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Repairing a compacted turfgrass athletic field is a laborious activity, requiring significant expense. The objective of this project is to develop a rapid survey method for mapping soil compaction that occurs from player trafficking. Once mapped, field managers can target compacted regions of their fields for site-specific remediation; thereby, reducing their labor and expenses.

Historically, bronchioalveolar lavage (BAL) samples have been prepared by a direct smear (DS) technique. Recent advances in liquid-based cytology have led to a revolution in cytological specimen preparation. Cyto-SEDTM system (CS) is a manual liquid-based cytology system, designed for small-scale use. A total of 137 samples from patients with radiographically detectable lesions underwent BAL procedures at Papworth Hospital NHS Trust over a 4-month period. After preparation for diagnostic purposes with the DS method, the remaining sample was prepared using the CS system. The slides produced were allocated a blind study number and screened by three independent screeners. The cellular morphology was well preserved and comparable between both techniques. Of the 137 patients, 38% were confirmed as malignant by cytology or histology; 71% of these malignant diagnosis were confirmed by the DS technique and 91% confirmed by the CS. The results demonstrate that the CS is a viable alternative to the DS technique. The cytological detail is clearly defined without a loss of three-dimensional information, thus aiding the differential diagnosis of malignancy. Cyto-SEDTM cytology system yields a higher diagnostic accuracy than the conventional direct smear technique without compromising on cytological detail.

The classical chronic carcinogenicity bioassay has served researchers well over the last few decades. Recently, however, several factors have prompted a reevaluation of this approach, including budget pressures, a growing list of agents for study, and a better understanding of carcinogenesis. Herein some emerging strategies for obtaining similar or better information are considered. Rather than basing hazard identification and risk estimation on chronic bioassays of two sexes in two species, the possibility of a “reduced protocol” using a subset of the four assays is considered. The possibility of supplementing reduced protocol results from maximum tolerated dose information is raised. The trend to biologically based dose response models is considered, especially with reference to statistical issues associated with the “two-stage birth-death” model and physiologically-based pharmacokinetic models.

Quantitative estimates of human health risk are often based on mathematical models fit to experimental or epidemiological data. Recent years have witnessed a trend towards the use of mechanistic models in risk assessment applications. Such models afford a more biologically based interpretation of the data and a firmer scientific basis for extrapolation beyond the conditions under which the original data were obtained. In this article, we review some recent advances in the development of biologically based models for mutagenesis, carcinogenesis and developmental toxicity. Pharmacokinetic and receptor-binding models and their roles in mechanistic risk assessment are also discussed. The future of mechanistic research in risk assessment is contemplated, including the need for more elaborate experiments to obtain the data necessary for mechanistic modeling.

Although many laboratory studies are conducted with the dose level held constant for the duration of the experimental period, human exposure to toxic substances can vary widely over time. In this article we discuss methods for toxicologic risk assessment with time-dependent exposure patterns. In particular, methods for carcinogenic risk assessment under both the multistage and two-stage models are reviewed. It is shown that the use of a lifetime average daily dose or LADD can overestimate or underestimate the actual lifetime risk associated with time-dependent exposure patterns. It is also shown that there exists a lifetime equivalent constant dose or LECD that leads to the same lifetime risk as the actual time dependent exposure pattern. The ratio C = LADD/LECD thus provides a measure of accuracy of the LADD. Several applications are summarized to illustrate the application of currently available risk assessment methods for time-dependent exposures

A case-control study of lung cancer in relation to exposure to radon in homes in Winnipeg, Manitoba, Canada, was conducted during 1983-1990. In total, 738 individuals with histologically confirmed incident cases of lung cancer were interviewed, along with 738 controls matched on age (+/- 5 years) and sex. Radon dosimeters were placed in all residences in which the study subjects had reported living within the Winnipeg metropolitan area for at least 1 year. Radon dosimetry was done by means of integrated alpha-track measurements over a 1-year period. In the homes monitored, the average level of radon-222 was about 120 becquerels (Bq)/m3 in the bedroom area and 200 Bq/m3 in the basement. After adjusting for cigarette smoking and education, no increase in the relative risk for any of the histologic types of lung cancer observed among the cases was detected in relation to cumulative exposure to radon.

The utility of many standard control charts is closely related to the sensitivity of the mean and range to a few extreme observations. Such sensitivity is undesirable, however, when designing the charts. One way to minimize the effect of extreme data in determining control chart limits is to use robust statistics. Langenberg and Iglewicz (1986) discuss one approach and provide a table of factors to estimate untrimmed ranges from trimmed ranges. Herein, a similar table provides values categorized by the number of observations trimmed, rather than by the proportion trimmed. Another table for estimating untrimmed standard deviations from trimmed standard deviations is also presented

Levels of uranium in urine are used to monitor occupational exposure to uranium. Health and Welfare, Canada, offers a laboratory performance check program that serves as external quality control to laboratories measuring uranium in urine. Herein, we describe the system we now use. We modified the method described by Measures and LeCompte (1980) to include replicate samples and internal measures of variability. We suggest a slightly different design and a new method of evaluation. The proposed approach tracks accuracy and precision performances separately and bases performance evaluations on fixed limits, providing a consistent evaluation system and better handling of outliers. The new approach draws on traditional statistical methodology and expands concepts of modern quality improvement advocated by Taguchi.

Three situations in which the interpretation of categorical data can appear anomalous are considered: (a) Berkson's fallacy, (b) an example involving retrospective and prospective epidemiological studies from Neyman, and (c) Simpson's paradox. The odds ratio is used as the statistic of interest. Methods are presented to determine whether an anomaly could exist for a given parameterization and to construct an anomaly where feasible. The methods may require at most the preparation of a simple graph and some simple hand calculator computations.

A Hurthle cell tumour is a variant of follicular thyroid cell carcinoma. This is a report of metastatic Hurthle cell tumour causing central airway obstruction, emphasizing the difficulty in differentiating benign from malignant lesions.

To show lipid deposits in the lung of patients treated with amiodarone.Formalin-fixed, unstained frozen sections were used to reveal lipid deposits by means of polarized light. Lung tissues obtained at the postmortem examination of one patient and the surgical biopsy of another were available.Birefringent lipid deposits were seen in the alveolar lining cells and macrophages, as well as in the walls of arterioles and venules.To assess the effect of amiodarone on the lung, polarized light microscopy of unstained, frozen sections is a simple and rapid method.

AIMS: To establish criteria for the information to be included in a necropsy report, and to improve the quality of necropsy reporting in the Anglia Region. METHODS: Discussion between Anglia histopathologists, based on the guidelines of the Royal College of Pathologists, led to a consensus about the ideal content of a necropsy report. Fifteen consecutive necropsies subsequently undertaken by each consultant were assessed against agreed standards. Reaudit was undertaken nearly two years later, without prior announcement. RESULTS: The initial standards achieved for demographic details (70%), history (87%), external examination (43-97%), internal examination (76-95%), organ weights (73%), cause of death in OPCS format (94%), and conclusion (90%) were discussed by the group. Changes to necropsy reporting documentation were proposed. Reaudit showed improvement in nearly all categories. CONCLUSIONS: Necropsy reporting in East Anglia is currently carried out to a reasonably high standard, and improvements have occurred as a result of the audit. There was no evidence that reports on coroners9 necropsies were of a lower standard than those done for the hospital. Improvement in the format of the documentation increases the likelihood that all relevant and important data are recorded.

AIM: To examine current practice and to establish criteria for the use of histopathology in necropsy practice. METHODS: During an audit of necropsy reporting, consensus could not be reached about the use of routine histopathology. Therefore local guidelines were formulated and current practice was compared with these guidelines. Fifteen consecutive necropsies undertaken by each consultant were reviewed and the use of histopathology noted. RESULTS: In general, the standard of necropsy reporting was reasonably high. Tissue was retained for histopathology in 25% of necropsies and 72% of these necropsy reports included a histopathology report. Using the guidelines, the assessors judged that histopathology might have been valuable in a further 19%. It was felt that routine histopathology would not have been helpful in determining the cause of death in the remaining 56%. The importance of the pathologist's clinical judgement in individual cases was stressed. At reaudit, nearly two years later, there was no significant change in practice, reflecting the lack of consensus. CONCLUSIONS: Even when histopathology might contribute to finding the cause of death, it was not always done. However, the assumption that histology is invariably helpful in determining the cause of death is challenged.

When an unconditioned stimulus (US) signals the delivery of a second US, there is poor conditioned responding to a conditioned stimulus (CS) that signals the second US. Using an appetitive conditioning preparation with rats, 3 experiments examined the factors that contribute to this poor conditioned responding. In Experiment 1, conditioned responding was improved when US-alone presentations came before, but not after, CS training. Experiment 2 showed that the effect in Experiment 1 was not due to context extinction, and Experiment 3 showed that context-US associations do not significantly contribute to responding in the US-US training procedure. The results show that poor conditioned responding is an acquisition deficit, arising from US, rather than context, signal value.

Epithelial-myoepithelial carcinoma (EMC) accounts for approximately one per cent of salivary gland tumours. This tumour is gaining wider recognition following inclusion into the WHO histological classification of salivary gland tumours in 1990. Salivary gland tumours characteristically present with an enlarging mass. We describe an unusual presentation of a salivary gland tumour with stenosis of the external ear canal in the absence of a palpable mass. EMC usually arises from the salivary glands but isolated cases have been described arising primarily from the paranasal sinuses, trachea and lacrimal gland. The management of this tumour is still evolving with surgical excision being the main-stay of treatment. The efficacy of radiotherapy has not yet been established but high local recurrence rates despite apparently adequate excision and the possibility of a multicentric origin of the tumour may herald an increasing role for radiotherapy in the future. We stress the importance of awareness of adjacent structures when considering the cause of cartilaginous canal stenosis.

This self-directed learning module highlights advances in therapeutic options in pain management. It is part of the chapter on pain rehabilitation for the Self-Directed Medical Knowledge Program for practitioners and trainees in physical medicine and rehabilitation. This section discusses pharmacologic agents, modalities, behavioral strategies, and invasive techniques in pain management, with case studies illustrating pain management approaches in clinical practice. Advances that are covered include use of opioid receptors, receptor-specific categories of drugs used in painful conditions, components of behavioral programming for chronic pain, and the limitations of invasive techniques in chronic pain patients.

This article highlights chronic pain syndrome and myofascial pain. It is part of the chapter on pain rehabilitation in the Self-Directed Medical Knowledge Program for practitioners and trainees in physical medicine and rehabilitation. This article discusses behavioral maladaptations to chronic pain which lead to global physical, psychologic, social, and vocational impairments--the chronic pain syndrome. The spectrum of myofascial pain syndromes, contributing factors, and interventions are detailed. New advances that are covered in this section include controversies in long-term use of opioids and muscle relaxants; differentiating fibromyalgia, myofascial pain syndromes, and chronic fatigue syndrome; pathophysiology of myofascial pain; and beneficial treatments.

This self-directed learning module highlights advances in pain basic science as well as the management of acute and neuropathic pain. It is part of the chapter on pain rehabilitation for the Self-Directed Medical Knowledge Program for practitioners and trainees in physical medicine and rehabilitation. This section discusses pharmacologic and nonpharmacologic techniques in pain management. Advances that are covered include updated theories on etiology of central pain, the use of patient-controlled analgesia and blocks in pain control, and management and patterns of headache after brain injury and in subarachnoid hemorrhage.

Summary Myositis due to spontaneous cholesterol embolization is uncommon and usually associated with cutaneous abnormalities at presentation. A case of myositis due to cholesterol emboli is reported. The patient presented with painful weak legs, and the diagnosis was confirmed by muscle biopsy.

Acute arsenic intoxication may present as Landry-Guillain-Barré syndrome because of similarities in clinical symptoms involving the gastrointestinal tract, weakness, and sensory symptoms. Electrodiagnostic findings may be similar with demyelinating changes predominating early in both diseases. A case is presented of repeated arsenic poisoning over two years misdiagnosed as Landry-Guillain-Barré syndrome. Proximal F-loop latency (M-wave latency at wrist + F-wave latency at wrist - 2 M-wave latency at axilla) helped to establish the correct diagnosis. Serial electrodiagnostic studies were done documenting the evolution of chronic repeated arsenic poisoning from a picture showing demyelination to one with severe axonal loss.

Considerable information on the carcinogenic potential of chemical and radiological agents has accumulated from the epidemiological and toxicological studies conducted to date. In this article, we discuss dose-response relationships in carcinogenesis from both empirical and theoretical points of view. Emphasis is placed on the application of biologically based models to describe observed dose-response relationships for exposure to single and multiple agents known to increase cancer risk. The implications of these observations for inferences about possible mechanisms of carcinogenesis are explored.

Five commercially available cytokeratin antibodies (lu-5, AE1/AE3, CAM 5.2, MFN116 and anti-cytokeratin 18) were used to stain a wide range of normal and neoplastic epithelial and non-epithelial tissues to assess their potential value in diagnostic histopathology. All five showed good specificity, with some cross-reactivity in smooth muscle cells. The wider reactivity of AE1/AE3, lu-5, and MFN 116, which includes cytokeratins 8,18 (Moll's catalogue) expressed in simple epithelia and their tumours, as well as cytokeratins expressed in complex stratified squamous epithelia, permits identification of a wider range of epithelial derived tumours. This wider spectrum of reactivity may allow these antibodies to be used in a diagnostic panel for the identification of poorly differentiated tumours.

This paper evaluates the performance of several diagnostic kits for assessing levels of serum prostatic acid phosphatase on patients at different stages of cancer of the prostate. Each patient was studied with several kits. We compare results obtained for receiver operator characteristic (ROC) curve methodology with data assumed to follow a normal distribution, with log-transformed data assumed to follow a normal distribution, and when neither of these assumptions holds. There were important differences between the results of the different approaches. For these data, the normal distribution assumption should be used with extreme caution. The log-transformed based results compared favourably with the non-parametric, but unconsidered application of the method should be avoided.

By means of techniques of analyses of survival data developed for cancer trials it is possible to study aspects of the natural history of the infection of schistosomiasis on the intermediate host of transmission, the snail.The simultaneous study of three response variables is largely based on a model of Lagakos (1976). When using this approach in the schistosomiasis setting it seems inappropriate to assume that one process, the duration of latency, follows an exponential distribution. Thus this stage is modified to follow a normal distribution and the derivatives required to obtain maximum-likelihood estimates and approximate variances of all parameters are provided.Simple graphical tools for assessing the validity of distributional assumptions in survival data are available from industrial research. The reader's attention is drawn to a paper by Nelson (1972). The relevance and application of these methods to the current problem are described in Section 4.In the event that the times to death of prepatent and patent snails do not follow exponential distributions as assumed in the primary model, a further modification is introduced to enable either or both to follow Weibull densities.Lastly it is possible to adapt both the primary model of Section Three and the modified model of Section Five to allow for the inclusion of auxiliary variables or covariates. Again the required derivatives to obtain maximum likelihood estimates and approximate variances are provided.I wish to thank Sheila Gore, Stuart Pocock and Professor Michael Healy for many useful discussions. Sheila Gore and Professor Peter Armitage provided many recommendations for the improvement of the manuscript for which I am most grateful.

Embryos from certain strains of mice do not develop into blastocysts when cultured in vitro from the 1- or 2-cell stages but arrest development as 2-cell embryos--a phenomenon referred to as the '2-cell block'. Reciprocal crosses between eggs and sperm of a 'blocking' (CFLP) and 'non-blocking' (F1) strain show that in this combination the genotype of the egg alone determines whether the embryo 'blocks' at the 2-cell stage (or continues retarded development to the 4- to 6-cell stage in a minority of cases). A comparison of molecular and cellular development in normal and 'blocked 2-cell' embryos was therefore undertaken to investigate the influence of these maternal components on early mouse development. The results show that the majority of 'blocked 2-cells' arrest development at a stage equivalent to the late 2-cell stage in terms of cellular and nuclear division, DNA synthesis, activation of the embryonic genome, qualitative and quantitative changes in amino acid uptake, polypeptide synthesis and morphological maturation of organelles. These observations are compatible with the notion that maternally inherited developmental information plays an important role in controlling early cleavage of the mouse embryo.

The accuracy of results from any epidemiological project depends upon the performance of all stages of data collection and handling. One link in this chain may involve microscopic inspection of specimens and the purpose of this article is to describe means of assessing the accuracy of this stage. Two aspects merit consideration: the design of a sampling system and the collection and interpretation of the results. The importance of design is stressed, but the considerable variation in individual circumstances rules out a full treatment of the topic. A method of record keeping is described together with a method for graphical presentation of results. A procedure is outlined for detecting unacceptable performances and some of the statistical considerations are discussed.

A method is described for the supervision of technicians engaged in microscopical screening of large numbers of stools for Schistosoma mansoni ova. The scheme presents graphically a regularly updated longitudinal evaluation of both individual and group standards of technical competence.

Some possible effects of misdiagnosis for Schistosomiasis in epidemiological measurements are investigated. With greater chances of misdiagnosis for lower prevalence levels, expectations of control programmes might be reassessed. As prevalence decreases, the fraction of missed positives over all apparent negatives need not uniformly decrease. In control situations even perfect treatment rates may produce very small changes in prevalence and other indices of infectivity level.

ASTM Standard Practice D 2777-86 provides simplified numerical methods for the statistical analysis of collaborative tests of chemical assays. Herein, we discuss the critical assumptions underlying the statistical methods in the standard practice. Further statistical analyses are discussed to indicate additional information which may be obtained through a more rigorous statistical treatment.