Monitoring of impurities using high-performance liquid chromatography with diode-array detection: eigenvalue plots of partially overlapping tailing peaks

The chromatogram of ropinirole in the presence of about 5% of a closely eluting impurity, obtained by HPLC with diode-array detection, was analysed by chemometric procedures. Log eigenvalue plots were used to determine the relative composition of regions of the chromatogram. It is shown that since the peaks exhibit tailing, unusual behaviour is found in the plots. This is verified by performing simulations, in which it is demonstrated that peak asymmetry has a pronounced influence on this chemometric approach. In many cases of liquid chromatographic analysis, asymmetric peak shapes are encountered and methods for peak purity assessment should be re-evaluated in the light of these asymmetries.     

Of sick turkeys, kwashiorkor, malaria, perinatal mortality, heroin addicts and food poisoning: research on the influence of aflatoxins on child health in the tropics

Similarities between the geographical and climatic prevalences of kwashiorkor and of exposure to dietary aflatoxins, and between the biochemical, metabolic and immunological derangements in kwashiorkor and those in animals exposed to aflatoxins, prompted investigation of the associations between kwashiorkor and aflatoxins. Studies in Africa in the 1980s indicated a role for these toxins in the pathogenesis of the disease. Paediatric cases of kwashiorkor are less prone to severe Plasmodium falciparum malaria than normal children. In mice infected with P. berghei, aflatoxin exposure inhibits parasite growth and ameliorates morbidity. Aflatoxins occur in < or = 40% of samples of breast milk from tropical Africa, usually as low concentrations of the relatively non-toxic derivatives of aflatoxin B1 (AFB1) but sometimes as high concentrations of the very toxic AFB1. This could explain kwashiorkor in breast-fed babies. Aflatoxin exposure occurs in > or = 30% of pregnancies in tropical Africa and the toxins are often in cord blood, sometimes at extremely high concentrations. Aflatoxins are now incriminated in neonatal jaundice and there is circumstantial evidence that they cause perinatal death and reduced birthweight. Aflatoxin-induced immunosuppresion may explain the aggressive behaviour of HIV infection in Africa. There are similarities between observations on HIV cases in Africa and those on heroin addicts in Europe, where 'street' heroin is frequently contaminated with aflatoxin. Aflatoxins were found in 20% of random urine samples from heroin addicts in the U.K. and the Netherlands. Aflatoxins have also been incriminated in episodes of food poisoning which have been associated with serious morbidity and mortality, particularly among young children.     

Danger ideation reduction therapy (DIRT): preliminary findings with three obsessive-compulsive washers

Three obsessive-compulsive patients received Danger Ideation Reduction Therapy (DIRT) in an initial treatment trial. All three subjects presented with contamination/washing concerns but refused to participate in exposure and response prevention. DIRT is solely directed at decreasing danger-related expectancies concerning contamination. DIRT procedures do not attempt to address inflated personal responsibility. In addition, DIRT does not involve direct or filmed exposure to contamination-related stimuli, or behavioural experiments. Components of DIRT include corrective information cognitive restructuring, filmed interviews, microbiological experiments, attentional focusing and Hoekstra's (1989) probability of catastrophe estimation task. Treatment consisted of between six and ten 1-hr weekly sessions. At post-treatment, substantial reductions in scores on the Padua Inventory, Maudsley Obsessional-Compulsive Inventory and two global rating scales were apparent for all subjects. These improvements were maintained at a 3-month follow-up. The theoretical and clinical implications of these preliminary findings are discussed.     

Nationwide survey of fluoroscopy: radiation dose and image quality

PURPOSE: To determine the average abdominal entrance air kerma, low-contrast sensitivity, and spatial resolution in upper gastrointestinal tract fluoroscopy in the United States. MATERIALS AND METHODS: A random sample of fluoroscopic facilities was selected to be surveyed for the Nationwide Evaluation of X-ray Trends program. Measurements were performed by using a newly developed fluoroscopic phantom. The surveys were conducted by state radiation control personnel. RESULTS: Average air kerma rates 1 cm above the tabletop, free in air, were 43 mGy/min (n = 340). The rate increased to 64 mGy/min when a 1.6-mm-thick copper filter, which simulated the use of barium contrast medium, was added to increase attenuation. The average entrance air kerma, free in air, for radiographs was 3.4 mGy, and an average of 12 radiographs were obtained per examination. Of 352 facilities surveyed, 306 (87%) were able to resolve wire mesh with 20 or more lines per inch. Of 339 facilities for which percentage contrast could be calculated, 192 (57%) had minimum percentage contrast values of 4% or more. CONCLUSION: Spatial resolution for fluoroscopy is adequate for most of the facilities surveyed, but a substantial proportion of facilities could not visualize low-contrast test objects, which strongly suggests image quality problems.     

Effect of ectoparasite removal procedures on recapture of Microtus californicus

We tested the null hypothesis that anesthetizing meadow voles (Microtus californicus) and brushing them vigorously for ectoparasites would have no effect on the later recapture of these voles. Voles were trapped from 6 December 1993 to 10 January 1994 at Faye Slough Wildlife Area near Eureka, Humboldt County, California (USA). Alternate trapped voles were anesthetized with ethyl ether and brushed vigorously for ectoparasites. There was no significant difference in the frequency of recapture nor in the time to first recapture between those voles anesthetized and brushed, compared to control animals.     

Hepatic hemangioma. Analysis of 103 cases. Clinical considerations and imaging methods

Hemangiomas are the most common benign vascular tumor found in the liver. In this study, 103 cases of hepatic hemangiomas were analysed in a retrospective manner. Image aspects such as those seen in ultrassonography, computed tomography, nuclear magnetic resonance and arteriography are discussed. The incidence was higher amongst the female sex, between individuals from 40 to 60 years old, which presented predominantly without symptoms (66%) and localized mainly in the right hepatic lobe (74%). The meaning of those aspects, when adopted, permits the clinicians to differentiate benign from malignant nodular lesions in the liver.     

Imbalance of morphologically addressed telophases reflects interphase DNA aneuploidy in tumorigenesis

Chromosome division figures (CDFs) are quantitatively different from normal mitoses and represent a novel cytogenetic phenomenon. This investigation was focused on morphologically addressed bipolar telophases in histologically defined human biopsies and in the tumour breast cell-line MDA231. Single cell nuclei were recorded by image microphotometry on inflamed and premalignant lesions of skin (49 cases), oral mucosa (43) and colon mucosa (46). DNA content and replication status were analysed in interphase nuclei as well as in mitoses and in CDFs. In contrast to inflamed lesions, premalignancies were characterised by pronounced endoreplication, when the rate exceeding 5 c was > or = 10% in interphase nuclei. CDFs from the corresponding lesions showed an aberrant DNA content beyond 5 c even more frequently. DNA profiles of metaphases and telophases resembled those of prophases. Therefore, the DNA content of corresponding telophase hemispheres was measured. Severe differences averaged 0.3 c in MDA231 and up to 0.5 c in premalignant lesions. The mean difference between two corresponding hemispheres was 0.39 +/- 0.09 c in Bowenoid keratosis (n = 31), 0.40 +/- 0.08 c in high-grade dysplasia of oral mucosa (n = 16) and 0.21 +/- 0.03 c in high-grade dysplasia of colon adenoma (n = 65 telophases). As a control, the telophase difference was only 0.07 +/- 0.02 c (n = 23) in foetal liver and 0.06 +/- 0.01 c in 24 amnion cells. Thus, genomic instability and, in consequence, genomic imbalance can best be quantified from the DNA profiles of telophase CDFs and from the various DNA amounts in their hemispheres. A strong selection against telophases was observed in neoplasias developing DNA aneuploidy. Those aberrant telophases which escape selection are thought to enhance tumour progression.