[Analytical methods at the boundary between biochemistry and immunology]

The article presents assays shared by both disciplines; i.e the specialization 801 (Clinical Biochemistry) and 813 (Laboratory of Allergology and Immunology), and it covers over 60 tests. It is intended as reference information for general practitioners, as well as for laboratory workers at the beginning of their studies. Emphasis is laid on some facts which GPs ordering laboratory determinations should be familiar with; the pre-analytical stage (specimen collection, their transport and storage), the analytical reliability of particular methods, their accessibility, frequency and total costs. Analytical techniques are only mentioned marginally as their understanding is not essential for GPs. Assuming the readers' fundamental experience of diagnostic applications of the methods discussed; we only comment some obsolete or rare tests. The shared assays cover selected analyses of proteins (incl. some enzymes and tumormarkers), ions, osmolality and quantitative microscopic urinalysis.

A vaccinia-based vaccine (TroVax) targeting the oncofetal antigen 5T4 administered before and after surgical resection of colorectal cancer liver metastases: Phase II trial

2574

Background: Oncofetal antigen 5T4 is expressed by most colorectal cancers. Administration of a vaccine combining a Modified Vaccinia Ankara (MVA) vector with 5T4 elicits immune responses in late-stage colorectal cancer patients. This trial seeks to investigate the immunological effects of the vaccine both in peripheral blood and locally in tumour tissue resected during potentially curative surgery for colorectal liver metastases. Some patients may have micrometastatic disease, a potential target for immunotherapy. Methods: Colorectal cancer patients selected for resection of liver metastases were eligible. Recruitment of up to 20 patients was planned. Following screening they received 2 vaccinations prior to, and 2 after, surgery. Primary endpoint was assessment of the immune response at time of surgery. Blood was taken for analysis at screening and 2 weeks after each vaccination. A tumour biopsy was obtained at surgery. T-cell responses were assessed using proliferation and gamma-interferon ELISPOT assays; ELISA used to assess serological response. Immunohistochemical analysis was used to confirm tumour antigen expression and the nature of T-cell infiltration into the liver. If 5T4-specific immune responses were demonstrated patients were offered further vaccinations at 20 and 28 weeks post surgery. Results: Of 20 patients recruited, 16 were eligible for assessment, 4 excluded, 1 due to hepatocellular carcinoma, 3 with inoperable disease. There was no grade III/IV toxicity related to vaccination. Tumour expression of 5T4 was confirmed in all cases, local T-cell infiltration consisted predominantly of CD4 cells. According to proliferation assays, 8 of 16 patients had T-cell responses at time of surgery and 12 of 16 in total to date. 14 patients have developed 5T4-specific antibody responses. At median follow up of 8.4 months 7 of 16 patients have disease recurrence. Conclusions: The MVA-5T4 vaccine (TroVax) was safe and well tolerated in all patients undergoing resection of colorectal liver metastases. 5T4 specific cellular and/or humoral immune responses were induced in the majority of patients following vaccination with TroVax.

[Table: see text]

Amplification of chromosome 5p correlates with increased expression of Skp2 in HPV-immortalized keratinocytes

The oncogenic HPVs immortalize primary genital keratinocytes in vitro and there is evidence that such lines represent suitable models to examine HPV-induced carcinogenesis. Early in vivo studies and more recent CGH analyses have revealed amplification of chromosome 5p in advanced stage carcinoma of the uterine cervix (CaCx). In the present study, a panel of established CaCx-derived cell lines were analysed by M-FISH to identify recurrent karyotypic abnormalities. Amplification of 5p was observed in 11 of 13 CaCx cell lines harbouring HR (high-risk) HPV. The region of 5p undergoing amplification was confirmed using human band-specific paints. The F-box protein Skp2 is present at 5p13 and its protein is present at increased levels in many cancers of an advanced stage. The HPV16-harbouring cell line W12 shows progressive morphological abnormality with in vitro passage, culminating in an invasive phenotype. The expression of Skp2 at different stages of this progression was investigated utilizing Western blot and TaqMan quantitative PCR. At medium to late passage, gain of 5p as an isochromosome was observed. Increased expression of Skp2 and a reduction in the expression of its target p27 correlated with increasing passage in this line.

Speciation of Cu, Se, Zn and Fe in blood serum of hemodialysed patients

The speciation of trace elements in serum samples of hemodialysed patients was investigated using on-line connection of SEC and ICP-MS. The 0.02 mol/l TRIS-HCl buffer of pH 7.5 was used as mobile phase. The results of speciation as well as the total concentration data were compared with those of control group of healthy person. Alterations of total concentration were observed in case of selenium and zinc only. Iron was present in form of transferrin and ferritin, main amount of copper was bound to ceruloplasmin and selenium compounds were identified as selenoproteine P and glutathione peroxidase. The latter compound was detected in samples of control group only. The chromatograms of the other elements were similar and no substantial changes between both investigated groups were observed.

[Freely programmable automatic radioimmunoanalysis on the STRATEC ST 300 analyzer]

We compared the free programmable automatic radioimmunoassay on analyser STRATEC SR 300 to the manual performance of RIA and IRMA. One-step and two-step methods were evaluated. Manual delivery proved to be faster than the automatic one. The speed of dispensing depends on the volume of the dose sample and of the reagent, on the adjustment of rinsing volumes of the needle, washing volumes among separate doses and also on the size of the sample set. The total efficiency of the manual and the automatic analysis is also affected by other operations, especially by washing test tubes and the administration of reports. For a set of 100 analyses, the manual process is from 20 to 90 minutes longer than the automatic one, depending on the analytical method used. Thus, the automatic analysis proved to be significantly faster. Nor the comparison of isotope and non-isotope immunoassays showed any relevant qualitative or quantitative differences in analytical response. At the same time the prices of radioimmunoassays are more favourable, and in addition to that, a big choice of analytical sets is available which are not dependent on the user's instrumentation. However, this does not concern very small series, or separate tests where size of calibration is important. Moreover, the turn-around-time of RIA and IRMA is in these cases longer than when automatic non-isotope methods are used.

Comparison of different immunoassays for CA 19-9

We compared six routinely employed immunoassay kits: Architect i2000 and AxSYM, Abbott Laboratories; Elecsys 2010, Roche Diagnostics; ELSA, CIS-BioInternational; Immulite 1, Diagnostic Products Corporation; and IRMA-mat, Byk-Sangtec Diagnostica. Using all analytical systems, we measured identical groups of clinical samples completed with selected control samples. The repeatability of measurements (coefficient of variation) ranged from 2.1% (Elecsys 2010) to 6.7% (ELSA). The parameters of Passing-Bablok regression show significant systematic differences among analytical systems. Data from a Bland-Altman diagram suggest that these differences project onto other, still more significant individual differences among individual samples. Though the cut-off values differ between various systems, no similar clinical efficacy appears to be attained. The behavior of individual systems is quite different for identical control materials and does not necessarily duplicate the calibration for biological samples. The results of determining CA 19-9 cannot be extrapolated from one analytical technique to another, even in cases where the same monoclonal antibody is used. Standardization of CA 19-9 measurement systems is necessary to allow use of the results for the purposes of evidence-based medicine.

Frequency of fibroblast growth factor receptor 3 mutations in sporadic tumours

Mutations in FGFR3 have been identified in several tumour types including bladder carcinoma, cervical carcinoma, and multiple myeloma. In bladder carcinoma, we recently identified FGFR3 mutations in 41% of tumours, making this the most frequently mutated putative oncogene identified in bladder cancer to date. We have now investigated the frequency of FGFR3 mutation in a panel of 125 tumours and 13 cell lines from various other organs. We analysed the mutation hotspots in exons 7, 10 and 15 by direct DNA sequencing, and found one mutation in exon 7 (S249C) in 1/28 (3.5%) cervical tumours. Mutations were not detected in stomach, rectum, colon, prostate, ovarian, breast, brain, or renal tumours, nor were they found in any of the cell lines included in this study. We conclude that FGFR3 is commonly mutated in bladder carcinoma and only rarely in cervical carcinoma. Several tumour types appear not to possess any mutations in FGFR3, suggesting that these mutations are important only in the development of certain types of tumour.

Problem effectiveness in an occupational therapy problem-based learning course

OBJECTIVE

The purpose of this study was to evaluate students' perceptions of the extent to which faculty-generated learning objectives were addressed in a problem-based learning (PBL) course.

METHOD

Twenty-seven students enrolled in a 12-week PBL course were randomly divided by age, gender, and grade point average into four tutorial groups. Each group rated on a 10-cm visual analog scale their perceptions of how well they believed the objectives for each of four cases were addressed. Repeated-measures analysis of variance was used to test the average differences among the tutorial groups for each case. Further, post hoc tests were performed to compare the means among groups for each objective.

RESULTS

No significant differences were found in the average perceptions among the tutorial groups for any of the four cases. Student ratings indicated their overall perception that within each problem, preset objectives had been met.

CONCLUSION

The results support that students' interpretations of learning objectives for PBL cases are consistent with the problem developers' intended learning objectives. In addition, the similarities in the average scores for learning objectives across the four tutorial groups support the notion that PBL outcomes can be consistent among students, even though their study and discussions are in separate groups with different facilitators.

The pattern of expression of the 5T4 oncofoetal antigen on normal, dysplastic and malignant oral mucosa

The human 5T4 oncofoetal antigen is expressed by all types of trophoblast in pregnancy but is not detected on most adult tissues, although low levels are found on some epithelia. However, this antigen is strongly expressed by many cancers and tumour-associated labelling correlates with metastatic spread and poor clinical outcome for patients with gastric and colon cancer. Over-expression of the gene influences cell adhesion, shape and motility, which may be related to changes in the cellular localisation of the 5T4 oncofoetal antigen as malignancy develops. To establish whether the 5T4 oncofoetal antigen can serve as a tumour-specific marker for oral cancer and precancer, we have evaluated the pattern of expression on biopsies of normal, inflamed and dysplastic oral mucosa using immunohistochemistry. Oral mucosa, taken from different sites in the mouth, expressed the 5T4 oncofoetal antigen with varying intensity and pattern. The majority of the immunoreactivity was detected in the basal and suprabasal layers, with expression extending into the spinous cells at fully keratinised sites and when inflammation was present. This antigen was also detected in the underlying connective tissue. Oral squamous cell carcinoma showed a variety of patterns and intensity of staining corresponding to those found for normal mucosa. However, 21 of 41 cases showed no stromal labelling, a finding also observed for dysplastic lesions. The alterations in the pattern and intensity of 5T4 oncofoetal antigen expression were not related to clinicopathological features of the tumours examined. These data show that the 5T4 oncofoetal antigen is expressed on normal oral mucosa, such that this target cannot be used for detection of neoplastic or preneoplastic cells, although altered expression may contribute to the pathogenesis of these lesions.

Degradation of proteins from the ER of S. cerevisiae requires an intact unfolded protein response pathway

To dissect the requirements of membrane protein degradation from the ER, we expressed the mouse major histocompatibility complex class I heavy chain H-2K(b) in yeast. Like other proteins degraded from the ER, unassembled H-2K(b) heavy chains are not transported to the Golgi but are degraded in a proteasome-dependent manner. The overexpression of H-2K(b) heavy chains induces the unfolded protein response (UPR). In yeast mutants unable to mount the UPR, H-2K(b) heavy chains are greatly stabilized. This defect in degradation is suppressed by the expression of the active form of Hac1p, the transcription factor that upregulates UPR-induced genes. These results indicate that induction of the UPR is required for the degradation of protein substrates from the ER.

Genetic and epigenetic regulation of NMDA receptor expression in the rat visual cortex

The susceptibility of cortical networks to use-dependent modifications declines with age (critical period) and this decline of neuronal plasticity during development is paralleled by the shortening of NMDA receptor EPSCs. We showed previously in the somatosensory cortex that the shortening of NMDA receptor kinetics correlates with a developmentally-regulated increase in the NR2A subunit expression. Here we examine whether this developmental regulation of NR2A expression is related to the duration of critical periods and whether it is influenced by experience. Functional NMDA receptors and their molecular characteristics are studied in identified layer IV neurons of rat visual cortex. In this structure the time course of the critical period differs from that in the somatosensory cortex and can be changed by sensory deprivation, thus permitting examination of correlations between the time course of receptor expression and the duration of the critical period. We find that the developmental expression of the NR2A subunit is delayed compared with the somatosensory cortex, in agreement with the prolonged critical period in the visual cortex. Moreover, sensory deprivation further delays the developmental change in the NMDA receptor subunit composition, demonstrating the activity dependence of this process and strengthening the correlation between changes in subunit composition and the time course of the critical period.