Medical technology assessment: the use of the analytic hierarchy process as a tool for multidisciplinary evaluation of medical devices

Most types of medical technology assessment are performed only after the technology has been developed. Consequently, they have only minor effects on changes in clinical practice. Our study introduces a new method of constructive medical technology assessment that can change the development and diffusion of a medical device to improve its later clinical effectiveness. The method, based on Saaty's Analytic Hierarchy Process, quantitatively supports discussions between various parties involved in technological development and diffusion. We applied this method in comparing a new blood pump with two competitors based on technical, medical and social requirements. These discussions changed the evaluators' perspectives, reduced diasagreements, and ended in a reliable evaluation of the pump's performance. On the basis of these results, adaptations were derived which improved the design and diffusion of the blood pump. This application shows the adequate potential of our method to steer technological development and diffusion of artificial organs.     

Effects of riluzole on electrically evoked neurotransmitter release

1. The main purpose of the present study was to investigate the effects of the neuroprotective agent riluzole on the electrically evoked release of [(3)H]-glutamate ([(3)H]-Glu) in mouse neocortical slices. The reported selectivity of riluzole for excitatory amino acids was tested in release experiments with further neurotransmitters. Also distinct species, mouse, rat and man were compared. 2. [(3)H]-Glu was formed endogenously during incubation of slices with [(3)H]-glutamine ([(3)H]-Gln). Released [(3)H]-Glu and tissue [(3)H]-Glu was separated by anion exchange chromatography. Electrically evoked [(3)H]-Glu release was strongly diminished by tetrodotoxin (TTX) and Ca(2+)-withdrawal. 3. Riluzole (100 microM) depressed the release of [(3)H]-Glu up to 77% (IC(50)=19.5 microM). Riluzole was also able to inhibit strongly the electrically evoked release of [(3)H]-acetylcholine ([(3)H]-ACh) (at 100 microM by 92%, IC(50)=3.3 microM, and [(3)H]-dopamine ([(3)H]-DA) (at 32 microM by 72%, IC(50)=6.8 microM). However, the release of [(3)H]-serotonin ([(3)H]-5-HT) was less diminished (at 100 microM by 53%, IC(50)=39.8 microM). Riluzole up to 100 microM did not affect [(3)H]-noradrenaline ([(3)H]-NA) release. 4. Between species, i.e. in mouse, rat and human neocortex, no significant differences between the effects of riluzole could be observed. 5. The NMDA-receptor blocker MK-801 (1 microM) and the AMPA/Kainate-receptor blocker NBQX (1 microM) did neither affect the electrically evoked [(3)H]-ACh release nor its inhibition by riluzole, indicating that effects of riluzole on transmitter release were neither due to modulation of ionotropic Glu receptors, nor due to indirect inhibition of Glu release through these receptors. 6. Taken together, riluzole inhibits the release of distinct neurotransmitters differently, but is not selective for the excitatory amino acid Glu.     

Gustatory and olfactory function in the first trimester of pregnancy.

OBJECTIVE: To investigate gustatory and olfactory sensitivity in the first trimester of pregnancy using validated test kits. DESIGN: Prospective study. SETTING: Department of Obstetrics, University Hospital Zurich, Switzerland. POPULATION: Total 53 pregnant women and 59 controls in a known phase of the menstrual cycle. METHOD: Gustatory sensitivity was assessed by requiring subjects to discriminate between four basic-taste tablets ('sweet', 'salty', 'sour', and 'bitter'). Olfactory testing was performed using the 'Sniffin' sticks' kit. Subjects rated the intensity and hedonic tone of the four tastants and of 10 common odors. RESULTS: Pregnant women had significantly lower overall gustatory sensitivity scores. There were no differences in olfactory sensitivity. However, pregnant women rated the odors 'rum', 'cigarette' and 'coffee' as more aversive than did non-pregnant women. CONCLUSION: Our data do not support the hypothesis of a generalized increase in chemosensitivity in early pregnancy. In terms of adaptive changes of the olfactory system may act as a sentinel to potentially harmful chemicals. In contrast, the gustatory system appears to retreat to allow a greater intake of electrolytes and a more widely sourced diet.     

Review on early technology assessments of nanotechnologies in oncology

Nanotechnology is expected to play an increasingly important role in the diagnostics, prognostics, and management of targeted cancer treatments. While papers have described promising results for nanotechnology in experimental settings, the translation of fundamental research into clinical applications has yet to be widely adopted. In future, policy makers will need to anticipate new developments for clinical implementation and introduce technology assessments. Here we present an overview of the literature on the technology assessments that have already been undertaken on early stage nanotechnology in cancer care, with particular emphasis placed on clinical efficacy, efficiency, logistics, patient-related features and technology dynamics.Owing to the current stage of development of most nanotechnologies, we found only a limited number of publications describing the application of either Health Technology Assessment (HTA) or Constructive Technology Assessment (CTA). In spite of the promising conclusions of most papers concerning the benefits of clinical implementation, actual clinically relevant applications were rarely encountered, and so far only a few publications report application of systematic forms of technology assessment. Most articles consider aspects of environmental safety, regulation and ethics, often mentioning the need to investigate such issues more thoroughly. Evaluation of financial and organizational aspects is often missing. In order to obtain a realistic perspective on the translation and implementation process there is a need for a broad and systematic evaluation of nanotechnologies at early stages of development. Assessment methods taking technology dynamics into account, such as Constructive Technology Assessment (CTA) should be considered for evaluation purposes.     

Cellular origin and clonality of classic Hodgkin's lymphoma: immunophenotypic and molecular studies.

The cellular origin of Hodgkin and Reed-Sternberg (HRS) cells, the neoplastic cells of classic Hodgkin's lymphoma (HL), resisted clarification until the second half of this decade. One major obstacle to successful experimental investigations was the rarity of the HRS cells in the tissue affected by HL. Immunophenotypical studies using monoclonal antibodies already pointed in the early 1980s towards a lymphocytic origin for HRS cells, but were not definitive because of the usually variable expression of B-cell and/or T-cell antigens, and the additional expression of markers typical for other cell lineages, especially dendritic cells. Attempts to elucidate the cellular derivation of HRS cells by demonstrating the clonal rearrangements of the immunoglobulin (Ig) or T-cell receptor (TCR) genes in the DNA of whole-tissue extracts also remained inconclusive due to inconsistent results. In frustration with whole-tissue DNA studies, genetic approaches were turned to the single cell level. Among the techniques developed for the isolation of HRS cells, the extraction of single CD30+ HRS cells from immunostained frozen sections by means of hydraulic micromanipulation proved to be the most suitable. Using this method, monoclonal Ig gene rearrangements were detected in the HRS cells in 36 of 38 (95%) HL cases. Sequence analysis demonstrated high loads of somatic mutation in the rearranged variable regions. Molecular investigation of three cases of HL occurring in association with non-Hodgkin's lymphomas (NHLs) showed that all of the lymphoma lesions had an identical precursor with the molecular features of a germinal center B cell. In summary, these findings indicate that (1) approximately 95% of classic HLs originate from B cells; (2) the direct cellular precursors of the HRS cells are germinal center B cells; (3) the transforming event that causes HL leads to the complete morphologic and immunophenotypical change of the HRS cell precursors; and (4) the HRS cell population of a given case exclusively arises from a single transformed cell and expands by clonal growth. It remains to be shown whether the 5% of HLs for which a B-cell derivation could not be demonstrated are T-cell related.     

Tests for screening olfactory and gustatory function in school-age children.

OBJECTIVE: Determine the suitability of three tests based on the identification of familiar odors and tastes for the clinical assessment of olfaction and gustation in children. STUDY DESIGN AND SETTING: A total of 232 children aged 5 to 7 years from Sydney public schools and 56 adults aged 18 to 51 years participated in a cross-sectional study. RESULTS: The children demonstrated they can identify the majority of the 16 test odorants and 4 common tastes that describe gustatory function. The response distributions obtained for each test provide the basis for a set of normative data for young children. CONCLUSION: Olfactory and gustatory function can be determined in school-age children using the three tests described. SIGNIFICANCE: Currently no satisfactory clinical tests of olfaction and gustation for children or normative data are available. The present study resolves these shortcomings and provides normative data that can be used in the diagnosis of olfactory and gustatory impairment in school-age children.     

A PC-at based video device for flow cytometrically triggered cell imaging in flow

A personal computer-based system of imaging in flow is described which takes cell images directly from the transducer of a flow cytometer. Imaging is triggered by the pulses of the flow system. The movement of the cells is frozen by ultra-short flashes from pulsed light emitting diodes (LED). The images are taken up by a video camera, transferred to an add-in board of the PC and then stored on disk. A novel method has been developed for capturing the video images which normally arise in asynchronism with the video frame. Images of different cells and particles exposed during flow analysis are shown.