Risk factors for rejection for morphological reasons of heart valves for transplantation

The study aim was to identify risk factors for morphological rejection of aortic and pulmonary valves for transplantation that could be used to optimize donor selection. The files of all Dutch heart valve donors, donating in a 2.5 years period, whose hearts were processed at Heart Valve Bank Rotterdam, were reviewed for all factors that could be relevant for valve rejection and related to outcome of morphological assessment of the valves. Valves were retrieved from 813 deceased Dutch donors, 24.1% also donating organs. For 797 aortic and 767 pulmonary valves, who met retrieval criteria, morphological assessment was done. 69.5% of aortic and 37.5% of pulmonary valves were considered unsuitable for transplantation at morphological assessment. Backward stepwise multivariate logistic regression analysis, showed age, cardiac cause of death, cerebrovascular accident as cause of death or in medical history, and number of cardiovascular risk factors in a donor to be independent risk factors for morphological rejection of aortic valves. Age, sex, weight >100 kg and ruptured aortic aneurysm as cause of death were independent risk factors for morphological rejection of pulmonary valves. Being an organ donor was an independent predictor of morphological approval of aortic and pulmonary valves, while hypertension was an independent predictor for morphological approval of aortic valves. Thus, independent factors were identified that are associated with morphological rejection of aortic and pulmonary valves for transplantation, and that could be used to optimize donor selection by preventing unnecessary retrievals, limiting costs, while improving yield per donor with minimal compromise for availability.     

Prospects for use of iodine-free radiopaques for cholecystocholangiography

By using the compounds tantalum and lanthanum, a new radiopaque substance (ROS) was synthesized at the Institute for Chemistry of Solids, Urals Branch of the Russian Academy of Sciences. Experiments on laboratory animals provided evidence that there was no acute or chronic toxicity of helium-based lanthanum orthotantalate. The specific radiopaque properties of the agent versus iodine- and barium-containing ROSs were studied in in vitro and in vivo experiments. The radiodiagnostic properties and locally irritant effect of the test ROS versus iodine-containing agents were evaluated in dogs at cholecystocholangiography.     

Method for epitope selection of antisera for immunohistology

Polyclonal anti-laminin serum was affinity-purified on paraformaldehyde-fixed laminin on a nitrocellulose filter. The purified antibodies were tested for their specificity in immunohistological stainings on frozen sections of paraformaldehyde-fixed tissue. As compared to the initial polyclonal serum, the purified antibodies increased the specificity of antigen detection, since all background caused by nonspecific reactions was eliminated. This technique promises to be very useful for immunohistological analysis using light and electron microscopy.     

Standards for Approval of Hospitals for Graduate Training

The assessment program for approval of hospitals for training in specialties has been augmented by survey visits. Surveyors for the Canadian Council on Hospital Accreditation have acted on behalf of the Royal College of Physicians and Surgeons of Canada and have assisted in the formulation of standard criteria for evaluation of teaching programs. Areas where considerable variation in program exists and where further standardization might profitably be developed are suggested. It is recommended that periodic on-the-site visits be made to all specialty training hospitals. Standards should be further elucidated to guide teachers, students and Royal College surveyors alike. It is emphasized that standards cannot be used to assess the calibre of teaching and learning, but can be employed to assist in evaluating the teachings and learning media that are likely to produce good (or poor) results.     

Algorithms for mapping of mRNA targets for microRNA

MicroRNAs (miRNAs) are involved in human health and disease as endogenous suppressors of the translation of coding genes. At this early point of time in miRNA biology, it is important to identify specific cognate mRNA targets for miRNA. Investigation of the significance of miRNAs in disease processes relies on algorithms that hypothetically link specific miRNAs to their putative target genes. The development of such algorithms represents a hot area of research in biomedical informatics. Lack of biological data linking specific miRNAs to their respective mRNA targets represents the most serious limitation at this time. This article presents a concise review addressing the most popular concepts underlying state-of-the-art algorithms and principles aimed at target mapping for specific miRNAs. Strategies for improvement of the current bioinformatics tools and effective approaches for biological validation are discussed.     

Cercariometry for detection of transmission sites for schistosomiasis

Cercariometry provided information on diurnal fluctuation, seasonal and spatial distribution of cercariae in the suitable natural water bodies. There was an apparent mismatch between the results of cercariometry and snail sampling. Water, which cercariometry showed to contain cercariae was potentially infective, although the resultant worm load of sentinel rodents may not bear a linear relationship with cercarial density. Cercariometry has some weakness in practices and analysis of data, however, it provides the valuable information on the active transmission sites of schistosomiasis.     

Equipment for Simultaneous Processing of Groups of Slides for Radioautography

The equipment consists of commercially available 5-slide plastic grips (obtained from Lipshaw Manufacturing Co., 7446 Central Ave., Detroit, Mich. 48210) and specially designed lightproof exposure boxes to hold the grips. After deparaffinization and hydration, slides are inserted into the grips, dipped in liquid emulsion, drained, and sealed in the exposure box. After exposure, the 5-slide units are removed from the box (in darkness) and inserted into specially made Plexiglas racks that hold four 5-slide units (20 slides). Photographic developing, fixing, and washing are performed by immersing the 20-slide group in fluids contained in 30-slide glass staining dishes (Lipshaw No. 122 dishes). The equipment simplifies darkroom operations and provides means for standardizing the preparation of radioautographs.     

Semiautomatic regulator for the preparation of microelectrodes for electrophysiology

This paper describes an electronic device for making metallic microelectrodes to be used for electrophysiological experiments. These microelectrodes are endowed with a small tissue-electrode capacity and a high mechanical strength. The same microelectrodes are applicable for derivation of spikes as in the case of microstimulation of nervous structures during repeated penetrations.     

Assessment of Needs for Plasma for Fractionation in Europe

In the early 1990s, a series of outbreaks of hepatitis C (HCV) infections clustering among recipients of certain lots of plasma-derived medicinal products (PDMP) alarmed regulatory authorities, manufacturers and the public alike. Also, a few episodes of Hepatitis A (HAV) infections occurred in haemophiliacs receiving solvent-detergent-treated factor VIII concentrates. Thus, several measures were brought into effect to reestablish the safety of the incriminated products and to further increase the margin of safety of PDMP in general. Therefore, intramuscular immunoglobulins had to be free of HCV RNA as shown by nucleic acid amplification technology (NAT) in the final products. Furthermore, the manufacturing process of PDMP had to be validated for both viral inactivation and elimination. Finally, HCV-NAT was to be standardised and implemented as a validated test of plasma pool samples.In 1994, a joint meeting of EPFA, EAPPI and Regulatory Authorities was held in Brussels to outline the state of the art and to delineate the actions to be taken. Five years later, in 1999, the incidence rates of HIV, HBV and HCV in unpaid blood donors have been minimized, especially in European countries. With probabilities for window period donations as low as 0.6 in 1 million for both HIV and HCV and 2.1 in 1 million for HBV in Switzerland, labile blood products have reached extreme, but not absolute safety. The introduction of HCV-NAT roughly doubles this safety resulting in a 1 in 3 million probability of a window donation.Concomittantly, extensive viral validation studies document effective inactivation and removal of viruses in PDMP. The demonstrated margins of safety, expressed as logarithmical reduction factors (LRF), range from 4 to over 20 log(10), depending on product, virus, and inactivation procedure used. Further progress to even safer PDMP shall be acomplished by consolidating the GMP processes, abandoning of obsolete requirements and harmonising national regulations within Europe. Before introducing new measures for additional agents such as HAV or Parvovirus B 19, gains and risks and even potential new threats have to be carefully assessed. Alternative efforts for the safeguard of patients, e.g. vaccination for HAV, need to be balanced against the risks of changing established and validated manufacturing procedures of PDMP with long-lasting safety records.