional) tightening strategies. Although the TurboTight® strategy overall showed reduced peak muscular activities compared to the QuickStep®, the participant-rated acceptable torque levels were similar, plausibly due to TurboTights' high jerk levels. Jerk and impulse are hypothesized to influence the perception of reaction loads.

Use of metagenomic microbial source tracking to investigate the source of a foodborne outbreak of cryptosporidiosis

Cryptosporidium is a protozoan parasite of global public health importance that causes gastroenteritis in a variety of vertebrate hosts, with many human outbreaks reported yearly, often from ingestion of contaminated water or food. Despite the major public health implications, little is typically known about sources of contamination of disease outbreaks caused by Cryptosporidium. Here, we study a national foodborne outbreak resulted from infection with Cryptosporidium parvum via romaine lettuce, with the main goal to trace the source of the parasite. To do so, we combined traditional outbreak investigation methods with molecular detection and characterization methods (i.e. PCR based typing, amplicon and shotgun sequencing) of romaine lettuce samples collected at the same farm from which the contaminated food was produced. Using 18S rRNA typing, we detected C. parvum in two out of three lettuce samples, which was supported by detections in the metagenome analysis. Microbial source tracking analysis of the lettuce samples suggested sewage water as a likely source of the contamination, albeit with some uncertainty. In addition, the high degree of overlap in bacterial species content with a public human gut microbial database corroborated the source tracking results. The combination of traditional and molecular based methods applied here is a promising tool for future source tracking investigations of food- and waterborne outbreaks of Cryptosporidium spp. and can help to control and mitigate contamination risks.

Evaluating the hip-flask defence using analytical data from ethanol and ethyl glucuronide. A comparison of two models

AIM

Claimed intake of alcohol after a traffic incident, called the hip-flask defence, can be objectively assessed by different methods. One of them is the use of two consecutive ethanol concentrations in urine and the ratio between ethanol concentrations in urine and blood. Another one is the concentrations of ethyl glucuronide (EtG) and ethyl sulphate (EtS) in blood and their ratio to ethanol. The experimental basis for both these models is from single dose studies only. The aim of this study was therefore to describe the kinetics of ethanol, EtG and EtS after ingestion of two repeated doses of ethanol and to investigate the usefulness of the different models for the assessment of the hip-flask defence.

METHODS

Thirty-five subjects ingested a first dose of 0.51 g of ethanol per kilo body weight, and two hours later a second dose (the hip-flask drink) of 0.25, 0.51 or 0.85 g of ethanol per kilo body weight. Ten urine and 17 blood samples were collected and analysed for ethanol, EtG and EtS using fully validated methods. It was investigated if all subjects fulfilled the criteria for recent drinking, according to the two different models, when using the samples collected 180-240 minutes after start of first dose drinking. According to the first model, increase in urinary ethanol concentrations and a ratio UAC/BAC below 1.3 indicated recent drinking. According to the second model, increase in blood EtG concentrations and a ratio ethanol (g/kg)/EtG (mg/L) above 1 indicated recent drinking.

RESULTS

All subjects in the high dose group fulfilled all criteria for recent drinking. One subject in the medium dose group and nine subjects in the low dose group failed to show increasing UAC and/or a UAC/BAC ratio below 1.3. One subject in the low dose group failed to show increasing concentrations of blood EtG, but all subjects showed a ratio ethanol/EtG above 1.

CONCLUSIONS

The present study showed, by the use of experimental data, that both two models used to investigate the hip-flask defence can be used, but only when the hip-flask dose is sufficiently high.

Prefrontal Cortex Oxygenation Evoked by Convergence Load Under Conflicting Stimulus-to-Accommodation and Stimulus-to-Vergence Eye-Movements Measured by NIRS

Purpose: To extend our knowledge of the functional linkages between visual fatigue and regional cerebral prefrontal cortex (PFC) oxygenation, we measured time related hemodynamic changes over the right dorsolateral prefrontal cortex (dlPFC) during convergence load under conflicting stimulus-to-accommodation and stimulus-to-vergence eye movements with and without concurrent mental load.

Methods: Twenty healthy participants with a median age of 28 years (range: 18–44 years) fixated upon a vertical bar presented separately to the left and right eyes, using polarized filters, during four counterbalanced 10-min periods: (i) no accommodation/vergence conflict (Control, Ctrl); (ii) added convergence load and accommodation/vergence conflict (Conv); (iii) added cognitive load only (Cog) and; (iv) a combination of added cognitive and convergence load and accommodation/vergence conflict (Cc). Viewing distance was 65 cm. Non-invasive measurements of hemodynamic activity over the dlPFC were quantified by functional near-infrared spectroscopy (fNIRS). During the two-convergence load conditions, the horizontal disparity of the two bars varied dynamically from no disparity to a disparity set 20% below the individual threshold for diplopia. Cognitive load was induced by the n-back-2 test which required the subject to memorize and recall the changing colors of the horizontal bars and decide when a given color was the same as that occurring two colors previously. fNIRS data were averaged over 10-s windows centered at 0, 2, 4, 6, 8, and 10 min of each task, subtracted from a 20-s baseline window immediately preceding the visual task, and then represented as changes in oxygenated hemoglobin (ΔHbO₂)_, deoxygenated hemoglobin (ΔHHb) and total hemoglobin (ΔtHb).

Results: Linear mixed model analyses showed that hemodynamic activity was systematically influenced by time (p < 0.001). The group-averaged time-related level of change across the viewing conditions did not differ when compared with one another (p > 0.05). Larger convergence eye-movement responses under conflicting stimulus-to-accommodation, and stimulus-to-vergence over time, increased ΔHbO₂ and ΔtHb only in condition Cc and after 8 min of task time (p < 0.10 for min^-6 and min^-8: p < 0.05 for min^-10).

Discussion: Collectively, our data suggest that HbO₂, HHb, and tHb, recorded over the dlPFC with fNIRS, can be used to assay the degree to which supervisory oculomotor control processes are activated during visually deficient near work.

[Research on the reliability and validity of postural workload assessment method and the relation to work-related musculoskeletal disorders of workers]

OBJECTIVE

To form a new assessment method to evaluate postural workload comprehensively analyzing the dynamic and static postural workload for workers during their work process to analyze the reliability and validity, and to study the relation between workers' postural workload and work-related musculoskeletal disorders (WMSDs).

METHODS

In the study, 844 workers from electronic and railway vehicle manufacturing factories were selected as subjects investigated by using the China Musculoskeletal Questionnaire (CMQ) to form the postural workload comprehensive assessment method. The Cronbach's α, cluster analysis and factor analysis were used to assess the reliability and validity of the new assessment method. Non-conditional Logistic regression was used to analyze the relation between workers' postural workload and WMSDs.

RESULTS

Reliability of the assessment method for postural workload: internal consistency analysis results showed that Cronbach's α was 0.934 and the results of split-half reliability indicated that Spearman-Brown coefficient was 0.881 and the correlation coefficient between the first part and the second was 0.787. Validity of the assessment method for postural workload: the results of cluster analysis indicated that square Euclidean distance between dynamic and static postural workload assessment in the same part or work posture was the shortest. The results of factor analysis showed that 2 components were extracted and the cumulative percentage of variance achieved 65.604%. The postural workload score of the different occupational workers showed significant difference (P<0.05) by covariance analysis. The results of nonconditional Logistic regression indicated that alcohol intake (OR=2.141, 95%CI 1.337-3.428) and obesity (OR=3.408, 95%CI 1.629-7.130) were risk factors for WMSDs. The risk for WMSDs would rise as workers' postural workload rose (OR=1.035, 95%CI 1.022-1.048). There was significant different risk for WMSDs in the different groups of workers distinguished by work type, gender and age. Female workers exhibited a higher prevalence for WMSDs (OR=2.626, 95%CI 1.414-4.879) and workers between 30-40 years of age (OR=1.909, 95%CI 1.237-2.946) as compared with those under 30.

CONCLUSION

This method for comprehensively assessing postural workload is reliable and effective when used in assembling workers, and there is certain relation between the postural workload and WMSDs.

Genomic analyses of Francisella tularensis strains confirm disease transmission from drinking water sources, Turkey, 2008, 2009 and 2012

Waterborne epidemics of tularaemia caused by Francisella tularensis are increasingly reported in Turkey. We have used whole genome sequencing to investigate if F. tularensis isolated from patients could be traced back to drinking water sources. Tonsil swabs from 33 patients diagnosed with oropharyngeal tularaemia in three outbreaks and 140 water specimens were analysed. F. tularensis subsp. holarctica was confirmed by microagglutination and PCR in 12 patients and five water specimens. Genomic analysis of three pairs of patient and water isolates from outbreaks in Sivas, Çorum, and Kocaeli showed the isolates to belong to two new clusters of the F. tularensis B.12 genetic clade. The clusters were defined by 19 and 15 single nucleotide polymorphisms (SNPs) in a multiple alignment based on 507 F. tularensis genomes. One synonymous SNP was chosen as a new canonical SNP (canSNP) for each cluster for future use in diagnostic assays. No SNP was identified between the genomes from the patient–water pair of isolates from Kocaeli, one SNP between the pair of isolates from Sivas, whereas the pair from Çorum differed at seven SNPs. These results illustrate the power of whole genome sequencing for tracing F. tularensis patient isolates back to their environmental source.

Phylogeographical pattern of Francisella tularensis in a nationwide outbreak of tularaemia in Norway, 2011

In 2011, a nationwide outbreak of tularaemia occurred in Norway with 180 recorded cases. It was associated with the largest peak in lemming density seen in 40 years. Francisella tularensis was isolated from 18 patients. To study the geographical distribution of F. tularensis genotypes in Norway and correlate genotype with epidemiology and clinical presentation, we performed whole genome sequencing of patient isolates. All 18 genomes from the outbreak carried genetic signatures of F. tularensis subsp. holarctica and were assigned to genetic clades using canonical single nucleotide polymorphisms. Ten isolates were assigned to major genetic clade B.6 (subclade B.7), seven to clade B.12, and one to clade B.4. The B.6 subclade B.7 was most common in southern and central Norway, while clade B.12 was evenly distributed between the southern, central and northern parts of the country. There was no association between genotype and clinical presentation of tularaemia, time of year or specimen type. We found extensive sequence similarity with F. tularensis subsp. holarctica genomes from high-endemic tularaemia areas in Sweden. Finding nearly identical genomes across large geographical distances in Norway and Sweden imply a life cycle of the bacterium without replication between the outbreaks and raise new questions about long-range migration mechanisms.

Phylogeographical pattern of Francisella tularensis in a nationwide outbreak of tularaemia in Norway, 2011

In 2011, a nationwide outbreak of tularaemia occurred in Norway with 180 recorded cases. It was associated with the largest peak in lemming density seen in 40 years. Francisella tularensis was isolated from 18 patients. To study the geographical distribution of F.tularensis genotypes in Norway and correlate genotype with epidemiology and clinical presentation,we performed whole genome sequencing of patient isolates. All 18 genomes from the outbreak carried genetic signatures of F. tularensis subsp. holarctica and were assigned to genetic clades using canonical single nucleotide polymorphisms. Ten isolates were assigned to major genetic clade B.6 (subclade B.7),seven to clade B.12, and one to clade B.4. The B.6 subclade B.7 was most common in southern and central Norway, while clade B.12 was evenly distributed between the southern, central and northern parts of the country. There was no association between genotype and clinical presentation of tularaemia, time of year or specimen type. We found extensive sequence similarity with F. tularensis subsp. holarctica genomes from high-endemic tularaemia areas in Sweden.Finding nearly identical genomes across large geographical distances in Norway and Sweden imply a life cycle of the bacterium without replication between the outbreaks and raise new questions about long-range migration mechanisms.

Trapezius muscle activity increases during near work activity regardless of accommodation/vergence demand level

Aim

To investigate if trapezius muscle activity increases over time during visually demanding near work.

Methods

The vision task consisted of sustained focusing on a contrast-varying black and white Gabor grating. Sixty-six participants with a median age of 38 (range 19–47) fixated the grating from a distance of 65 cm (1.5 D) during four counterbalanced 7-min periods: binocularly through −3.5 D lenses, and monocularly through −3.5 D, 0 D and +3.5 D. Accommodation, heart rate variability and trapezius muscle activity were recorded in parallel.

Results

General estimating equation analyses showed that trapezius muscle activity increased significantly over time in all four lens conditions. A concurrent effect of accommodation response on trapezius muscle activity was observed with the minus lenses irrespective of whether incongruence between accommodation and convergence was present or not.

Conclusions

Trapezius muscle activity increased significantly over time during the near work task. The increase in muscle activity over time may be caused by an increased need of mental effort and visual attention to maintain performance during the visual tasks to counteract mental fatigue.

Francisella tularensis subspecies holarctica occurs in Swedish mosquitoes, persists through the developmental stages of laboratory-infected mosquitoes and is transmissible during blood feeding

In Sweden, mosquitoes are considered the major vectors of the bacterium Francisella tularensis subsp. holarctica, which causes tularaemia. The aim of this study was to investigate whether mosquitoes acquire the bacterium as aquatic larvae and transmit the disease as adults. Mosquitoes sampled in a Swedish area where tularaemia is endemic (Örebro) were positive for the presence of F. tularensis deoxyribonucleic acid throughout the summer. Presence of the clinically relevant F. tularensis subsp. holarctica was confirmed in 11 out of the 14 mosquito species sampled. Experiments performed using laboratory-reared Aedes aegypti confirmed that F. tularensis subsp. holarctica was transstadially maintained from orally infected larvae to adult mosquitoes and that 25% of the adults exposed as larvae were positive for the presence of F. tularensis-specific sequences for at least 2 weeks. In addition, we found that F. tularensis subsp. holarctica was transmitted to 58% of the adult mosquitoes feeding on diseased mice. In a small-scale in vivo transmission experiment with F. tularensis subsp. holarctica-positive adult mosquitoes and susceptible mice, none of the animals developed tularaemia. However, we confirmed that there was transmission of the bacterium to blood vials by mosquitoes that had been exposed to the bacterium in the larval stage. Taken together, these results provide evidence that mosquitoes play a role in disease transmission in part of Sweden where tularaemia recurs.

Outcomes of child psychiatric treatment

OBJECTIVE

The aim of this study was to investigate outcomes of child psychiatric outpatient treatment as usual and to identify outcome predictors, with special regard to attention-deficit/hyperactivity disorder (ADHD), mood disorder, obsessive-compulsive disorder and conduct disorder.

METHOD

Routinely collected data from 12 613 outpatients between July 2006 and January 2010 in Stockholm, Sweden were analysed. The outcome measure was change in Children's Global Assessment Scale (CGAS) ratings between first visit and case closure (∆CGAS).

RESULTS

CGAS improved during the course of treatment across all diagnostic groups, ranging from a mean change of 4 (mental retardation) to 16 (suicide attempts). ∆CGAS was two times higher in the mood disorder group compared with the ADHD group. In the mood disorder group, several psychotherapies were associated with better outcome but not medication. In the ADHD group, psychotherapeutic interventions were also associated with better outcome, but those who received treatment with central stimulants received less non-medical interventions.

CONCLUSION

Whereas the functional impairment and the level of improvement in mood disorder corresponded to previous efficacy studies, the ADHD patients were more impaired and improved less after treatment. This should prompt a critical discussion as to whether ADHD patients receive the best available treatment in CAMHS in Stockholm and elsewhere.

Child maltreatment and adult violent offending: population-based twin study addressing the 'cycle of violence' hypothesis

BACKGROUND

Associations between child maltreatment and adult violence, often termed the 'cycle of violence', are well documented. However, the nature of such links after appropriate control for confounding remains uncertain. We aimed to determine whether child maltreatment causes adult violent offending or whether suggested links are due to genetic or family environment confounding.

METHOD

A total of 18 083 20- to 47-year-old twins from the Swedish population-based Study of Twin Adults: Genes and Environment (STAGE) participated. We linked information on self-reported child maltreatment with national register data on convictions for adult crime. We used a case-control design to elucidate associations among unrelated individuals and also conducted within-discordant twin pair analyses to estimate the influence of familial confounding on this association.

RESULTS

The odds ratio (OR), adjusted for age, sex and education, for violent offending in maltreated children grown up versus unrelated controls was 1.98 [95% confidence interval (CI) 1.52-2.57]. However, the association decreased to 1.18 (95% CI 0.62-2.25) when maltreated children were compared to their non-maltreated twins, suggesting substantial confounding by genetic or family environmental factors (within-twin OR<1.98) and a weak, non-significant causal effect (within-twin OR>1.00). Familial confounding was also pronounced for the association between child maltreatment and any offending.

CONCLUSIONS

Childhood maltreatment was found to be a weak causal risk factor for adult violent offending; hence, reducing maltreatment might decrease violent crime less than previously expected. Instead, considerable familial confounding of the link between child maltreatment and adult violent offending suggests that prevention strategies need to address overlapping genetic and/or family environmental liability for abusive and violent behavior.

Molecular Detection of Persistent Francisella tularensis Subspecies holarctica in Natural Waters

Tularemia, caused by the bacterium Francisella tularensis, where F. tularensis subspecies holarctica has long been the cause of endemic disease in parts of northern Sweden. Despite this, our understanding of the natural life-cycle of the organism is still limited. During three years, we collected surface water samples (n = 341) and sediment samples (n = 245) in two areas in Sweden with endemic tularemia. Real-time PCR screening demonstrated the presence of F. tularenis lpnA sequences in 108 (32%) and 48 (20%) of the samples, respectively. The 16S rRNA sequences from those samples all grouped to the species F. tularensis. Analysis of the FtM19InDel region of lpnA-positive samples from selected sampling points confirmed the presence of F. tularensis subspecies holarctica-specific sequences. These sequences were detected in water sampled during both outbreak and nonoutbreak years. Our results indicate that diverse F. tularensis-like organisms, including F. tularensis subsp. holarctica, persist in natural waters and sediments in the investigated areas with endemic tularemia.

Trapezius muscle rest time during standardised computer work – A comparison of female computer users with and without self-reported neck/shoulder complaints

Work related musculoskeletal disorders (WMSDs) in the shoulder/neck area are a common and increasing problem among European computer workers, especially women. Long-term low-level workloads with low degree of muscle rest are a potential risk factor for developing WMSDs. The purpose of the present study of female computer users (age 45-65 years) in Denmark and Sweden was to investigate if subjects with self-reported neck/shoulder complaints (cases, N=35) show less trapezius muscle relative rest time (RRT) than controls (N=44) when performing standardised short-term computer work tasks in controlled laboratory conditions. Surface electromyography (EMG) signals were recorded bilaterally from the upper trapezius muscles during a type, edit, precision and colour word stress task. Besides RRT, 10th percentile RMS values were calculated. On the average, 15 of the cases and 18 of the controls showed analysable EMG files per task. For the colour word stress task, the results showed lower RRT values and higher 10th percentile RMS amplitude levels among cases compared to controls. No such signs could be found for the other tasks performed. The present results indicate an increased motor response to a psychological stressor among subjects with self-reported neck/shoulder complaints.

Dupuytren's contracture; increased cellularity--proliferation, is there equality?

BACKGROUND

Dupuytren's disease is a chronic inflammatory process which causes contractures of the fingers by shortening and thickening the palmar fascia. During the proliferative phase, fibroblasts transform into myofibroblasts apparently under the influence of several different factors. The disease usually develops slowly, but in some patients it tends to develop aggressively. The pathogenesis of Dupuytren's disease remains unsolved. In this study, we analyzed some histological characteristics that seem to predict rapid recurrence.

MATERIAL AND METHODS

21 patients were divided into two groups. In 11 patients the disease was classified as aggressive because it had recurred within two years after an operation. In 10 cases it was non-aggressive, as no recurrence had been seen. Five control samples were taken from healthy palmar aponeurosis. The differences in cellularity, collagen, Ki-67, MSA, alpha-SMA and tenascin between the specimens were analyzed using immunohistochemistry.

RESULTS

Alpha-SMA and Ki-67 were present more often in the aggressive specimens. Immunohistochemical stainings for macrophages and lymphocytes were negative.

CONCLUSION

There may be differences in the histology and/or immunohistochemical appearance of pathological palmar connective tissue cords in aggressive and normal Dupuytren's disease. Further studies are needed to elucidate the pathogenesis of this disease.

A method for evaluation of manual work using synchronised video recordings and physiological measurements

Industrial interventions that focus on increased productivity may impair the ergonomics, on a workstation or individual level. This paper presents a method that characterises work time consumption and physical work load of manual work, using video recordings synchronised with physiological measurements of, e.g. muscular activity, and postures. The underlying idea was that it is possible to amalgamate technical and human aspects resulting in a synergetic evaluation. The method was developed through two case studies within the Swedish automotive industry, where manual materials handling was studied. A methodological result was that the synchronising procedure was sufficiently precise to allow work activities to be assigned significantly different levels of physical work load. These different levels may be used to predict physical work load in the design and change of production systems. It was concluded that the method is accurate enough to be a useful tool in industrial interventions.

[Anthrax--the Swedish perspective]

The recent occurrence in the USA of deliberate release of virulent Bacillus anthracis in letters sent to three media corporations and to the American senate has led to a great anxiety in Sweden and elsewhere in Europe. Numerous letters have been suspected to contain B. anthracis spores and several have contained powder of different types. In none of the tested letters collected by the Swedish police have we been able to detect anthrax bacilli. Powder containing letters have been tested with either bacterial isolation and/or B. anthracis specific PCR. Anthrax is a disease found naturally in herbivores and is occasionally spread to humans. It is caused by the gram-positive rod B. anthracis that was discovered by Robert Koch in 1876. Beginning in the 1930s many states have developed B. anthracis for use as a weapon. A few releases of the bacteria have been reported before October 2001. B. anthracis causes three forms of disease, cutaneous, pulmonary and gastro-intestinal. The pulmonary form is the most dangerous and may lead to death merely one to two days after onset of severe symptoms. This is due to the rapid growth and release of several potent toxins that engage the immune system and promote tissue destruction. B. anthracis infection can be treated with several antibiotics, among which quinolones and tetracyclins have been recommended. Diagnosis can readily be achieved by microscopy, bacterial isolation and PCR at the Swedish Institute for Infectious Disease Control and the Swedish Defence Research Agency. Antibiotics relevant for treatment of B. anthracis infections are already stockpilled in our country. Further actions to strengthen our capability to deal with bioterrorism are ongoing.

Biomonitoring of continuous microbial community adaptation towards more efficient phenol-degradation in a fed-batch bioreactor

The anaerobic degradation of phenol was studied in a fed-batch culture. Nitrate was added as electron acceptor and phenol was provided three times, to a final concentration of 200 mg/l. Randomly amplified polymorphic DNA (RAPD) and terminal fraction fragment length polymorphism (T-RFLP) were used and compared in order to monitor the microbial succession in the reactor. Phenol degradation started after an initial lag phase of 14 days and was then completed within a few days. In addition, the duration of the lag phase was shortened and the degradation rate was increased after each phenol amendment. Nitrate reduction correlated with microbial growth and phenol depletion, confirming that the degradation was carried out anaerobically. Results from the DNA analysis showed that the structure of the microbial community changed after each phenol amendment. This study confirms the potential for anaerobic degradation of environmental pollutants and also confirms that microbial acclimation towards faster degradation rates occurred upon repeated substrate amendments. Furthermore, both of the DNA-based techniques described the phenol degradation-linked community shifts with similar general results. RAPD is a faster, simpler technique that gives a higher resolution and consequently reflects the shifts in the microbial community structure better, whereas T-RFLP is more suitable for phylogenetic studies.

Motor unit recruitment in the trapezius muscle with special reference to coarse arm movements

Chronic shoulder pain is common in a variety of occupations. The "Cinderella hypothesis" suggests that the pain originates from damaged type I muscle fibres driven into degenerative processes as a result of too long activation and too short recovery time. The main purpose of this study was to investigate if the same motor units are active during all phases of coarse arm movements. Eight healthy volunteers participated in the study. Intramuscular electromyographic signals were picked up with a four-lead fine wire electrode, during a unilateral straight arm movement. The movement started with either (part 1) an abduction or a flexion, then (2) a movement in the horizontal plane from the sagittal to the frontal plane or vice versa, and finally (3) an adduction or an extension to the start position. The movement cycle was performed in three different speeds, slow, medium, and high, with one, two or five cycles per 20 s, respectively. On an average, the motor unit action potentials (MUAPs) of 6 motor units (range, 1-15) were identified per trail. In total 94% of the MUAP trains that were identified showed firings in all 3 parts of the movements. The findings support the Cinderella hypothesis, although there is a need to further investigate the temporal pattern of long-term motor unit activity.

Identification and analysis of unsatisfactory psychosocial work situations: a participatory approach employing video-computer interaction

A method for psychosocial evaluation of potentially stressful or unsatisfactory situations in manual work was developed. It focuses on subjective responses regarding specific situations and is based on interactive worker assessment when viewing video recordings of oneself. The worker is first video-recorded during work. The video is then displayed on the computer terminal, and the filmed worker clicks on virtual controls on the screen whenever an unsatisfactory psychosocial situation appears; a window of questions regarding psychological demands, mental strain and job control is then opened. A library with pictorial information and comments on the selected situations is formed in the computer. The evaluation system, called PSIDAR, was applied in two case studies, one of manual materials handling in an automotive workshop and one of a group of workers producing and testing instrument panels. The findings indicate that PSIDAR can provide data that are useful in a participatory ergonomic process of change.

Role of the DmpR-mediated regulatory circuit in bacterial biodegradation properties in methylphenol-amended soils

Pathway substrates and some structural analogues directly activate the regulatory protein DmpR to promote transcription of the dmp operon genes encoding the (methyl)phenol degradative pathway of Pseudomonas sp. strain CF600. While a wide range of phenols can activate DmpR, the location and nature of substituents on the basic phenolic ring can limit the level of activation and thus utilization of some compounds as assessed by growth on plates. Here we address the role of the aromatic effector response of DmpR in determining degradative properties in two soil matrices that provide different nutritional conditions. Using the wild-type system and an isogenic counterpart containing a DmpR mutant with enhanced ability to respond to para-substituted phenols, we demonstrate (i) that the enhanced in vitro biodegradative capacity of the regulator mutant strain is manifested in the two different soil types and (ii) that exposure of the wild-type strain to 4-methylphenol-contaminated soil led to rapid selection of a subpopulation exhibiting enhanced capacities to degrade the compound. Genetic and functional analyses of 10 of these derivatives demonstrated that all harbored a single mutation in the sensory domain of DmpR that mediated the phenotype in each case. These findings establish a dominating role for the aromatic effector response of DmpR in determining degradation properties. Moreover, the results indicate that the ability to rapidly adapt regulator properties to different profiles of polluting compounds may underlie the evolutionary success of DmpR-like regulators in controlling aromatic catabolic pathways.

Phenotypic biomonitoring using multivariate flow cytometric analysis of multi-stained microorganisms

A new method for monitoring phenotypic profiles of pure cultures and complex microbial communities was evaluated. The approach was to stain microorganisms with a battery of fluorescent dyes prior to flow cytometry analysis (FCM) and to analyse the data using multivariate methods, including principal component analysis and partial least squares. The FCM method was quantitatively evaluated using different mixtures of pure cultures as well as microbial communities. The results showed that the method could quantitatively and reproducibly resolve both populations and communities of microorganisms with 5% abundance in a diverse microbial background. The feasibility of monitoring complex microbial communities over time during the biodegradation of naphthalene using the FCM method was demonstrated. The biodegradation of naphthalene occurred to differing extents in microcosms representing three different types of aromatic-contaminated groundwater and a sample of bio-basin water. The FCM method distinguished each of these four microbial communities. The phenotypic profiles were compared with genotypic profiles generated by random-amplified polymorphic DNA analysis. The genotypic profiles of the microbial communities described only the microbial composition, and not their functional change, whereas the phenotypic profiles seemed to contain information on both the composition and the functional change of the microorganisms. Furthermore, event analysis of the FCM data showed that microbial communities with initially differing compositions could converge towards a similar composition if they had a capacity for high levels of degradation, whereas microbial communities with similar initial compositions could diverge if they differed in biodegrading ability.

Intramuscular pressure of the infra- and supraspinatus muscles in relation to hand load and arm posture

In work engaging the upper extremities, the musculoskeletal system of the shoulder is sometimes exposed to prolonged excessive load, leading to musculoskeletal disorders of the shoulder. One way of reducing work-related shoulder disorders is to establish guidelines for working postures. The purpose of this study was to identify harmful working positions, by performing a comprehensive survey of the intramuscular pressure (IMP) in the infra- and supraspinatus muscles in relation to different arm positions and external loads. Ten healthy males participated, and the IMP in the infra- and supraspinatus muscles was studied in a total of 112 combinations of arm positions and hand loads at levels that occur frequently in industrial work. High-precision spatial recordings were accomplished with a three-dimensional motion-analysis system, and the IMP was measured using the microcapillary infusion technique. The mean IMP of the infraspinatus muscle as well as that of the supraspinatus muscle increased continuously from a resting pressure at 0 degrees of upper arm elevation to a maximal pressure at 90 degrees of upper arm elevation, for all elevation planes. The mean IMP of the supraspinatus muscle appeared to be more dependent upon the elevation plane and less dependent upon the hand load, compared to the infraspinatus muscle. Even during only moderate arm elevation, the mean IMP of the infra- and supraspinatus muscles, presented here in polar diagrams, had already exceeded the levels of reduced recovery from local muscle fatigue and blood flow impairment. The elevation angle and the hand load primarily influence the development of IMP in the infra- and supraspinatus muscles.

Influence of TNT transformation on microbial community structure in four different lake microcosms

After World War II, large amounts of obsolete ammunition were dumped in various lakes in Sweden. Trinitrotoluene, TNT, was one of the main components of the dumped explosives. In this study, four different lake microcosms originating from lakes where relatively large amounts of ammunition were dumped were used to mimic the effect of TNT release on the natural microbial community. Increased microbial growth was found in lake microcosms amended with TNT. However, negligible mineralization of TNT was detected, suggesting that TNT was not utilized as a carbon source, but as a nitrogen source. Random amplified polymorphic DNA (RAPD) analysis indicated that the TNT induced no significant differences in microbial community composition and therefore, no major changes in natural selection, despite the increased microbial growth in the presence of the compound. More than 95% of the added TNT bound irreversibly to the sediments, possibly as a result of microbial transformation to reactive metabolites that subsequently bound covalently to components of the sediment. The results, taken together, suggest that no permanent change in the microbial ecology occurred as a result of the TNT amendment. This was probably due partly to the transient exposure of the microbial communities to the TNT before it became irreversibly bound to the sediment, and partly to the fact that TNT was not a primary growth substrate that strongly affects natural selection.

Structure of a Natural Microbial Community in a Nitroaromatic Contaminated Groundwater Is Altered during Biodegradation of Extrinsic, but Not Intrinsic Substrates

A BSTRACTThis study demonstrates microbial community changes over time in a nitroaromatic-contaminated groundwater upon amendment with hydrocarbons previously unknown to the microbial community (extrinsic) and hydrocarbons previously known to the microbial community (intrinsic). Sealed flasks, shaken and incubated at 25 degrees C, containing contaminated groundwater and salts were amended twice with extrinsic hydrocarbons including phenol, benzoic acid, and naphthalene, and intrinsic hydrocarbons including 2,4-dinitrotoluene (2,4-DNT) and para-nitrotoluene ( p-NT). Microbial growth, biodegradation, and community structure changes measured by random amplified polymorphic DNA (RAPD) and quantitative PCR (qPCR) targeting catechol-2,3-dioxygenase (C23O) genes were monitored over time. All amended substrates were biodegraded after both substrate amendments except for 2,4-DNT, which was only partially degraded after the second amendment. Unique microbial communities were developed in flasks amended with phenol, benzoic acid, and naphthalene. However, in the flasks amended with intrinsic hydrocarbons the microbial community remained similar to the unamended control flasks. The relative amount of C23O genes detected by qPCR correlated with the biodegradation of phenol and naphthalene but not with 2,4-DNT. The results showed that a selection for microorganisms capable of catabolizing extrinsic hydrocarbons naturally and initially present in the nitroaromatic-contaminated groundwater occurred. However, growth-linked biodegradation of added intrinsic hydrocarbons was not selective.

Intragastric movement assessment by measuring magnetic field decay of magnetised tracer particles in a solid meal

The aim of the study is to evaluate and further develop a non-invasive method for the measurement of intragastric movements. Ferrimagnetic particles (gamma-Fe2O3) are ingested within a standard test meal (pancakes), and given a permanent magnetisation by an applied homogeneous magnetic field. Magnetic measurements are performed outside the stomach, using fluxgate magnetometers anterior and posterior, in seven periods of 12 minutes each. Any movements caused by grinding and mixing in the ingesta would result in a misalignment of the magnetic moments, and hence in a decay of the external magnetic field. Twelve healthy male volunteers, aged 26.7 +/- 2.7 years (mean +/- SD), are studied. After an initial phase of low and almost linear flux density decay (32 +/- 19%, from minute 10 to minute 22 postprandially), the mean rotation and decay gradually increases (67 +/- 21%, from minute 100 to 112), and the decay becomes bi-exponential. It is hypothesised that the bi-exponential nature of the decay corresponds to the relative fractions, solid and semifluid, of gastric content. The decay curves often show superimposed 3 cycles min-1 variations, which correlate well with the basic electrical rhythm of the stomach measured by electrogastrography (EGG). It is concluded that these variations are induced by gastric contractions.

Comparative analysis of PCR versus culture for diagnosis of ulceroglandular tularemia

PCR and culture were comparatively evaluated for their abilities to demonstrate Francisella tularensis in wound specimens from tularemia patients during an outbreak in Sweden in 1998. For transport of the specimens used for PCR, a buffer solution containing a nuclease inhibitor was used, and for transport of the specimens used for culture, a commercial transport system was selected after experimental comparison of various systems. Of 40 patients with culture- and/or serology-verified ulceroglandular tularemia, PCR detected F. tularensis DNA in 30 (75%) patients, whereas culture detected bacterial growth in 25 (62%) patients. Compared to data from a previous study, the present inclusion of a nuclease inhibitor in the transport medium did not improve the sensitivity of the PCR, whereas the sensitivity of the culture procedure was significantly increased by selection of the system used for transport. Among eight patients with clinically suspected tularemia but with negative serology and culture, specimens from four patients showed detectable DNA. In three of these patients the diagnosis was verified by the demonstration of an F. tularensis-specific T-cell response in vitro. In conclusion, PCR was more sensitive than culture for demonstration of F. tularensis in wound specimens. Besides, we showed that tularemia may proceed without development of serum antibodies, and in these patients, PCR may be of special importance for verification of the diagnosis.

Paraplegia after thoracotomy--not caused by the epidural catheter

BACKGROUND

Paraplegia and peripheral nerve injuries may arise after general anaesthesia from many causes but are easily ascribed to central block if the latter has been used.

CASE REPORT

A 56-yr-old woman, with Bechterev disease but otherwise healthy, was operated with left-sided thoracotomy to remove a tumour in the left lower lobe. She had an epidural catheter inserted in the mid-thoracic area before general anaesthesia was started. Bupivacaine 0.5% 5 ml was injected once and the infusion of bupivacaine 0.1% with 2 micrograms/ml fentanyl and 2 micrograms/ml adrenaline (5 ml/h) started at the end of surgery. The patient woke up with total paralysis in the lower limb and sensory analgesia at the level of T8, which remained unchanged at several observations. Laminectomy, performed 17 h after the primary operation, showed a large piece of a haemostatic sponge (Surgicel) compressing the spinal cord, which was then decompressed but the motor and sensory deficit remained virtually unchanged both then and a year later.

CONCLUSIONS

This case shows--once again--that although central blocks may cause serious neurological complications and paraplegia, other causes are possible and have to be considered. However, all patients with an epidural catheter must be monitored for early signs and symptoms of an intraspinal process and the appropriate treatment has to be instituted instantly.

Recruitment of low threshold motor-units in the trapezius muscle in different static arm positions

A prevailing hypothesis for development of myalgia symptoms in the trapezius muscle is based on observations that in stereotypic activation of muscle the same low-threshold motor-units are the first ones to be recruited, and that these units are active throughout the contraction, until total relaxation. The theory suggests that these units are the first ones in monotonous repetitive work to be subject to degenerative processes, causing pain. The present project was undertaken to evaluate to what extent recruitment of motor-units in the trapezius muscle is position-specific, i.e. if there are motor-units that are recruited over a wide range of arm postures. Fine wire electrode pairs, inserted 2 cm lateral to the midpoint between the acromion and the C7 spinous processus, were used for signal acquisition. Methods for decomposition of the interference patterns were developed, allowing identification of single motor-units in signals registered in different arm positions. Voluntary recruitment of motor-units in the descending portion of the trapezius muscle was studied in 24 different arm positions (0-90 degrees shoulder flexion, 0-45 degrees humeral abduction, and 45-135 degrees elbow flexion) in three subjects. The results showed that the wire electrode technique and the signal processing algorithm employed allowed motor-unit identification in non-isometric conditions. It was found that low threshold motor-units in the trapezius muscle, active over a wide range of arm positions, could be identified in all three subjects. We refer to those as Cinderella, or C, units. These results support the research hypothesis addressed.

Comparison of multipole and mean value methods to quantify dust in human lungs: simulating the magnetopneumography procedure

Magnetopneumography (MPG) can quantify the retention of magnetisable particles in the lung acquired, for instance, in welding work. MPG is non-invasive and is used in occupational health, industrial hygiene and lung physiology. Following a brief magnetisation, the remanent magnetic field is mapped with magnetometers outside the thorax. There is no unique analytical inverse solution to this class of magnetostatic problem, and various inverse methods have been proposed. In the present study, the influence of variations in size and shape of the lungs and chest, magnetic measurement noise, positional noise and spatial dust distribution are investigated in five inverse methods. The mean value of the field map, calibrated against a lung phantom, is the commonly used method. Lung and chest size influence the mean value method solutions strongly. Correction for chest size reduces these errors, but bias errors and sensitivity to the deposition pattern remains a problem. A multipolar expansion, including dipolar, quadrupolar and octopolar moments, yields best results overall, provided the single-to-noise ratio is sufficient. This inverse solution is unbiased, requires no calibration with phantom lung models and serves to minimise errors due to inter-individual differences in anatomy and to inhomogeneous retention of inhaled dust.

Gastric emptying of solids measured by means of magnetised iron oxide powder

The aim of this study was to develop a radiation-free method to measure gastric emptying. Such a method would be useful e.g. for patients who need repeated measurements and in pregnancy. Ferrimagnetic particles (gamma-Fe2O3), ingested within a solid test meal (pancakes), were magnetised by an applied magnetic field. After magnetisation, the remanent magnetic field was measured with fluxgate magnetometers outside the stomach (anterior and posterior). The intragastric contents was estimated from the strength of the remanent field. The procedure was repeated 18 times over a period of up to 2 h postprandially. The test meal was chosen to correspond to a radiolabelled test meal that had previously been used in a scintigraphic study with (other) healthy persons. In vivo measurements were carried out on 16 healthy male volunteers. The estimated retained magnetic tracer in the stomach after the 2 h measurement time was 31 +/- 12% (mean +/- SD) and the lag phase time was 31 +/- 11 min. The corresponding scintigraphic curve (from the previous study) from 16 males showed 40 +/- 14% retained isotope after 2 h. The early part of the mean emptying curve decreased slightly faster than the corresponding scintigraphic one, but the similarity of the two seems promising enough for further development of the present method.

The two beta-lactamase genes of Streptomyces cacaoi, blaL and blaU, are under the control of the same regulatory system

The production of beta-lactamase in Streptomyces cacaoi, which contains two beta-lactamase-encoding genes, blaL and blaU, is inducible by beta-lactam compounds. The two genes have been cloned independently in S. lividans TK24, a beta-lactamase-negative species. The blaU clone did not respond to the presence of beta-lactams, whereas the blaL clone appeared to be inducible in S. lividans. The latter clone contains two open reading frames, blaA and blaB, located just upstream of but transcribed divergently from blaL, which were shown to be required for the production as well as the induction of BlaL. The deduced BlaA protein belongs to the LysR family of transcription regulators. In order to examine the role of BlaA in regulation, we here report on over-expression of a GST-BlaA fusion protein in Escherichia coli and its use for antibody preparation. The GST-BlaA fusion protein was partially purified and bandshift assays showed that it bound the 197-bp blaL-blaA intergenic region. The BlaA DNA binding-site was further restricted to a 30-bp sequence containing a T-N11-A motif, a characteristic of LysR-type promoters. Another T-N11-A motif upstream of the blaU gene was also shown to bind BlaA. The affinities of these two T-N11-A motifs in BlaA binding were comparable. A plasmid bearing the blaU structural gene and the blaA-blaB regulatory region was constructed and shown to confer on an S. lividans host the capacity to produce inducible beta-lactamase. It can thus be concluded that the S. cacaoi blaL and blaU genes are controlled by the same regulatory system.

DNA recovery and PCR quantification of catechol 2,3-dioxygenase genes from different soil types

With the objective of monitoring xenobiotic degrading bacteria in soil, a method for rapid extraction of DNA from soil, amenable to amplification by PCR, was developed. The method was based on lysis by freeze-thawing and subsequent addition of sodium dodecyl sulfate (SDS), hexadecyltrimethylammonium bromide and proteinase K. The extraction method required 2 h and was tested on six different soils differing in organic content, water holding capacity and pH, including ones from which DNA extraction is difficult. DNA yields from the soils ranged from 6.1 to 54.0 micrograms of DNA per g soil. The efficiency and reproducibility of the DNA extraction method were evaluated by competitive PCR. The organic content in the soils was a major factor affecting the amount of obtained DNA amenable for amplification by PCR. A PCR primer-pair was designed on the basis of the known nucleotide sequences of several catechol 2,3-dioxygenase genes. The specificity of the primer-pair was demonstrated on different sequenced catechol 2,3-dioxygenase genes and on site-specific bacterial isolates from polycyclic aromatic hydrocarbon (PAH)-contaminated soil. The concentration of catechol 2,3-dioxygenase DNA in PAH-contaminated sediment undergoing an ex situ compost process was quantified by competitive PCR over a period of 16 weeks. The concentration of PAHs and catechol 2,3-dioxygenase DNA in the soil samples, was found to correlate.

Adverse effects of hyperoxemia during cardiopulmonary bypass

OBJECTIVE

Aiming at elucidating the effects on capillary blood flow and tissue oxygenation of hyperoxemia during cardiopulmonary bypass, we studied skeletal muscle surface oxygen tensions in 10 patients undergoing elective cardiac operations.

METHODS

In a prospective investigation each patient was exposed to normoxemia (arterial oxygen tension 75 to 115 mm Hg) and hyperoxemia (arterial oxygen tension > 185 mm Hg, inspired oxygen fraction = 1.00) during normal anesthetized conditions before and after cardiopulmonary bypass, as well as during normothermic and hypothermic continuous-flow bypass. In each state hemodynamic variables and arterial and mixed venous blood gas and acid base values were measured. From these data oxygen transport variables were calculated. Tissue oxygenation was studied with the use of a multiple-point polarographic oxygen microelectrode, known to provide measures of oxygen tensions at the capillary level. The oxygen distribution profile of such a sample is also indicative of capillary blood flow distribution changes.

RESULTS

In all patients and at each occasion of the investigation markedly low mean surface oxygen tensions in skeletal muscle were registered. When hyperoxemia was instituted, a significant decrease in these surface oxygen tensions together with an increase in distribution heterogeneity was seen during all stages. Contrary to prebypass, postbypass, and hypothermic bypass, where vascular resistance, oxygen delivery, and oxygen consumption remained similar during hyperoxemia and normoxemia, a significant (p < 0.05) increase in vascular resistance together with a decline in oxygen consumption was seen during hyperoxemic normothermic (35 degrees to 36 degrees C) cardiopulmonary bypass.

CONCLUSION

These findings show that the microcirculatory response to hyperoxemia, seen under other circumstances, persists during continuous-flow cardiopulmonary bypass, normothermic as well as hypothermic. If these adverse effects on tissue oxygenation by hyperoxemia can be further verified and shown to be valid for other organs than skeletal muscle, we would suggest that hyperoxemia should be avoided, especially during normothermic cardiopulmonary bypass.

Nitrendipine and mefruside in elderly hypertensives: effects on blood pressure, cardiac output, cerebral blood flow and metabolic parameters

In this multicentre, randomised, double-blind, cross-over study, we evaluated and compared the effects of nitrendipine (a calcium entry blocker of the dihydropyridine group) and mefruside (a diuretic) on BP, cardiac output, cerebral blood flow and metabolic parameters in 22 elderly hypertensives. Eight weeks of treatment with nitrendipine (27.3 mg daily) and mefruside (30.7 mg daily) significantly reduced BP values to almost the same extent. Heart rate, cardiac output (n = 14), cerebral blood flow (n = 20), renin activity and aldosterone remained unchanged during nitrendipine and mefruside treatment. Nitrendipine did not alter any metabolic parameter (electrolytes, lipid values and blood glucose); in patients treated with mefruside serum potassium fell by 0.4 mmol/l (P < 0.001). Minor adverse events were reported in both treatment groups, mostly due to vasodilation. We conclude that both drugs possess potent and comparable haemodynamic and anti-hypertensive properties. They reduce BP by reducing total peripheral vascular resistance with maintained autoregulation of cerebral blood flow. The metabolic disturbances induced by mefruside seem to be less pronounced than that observed with other thiazide diuretics.

An aromatic effector specificity mutant of the transcriptional regulator DmpR overcomes the growth constraints of Pseudomonas sp. strain CF600 on para-substituted methylphenols

The pVI150 catabolic plasmid of Pseudomonas sp. strain CF600 carries the dmp system, which comprises the divergently transcribed dmpR gene and the dmp operon coding for the catabolic enzymes required for growth on (methyl)phenols. The constitutively expressed DmpR transcriptional activator positively controls the expression of the RpoN-dependent dmp operon promoter in the presence of the aromatic effector in the growth medium. However, the magnitude of the transcriptional response differs depending on the position of the methyl substituent on the aromatic ring. Experiments involving an elevated copy number of the dmp system demonstrate that growth on para-substituted methylphenols is limited by the level of the catabolic enzymes. An effector specificity mutant of DmpR, DmpR-E135K, that responded to the presence of 4-ethylphenol, a noneffector of the wild-type protein, was isolated by genetic selection. The single point mutation in DmpR-E135K, which results in a Glu-to-Lys change in residue 135, also results in a regulator with enhanced recognition of para-substituted methylphenols. The DmpR-E135K mutation, when introduced into the wild-type strain, confers enhanced utilization of the para-substituted methylphenols. These experiments demonstrate that the aromatic effector activation of wild-type DmpR by the para-substituted methylphenols is a major factor limiting the catabolism of these compounds.

General intelligence and cognitive profile in women with congenital adrenal hyperplasia (CAH)

To investigate possible effects of prenatal androgen exposure on cognitive functions, general intelligence and cognitive profile were studied in 22 women, 17-34 years old, with prenatal virilization due to congenital adrenal hyperplasia (CAH) (21-hydroxylase deficiency) and 22 healthy controls matched for region and date of birth. The tests were selected to measure abilities where gender differences repeatedly had been observed or that had earlier shown differences between CAH subjects and controls. The following cognitive functions were tested: Verbal, Visuo-Spatial, Visuo-Motor, Arithmetical, Logical Inductive abilities, and Field Dependence. Contrary to earlier reports, the mean general intelligence level of the CAH (22) group was significantly lower than the controls' and the earlier observed inferiority for calculation abilities in female CAH subjects was not supported by the results of the present study. A possible verbal disadvantage with significantly inferior results was noted for the two verbal tests for the CAH (22) group. For the 13 CAH/control pairs with equal general intelligence levels, the discrepancy between the inferior verbal vs. visual, arithmetic, and logical category scores was significantly larger for the CAH group than the controls. These results may suggest that CAH women develop a more masculine cognitive pattern under the influence of increased prenatal androgen exposure.

Analysis of 16S ribosomal DNA sequences of Francisella strains and utilization for determination of the phylogeny of the genus and for identification of strains by PCR

The 16S ribosomal DNAs (rDNAs) of two strains of Francisella tularensis and one strain of Francisella philomiragia were sequenced. On the basis of phylogenetic analysis data, the genus Francisella was placed in the gamma subclass of the Proteobacteria. The most closely related organism was the intracellular bacterium Wolbachia persica. The sequenced 16S rDNA molecules of the Francisella species exhibited very high levels of similarity (98.5 to 99.9%). Two variable regions, comprising 390 to 450 nucleotides of the 16S rDNA molecules of 17 additional Francisella strains, including members of the species F. tularensis and F. philomiragia, were also sequenced. At most, six nucleotide differences were observed among the sequences of the F. tularensis strains. The sequence of Francisella novicida was virtually identical to the sequences of the F. tularensis strains, thereby supporting the hypothesis that these organisms are members of the same species. On the basis of the observed differences, primer pairs were designed to distinguish strains by using the PCR at the genus, species, and subspecies levels. This permitted sensitive identification of strains belonging to the genus Francisella and discrimination of the species F. tularensis and F. philomiragia.

Identification and classification of different isolates of Francisella tularensis

The causative agent of tularemia, Francisella tularensis, occurs in two main biovars, the highly virulent F. t. biovar tularensis, found in North America; and the less virulent biovar palaearctica, found all over the northern hemisphere. Two other biovars have been proposed, F. t. biovar mediaasiatica and F. t. biovar palaearctica var. japonica. In Sweden tularemia is most frequently observed in man and varying hares (Lepus timidus), and occasionally in other species. Tularemia in hares is normally an acute fatal disease, although less fatal infections have been reported. The diagnosis of tularemia is routinely based on immunological reactions. We studied 10 different isolates of F. tularensis from varying hares, one isolate from an Ural owl (Strix uralensis), one vaccine strain, one strain of F. t. biovar japonica, and six isolates from a virulence study of F. tularensis, by biochemical tests and by hybridization experiments with probes complementary to 16S rRNA. All isolates, except the isolate F. t. biovar japonica, were characterized as F. t. biovar palaearctica by biochemical tests. In the 16S rRNA analysis all isolates were positive to the probe for Francisella tularensis and the probe for F. t. biovar palaearctica with the exception that F. t. biovar japonica reacted with the probe specific to F. t. biovar tularensis. To further confirm that the strains used belonged to F. t. biovar palaearctica virulence tests in rabbits were performed which disclosed this phenotype. The results presented in this work show that the isolated strains from the western part of Europe were F. t. biovar palaearctica, irrespective of animal origin or virulence.

Azepexole, a potent alpha 2-agonist with anaesthetic effects, does not affect cerebral energy consumption in dogs given isoflurane

The effects of the alpha 2-agonist azepexole on the cerebral blood flow (CBF) and cerebral metabolic rate for oxygen (CMRO2) were studied by a sagittal sinus outflow technique in dogs. Azepexole, 1 mg kg-1 (reported to decrease the anaesthetic requirement for isoflurane by almost 90%), caused no change in CMRO2 when given during 1.4% isoflurane anaesthesia. CBF was reduced by 26%. When the concentration of isoflurane was reduced to 0.2%, CMRO2 increased by 26% as would have been expected for the change in isoflurane concentration alone. Concomitantly CBF increased to a level not significantly different from control. Azepexole might be a useful adjunct to inhalational anaesthetics, and combined with a low dose of isoflurane it should be an excellent background anaesthetic when studying the effect of other drugs on CMRO2 in dogs as the combination seems to have little effect on the CMRO2.

Two different beta-lactamase genes are present in Streptomyces cacaoi

Two beta-lactamase genes called blaL and blaU have been cloned independently in Liège and in Umeå, from Streptomyces cacaoi. Genes blaL and blaU were found to differ largely in their nucleotide sequences, although the encoded proteins both belonged to the class A of beta-lactamases (active-site serine penicillinases). DNA-hybridization and polymerase chain reaction assays have now demonstrated that both blaL and blaU genes were present in the S. cacaoi strains used in Liège and in Umeå.

Mutagenic analysis of the promoter of the Streptomyces fradiae beta-lactamase-encoding gene

The Streptomyces fradiae beta-lactamase promoter (PblaF) was sequenced and characterized by promoter probing, primer extension, and exonuclease III-mediated deletions. The transcription start point (tsp) was the same in both S. lividans and S. fradiae. Oligodeoxyribonucleotide-directed random mutations and site-specific mutations were introduced in the promoter region. The effects of these mutations on transcription were assayed by an RNA colony hybridization method. This analysis identified cis-acting sequence determinants located similarly to the -10 and -35 regions of a typical Escherichia coli promoter. Also, a change in the distance between these regions from 19 to 17 bp drastically reduced promoter activity. PblaF was shown not to be recognized by sigma-whiG or by sigma-hrdA, hrdC, or hrdD. Sequence alignment of PblaF to sigma factor-classified Streptomyces promoters revealed little homology. Thus, PblaF is probably recognized by an as yet unidentified sigma factor.

Characterization and classification of strains of Francisella tularensis isolated in the central Asian focus of the Soviet Union and in Japan

The two subspecies of Francisella tularensis, F. tularensis subsp. tularensis (type A) and F. tularensis subsp. palaearctica (type B), differ from each other in biochemistry and virulence. Strains of F. tularensis subsp. tularensis are believed to be confined to North America, whereas strains of F. tularensis subsp. palaearctica occur in Europe, in Asia, and in North America. Moreover, the existence of two other subspecies, designated F. tularensis subsp. mediaasiatica and F. tularensis subsp. palaearcitica japonica, has been suggested for strains of F. tularensis isolated in the central Asian focus of the Soviet Union and in Japan, respectively. In the present study, strains biochemically classified as F. tularensis subsp. mediaasiatica or F. tularensis subsp. palaearctica japonica have been investigated by hybridization with probes specific to 16S rRNAs of the two main subspecies. Furthermore, the virulence and biochemical characteristics of the strains were compared with those of strains belonging to F. tularensis subsp. palaearctica and F. tularensis subsp. tularensis. It was found that 16S rRNAs of F. tularensis subsp. mediaasiatica and F. tularensis subsp. palaearctica japonica hybridize with the probe specific to a genotype proposed herein, genotype A (F. tularensis subsp. tularensis), which shows that strains genetically related to this subspecies are found outside North America. However, the central Asian strains differed from F. tularensis subsp. palaearctica and F. tularensis subsp. tularensis strains when investigated by fermentation of glucose. The results of the biochemical tests could not be unambiguously used for differentiation of strains into F. tularensis subsp. palaearctica or F. tularensis subsp. tularensis. These drawbacks suggest that classification of strains of Francisella on the basis of 16S rRNA analysis may be preferable to classification on the basis of biochemical analysis.