Occupational laryngitis caused by formaldehyde: A case report

Formaldehyde is commonly accepted to be an allergen and irritant. However, specifically diagnosed occupational respiratory diseases caused by formaldehyde are relatively rare. Occupational laryngitis was diagnosed in a 47-year-old dairy foreman. He had been exposed for 9 years to formaldehyde emitted from a milk-packing machine situated underneath his office. His exposure level varied considerably. Under normal process conditions, the measured formaldehyde level was 0.03 mg/m³. The patient was examined by different specialists over 1½ years. It was concluded that that he had psychogenic dysphonia. However, a specific laryngeal provocation test with formaldehyde carried out at the Finnish Institute of Occupational Health was positive. His laryngitis was so serious that he was pensioned. During the 3 years of follow-up his condition gradually worsened. He now reacts especially to tobacco smoke and other air impurities known to contain formaldehyde. © 1996 Wiley-Liss, Inc.     

Molecular fragile X screening in normal populations

In December, 1993, we initiated a pilot project in which DNA fragile X (fraX) testing was offered during routine prenatal or genetic counseling to all pregnant women seen at the Genetics & IVF Institute, most of whom were referred for the indication of advanced maternal age. A brochure on fragile X syndrome was sent to each patient prior to her appointment and was reviewed by a counselor or physician during the counseling session. As of June 1995, 3,345 patients were offered testing; 474 women with no identified family history of mental retardation or learning disability and 214 women with a positive family history accepted the test on a self-pay basis. The second population screened was 271 potential donors in our anonymous egg donor program. DNA from blood was tested by Southern blot using EcoRI/EagI and StB12.3. If an expansion was detected, CGG repeat number was determined by PCR-based analysis. Among the 474 patients with unremarkable family histories, three fraX carriers were identified (repeat sizes = 60+), whereas none were found in the 214 patients with a positive family history. Among the potential egg donors, two high borderline patients were identified (repeat sizes = between 50 and 59). Our ongoing study indicates that screening of pregnant or preconceptual populations for fraX carrier status using DNA testing is accepted by many patients and is an important addition to current medical practice. © 1996 Wiley-Liss, Inc.     

Research on the mechanisms of action of aneugenic chemicals and regulatory approaches for their control in the European communities

The European Communities have developed a wide range of regulatory instruments for the control of chemical products sold and used within its geographical area. An important part of the testing requirements for most chemicals within the European Communities is the preparation of an information package on the potential mutagen properties of each chemical. Currently, no test requirements specify a unique test for aneugenic activity, although current methods such as in vitro cytogenetic and bone marrow micronucleus assays provide some useful indirect information on aneugenic activity. During the past 15 years the European Communities supported a series of collaborative research projects that have investigated the mechanisms by which chemicals induce aneuploidy and developmental studies of test methods for the detection of aneugenic chemicals. These projects led to the development of in vitro methods for the detection and quantification of induced nondisjunction and chromosome loss and the measurement of aneuploidy in rodent bone marrow. The European Communities projects have demonstrated the aneugenic potential of a diverse range of chemicals and their potential role in inherited disease and tumour induction. However, regulatory guidelines have yet to be modified to take advantage of the methods developed for the detection and evaluation of aneugenic chemicals. © 1996 Wiley-Liss, Inc.     

Other transgenic mutation assays: Tissue specificity of spontaneous point mutations in λsupF transgenic mice

Transgenic mice carrying multiple copies of a recoverable λ phage shuttle vector carrying the supF mutation reporter gene (λsupF) were constructed for the purpose of studying mutagenesis in a whole animal. Spontaneous mutations in rescued supF target genes from mouse liver and skin were analyzed. The mutation frequency was similar in both tissues (in the range of 2 × 10⁻⁵), but the spectrum of point mutations was distinct, with transitions common in the skin and transversions more prominent in the liver (P = 0.01). These results may help to elucidate pathways of endogenous mutagenesis in vivo, and they illustrate potentially important tissue-specific differences in genetic instability. © 1996 Wiley-Liss, Inc.     

LATE ONSET HUNTINGTON'S DISEASE AS A CAUSE OF DEMENTIA: WHERE SHOULD THE CLINICIAN'S INDEX OF SUSPICION LIE?

Our experience with two genetically confirmed cases of late onset Huntington's disease (HD) in a longitudinal dementia research study suggested that clinical misdiagnosis can easily occur. We therefore undertook genetic testing for HD in a further 84 elderly subjects, 81 of whom had come to postmortem; 75 subjects had dementia and nine were normal controls. A quarter of the demented group had demonstrated extrapyramidal symptoms in life but in none had HD formed part of the differential diagnosis. Although no genetically confirmed cases were found in this second group, the original cases serve as a reminder that late onset HD is a cause of dementia. Genetic confirmation should be sought when the condition forms part of the final differential diagnosis. Further studies conducted in the routine clinical setting are now required since it is in this environment that late onset HD is likely to be misdiagnosed in favour of other forms of dementia.     

表皮肿瘤中COX-2,VEGF表达的意义

目的:了解表皮肿瘤组织环氧合酶-2(COX-2)及血管内皮生长因子(VEGF)表达的情况及其临床意义.方法:免疫组织化学法检测脂溢性角化病(SK)15例,皮肤原位癌(BD)15例,基底细胞上皮瘤(BCE)20例,鳞癌(SCC)20例及正常组织5例COX-2和VEGF的表达.结果:所检测的各种组织标本均有COX-2的表达,分别为SCC 95.0%,BD 73.3%,SK 46.6%,BCE 68.0%,表达强度以SCC最为显著.VEGF在SCC(85.0%),BD(60.0%),SK(53.3%)的表达阳性率较高,而在正常组织和BCE(13.3%)中基本不表达.SCC COX-2表达阳性者其VEGF表达的阳性率较COX-2表达阴性者高(P＜0.05).结论:表皮肿瘤存在COX-2的过表达;VEGF表达与否与组织细胞的性质无关;VEGF的表达与COX-2的过表达有关,COX-2可能与VEGF发挥协同作用,促进SCC的形成及发展.     

Influence of Strain Gradient on Fatigue Life of Carbon Steel for Pressure Vessels in Low-Cycle and High-Cycle Fatigue Regimes

This paper discusses how the strain gradient influences the fatigue life of carbon steel in the low-cycle and high-cycle fatigue regimes. To obtain fatigue data under different strain distributions, cyclic alternating bending tests using specimens with different thicknesses and cyclic tension–compression tests were conducted on carbon steel for pressure vessels (SPV235). The crack initiation life and total failure life were evaluated via the strain-based approach. The experimental results showed that the crack initiation life became short with decreasing strain gradient from 10² to 10⁶ cycles in fatigue life. On the other hand, the influence of the strain gradient on the total failure life was different from that on the crack initiation life: although the total failure life of the specimen subjected to cyclic tension–compression was also the shortest, the strain gradient did not affect the total failure life of the specimen subjected to cyclic bending from 10² to 10⁶ cycles in fatigue life. This was because the crack propagation life became longer in a thicker specimen. Hence, these experimental results implied that the fatigue crack initiation life could be characterized by not only strain but also the strain gradient in the low-cycle and high-cycle fatigue regimes.     

Magnetic Recording Method (MRM) for Nondestructive Evaluation of Ferromagnetic Materials

This paper proposes and experimentally investigates a novel nondestructive testing method for ferromagnetic elements monitoring, the Magnetic Recording Method (MRM). In this method, the inspected element must be magnetized in a strictly defined manner before operation. This can be achieved using an array of permanent magnets arranged to produce a quasi-sinusoidal magnetization path. The magnetic field caused by the original residual magnetization of the element is measured and stored for future reference. After the operation or loading, the magnetic field measurement is repeated. Analysis of relative changes in the magnetic field (for selected components) allows identifying applied stress. The proposed research methodology aims to provide information on the steel structure condition unambiguously and accurately. An interpretation of the results without referring to the original magnetization is also possible but could be less accurate. The method can be used as a standard technique for NDT (Non-Destructive Testing) or in structural health monitoring (SHM) systems.