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The aim of the study was to determine the sensitivity and specificity of the lactate stress test in the detection of mitochondrial myopathies. Thirty one healthy subjects, 10 patients with non-mitochondrial myopathy and 26 patients with mitochondrial myopathy underwent lactate stress testing at a standardized workload of 30 W during 15 min on a bicycle ergometer. Lactate was determined before the exercise (R1), 5, 10, 15 min after starting the exercise (S5, S10, S15) and 15 min after finishing the exercise (R2). A result was interpreted as pathologic if more than two of the five lactate values were above the corresponding upper reference limits. The upper reference limits for the venous lactate at R1, S5, S10, S15 and R2 were 1.9, 2.0, 2.1, 2.0 and 1.7 mmol/l respectively. The lactate stress test was pathologic in 1/10 of the non-mitochondrial myopathies and in 18/26 of the mitochondrial myopathies. The sensitivity of the lactate stress test was 69%. The specificity of the test was 90%. In conclusion, the lactate stress test proved to be helpful for evaluating the integrity of the oxidative metabolism in the majority of patients with mitochondrial myopathy.

Novel applications for cellulases have reinitiated interest in the regulation of production of these enzymes by the soft rot fungus Trichoderma reesei and related species. This paper reviews the current state of knowledge concerning the question "How can insoluble molecules like cellulose initiate their own breakdown by a microorganism?" The evidence available--based on biochemical as well as molecular biological approaches--favors a model in which conidial bound cellobiohydrolases carry out a first exo-exo-wise attack on the cellulose molecule. The disaccharides so formed (cellobiose, alpha-cellobiono-1,5-lactone) are then taken up by the mycelia and promote further cellulase biosynthesis. Evidence available suggests that they are further metabolized to, rather than being, the "true" inducer. Speculations on the nature of the inducer are presented. The roles of the beta-glucosidases of Trichoderma in this process are discussed. The pathway of cellulase secretion is discussed on the basis of electron microscopical as well as gene sequence information.

The bacterium Brucella melitensis has been shown to bind selectively to human B-lymphocytes. The specificity of this binding can be exploited in a rapid technique for the determination of human B-lymphocytes and monocytes by use of rhodamine-labeled Brucella melitensis. This fluorescent labeled regent is simple to use and provides highly specific identification of human B-lymphocytes and monocytes, as demonstrated in a series of experiments characterizing known cellular markers on T- and B-lymphocytes, their separated cellular subpopulations and lymphoblastoid cell lines. The use of fluorescence conjugated bacteria greatly simplifies the application of this highly specific technique and makes its use more practical in routine screening for B-cell and monocyte populations.