Evaluation of the micronucleus test in vitro using chinese hamster cells: Results of four chemicals weakly positive in the in vivo micronucleus test

A rapid and simple procedure for the micronucleus test (MNT) in vitro using Chinese hamster ovary (CHO) cells was established in our laboratory. The assay is intended to quickly screen chromosomal aberrations in vitro within the framework of industrial genotoxicity studies. To test the sensitivity of the assay in the experiments described here, four substances, classified as noncarcinogens but reported as weak inducers of micronuclei (MN) in bone-marrow cells of mice, were evaluated in the MNT in vitro. Of the four compounds, ascorbic acid, phenol, and 2,6-diaminotoluene proved to be genotoxic in the MNT in vitro. Titanium dioxide, which could not be dissolved in the culture medium, did not induce MN. The MNT in vitro proved to be quick and relatively simple and to yield highly reproducible results when testing the four chemicals. © 1995 Wiley-Liss, Inc.     

Screening for minimal brain dysfunction (MBD/DAMP) at six years of age: results of motor test in relation to perinatal conditions, development and family situation

The aim of this study was to investigate if children aged 6 years of age, classified as having minimal brain dysfunction (MBD) or deficit in attention, motor control and perception (DAMP), exhibit special medical problems, specific developmental features or if special psychosocial conditions exist in the family. The screening program, using the psychoneurological part of the method developed by Gillberg et al., included 234 children who were followed-up prospectively from pregnancy and birth. The results were related to the physical and mental development of the children, to the psychosocial and socioeconomic conditions of the families, to pre- and postnatal conditions and to “reduced optimality score”, as defined by Prechtl. Mental development was assessed by the use of Griffiths' test at 10-14 months and at 4-5 years of age. At the second Griffiths' test, the mother was also interviewed about the presence of aggressiveness and other symptoms of childhood psychopathology in her child, as defined by the DSM-III criteria, and a psychological observation was also made. In addition to screening for MBD/DAMP, at 6 years of age the parents were asked to complete a questionnaire aimed at identifying attention deficit disorder (ADD). No medical or psychological intervention was made before this stage. Fourteen children (9M, 5F) (6%) were identified as having a positive MBD/DAMP screening result. The results of the screening procedure showed a weak correlation with those obtained using the questionnaire based on the DSM-III criteria for ADD. Compared with the rest of the children, those with a positive MBD/DAMP screening result had an increased number of complications during pregnancy but not a reduced optimality score. At 4 years of age the performance on the Griffiths' test was lower and the rate of child psychiatric symptoms such as aggressiveness and signs of the mother having difficulties in setting limits for the child were more common than among the rest of the cohort. No relation was found with the psychosocial or socioeconomic conditions of the family. We conclude that children suspected of having MBD/DAMP at the start of school may have exhibited signs of delayed psychoneurological development and symptoms of psychopathology at 4 years of age.     

Cellular PSA in benign and malignant prostate

To determine the relationship of carcinoma of the prostate and cellular production of prostate-specific antigen, cytosol levels of PSA were measured in benign and malignant fresh prostate tissue harvested from radical prostatectomy specimens. Wedge biopsies were taken from benign (N = 21) and malignant (N = 74) prostate tissue and were immediately fixed in liquid nitrogen, and then homogenized and differentially centrifuged, and the cytosol fractions extracted. The remaining specimen was sent for routine pathologic assessment. The Hybritech methodology was used to measure the cytosol PSA and standard protein analysis was used for cytosol protein (CP) measurement. There was a significantly greater concentration of PSA in malignant tissue (P = 0.046). Also, when benign and malignant tissue were available from a single prostate (N = 17), these differences in cytosol PSA were even greater (P = 0.002). In addition, there was no significant difference when serum PSAs from the malignant tissue were ranked according to Gleason score and placed into three different histologic grades (i.e., Gleason scores 2–4, 5–6, and 7–10).     

Tuberculosis in South-East Asian Refugees after Resettlement-Can Prevention Be Improved by Better Policy and Practice?

Objective.This study aimed to determine whether incident cases of tuberculosis (TB) in a cohort of South-East Asian refugees followed for 5 years after resettlement were potentially preventible and whether prevention of TB was optimal in a state refugee TB screening program in Victoria, Australia.Design.A retrospective cohort study of 1,101 refugees from Laos, Cambodia, and Vietnam screened for TB in the 6-month period from July 1989 to January 1990 was conducted. Incident cases of TB were identified by matching each refugee with the TB notification database for 5 years from the date of initial screening. Preventability was assessed for incident cases by reviewing medical records. Screening guidelines and practice were reviewed.Results.The main outcome was the preventability of cases of active tuberculosis that developed in the study population in the first 5 years after resettlement. The incidence of active TB was 363/100,000 during the first year and 109/100,000/year during the first 5 years. Five of six incident cases were assessed aspotentiallypreventable, which if prevented would have resulted in an annual incidence of 18/100,000 over the first 5 years. Use of a more sensitive skin test definition of infection would have made an additional 245 refugees eligible for prevention and potentially prevented an additional 25 cases of TB over a lifetime.Conclusions.There is a high incidence of tuberculosis among SE Asian refugees, particularly in the first year after resettlement. A large proportion of TB may be preventable. Improvement in case prevention may be possible with updated guidelines and better implementation of screening policy.     

Ethical issues in investigation of screening strategies

Screening programs can be designed to be useful for data collection to study effectiveness of screening. High-risk populations may be identified, and screening techniques applied to a randomly selected subgroup with another subgroup serving as controls. This raises the ethical question of not applying helpful surveillance to individuals known to be at high-risk. Attention should be paid to management of controls, for example, to screen them less frequently, or at least to inform them of their increased risk and advise periodic exams. Against such recommendations is that differences between test and control groups would be minimized and the study less conclusive. Another approach is to use adaptive design, selecting the study group from a large population which is being subject to medical surveillance for some other reason. As in other clinical trails, studies of screening programs must include appropriate surveillance for controls to properly safeguard their rights and medical needs.     

Control of homozygous β-thalassemia by carrier screening and antenatal diagnosis in Sardinians

This paper reports the present results of an ongoing program aimed at preventing homozygous beta-thalassemia by means of heterozygote screening and antenatal diagnosis in the Sardinian population. Screening based on the knowledge of carrier frequency and types of thalassemia prevalent in this population was designed to discover all heterozygotes except the few silent beta-thalassemia carriers. Most of the couples at risk were informed and accepted testing. Information was conveyed by mass media, midwives and marriage registry offices. Antenatal diagnosis was accepted by the majority of the couples counselled. The results of antenatal testing were very accurate. There was only one misdiagnosis out of 949 pregnancies tested. This risk of fetal loss was 7.5%. The program was highly effective, as shown by the decline of the incidence of the homozygous state from 1:205 live births in 1976 to 1:557 in 1981.     

Quantitative glucose measurement in urine as screening test for urinary tract infections

Summary Subject: In urological patients the value of quantitative glucose measurement in urine as a screening test for urinary tract infections is examined.Method: Glucose content, species and concentration of microorganisms in the urine of 334 urological patients were analysed and the bacteriological findings compared with the result of chemical measurement.In vitro, the dependence of bacterial growth on different properties of urine was examined.Results: A diagnostic decrease in glucose concentration was found in only about 48% of the infected urines. The result of the glucose test is influenced unfavourably by humerous factors which cannot be standardized.Conclusions: In its present form, this method is not yet suitable for use as a reliable screening test for urological patients.     

Eliciting relative preferences for two methods of colorectal cancer screening

Two methods of mass population screening for colorectal cancer - faecal occult blood testing and sigmoidoscopy - have been the subject of randomized controlled trials in the UK. A national screening programme is currently under consideration and the choice of screening method remains open. To be successful, a programme will require high levels of uptake, and uptake is likely to depend upon subjects' attitudes towards the screening method introduced. Although a preferred screening method has already been identified from a questionnaire survey, we undertook a further interview study (n = 106), with a view to comparing the results of two different approaches to eliciting public preferences. In comparison with the questionnaire study, a higher proportion of interview subjects stated a preference. Interview subjects were generally more favourably disposed towards sigmoidoscopy, excepting those with previous experience. Compared with the questionnaire survey, the interviews provided richer information on the reasons for preferences offered. Individual preferences were evidently subjective and dependant on attitudes towards a variety of method characteristics, such as discomfort, convenience and perceived sophistication. Characteristics such as age and low income, which had predicted preferences in the questionnaire study, predicted preferences in the interview study also. The difference between the results obtained by the different elicitation techniques can be explained in terms of the differential provision of information and sample selection. Conclusions made about public preferences are likely to depend on the technique employed in eliciting them.