Enzyme immunoassays and related procedures in diagnostic medical virology

This review article describes several applications of the widely used enzyme immunoassay (EIA) procedure. EIA methods have been adapted to solve problems in diagnostic virology where sensitivity, specificity, or practicability is required. Concurrent developments in hybridoma and conjugation methods have increased significantly the use of these assays. A general overview of EIA methods is given together with typical examples of their use in diagnostic medical virology; attention is drawn to possible pitfalls. Recent advances in recombinant DNA technology have made it possible to produce highly specific nucleic acid probes that have a sensitivity approximately 100 times greater than that of EIA. Some applications of these probes are described. Although the non-labelled nucleic acid probes for use in the field are not as refined as non-labelled immunoassays, their range of applications is expected to expand rapidly in the near future.     

Detection and maturation of VEP albino asymmetry: an overview and a longitudinal study from birth to 54 weeks.

The genetic anomaly in albinism prevents adequate melanin metabolism within the fetal eye cup and stalk. This results in severe disruption of pre- and postnatal retinal development and the condition of abnormal temporal retinal projections. The obligate misrouting of retinal-geniculate-cortical projections in albinism can be detected in the topographical representation across the occiput of the visual evoked potential (VEP). Age-dependent misrouting detection methods are described which yield 100% detection rates with zero false positives across the life span. By combining appropriate state-defined neonatal recording procedures with the albino infant VEP test paradigm, the presence of aberrant optic pathway projections was observed in a 5-day-old full-term infant. Maximum asymmetry was observed within a long-latency window of the response which shifted during the postpartum period to shorter latencies. Longitudinal studies show two specific latency regions of significant VEP asymmetry. The first occurs within 40-70 ms after stimulus onset and remains constant across the age range. The second, more robust, cluster of asymmetry occurs within a longer latency window and shows an age-related shift towards shorter latencies. The decreasing latency of this asymmetry is concomitant with normal maturational changes of the evoked response. These results show that VEP misrouting can be extended to reliable albino diagnosis within the neonatal period and to the assessment of visual maturation.     

Propriospinal myoclonus after treatment with ciprofloxacin.

The clinical and electrophysiological features of a truncal myoclonus in a 55-year-old man are described. The electromyographic characteristics point toward propriospinal myoclonus. It is suggested that a myoclonic generator was released after use of ciprofloxacin, by antagonising the gamma-aminobutyric acid metabolism.     

The effects of co-culture with human fibroblasts on human embryo development in vitro and implantation

In a human in-vitro fertilization (IVF) programme, the effect of co- culture of embryos with human fibroblasts was evaluated with respect to pregnancy rate and embryo development. Patients were included in the study after giving informed written consent. The IVF treatments were randomly assigned by stratification of both age (<36 versus > or =36 years) and previous IVF attempts (yes versus no). After fertilization was established, the zygotes were transferred to a 4-well dish with or without fibroblasts and cultured for 2 days. On the third day after ovum pick-up (OPU), cell number and quality [5 (good) to 1 (poor)] of the embryos were scored and a maximum of three embryos was transferred. Supernumerary embryos of good quality were cryopreserved. The design of this study was a group sequential trial with the objective of detecting differences between pregnancy rates following IVF with conventional incubation or incubation in co-culture with fibroblasts. This design included one evaluation at half-way data collection. In the study, 148 patients had an OPU, of whom 77 were allocated to the co-culture group. There was no statistically significant difference in pregnancy rate, cell number and embryo quality between the two groups. The ongoing pregnancy rate per embryo transfer was 27% in co-culture and 30% in the conventional culture group. The implantation rates per transferred embryo were 17 and 18% respectively. Using a multivariate logistic regression model for the probability of ongoing pregnancies, the odds ratio of co-culture, adjusted for age and previous IVF attempts, was not statistically significant. In conclusion, co-culture with human fibroblasts does not contribute to an improvement of embryo quality nor to a higher pregnancy rate after IVF in an unselected group of patients.