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One of the major clinical problems in the treatment of people with schizophrenia is suboptimal medication adherence. Most research focusing on determinants of nonadherence use quantitative research methods. These studies have some important limitations in exploring the decision-making process of patients concerning medication. In this study we explore factors influencing medication adherence behavior in people with schizophrenia using concept mapping. Concept mapping is a structured qualitative method and was performed in 4 European countries. Participants were 27 patients with schizophrenia, 29 carers, and 28 professionals of patients with schizophrenia. Five clinically relevant themes were identified that affect adherence: medication efficacy, external factors (such as patient support and therapeutic alliance), insight, side effects, and attitudes toward medication. Importance ratings of these factors differed significantly between professionals and carers and patients. Professionals, carers, and patients do not have a shared understanding of which factors are important in patients' medication adherence behavior. Adherence may be positively influenced if professionals focus on the positive aspects of medication, on enhancing insight, and on fostering a positive therapeutic relationship with patients and carers.

We present a statistical path analysis model for the evaluation of two tests in the absence of a "gold standard" method. This model is applied to the evaluation of flow-cytometric and visual reticulocyte counting by using as the comparison method a combination of three hematological measurements: hemoglobin concentration (HGB), mean cellular volume (MCV), and erythrocyte density width (EDW). We assumed that, in general, a higher reticulocyte count is associated with a lower HGB value and with greater values for MCV and EDW. Applying this assumption and the statistical model, we demonstrated that flow cytometry was superior to visual reticulocyte counting in the low-value range studied. The path analysis model is potentially applicable in other cases where two tests are to be compared, and when no gold standard is available.

Receiver-operating characteristic curves of the IgG synthesis rate and the IgG index show that the IgG index has better discriminating properties with respect to multiple sclerosis. This, added to the fact that the precision of determining the index is much higher than that of the synthesis rate, makes the IgG index the parameter of choice in the diagnosis of multiple sclerosis.

We describe a two-stage method for measuring thromboplastin in cerebrospinal fluid, based on the amidolytic determination of the generation rate of Factor Xa. We investigated the effect of variations in the duration of incubation, and in pH, temperature, and concentrations of calcium, buffer, and prothrombin complex (source of Factors VII and X). Optimal assay conditions are specified. The detection limit is 6 units/L and the results indicate an upper limit of normal of 14 units/L. The coefficients of variation were 7.7% within-day and 9.2--16.0% day-to-day, depending on the concentration.

Estimates of thromboplastic activity in 1100 samples of cerebrospinal fluid indicate that an increased activity of this clotting factor is a nonspecific indicator of abnormality in the central nervous system, much like (e.g.) an increased count of mononuclear cells and an increased protein content. However, the proportion of abnormal results obtained by these three tests can differ markedly in different neurological disorders. Increased thromboplastic activity is about 14-fold more common in bacterial meningitis than in viral meningitis; thus the thromboplastin determination can be of value in discriminating between bacterial and viral meningitis.

Serological and non-serological tests were performed in matched samples of cerebrospinal fluid and serum from 236 syphilitic patients. An increased IgG or IgM index, or both, was found about 70 times more often in symptomatic neurosyphilis than in latent syphilis without involvement of the central nervous system. An increased Ig index, together with a cell count greater than 5/microL, was only found in symptomatic neurosyphilis. Although the numbers of data are small, we conclude that the IgG and IgM indexes are valuable tests in the diagnosis of syphilitic involvement of the central nervous system.

The diagnostic implication of a certain test result with regard to a certain condition can be expressed as a single number, L, the likelihood ratio of this result. This ratio allows Bayes's theorem to be written in a convenient form. We show that the practice of calculating predictive values for the results of quantitative tests by use of discrimination limits leads to incorrect predictive values. Including L values in laboratory reports seems a more logical approach to optimum interpretation of laboratory results than the use of discrimination values.

Sensitized erythrocytes carrying the first and fourth components of complement (EAC14) were prepared by incubating optimally sensitized sheep erythrocytes with normal serum appropriately diluted in Mg2+-free diethylbarbiturate buffer containing Ca2+. EAC14 cells so prepared were found to be suitable for use in estimating the second component of complement (C2) in human serum, and the method is described here.

Having determined immunoglobulin G (IgG) and albumin concentrations in 1100 cerebrospinal fluid and serum samples, we calculated the IgG index. Likelihood ratios for multiple sclerosis were calculated by using a training set consisting of 100 patients with definite multiple sclerosis and one consisting of 97 patients suffering from diseases from which multiple sclerosis must be differentiated. Predictive values for multiple sclerosis, given different values for the IgG index, are given in a graphical representation of Bayes' theorem. We conclude that this approach increases the diagnostic usefulness of the IgG index for the diagnosis of multiple sclerosis.

After ischemic exercise tests, performed to detect glycogenoses or myoadenylate deaminase (EC 3.5.4.6) deficiency, the increases in serum lactate and ammonia usually are measured. Determination of hypoxanthine instead of ammonia can also be used to show myoadenylate deaminase deficiency, but HPLC of hypoxanthine is time-consuming. As a substitute, we developed an indirect enzymatic equilibrium method for hypoxanthine based on coupling the chromogenic system 3,5-dichloro-2-hydroxy-benzenesulfonic acid/4-aminophenazone with formation of hydrogen peroxide by xanthine oxidase (EC 1.1.3.22). The pH optimum is at 7.8 and the absorbance maximum at 510 nm. The calibration curve is linear from 0 to 100 mumol/L and the detection limit is 0.9 mumol/L. Analytical variability (CV) was 1.5% to 3.6% within-run, 4.5% to 8.5% between-run. The assay can be performed with a standard spectrophotometer or a centrifugal analyzer. The coefficient of correlation was 0.68 between hypoxanthine and ammonia increases in plasma from controls who performed the exercise test.