Notizen: III) and invasive cervical carcinoma: the yawning gap revisited and the treatment of riskIn a 3-year study of the population of Southampton and south-west Hampshire there were 10 times as many cases of CIN III compared with invasive squamous carcinoma (700 compared with 70). The peak incidence of CIN III per 1000 screened women years was in those aged 25–29 years, which was 20 years earlier than the peak incidence of invasive cervical cancer per 1000 women years at risk. Ninety percent of CIN III was diagnosed in women under 50 years. There were 14 cases of cervical glandular intraepithelial neoplasia grade III (CGIN III), three coexisting with CIN III, all in women aged under 50 years: the gap between intraepithelial and invasive lesions was not seen for glandular neoplasia. Although referral was for at least moderate dyskaryosis in 86.8% of women with CIN III or CGIN III, most had been screened previously, either having had mild abnormalities requiring repeat cytology (39.8%) or negative cytology (34.5%). Only 12 women aged ≥ 50 years had previous negative cytology: 21.4% compared with 35.6% of women aged 〈 50 years (P = 0.034). The results of this study suggest that the best opportunity for preventing invasive squamous cell carcinoma lies in screening women aged 20–39 years when the incidence of CIN III in the screened population is highest and before the peak incidence of invasive disease. The results also indicate the importance of repeated screening and follow up of minor cytological abnormalities in the detection of CIN III. The benefit of screening must be regarded as a treatment of risk, since it is almost certain that a high proportion of CIN III regresses or persists unchanged.

Notizen: We have studied the reliability of two simple pre-induction tests used to select the more patent nostril for nasotracheal intubation by comparing their results with those obtained from fibreoptic examination of the nostrils, in 75 maxillo-facial patients requiring nasotracheal intubation under general anaesthesia, who had no history of nasal obstruction. The tests comprised (1) estimation of the rate of airflow through each nostril during expiration by palpating the passage of air when the contralateral nostril was occluded, and (2) asking for the patient's assessment of airflow through the nostrils, following the administration of a vasoconstrictor. After each test, noses were classified as left or right nostril clearer or nostrils equally clear. After the induction of general anaesthesia, bilateral nasendoscopies were performed and videotape recordings of these were later analysed by an otolaryngologist who had no knowledge of the test results. Intranasal abnormalities were identified and noses were again classified as left or right nostril clearer or nostrils equally clear. There was no significant difference between the overall diagnostic success rates of the two tests (44% and 47%, respectively). In patients with intranasal abnormalities, the numbers of correct diagnoses made by the two tests were not significantly different and were also not significantly different from the number of correct selections made if only the right nostril or only the left nostril had been used for the intubation. In view of the relatively high diagnostic failure rates, anaesthetists should not rely on the two tests investigated when selecting the best nostril for nasotracheal intubation.

Notizen: We have investigated the extent to which the laryngeal mask airway, when used as an aid to fibreoptic nasotracheal video-endoscopy training, could reduce endoscopy apnoeic time in anaesthetised, paralysed oral surgery patients. Twenty anaesthetic trainees were randomly allocated to the laryngeal mask airway or control group. Laryngeal mask airway group endoscopies were performed in three stages following insertion of the laryngeal mask airway: stage 1: nasendoscopy, with the lungs ventilated automatically through the laryngeal mask airway; stage 2: removal of the laryngeal mask airway; stage 3: pharyngoscopy, larygoscopy and tracheoscopy. Control group endoscopies were performed conventionally, in one stage. Each trainee performed five nasotracheal intubations. Though total endoscopy time in the laryngeal mask airway group (stage 1 + stage 2 + stage 3 times) was significantly longer (average 136 s vs. 108 s), apnoeic time (stage 2 + stage 3 times) was significantly shorter (average 59 s vs. 108 s) than endoscopy time in the control group. This application of the laryngeal mask airway may have a useful role to play in ensuring patient safety during early fibreoptic training.

Notizen: Thlaspi caerulescens J. & C. Presl is a distinctive metallophyte of central and western Europe that almost invariably hyperaccumulates Zn to〉 1.0% of shoot dry biomass in its natural habitats, and can hyperaccumulate Ni to〉 0.1% when growing on serpentine soils. Populations from the Ganges region of southern France also have a remarkable ability to accumulate Cd in their shoots to concentrations well in excess of 0.01% without apparent toxicity symptoms. Because hyperaccumulation of Cd appears to be highly variable in this species, the relationship between Cd tolerance and metal accumulation was investigated for seven contrasting populations of T. caerulescens grown under controlled conditions in solution culture. The populations varied considerably in average plant biomass (3.1-fold), shoot : root ratio (2.2-fold), Cd hyperaccumulation (3.5-fold), shoot : root Cd-concentration ratio (3.1-fold), and shoot Cd : Zn ratio (2.6-fold), but the degree of hyperaccumulation of Cd and Zn were strongly correlated. Two populations from the Ganges region were distinct in exhibiting high degrees of both Cd tolerance and hyperaccumulation (one requiring 3 µM Cd for optimal growth), whereas across the other five populations there was an inverse relationship between Cd tolerance and hyperaccumulation, as has been noted previously for Zn. Metal hyperaccumulation was negatively correlated with shoot : root ratio, which could account quantitatively for the differences between populations in shoot Zn (but not Cd) concentrations. On exposure to 30 µM Cd, the two Ganges populations showed marked reductions in shoot Zn and Fe concentrations, although Cd accumulation was not inhibited by elevated Zn; in the other five populations, 30 µM Cd had little or no effect on Zn or Fe accumulation but markedly reduced shoot Ca concentration. These results support a proposal that Cd is taken up predominantly via a high-affinity uptake system for Fe in the Ganges populations, but via a lower-affinity pathway for Ca in other populations. Total shoot Cd accumulated per plant was much more closely related to population Cd tolerance than Cd hyperaccumulation, indicating that metal tolerance may be the more important selection criterion in developing lines with greatest phytoremediation potential.

Notizen: Aims:  Alveolar soft part sarcoma (ASPS) is a rare sarcoma in the buttocks or thigh of young adults, often with metastases to lung, brain, or bone. This study examines the morphological and clinical features of lingual ASPS.Methods and results:  Fourteen cases, in eight males and six females (ages 3–21 years, median 5 years), ranged from 8 to 50 mm, median 25 mm. All tumours were intramuscular, circumscribed and multinodular. Tumours from all but the oldest patient exhibited a predominantly solid (non-alveolar) growth pattern. Vascular invasion was common. Crystals varied in number from none or extremely rare to nearly 100% of tumour cells.Immunohistochemical results:  Fifty percent desmin positive, all focally smooth muscle antigen (SMA) positive; negative for vimentin, neural/melanocytic, myoid, histiocytic, and epithelial markers. All tumours were surgically excised; only two patients received chemotherapy. Follow-up on 10 patients showed that all patients were alive without disease (4–32, median 22 years). Only one patient had a microscopic metastasis to lung (3 years) but was without disease at 11 years.Conclusions:  Lingual ASPS is a tumour of childhood with a distinctive, predominantly solid growth pattern. Despite typical vascular invasion, the early diagnosis and small tumour size may explain its relatively good outcome.

Notizen: The aim of the present study was to develop and test an extended theory of the pressure-clamp technique that would allow the estimation of additional cell water-relation parameters using the pressure probe. It was assumed that intercellular water transport (vacuole → vacuole) occurs via a composite ‘membrane’ comprising the tonoplast, cytoplasm, plasma membrane, plasmodesmata and cell wall and that solute transport across the micropipette tip of the probe is dominated by convection. The extended theory allows the simultaneous estimation of cell volume (V), effective cell-sap osmotic pressure (σΠ0), composite-membrane hydraulic conductance (ALP) and the ‘instantaneous’ volume change (v0) at the start of the pressure clamp. With an estimate of cell-sap osmotic pressure (Π0), the weighted-average reflection coefficient (σ) of the composite membrane may also be determined from an endosmotic pressure-clamp experiment. In principle, the cell volume before the clamp (V0) can be estimated as V0 = V + v0, and the cell volumetric elastic modulus (ɛ) can be estimated as ɛ = –V0(ΔP/v0), where ΔP (〈 0) is the change in turgor pressure at t = 0. In practice it may be necessary to correct v0 for transmembrane water flow when estimating V0 and ɛ. To test this theory, a previously described pressure-probe system was upgraded by incorporating a data-acquisition system to record turgor pressure, meniscus position, the penetration depth of the pressure-probe micropipette and the micropipette profile. An air bubble in the system allowed the turgor pressure to be clamped at a near-constant value. For mesophyll cells in leaf discs of Kalanchoë daigremontiana, the estimated mean value of V0[(2·46 ± 0·24) × 10–13 m3] was in reasonable agreement with a value obtained from microscopy [(1·91 ± 0·10) × 10–13 m3]. When the positive correlation between ɛ and |ΔP| was taken into account, the parameter estimates obtained from pressure-clamp experiments were found to be consistent with those derived from pressure-relaxation experiments. The mean values of ɛ (1·4 ± 0·2 MPa) and LP[(5·76 ± 0·83) × 10–12 m s–1 Pa–1] were significantly different from previous estimates obtained with older leaves. Furthermore, in contrast to the estimated reflection coefficient of the plasma membrane/tonoplast (≈ 1), the mean value of σ obtained in the present study (0·62 ± 0·05) was significantly less than unity. This is attributed to a high hydraulic conductance and a low reflection coefficient of a symplastic pathway for intercellular water transport. The qualitative behaviour of LP and σ was consistent with a quasi-steady-state model of intercellular water transport that included volume flow through plasmodesmata. A quantitative description was obtained by fitting a simplified version of this model to the data. This led to the conclusion that significant volume flow can occur through plasmodesmata during pressure-clamp experiments, especially for small A and |ΔP|.

Notizen: The heat shock proteins (HSPs) are induced by stressful stimuli and have a protective effect. Different HSPs protect with different efficiencies against different stresses indicating that optimal protection would be obtained with a non-stressful agent which induced a range of HSPs. We have prepared a herpesvirus vector expressing a constitutively active mutant form of heat shock factor 1 (HSF1) which, unlike the wild-type form of this transcription factor, does not require stress for its activation. Upon infection of neuronal cells, this virus induced a more restricted range of HSPs than in non-neuronal cells. Infection with the virus protected neuronal cells against subsequent thermal or ischaemic stress in accordance with its ability to induce HSP70 expression but did not protect them against apoptotic stimuli. The mechanisms of these effects and their significance for the use of HSF to manipulate HSP gene expression is discussed.

Notizen: Dynamic simulation models are important tools for rationalizing complex changes in soil organic matter. Most such models for organic matter can be described as having either a pool structure or a continuous one. A pool structure can offer advantages in ease of use and transferability. Some pools are easily measured, whereas others cannot be measured directly. New methods of fractionation are being developed in an attempt to base models on measurable fractions. A requirement for such models is a demonstration that the measured fraction and model pool are equivalent. A measured fraction is equivalent to a model pool only if, within acceptable limits, it is unique as well as non-composite. If the measured fraction is not unique, describing it as a separate pool adds no extra information, while the added complexity can increase propagation of errors. If it is composite then the characteristics of the fraction will change with changing environment as a result of changing proportions of subpools. This will produce a model that cannot be applied without deriving parameters afresh: such a model is of greatly reduced value. Here we develop methods to examine if a fraction is both unique and non-composite. The tests for unique and composite pools were applied to the SUNDIAL (simulation of nitrogen dynamics in arable land) model of organic matter and nitrogen turnover in soil. Results suggest that the debris, biomass and humus pools are unique, but biomass and humus are composed of two or more subpools. This worked example illustrates how, given suitable data, any pool-based model can be tested by these methods.

Notizen: Dynamic models of nitrogen turnover in soil are being used increasingly in agricultural science. To be of value, a model must be thoroughly evaluated, and the expected accuracy of simulated values must be defined. Frequent field measurements are time-consuming and costly, and so models are often evaluated against only few data. However, this mismatch between the measured and simulated values can result in error statistics that are themselves subject to large errors and therefore unreliable. The dot-to-dot method quantifies the error associated with having too few measured values by interpolating linearly between measured data (hence, dot-to-dot) and evaluating the simulation at each time step using interpolated data where actual measurements are unavailable. A large error will be seen if the measured data do not capture the fluctuations predicted by the model. Other quantitative methods can be used to evaluate the performance of a model, but the dot-to-dot method can be used in conjunction with these to estimate whether or not the data are adequate for testing the model. If the performance of the model at the measured points is within the acceptable error, then the dot-to-dot method is used to judge whether there are too few points to evaluate the model's performance, and so to determine whether the evaluation of the model is valid.