High concordance between marker profiles of 22 human leukemia-lymphoma cell lines tested with the same monoclonal antibodies before and during the second international workshop on human differentiation antigens

Summary Our laboratory participated in the Second International Workshop and Conference on Human Leucocyte Differentiation Antigens. In this international study the reactivity profiles of monoclonal antibodies were analyzed on normal and malignant hematopoietic cells. The Workshop was divided into three categories: the T-cell, B-cell and myelomonocytic cell studies. We blindly tested 159 coded monoclonal antibodies of the panel for the T-cell study on 22 permanently established leukemia cell lines. The monoclonal antibodies were provided by the Workshop Committee and their reactivity with the target cells was visualized by standardized indirect immunofluorescence. After decoding it was recognized that 11 monoclonal antibodies had been examined on these cell lines prior to the Workshop. The reactivity of these 11 monoclonal antibodies was analyzed and compared with the earlier results. From a total of 217 paired tests done blindly in the Workshop study and prior to the Workshop, 191 tests (88%) did not show significantly different data. The possible reasons for discrepancies include nonspecific Fc-receptor-binding on some cell lines and a relatively nonspecific reactivity of some monoclonal antibodies.This analysis demonstrates the stability of the antigen expression on human leukemia-lymphoma cell lines grown at consistently optimal conditions, for the tests, using the same monoclonal antibodies as in the Workshop, had been performed 0.5–5 years prior to the Workshop study. On the other hand, nonspecific Fc-binding, wide specificity of monoclonal antibodies and a shift in antigen expression of the cells (due to poor growth conditions, involuntary induction of differentiation and other factors) must be taken into consideration upon immunological analysis.This study was supported in part by Veterans Administration RAG GrantH. G. D. is recipient of a Research Training Fellowship awarded by the Deutsche Forschungsgemeinschaft (Dr 157/1-1)     

Regeneration after cardiotoxin injury of innervated and denervated slow and fast muscles of mammals. Myosin isoform analysis

The regeneration of adult rat and mouse slow (soleus) and fast (sternomastoid) muscles was examined after the degeneration of myofibers had been achieved by a snake venom cardiotoxin, under experimental conditions devised to spare as far as possible the satellite cells, the nerves, and the blood vessels of the muscles. Three days after the injury, no myosin was detectable in selected portions of the muscles. New myosins of embryonic, neonatal, and adult types started to be synthesized during the following two days. Adult myosins thus appeared more precociously than in development, which implies that the synthesis of myosin isoforms during regeneration does not entirely 'recapitulate' the sequence of myosin transitions observed during normal development. Two weeks after the injury, the isomyosin electrophoretic pattern displayed by regenerated muscles was already the same as that of control muscles; the normal adult pattern was therefore expressed more rapidly in regenerating than in developing muscles. Except for the synthesis of the slow isoform which was generally inhibited in denervated muscles, the same types of myosins were expressed during the early stages of regeneration in denervated as in innervated muscles; long-term denervation prevented however the qualitative and quantitative recovery of the normal myosin pattern.     

Mannose inhibition as a significant marker for differentiating among novobiocin-resistant staphylococci of relevance in clinical microbiology

A specific method for the identification of Staphylococcus saprophyticus among novobiocin-resistant species isolated from man is described. The test is based on novobiocin resistance, non-fermentation of D-mannose and early inhibition with late secondary growth on glucose/mannose + novobiocin agar plates. On this medium novobiocin-resistant Staphylococcus cohnii showed a confluent, continuous and homogeneous growth after 24 h which remained unchanged at 48 h whether or not it fermented D-mannose, whereas novobiocin-resistant Staphylococcus xylosus fermented D-mannose. These results are discussed in relation to a possible causal role of PTS enzymes and phosphomannose isomerase deficiency in mannose inhibition.     

Biochemical and physiological studies of soluble esterases fromDrosophila melanogaster

Twenty-two soluble esterases have been identified inD. melanogaster by combining the techniques of native polyacrylamide gel electrophoresis and isoelectric focusing. The sensitivity of each isozyme to three types of inhibitors (organophosphates, eserine sulfate, and sulfydryl reagents) identified 10 as carboxylesterases, 6 as cholinesterases, and 3 as acetylesterases. Three isozymes could not be classified and no arylesterases were identified. The carboxyl- and cholinesterases could each be further divided into two subclasses on the basis of inhibition by organophosphates and sulfhydryl reagents, respectively. Cholineand acetylesterases have characteristic substrate preferences but both subclasses of carboxylesterases are heterogeneous in substrate utilization. Subclass 2 carboxylesterases exhibit diverse temporal expression patterns, with subclass 1 carboxylesterases generally found in larvae and subclass 1 cholinesterases and acetylesterases more characteristic of pupae and adults. Tissues showing the greatest number of isozymes are larval body wall (eight) and digestive tract (six in larvae, six in adults). Carboxylesterases are distributed across a wide range of tissues, but subclass 1 cholinesterases are generally associated with neural or neurosecretory tissues and subclass 2 cholinesterases with digestive tissues.This study was funded in part by the Rural Credits Development Fund.     

Response to denervation of rabbit soleus and gastrocnemius muscles. Time-course study of postnatal changes in myosin isoforms,fiber types,and contractile properties

Summary— In contrast to general belief, the response of rabbit muscles to denervation is maturation to slow-like type muscles [7]. We report now an investigation by biochemical, morphological, and mechanical studies of the time course effects of muscle denervation on the slow-type soleus and fast-type gastrocnemius to help clucidate the mechanism of maturation of rabbit denervated muscles to slow-like muscles. In both muscles, denervation induced selective progressive atrophy of most fast fibers and hypertrophy of many slow fibers which displayed wide Z-lines; this was accompanied by the appearance of hybrid LC1F- and LC1E-associated slow myosins. The percentage of slow myosins increased with age similarly in the contralateral and denervated soleus. On the other hand, the percentage of slow myosins remained low in the contralateral gastrocnemius, whereas it increased to 95% in the denervated gastrocnemius; in the denervated gastrocnemius, the percentage of slow myosins reached 50% at about 35 days postnatal. At this age, the maximal shortening velocity of the denervated gastrocnemius and its twitch contraction time were already those of a slow-type muscle. This suggests that in addition to myosin, other proteins contributed to the mechanical properties of the denervated gastrocnemius. Transformation of rabbit denervated muscles to slow-like type muscles, which are associated with a lower energy requirement and higher muscle endurance than fast-type muscles, may constitute an adequate model for human neuromuscular pathology.     

α-Methyl-l-tryptophan as a tracer to study brain serotonergic system

Special issue devoted to Dr. Leon S. Wolfe.     

Role of proteolytic enzymes in the development of amino acid imbalance in wheat endosperm proteins

Three proteases with caseinolytic activity have been isolated from the developing wheat endosperm. Two have been purified. The activity of protease A, the one that appears early in endosperm development, is inhibited by - SH inhibitors. Protease C, the one that appears late in endosperm development, is not affected. Protease A cleaves polyaspartic acid and polyglutamic acid but not polylysine. Protease C, on the other hand, cleaves polylysine but not polyaspartic acid and polyglutamic acid. Protease C degrades lysine-rich proteins isolated from wheat endosperm more efficiently than protease A.