Lag phase, dynamic alpha factor and ammonium adsorption behaviour: introduction of special activated sludge characteristics in the ASM3 + EAWAG-BioP-model.

In five full-scale municipal sequential batch reactor (SBR) wastewater treatment plants (WWTPs) indications for lag phases, a dynamic alpha factor and ammonium adsorption behaviour of the activated sludge were found. A dynamic simulation analysis of all WWTPs showed the need to implement these characteristics into the model in order to improve the calibration procedure, to meet better results for optimisation studies and even to calculate better fitting running costs including the aeration energy. Even if these effects could be characterised as minor effects, it is planned to utilise the knowledge about these effects for further optimisation of the SBR process and to achieve significant improvements.

New governance arrangements for research ethics committees: is facilitating research achieved at the cost of participants' interest.

This paper examines the UK's response to a recent European Clinical Trials Directive, namely the Department of Health, Central Office for Research Ethics Committee guidance, Governance Arrangements for NHS Research Ethics Committees. The revisions have been long awaited by researchers and research ethics committee members alike. They substantially reform the ethical review system in the UK. We examine the new arrangements and argue that though they go a long way toward addressing the uncertainty surrounding ethics committee function, the system favours the facilitation of research over the protection of the dignity and welfare of research participants.

A 15O-H2O PET study of meditation and the resting state of normal consciousness.

The aim of the present study was to examine whether the neural structures subserving meditation can be reproducibly measured, and, if so, whether they are different from those supporting the resting state of normal consciousness. Cerebral blood flow distribution was investigated with the 15O-H20 PET technique in nine young adults, who were highly experienced yoga teachers, during the relaxation meditation (Yoga Nidra), and during the resting state of normal consciousness. In addition, global CBF was measured in two of the subjects. Spectral EEG analysis was performed throughout the investigations. In meditation, differential activity was seen, with the noticeable exception of V1, in the posterior sensory and associative cortices known to participate in imagery tasks. In the resting state of normal consciousness (compared with meditation as a baseline), differential activity was found in dorso-lateral and orbital frontal cortex, anterior cingulate gyri, left temporal gyri, left inferior parietal lobule, striatal and thalamic regions, pons and cerebellar vermis and hemispheres, structures thought to support an executive attentional network. The mean global flow remained unchanged for both subjects throughout the investigation (39+/-5 and 38+/-4 ml/100 g/min, uncorrected for partial volume effects). It is concluded that the (H2)15O PET method may measure CBF distribution in the meditative state as well as during the resting state of normal consciousness, and that characteristic patterns of neural activity support each state. These findings enhance our understanding of the neural basis of different aspects of consciousness.

The activation pattern in normal humans during suppression, imagination and performance of saccadic eye movements.

The distribution of activated cerebral regions was examined in nine normal subjects during four different eye movement-related conditions: (1) fixation-fixation on a central light emitting diode; (2) saccadic suppression-fixation on a diode in the presence of flashing lateral targets; (3) reflexive/volitional saccades-performance of overt eye movements to two laterally lit targets and back to the centre; and (4) imagined saccades-imagining, but not performing, the same eye movements. The regional neural activity was measured indirectly using repetitive bolus injections of oxygen-15-labelled water and positron emission tomography (PET) to yield time-integrated images of the normalized count distribution. These were aligned and anatomically normalized to a standard stereotactic space and the averages of each condition were analysed categorically using statistical parametric mapping. Compared to central fixation, reflexive/volitional saccades significantly activated regions in the classically known cortical oculomotor regions. The most notable activation during the saccade suppression task, compared to central fixation alone, was a bilateral activation of the parietal cortex with a right-sided preponderance, activation of the supplementary eye field/caudal cingulate regions, and activation of frontal regions close to the frontal eye fields. Imagined performance of eye movements without overt eye movements activated the supplementary eye field and frontal eye fields identically to regions involved in overt eye movements, thus demonstrating that over eye movements are not a prerequisite of the activation of these regions in normal humans.

Antimicrobial screening of zinc in the absence or presence of oleoresins and various resin acids.

Zinc and oleoresins are the main components of several wound dressings, and are also frequently used in root canal treatment. The in vitro antibacterial effects of zinc, six highly purified resin acids and two commercial oleoresins alone or combined in varying proportions were analysed. Oleoresins are composed of approximately 90% resin acids and the most common acids were included in this study. The antibacterial activity of the various chemicals was estimated using a Bioscreen robot analyser, which allowed 24 h kinetic documentation of bacterial growth. The bacteria employed were reference species commonly occurring on human skin or of oral origin. Zinc as well as the oleoresins and the pure resin acids all showed antibacterial activity when present in growth media, but the sensitivity of the bacteria varied. The presence of resin acids and oleoresins increased the antibacterial effect of zinc to varying degrees depending on the combination and the bacterial species tested. The results of the present study indicate that zinc, resin acids, or oleoresins alone, as well as combined, show antibacterial activity against selected aerobic Gram-positive and anaerobic Gram-negative bacteria.

Absence of transsynaptic transport in cerebello-thalamo-cortical path of the rat.

Attempts to visualize the cerebello-thalamo-cortical path in the rat were made with different approaches. We tried (1) double labelling with somatopetal tracing from the motor cortex and somatofugal from the cerebellar nuclei, (2) transmembrane labelling by depositing biocytin or wheat germ agglutinin (WGA) into the motor cortex or cerebellum. WGA was either iodinated with 125I or conjugated with horseradish peroxidase (HRP). The double labelling technique showed an overlap of the tracers in the same thalamic region but no evidence of transsynaptic transport in either direction was obtained. Our results indicate a difference in the organization of this system in primates and rodents, since transsynaptic labelling in the cerebellar nuclei after injections of WGA-HRP conjugate in the monkey motor cortex has been found.

Gliadin-specific and cow's milk protein-specific IgA in human milk.

The presence of gliadin-specific IgA and IgG antibodies in colostrum and serum of 140 newly delivered mothers was assessed by enzyme-linked immunosorbent assay. In addition, cow's milk protein (CMP)-specific IgA was determined in the colostrum samples. From 14 of the mothers longitudinal milk samples were obtained after 1 and 2 months of lactation and from 12 mothers after 3 months. Gliadin-specific IgA was found in 97.1% and gliadin-specific IgG in 9.3% of the colostrum samples. Gliadin-specific IgA was detected in mature samples but at significantly lower levels after 1, 2, and 3 months of lactation (p less than 0.01) as compared with colostrum. Gliadin-specific IgA was found in 2.8% of the serum samples and gliadin-specific IgG in 40%; however, the levels of both isotypes were low. CMP-specific IgA was found in 78.1% of the colostrum samples. It is concluded that IgA antibodies to two common food proteins are frequently found in human milk and that food-specific IgA present in milk may play a role in adapting the infant's immune reactions to food antigens in the gut.

Clinical and bacteriological effects of therapy of urinary tract infection in primary health care: relation to in vitro sensitivity testing.

17 primary health care (PHC) centres participated in a 1-month evaluation of a county urinary tract infection (UTI) management program. A total of 302 patients contributing 355 episodes, dominated by female (93%), lower symptomatic (75%) and Escherichia coli (74%) episodes were studied. In therapeutic failure gram-negative bacteria other than E. coli showed an increased prevalence whereas Staphylococcus saprophyticus was not found. The general pattern of drug resistance was little influenced by UTI history and the mean pretherapy prevalence of resistance to the 7 antibacterial agents studied was low (7%). Drug resistance was increased in failure (mean 24%) also for agents not used for therapy (sulphonamides and nitrofurantoin) but not in early or repeated recurrence. UTI symptoms were eradicated in only two-thirds of bacteriologically cured episodes but in one-third of the failures at the posttreatment control. On average, therapy resulted in 8% bacteriological failure and 12% early recurrence. The bacteriological cure rate was the same irrespective of whether the infecting bacteria were classified as sensitive or resistant in vitro to the drug given. Thus, sensitivity testing of isolates is rarely needed in sporadic or recurrent UTI in PHC but may be relevant in failure. In order to be of prognostic value in uncomplicated UTI high-level breakpoints focusing more on peak urinary drug concentrations need to be studied.

Hydrocarbon exposure from handling jet fuel at some Swedish aircraft units.

The exposure to vapors from jet fuel under different work conditions was examined in three aircraft squadrons. Exposure measurements were made by charcoal sampling in the breathing zones of 23 randomly selected employees belonging to three different personnel groups. Each person was followed during two consecutive days by long-time sampling and, furthermore, by 15-minute sampling during work operations with possible high exposure. The charcoal tubes were eluted with carbon disulfide, and the hydrocarbons were analyzed with gas chromatography. The geometric mean of both the long- and the short-time exposure was only 1-2% of the corresponding occupational exposure limits. The highest long-time exposure observed was about 25% of the occupational exposure limit, while the highest short-time exposure was about 130% of the corresponding limit. Thus the present long-term exposure to solvent vapor in Swedish aircraft units is low, but infrequent short-time exposure above the present limit may occur in some work operations.

Studies in vivo on the killing rate and refractory period of penicillin V in an experimental streptococcal infection.

The refractory period and the killing rate of beta-haemolytic streptococci after exposure to phenoxymethylpenicillin were tested in an in-vivo model. beta-Haemolytic streptococci were injected into steel net chambers implanted subcutaneously on the backs of rabbits. The rabbits were treated with infusions of phenoxymethylpenicillin, either as a single dose to measure the refractory period or as repeated doses in order to measure the killing rate of streptococci. The peak concentration of phenoxymethylpenicillin in tissue chamber fluid occurred about 16-120 min post infusion, and reached 0.4 mg/l in infected and 0.6 mg/l in uninfected tissue cage fluid. In the tissue cage fluid the phenoxymethylpenicillin concentration exceeded 0.03 mg/l, the MIC-value for the streptococcal strain used, for at least 6 h. After a single infusion there was a decline in viable count. The bacteria did not reach their original numbers until 60-70 h later. After the sixth infusion streptococci were no longer detectable in tissue cage fluid. There was a close correlation between viable counts before treatment and the time required for eradication of bacteria. L-phase variants of beta-haemolytic streptococci were not found when tissue cage fluid was plated on special media.

A prospective, randomized study of amikacin and gentamicin in serious infections with focus on efficacy, toxicity and duration of serum levels above the MIC.

A multicentre prospective randomized study of amikacin and gentamicin in 135 patients with serious infections is presented. Most patients were additionally given a penicillin derivative according to Swedish therapeutic traditions. Synergism was noted in the majority of the tested strains. Clinical cure was recorded in 80% and 76% respectively of the amikacin and gentamicin patient groups. Nephrotoxic reactions were statistically (P less than 0.05) more common in gentamicin-treated patients (20%) than in the amikacin-treated ones (6%) while the corresponding figures for ototoxicity were 16% and 8% respectively (not statistically significant). Pharmacokinetic studies of the drugs showed that with the dose regimens used serum levels of amikacin above 10 times the MIC for the isolated micro-organism were registered during 75% of the 12-hour therapy interval and during 40% of the 8-hour therapy interval for gentamicin. This difference is statistically significant (P less than 0.01). We suggest that the pharmacokinetic advantages of amikacin in comparison to gentamicin might be of practical importance in the prediction of serum levels thereby lowering the risk of toxic reactions.

Clinical experience with azlocillin in the treatment of urinary tract infections with Pseudomonas aeruginosa.

27 patients, aged 19-23 yr, with symptomatic urinary tract infection or epididymitis due to Pseudomonas aeruginosa were treated with azlocillin. All pseudomonas strains were sensitive to azlocillin. The microorganism was eradicated in 25/26 evaluable patients. 25/27 patients were clinically cured. Bacteriological relapse occurred in 11 patients. No serious drug reactions were noted.