Harald Schlebusch

Point-of-care testing (POCT): Current techniques and future perspectives

Abstract Point-of-care testing (POCT) is a laboratory-medicine discipline that is evolving rapidly in analytical scope and clinical application. In this review, we first describe the state of the art of medical-laboratory tests that can be performed near the patient. At present, POCT ranges from basic blood-glucose measurement to complex viscoelastic coagulation assays. POCT shortens the time to clinical decision-making about additional testing or therapy, as delays are no longer caused by transport and preparation of clinical samples, and biochemical-test results are rapidly available at the point of care. Improved medical outcome and lower costs may ensue. Recent, evolving technological advances enable the development of novel POCT instruments. We review the underlying analytical techniques. If new instruments are not yet in practical use, it is often hard to decide whether the underlying analytical principle has real advantage over former methods. However, future utilization of POCT also depends on health-care trends and new areas of application. But, even today, it can be assumed that, for certain applications, near-patient testing is a useful complement to conventional laboratory analyses.

Vaccination of Patients with Advanced Ovarian Carcinoma with the Anti-Idiotype ACA125 Immunological Response and Survival (Phase Ib/II)

Purpose: A Phase I/IIb multicenter study was conducted to evaluate the safety and immunogenicity of the anti-idiotypic antibody vaccine ACA125 that functionally imitates the tumor antigen CA125 in 119 patients with advanced ovarian carcinoma. A preliminary report on the initial 42 patients demonstrated safety and immunogenicity. Experimental Design: Using the complete intention-to-treat population (n = 119) who received a mean of 9.7 ACA125 applications, survival was analyzed with respect to immunological responses. Results: In 81 patients (68.1%), a specific anti-anti-idiotypic antibody (Ab3) response could be induced. Additionally, the development of CA125-specific antibodies (Ab1′) and antibody-dependent cell-mediated cytotoxicity of CA125-positive tumor cells was observed in 50.4% and 26.9% of patients, respectively. The median survival of all patients was 19.4 months (range, 0.5–56.1 months). Ab3-positive patients showed a significantly longer survival (median, 23.4 months; P < 0.0001) as compared with Ab3-negative patients (median, 4.9 months). A positive Ab3 response remained associated with longer survival when controlling for other prognostic factors including FIGO (International Federation of Gynecologists and Obstetricians) stage, response to and type of first-line chemotherapy, number of previous treatments, or concomitant antitumor therapy. With regard to safety, repeated vaccination was well tolerated. No serious adverse events related to the application of ACA125 occurred. Conclusions: Although the uncontrolled design of this study prevents definitive conclusions with respect to subgroups, the data support a relationship between Ab3 response and survival time. Thus, the need for further randomized, controlled clinical trials to establish efficacy of the vaccine ACA125 seems to be indicated.

Point-of-Care Testing in Hospitals and Primary Care

BACKGROUND Many medical laboratory tests can now be done near the patient (point-of-care testing, POCT), ranging from basic blood glucose measurement to complex coagulation testing. Switching from conventional laboratory testing to POCT shortens the time to decision-making about further testing or treatment, as delays are no longer caused by specimen transport and preparation, and the test results are rapidly available at the point of care. Better medical outcomes and lower costs may ensue. METHOD Selective literature review. RESULTS The available methods and equipment enable persons not specially trained in laboratory medicine to perform high-quality laboratory testing at the point of care, under certain conditions. Before POCT is introduced in a hospital or outpatient practice, a cost-benefit analysis should be performed, because the introduction is costly and requires a certain amount of organizational work especially for quality management. The potential medical and economic benefits should be assessed individually in each case. CONCLUSION POCT for certain applications is a useful complement to conventional laboratory testing. The future utilization of POCT will depend not only on technical advances, but also on developments in costs and reimbursement.

Serum oxytocin concentration during embryo transfer procedure

OBJECTIVE To determine the effect of the embryo transfer (ET) procedure on serum concentration of oxytocin. STUDY DESIGN Prospective clinical study of 10 women undergoing in vitro fertilization (IVF) treatment with ET in the Section of Reproductive Medicine and Endocrinology at the Department of Obstetrics and Gynecology, University of Bonn, Germany. Serial blood samples were collected in time intervals of 20 s during embryo transfer procedure and serum oxytocin concentration was measured. RESULTS In the absence of tenaculum placement, none of the procedures associated with ET led to an increase in serum oxytocin concentration. When tenaculum placement was used, it was temporally (four out of five patients) associated with an elevation in oxytocin level, which remained elevated until of the end of ET procedure. CONCLUSION Application of a cervical tenaculum during ET or possibly also during intra uterine insemination (IUI) procedure can stimulate the release of oxytocin in some patients.

Cross-linked type I collagen C- and N-telopeptides in women with bone metastases from breast cancer

Abstract This study documents values of biochemical markers of bone remodeling in 106 patients with breast cancer. Based on scintigraphic and radiological findings, patients were divided into 3 groups: 19 patients with bone metastases, 65 patients without bone metastases and normal bone scintigrams, and 22 patients with pathological, non-malignant findings on scintigraphy without proof of bone metastases. Urinary cross-linked type I collagen N-telopeptides (NTx) and serum cross-linked type I collagen C-telopeptides (ICTP) were assessed as markers of bone resorption. Bone alkaline phosphatase (BAP) was assessed as a marker of bone formation. All three markers were significantly higher in patients with bone metastases compared to both patients without skeletal recurrence and those with pathological, non-malignant scintigraphic findings (p < 0.01). There were no statistically significant differences between the latter two groups. The clinical sensitivity for diagnosing bone metastases was 44% for NTx, 65% for ICTP, and 26% for BAP, respectively. The clinical specificitiy for discriminating patients with bone disease from those without were 79%, 91%, and 92% for NTx, ICTP, and BAP, respectively. In conclusion, markers of bone remodeling are increased in patients with breast cancer metastatic to the skeleton. The sensitivity of the markers presented in this paper did not seem to be sufficient enough for early identification of patients with subclinical bone recurrence in a clinical practice setting.

Polychlorinated Biphenyls: The Occurrence of the Main Congeners in Follicular and Sperm Fluids

We have studied the presence of polychlorinated biphenyls in human body fluids associated with reproduction. Since the polychlorinated biphenyls represent a family of compounds, 3 of the main congeners of this family were selected for this study. The distribution of these 3 congeners was investigated in 37 specimens of follicular fluid and in 16 specimens of sperm fluid. Both fluids showed a similar, low contamination with total polychlorinated biphenyls (ca. 10 micrograms/kg on average), but it was evident that the follicular fluids preferentially accumulated the more highly chlorinated components. This finding must be taken into account when interpreting the concentration levels of the main congeners in relation to total pollution and the toxic potential of polychlorinated biphenyls.

Blood Glucose Determinations in Newborns: Four Instruments Compared

Four portable analyzers, HemoCue B-Glucose (I), Accu-Check III (II), One-touch II (III), and Glucometer Elite (IV), with different measuring principles were tested for their suitability for measuring blood glucose in neonates. Precision of all instruments is satisfactory. In the analysis of capillary blood from newborns, two instruments show an excellent accuracy; however, the scatter of the results for instrument (II) is about 1.6 times greater than for instrument (I). The inaccuracy of instruments (III) and (IV) is not acceptable from a clinical point of view. All devices show an influence of hematocrit, the magnitude of which varies between 5% (I) and 12% (III) for every 10% change of hematocrit. Instruments II and IV show that temperature has a marked influence on the readings; the same is true for oxygen in instrument IV. In conclusion, only instrument (I) has met the requirements of accurate and precise blood glucose determinations in neonates.

Immunological properties of a single-chain fragment of the anti-idiotypic antibody ACA125.

Abstract Vaccination with anti-idiotypic antibodies has been described as a promising concept for treatment of several malignant diseases. The murine monoclonal anti-idiotypic antibody ACA125 imitates a specific epitope of the tumor-associated antigen CA125 expressed by 80% of ovarian carcinomas. In the first clinical trial it could be shown that mAb ACA125 is able to elicit anti-anti-idiotypic antibodies (Ab3) with anti-CA125 specificity in patients with advanced ovarian cancer. In order to improve the capabilities of anti-idiotype vaccines we generated a genetically engineered single-chain fragment (scFv) ACA125 composed of heavy- and light-chain variable regions connected by a flexible linker. The antigenicity of scFv ACA125 was demonstrated by immunizing rats i.p. with scFv or complete mAb in complete/incomplete Freunds adjuvants (CFA/IFA) or precipitated by aluminium hydroxide. Negative control groups included applications of irrelevant mouse IgG or adjuvants alone. Anti-anti-idiotypic antibodies (Ab3) directed against the mAb ACA125 as well as specific anti-CA125 antibodies (Ab1′) could be detected in all animals treated with scFv in CFA/IFA. Nevertheless, antibody titers were lower than when the complete mAb ACA125 was used. Suprisingly, an increase of specificity could not be observed in scFv-immunized animals, which had been expected because of the lack of heavy- and light-chain constant regions that could raise rather unspecific anti-isotypic and anti-allotypic rat anti-(mouse Ig) antibodies (RAMA). In contrast, the RAMA responses detected in these rats were even stronger than those following immunization with complete mAb ACA125. In conclusion, the anti-idiotypic scFv ACA125 alone cannot improve the immunogenic features of the corresponding mAb, but provides a useful tool for the further development of genetic vaccines.

Digoxin, flecainide, and amiodarone transfer across the placenta and the effects of an elevated umbilical venous pressure on the transfer rate.

Clinical observations suggest that flecainide might pass the placenta more easily than digoxin, and that its transfer is less disturbed in case of hydrops fetalis than that of digoxin. The purpose of the study was to compare the materno-fetal transplacental transfer of digoxin, flecainide, and amiodarone, another antiarrhythmic agent used in the treatment of fetal tachyarrhythmia, and to assess the effect of an elevated umbilical venous pressure (UVP) on the transfer rate. Isolated lobules of 16 human placentas were dually perfused after spontaneous delivery or caesarean section. The transplacental transfer (area under the curve in the maternal compartment [maternal AUC], area under the curve in the fetal compartment [fetal AUC], kinetic parameters) of digoxin, flecainide, and amiodarone was calculated after these drugs were added to the maternal circuit. In five experiments, the effect of increased UVP on the transplacental transfer rate was assessed by elevating the UVP by 10 cm H2O. Flecainide efflux out of the maternal compartment was significantly greater than that of digoxin (maternal AUC 57.4% ± 5.1%/min vs 73.9% ± 1.5%/min), whereas the flecainide influx into the fetal circulation was smaller (fetal AUC 9.3% ± 4.1%/min vs 11.5% ± 2.0%/min). Only in 50% of the experiments were the smallest amounts of amiodarone detectable in the fetal compartment. An elevation of the UVP reduced the influx of digoxin and flecainide into the fetal compartment (fetal AUC) from 11.5% ± 2.0%/min to 7.4% ± 1.9%/min and from 9.3% ± 4.1% to 4.7% ± 1.4%/min, respectively. Materno-fetal transplacental transfer of digoxin, flecainide, and amiodarone decreases in this sequence. Fetal cardiac insufficiency accompanied by an elevation of the UVP might reduce the transplacental transfer of these drugs, although no significant difference could be found between the reduction of transfer of digoxin and flecainide.

Adhesion molecules, activin and inhibin—candidates for the biochemical prediction of hypertensive diseases in pregnancy?

BackgroundThe aim of the prospective study was to compare standard parameters as Doppler ultrasound and 24-h blood pressure measurement with possible maternal serological markers regarding their prognostic value in predicting hypertensive diseases in pregnancy.MaterialsTwenty-four-hour blood pressure measurement was performed before and after 32+0 gestational week in 57 pregnant women with either chronic hypertension (n=13), preeclampsia (n=21), pregnancy-induced hypertension (PIH; n=12) or normotension (n=11). Blood samples were taken and the concentrations of soluble intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), activin A and inhibin A were determined as well as serum uric acid, creatinine, total serum protein and serum albumin. Doppler ultrasound of the uterine arteries was examined before 32+0 gestational week in the same patients. For the statistical evaluation Kruskal-Wallis-Test and Mann-Whitney-U-Test were performed. Differences in the predictive value were evaluated by receiver-operating characteristics.ResultsVCAM-1 was significantly elevated in women developing hypertensive diseases as compared to normotensive women (preeclampsia: p<0.001; PIH: p<0.05; chronic hypertension: p<0.001). In early pregnancy activin A and inhibin A were significantly higher in preeclamptic patients than in the other groups (activin A: normotension: p<0.005; PIH: p<0.001; chronic hypertension: p<0.005) (inhibin A: normotension: p<0.005; PIH: p<0.001; chronic hypertension: p<0.01), thus suggesting them to be specific markers for the development of preeclampsia. Mean arterial pressure was significantly elevated in preeclampsia (p<0.001) and chronic hypertension (p<0.005) as compared to normotensives.ConclusionTwenty-four-hour blood pressure monitoring with determination of mean arterial pressure and measurement of VCAM-1, activin A and inhibin A as serum parameters can be suggested as useful tests in the specific prediction of different types of hypertensive diseases in pregnancy.