Dental radiography: efficacy in the assessment of intraosseous lesions of the face and jaws in asymptomatic patients

In this investigation the efficacy of dental radiography for the detection of occult intraosseous lesions of the face and jaws was evaluated. An analysis of 30 million health insurance records indicated that the period prevalence of malignant lesions was less than 5 cases/million/year, and for benign lesions approximately 100 cases/million/year. Data from a controlled observer-performance study showed that radiographic sensitivities ranged between 50% and 80%. The cost per true-positive finding was estimated to be +8.6 million per malignant case and +430,000 per benign case. An assessment of the dosimetric literature indicated that the benefits of radiographic screening as a means for early detection of a malignancy appear to be counterbalanced by the risk of causing a radiation-induced malignancy. Taken together, these data demonstrate that dental radiography is not efficacious for the purpose of detecting occult lesions.     

Multimedia presentation of radiological image data using the internet

Summary Aim: Recent developments of the Internet (World Wide Web) allow the integration of audio, video, digital film sequences, and three-dimensional data. The applicability of these innovations for medical documentation is demonstrated. Methods: Our existing software for medical image processing and 3D reconstruction was extended to provide images, film sequences, and complex 3D models in an Internet-compatible data format. Results: The multimedia results of the image processing were integrated into Internet documents. Specialized programs are no longer necessary for visualization. The Internet software allows for user-friendly handling and interactive presentation of the 2D and 3D data. Conclusions: The Internet offers public-domain software for display of images, audio/video, and 3D data. Thus, the tools of the Internet represent an ideal basis for local hospital information systems, computer-aided medical education, and teleconferencing. Eingegangen am 16. September 1996 Nach überarbeitung angenommen am 11. November 1996     

Detection and quantification of melphalan-DNA adducts at the single cell level in hematopoietic tumor cells

Bifunctional alkylating agents, such as melphalan, are widely used in the treatment of hematological malignancies. The effects of these drugs on particular types of hematological cells and the causes of treatment failure are poorly understood. The aim of this work was to establish an ability to measure the extent to which melphalan reacts with the DNA of individual tumor cells, thereby creating new possibilities for molecular pharmacological studies on clinical samples. A novel approach for staining drug-DNA adducts is described in which cells were embedded in agarose and then lysed. The DNA from each cell remained in an ideal state for quantitative immunofluorescent staining using a previously described monoclonal antibody. Immunofluorescence and DNA-Hoechst dye fluorescence were quantified using a cooled slow scan charge coupled device camera and image analysis procedures. Immunofluorescence of drug- treated cells from a human leukemia cell line was partially correlated with DNA content. Mean integrated immunofluorescence of 50 to 100 cells was dependent on drug concentration and was linearly related to adduct levels. In these cells and in chronic lymphocytic leukemia cells obtained from patients, there was considerable intercell heterogeneity in apparent adduct levels. This was also seen in peripheral blood mononuclear cells isolated from a patient after melphalan therapy.     

Isolation of dimeric nonactic acid from the nonactin-producing Streptomyces spec. JA 5909-1

The formation of possible intermediates of nonactin (I) biosynthesis by Streptomyces spec. JA 5909-1 was investigated. In addition to monomer nonactic acid (II), the dimeric nonactic acid (III) was isolated suggesting that III could be an intermediate of nonactin biosynthesis. The structure of III was settled by electrospray mass-spectrometry and high-field FT-NMR methods. III displays no antibacterial and antifungal activities supporting the view that cation complex formation by nactin-type antibiotics requires the entire macrotetrolide ring.     

Myocardial angiotensin receptor type 1 gene expression in a rat model of cardiac volume overload

To investigate the regulation of the angiotensin receptor type 1 (AT1) in different organs in cardiac volume overload, we measured AT1 mRNA content in the atria, left and right ventricle, kidney and liver of rats with an aortocaval shunt, produced by infrarenal aortocaval puncture 4 weeks earlier. For angiotensin receptor mRNA quantitation a novel quantitative PCR procedure based on liquid phase hybridization was used that allowed the determination of absolute AT1 mRNA copy numbers and its comparison in different organs. Glyceraldehydephosphate dehydrogenase (GAPDH) mRNA was measured by RT-PCR to control externally equal mRNA content and quality of RNA extraction in shunt animals and controls. Heart weight was increased in the shunt animals, with the greatest increase in the atria. Blood pressure, plasma renin activity, plasma angiotensin I and II and aldosterone concentrations were not significantly altered. The AT1 mRNA content was significantly increased in the atria (shunt: 1167±350 copies AT1 mRNA/ng RNA vs controls: 803±240; p<0.05). No change was found in the right or left ventricle, in the kidney and liver. The findings document that atrial hypertrophy in cardiac volume overload parallel with a significant increase in atrial AT1 mRNA content.     

The comorbid association of migraine with osteoarthritis and hypertension: complement C3F and Berkson's bias

Migraine is known to have a major genetic component and has been associated with a wide variety of comorbid disorders including arthritis and heart disease. Since migraine and some of its comorbid disorders involve inflammation, complement C3, a protein involved in acute inflammation, was selected for analysis as a candidate gene in an ongoing study of the genetic basis of migraine. Polymorphism frequencies for complement C3F (0.19) and C3S (0.81) in a sample of 137 unrelated migraineurs were found to be consistent with a control group as well as previous population studies, indicating that this common polymorphism has no association with migraine susceptibility. However, C3F positive individuals with migraine were found to have an increased incidence of osteoarthritis (Chi square = 10.06; p < 0.0008) and hypertension (Chi square = 5.18; p < 0.01). Therefore, the data in the present study indicate that certain migraine comorbidities that have been reported in the literature may result from Berkson's bias as opposed to a shared pathophysiological variation in the C3 gene.