A simple model to estimate deposition based on a statistical reassessment of global fallout data.

Atmospheric testing of nuclear weapons began in 1945 and largely ceased in 1963. Monitoring of the resulting global fallout was carried out globally by the Environmental Measurements Laboratory and the UK Atomic Energy Research Establishment as well as at national level by some countries. A correlation was identified between fallout deposition and precipitation and an uneven distribution with latitude. In this study, the available data from 1954 to 1976 for (90)Sr and (137)Cs were reanalysed using analysis of covariance (ANCOVA) and logarithmically transformed values of the monthly deposition density as the response variable. Generalized additive models (GAM) were used to explore the relationship of different variables to the response variable and quantify the explanatory power that could be achieved. The explanatory variables which consistently explained most of the variability were precipitation at each site, latitude and change with time and a simple linear model was produced with similar explanatory power as the GAM. The estimates improved as the temporal resolution of the precipitation data increased. A good log-log fit could be obtained if a bias of about 1-6 mm precipitation per month was added, this could be interpreted as dry deposition which is not otherwise accounted for in the model. The deposition rate could then be explained as a simple non-linear power function of the precipitation rate (r(0.2-0.6) depending on latitude band). A similar non-linear power function relationship has been the outcome of some studies linking wash-out and rain-out coefficients with rain intensity. Our results showed that the precipitation rate was an important parameter, not just the total amount. The simple model presented here allows the recreation of the deposition history at a site, allowing comparison with time series of activity concentrations for different environmental compartments, which is important for model validation.

On the occurrence of radioactive fallout over Norway as a result of the Windscale accident, October 1957.

A fire at the Windscale plant at Cumbria in the UK between the 10th and the 11th of October 1957 resulted in the first publicised release of radioactivity to the wider environment. The cloud of contamination passed to the southeast of England before travelling northwards on the 14th of October as a result of weather fronts in Europe. Monitoring of radioactive fallout in Norway was at the time conducted by the Norwegian Defence Research Establishment (FFI) using a network of air and precipitation monitoring stations. This article presents results from these monitoring activities which were originally contained in laboratory journals and a series of internal reports produced by FFI. Although mainly classified during the 1950s and 1960s, recent years have seen the incremental declassification of these reports and as the 50th anniversary of the accident approaches, a distillation and reanalysis of this information has been conducted. Results indicate that radioactivity from Windscale was first detected at Bergen and Sola in the south west of Norway and a little later at Vaernes, significant amounts of radioactivity being deposited at these locations during the second and third weeks of that month. Results relating to concentrations of activity in air and precipitation and fallout levels are presented for the relevant period and discussed in relation to fallout levels in Norway during the period 1957-1960.

Antibiotic usage in Nordic countries.

The consumption of antibacterials has remained relatively stable in Scandinavia and is low compared with most other countries. Measured as "Defined Daily Doses" (DDD), the highest consumption is found in Iceland and Finland, and the lowest in Denmark and Norway. The consumption in Iceland, Finland and Sweden is about twice that in Norway. The distribution of different classes of antimicrobials shows striking differences. Phenoxymethyl and benzylpenicillin make up about 55% of the DDDs in Sweden and 40% of the DDDs in Denmark and Norway, whereas the narrow-spectrum penicillins represent 20% of the DDDs in Iceland. Fluoroquinolones are little used except in Sweden where they account for about 10% of DDDs. The use of cephalosporins ranges from 1% (in Denmark) to 15% (in Finland) and between 3 and 5% in the other countries. The policy that narrow-spectrum penicillins may be used when necessary but broad-spectrum compounds should be avoided has the positive effect that there is greater susceptibility in the Nordic countries to these antibiotics than elsewhere.

Chelating agents.

The antibacterial activity of metal ions, metal chelates, and molecules with chelating ability for polyvalent cations have been evaluated. The chelator N, N'-ethylenebis[2-(2-hydroxyphenyl)-glycine] (EHPG) exerted moderate-to-good activity against isolates of pathogenic bacteria and fungi. Other chelating agents such as ethylenediamine-tetraacetic acid (EDTA) and diethylene-triamine-pentaacetic acid (DTPA) revealed weak-to-moderate activity. Metal chelation of ligands reduced the activity of EDTA and DTPA.

Ground penetrating radar surveys to locate 1918 Spanish flu victims in permafrost.

The "Spanish Flu" killed over 40 million people worldwide in 1918. Archival records helped us identify seven men who died of influenza in 1918 and were interred in Longyearbyen, Svalbard, Norway, 1,300 km from the North Pole. Ground Penetrating Radar (GPR) was used successfully, in a high-resolution field survey mode, to locate a large excavation with seven coffins, near the existing seven grave markers. The GPR indicated that the ground was disturbed to 2 m depth and was frozen below 1 m. Subsequent excavation showed that: a) the GPR located the position of the graves accurately, b) the coffins were buried less than 1 m deep, and c) that the frozen ground was 1.2 m deep where the coffins were located. The GPR assisted in planning the exhumation, safely and economically, under the high degree of containment required. Virologic and bacteriologic investigations on recovered tissues may give us an opportunity to isolate and identify the micro-organisms involved in the 1918 influenza and expand our knowledge on the pathogenesis of influenza.

Vaginal disinfection with chlorhexidine during childbirth.

The purpose of this study was to determine whether chlorhexidine vaginal douching, applied by a squeeze bottle intra partum, reduced mother-to-child transmission of vaginal microorganisms including Streptococcus agalactiae (streptococcus serogroup B = GBS) and hence infectious morbidity in both mother and child. A prospective controlled study was conducted on pairs of mothers and their offspring. During the first 4 months (reference phase), the vaginal flora of women in labour was recorded and the newborns monitored. During the next 5 months (intervention phase), a trial of randomized, blinded placebo controlled douching with either 0.2% chlorhexidine or sterile saline was performed on 1130 women in vaginal labour. During childbirth, bacteria were isolated from 78% of the women. Vertical transmission of microbes occurred in 43% of the reference deliveries. In the double blind study, vaginal douching with chlorhexidine significantly reduced the vertical transmission rate from 35% (saline) to 18% (chlorhexidine), (P < 0.000 1, 95% confidence interval 0.12-0.22). The lower rate of bacteria isolated from the latter group was accompanied by a significantly reduced early infectious morbidity in the neonates (P < 0.05, 95% confidence interval 0.00-0.06). This finding was particularly pronounced in Str. agalactiae infections (P < 0.0 1). In the early postpartum period, fever in the mothers was significantly lower in the patients offered vaginal disinfection, a reduction from 7.2% in those douched using saline compared with 3.3% in those disinfected using chlorhexidine (P < 0.05, 95% confidence interval 0.01-0.06). A parallel lower occurrence of urinary tract infections was also observed, 6.2% in the saline group as compared with 3.4% in the chlorhexidine group (P < 0.01, 95% confidence p interval 0.00-0.05). This prospective controlled trial demonstrated that vaginal douching with 0.2% chlorhexidine during labour can significantly reduce both maternal and early neonatal infectious morbidity. The squeeze bottle procedure was simple, quick, and well tolerated. The beneficial effect may be ascribed both to mechanical cleansing by liquid flow and to the disinfective action of chlorhexidine.

Preparation and antimicrobial studies of acyclic sulfamates.

A series of acyclic sulfamates have been prepared and tested for antimicrobial activity. Thus, the oxysulfonyl isocyanates, ROSO2NCO (1a, R = 4-methoxyphenyl; 1b, R = phenyl; 1c, R = 4-chlorophenyl and 1d, R = 2,2,2-trifluoroethyl) have been prepared in 76-91% yield from chlorosulfonyl isocyanate. Treatment of 1a-d with glycidol gave the glycidyl carbamates 2a d. Internal cyclisation afforded the corresponding 4-hydroxymethyl-2-oxazolidinones 3a-d, which in turn were hydrolysed to give the free amino alcohols 4a-d. The yields were in the range 39-85%. A preliminary agar diffusion test of 2a-d, 3a-d, 4a-d indicated 2a-d and 3c to be possible antimicrobial agents. A more thorough analysis of these compounds revealed a minimum inhibition concentration (MIC) of 128 and 64 mg l-1 for glycidyl p-methoxyphenoxysulfonylcarbamate (2a) and glycidyl phenoxysulfonylcarbamate (2b) respectively, against Branhamella catarrhalis.

Organobismuth compounds: activity against Helicobacter pylori.

BACKGROUND AND METHODS: The antibacterial activity of originally devised and synthesized organobismuth compounds was tested against fresh clinical isolates of Helicobacter pylori and compared with clinically well-established inorganic bismuth salts currently used in triple antibacterial treatment to eradicate H. pylori. The test conditions in vitro were standard for determination of minimum inhibitory concentrations (MICs). RESULTS: Organic compounds with covalently bound bismuth showed stronger and more consistent antibacterial activity than inorganic bismuth salts. Whereas the most active among the standard therapeutic inorganic compounds showed MICs against the test organisms of 4-8 mg/l (bismuth salicylate) and 0.5-64 mg/l, the most active neosynthesized organic substance, tris(2.6-dimethylphenyl)-bismuthine, consistently showed an MIC of 4 mg/l against all bacterial strains. CONCLUSIONS: The new line of organobismuth compounds might offer a therapeutic potential against the bacteria causing peptic ulcer disease.

Susceptibility testing of Klebsiella spp.--an international collaborative study in quality assessment.

In order to compare the prevalence of antibiotic resistance in different geographical areas, it is necessary to ensure agreement between laboratories on the assignment of strains to 'susceptible' and 'resistant' categories. An international quality assessment was performed to investigate the performance of susceptibility testing of Klebsiella spp. Ninety-five strains of klebsiellae were selected from clinical isolates at the London Hospital Medical College (LHMC). These included strains with a diversity of susceptibility profiles to amoxycillin/clavulanate, piperacillin, ceftazidime, cefuroxime, ciprofloxacin, gentamicin and trimethoprim. The strains were sent to 13 participating laboratories in Europe and the USA and laboratories were asked to test the susceptibility of these strains to these antibiotics by their usual methods. They were also asked to provide details of the method used to test susceptibility. Several different standard recommended testing methods were used. Reporting of susceptibilities was generally accurate, but a number of anomalies were noted. Discrepancies of reporting between the LHMC and the participating laboratories was more marked for resistant strains, particularly in the detection of resistance to cefuroxime and ciprofloxacin, as well as the assignment of susceptibility and resistance to piperacillin and amoxycillin/clavulanate. Some discrepancies could be attributed to the use of different breakpoints, leading to differing assignment of susceptibility. Methodological variations including disc content, inoculum and failure to measure and interpret zone sizes consistently also led to anomalies. This quality assessment programme has helped to identify problems in susceptibility testing which should be investigated further.

Antibiotic resistance of pneumococci in Norway.

A collection of 178 pneumococcal isolates found in Norway during the period 1987-1994 were tested for their susceptibility to benzylpenicillin, macrolides (azithromycin, clarithromycin, dirithromycin, erythromycin, roxithromycin, spiramycin), fluoroquinolones (ciprofloxacin, sparfloxacin), imipenem, chloramphenicol, and vancomycin by a standard agar dilution procedure. To benzylpenicillin, two strains (1%) showed resistance and 14 strains (8%) intermediate susceptibility. Towards erythromycin, eight strains (4%) showed resistance and four strains (2%) intermediate susceptibility. Cross-resistance was demonstrated among the macrolides. Among the fluoroquinolones, intermediate susceptibility occurred with 42% of the isolates for sparfioxacin and 90% for ciprofloxacin; to the latter 5.1% proved resistant. The sum of intermediate and highly resistant isolates was 53% for chloramphenicol. Both penicillin-resistant strains were isolated during the last 2 years of collection and came from patients of non-Norwegian ethnic background. Imported strains appeared over represented among the strains resistant to penicillin and macrolides. Only imipenem and vancomycin showed full susceptibility for all pneumococci tested. An over representation of serogroup 6 strains was apparent among the strains with intermediate susceptibility and high resistance to benzylpenicillin. It is apparent that high-level resistance has, not so far, become a difficult problem in Norway. Nevertheless, the situation requires monitoring of the resistance level, particularly in meningitis and septic patients, and certainly in patients who cntail a higher than usual possibility of acquiring pneumococci from pools of resistant strains outside Norway (visitors, immigrants and recent returness from abroad).

Radioactive contamination from dumped nuclear waste in the Kara Sea--results from the joint Russian-Norwegian expeditions in 1992-1994.

Russian-Norwegian expeditions to the Kara Sea and to dumping sites in the fjords of Novaya Zemlya have taken place annually since 1992. In the fjords, dumped objects were localised with sonar and ROV equipped with underwater camera. Enhanced levels of 137Cs, 60Co, 90Sr and 239,240Pu in sediments close to dumped containers in the Abrosimov and Stepovogo fjords demonstrated that leaching from dumped material has taken place. The contamination was inhomogeneously distributed and radioactive particles were identified in the upper 10 cm of the sediments. 137Cs was strongly associated with sediments, while 90Sr was more mobile. The contamination was less pronounced in the areas where objects presumed to be reactor compartments were located. The enhanced level of radionuclides observed in sediments close to the submarine in Stepovogo fjord in 1993 could, however, not be confirmed in 1994. Otherwise, traces of 60Co in sediments were observed in the close vicinity of all localised objects. Thus, the general level of radionuclides in waters, sediments and biota in the fjords is, somewhat higher or similar to that of the open Kara Sea, i.e. significantly lower than in other adjacent marine systems (e.g. Irish Sea, Baltic Sea, North Sea). The main sources contributing to radioactive contamination were global fallout from atmospheric nuclear weapon tests, river transport from Ob and Yenisey, marine transport of discharges from Sellafield, UK and fallout from Chernobyl. Thus, the radiological impact to man and the arctic environment of the observed leakages from dumped radioactive waste today, is considered to be low. Assuming all radionuclides are released from the waste, preliminary assessments indicate a collective dose to the world population of less than 50 man Sv.

Radioactive contamination in the environment of the nuclear enterprise 'Mayak' PA. Results from the joint Russian-Norwegian field work in 1994.

A brief overview of the radioactive waste inventory of the 'Mayak' PA reprocessing plant, Chelyabinsk Region, Russia is given together with a description of the environmental contamination caused by its activities and the origins of contamination. The joint Russian-Norwegian field work in 1994 is described, together with the major analytical results. The field work was of a limited extent, and was not designed to include a complete mapping of the environmental contamination around the plant. The results are, however, in good agreement with the very extensive previous Russian investigations. The highest concentrations of radioactivity were found in Reservoirs 10 and 11 and at the floodplain of the upper Techa River (Asanov Swamp). Also high concentrations are found in biota, especially fish from Reservoir 10.

Susceptibility testing of Haemophilus influenzae--an international collaborative study in quality assessment.

In order to compare the prevalence of antibiotic resistance in different geographical areas, it is necessary to ensure that agreement is achieved between laboratories on the assignment of strains to 'susceptible' and 'resistant' categories. An international quality assessment study, involving 15 laboratories in eight countries, was performed to investigate the standard of performance of the susceptibility testing of Haemophilus influenzae. One hundred and fifty strains of H. influenzae were distributed from the London Hospital Medical College (LHMC) to all laboratories who were asked to test the susceptibility of the strains to ampicillin, chloramphenicol, tetracycline, trimethoprim, cephalosporins and ciprofloxacin. Laboratories were also asked to provide the details of methodology to test the susceptibility. Significant discrepancy between the LHMC and the participating laboratories appeared in the detection of resistance to ampicillin (especially beta-lactamase-negative strains resistant to ampicillin) as well as the assignment of susceptibility and resistance to chloramphenicol, tetracycline and trimethoprim. Often these reflected the use of inappropriate breakpoints which led to erroneous assignment of susceptibility. Other variations including disc content, medium and supplement, inoculum as well as failure to measure zone sizes properly also led to some repeating anomalies.

Psychological reactions during polar expeditions and isolation in hyperbaric chambers.

BACKGROUND: Psychological data from environments that are considered as analog to space was collected from 68 subjects; 18 in hyperbaric chambers, 16 in polar expeditions, and 34 on Arctic stations. The objective was to identify psychological reactions expected in different phases of spaceflights and examine personality variables associated with superior adaptation. METHOD: Helmreich Personality Characteristic Inventory was administered before the isolation. Adaptation to the environment was assessed through a questionnaire once a week. RESULTS: Crews in hyperbaric chambers indicated a steady increase in coping over the isolation. Polar expeditions members reported high aggressiveness and anxiety in the first quarter and an increase in homesickness over time. A personality characterized by strong expressiveness and instrumentality ("the right stuff") predicted superior adaptation in hyperbaric chambers. CONCLUSION: The data suggest that isolation in hyperbaric chambers and polar expeditions should be considered as models for different aspects of the space environment.

Quinolones in the elderly.

Aging results in a number of physiological changes that can affect drug disposition; these include reduced gastric acidity, decreased intestinal motility, lower lean body mass, and reduction in renal function. The age-related decline in renal function is the most important of these factors when administering quinolones to elderly patients. Elimination half-life (t1/2) values are prolonged in proportion to the degree to which the compound is normally eliminated by the renal route. Thus, age-related increases in t1/2 occur to a greater degree with ofloxacin (80 to 90% renal elimination) than with ciprofloxacin, which is also excreted by the gastro-intestinal route. Norfloxacin, pefloxacin, and sparfloxacin may also be eliminated to a substantial degree by the transintestinal route, as their excretion is not substantially affected by severe renal impairment. Prolonged drug elimination in the elderly can result in an increased incidence of adverse effects. Ofloxacin causes a higher frequency of drug-related events in the elderly, presumably reflecting the prolonged serum t1/2 and higher serum concentrations, and consequently higher tissue levels in this age group. Indeed, dosage reduction is recommended when treating elderly patients with ofloxacin, but does not appear necessary on the basis of advanced age for ciprofloxacin, norfloxacin and pefloxacin.

Topical metronidazole treatment in pouchitis.

Patients with pouchitis usually respond to oral metronidazole treatment, but side effects of the treatment are common. Eleven patients with pouchitis were given local treatment by instillation of metronidazole in doses of 40-160 mg daily into the reservoir. The effects of the treatment on the bacterial flora and short-chain fatty acids in reservoir contents, morphology of the ileal mucosa, and serum concentrations of metronidazole were studied. All patients responded to local administration of metronidazole. Three patients with chronic pouchitis remained well for 6 months, 3 years, and 4 years, taking 40 mg metronidazole daily. Three patients had one single treatment course, and four had repeated courses when they had recurrences. In one patient a continent reservoir had to be removed owing to a persistent ulcer causing chronic blood loss. The bacterial flora of reservoir contents showed no significant differences between patients with and without pouchitis. The number of anaerobic microorganisms and the concentration of short-chain fatty acids were reduced after metronidazole treatment. Serum concentrations of metronidazole were very low, and no patients experienced any side effects of the treatment. In conclusion, topical application of small doses of metronidazole relieved symptoms in most cases of pouchitis and was well tolerated, even as long-term treatment.