A human B cell differentiation antigen selectively expressed on mature B cells identified by a monoclonal antibody (HB-2)

A monoclonal IgM antibody (HB-2), produced against a membrane antigen on the Raji, B cell line, reacted by indirect immunofluorescence with 2 to 40% of lymphoblasts from the B cell lines, Raji, Daudi, SN-1036, and SB but not with other types of cell lines, including pre-B, myeloid, melanoma, or T cells. HB-2 antibody reacted with 10 ± 3% of normal blood mononuclear cells, and was unreactive with monocytes, granulocytes, platelets, or erythrocytes. Two-color immunofluorescence revealed that HB-2 antigen expression was confined to cells bearing surface Ig. An interesting finding was the fact that 25% of plasmablasts induced by pokeweed mitogen also expressed the HB-2 antigen. However, pre-B and plasma cells from normal bone marrow did not express the HB-2 antigen either on their membrane surface or in their cytoplasm. Analysis of 85 leukemias revealed that the HB-2 antigen was expressed on acute and chronic B cell leukemias and Burkitt's lymphomas, but not on malignacies of pre-B, T, myelocytic, or plasma cells. The results suggest that expression of the HB-2 antigen is confined to mature B cells.     

Preparing monolayers of non-adherent mammalian cells

A simple method is described for preparing monolayers of non-adherent cells, using concanavalin A to bind the cells to wells of plastic microtest plates. The method was used successfully with all 202 human cell types tested, which included 23 tissue culture lines, 165 fresh specimens of all major histological types of leukemia and lymphoma, 20 fresh myelomas, 2 fresh thymomas, normal spleen and lymph node cells, fractionated T lymphocytes and B lymphocytes from peripheral blood, and cultured fetal amniotic cells. All cell types attached firmly, and were not detached by subsequent vigorous washing. In contrast, attempted attachment of cells in serum free medium, or with poly-L-lysine or glutaraldehyde, was ineffective with many cell types. We used the monolayers as target cells for antibodies to cell surface antigens, utilizing immune rosetting or complement-mediated cytotoxicity. This procedure should simplify most assays involving non-adherent target cells.     

The flexor function of the m. pronator teres in man: a quantitative electromyographic study

Summary The muscle pronator teres was studied by surface electromyography during elbow flexion in a horizontal plane. The forearm was in semi-pronation and movement was performed at various velocities. A quantitative comparison was made between pronator teres activity and two main elbow flexors, biceps brachii and brachioradialis.The mean timing of the onset of activity was constant: biceps brachii was activated first followed by pronator teres and brachioradialis, and the lower the velocity of flexion, the earlier was the onset of biceps brachii activity.There was a linear relationship between the integrated EMG from each muscle and the work done. However, this relationship was less exact for pronator teres and brachioradialis at low values of work, a finding which opens questions about the generality of this relationship and about the muscle equivalent concept.Pronator teres appears to participate in elbow flexion besides its role in pronation.Despite similar anatomical peculiarities, pronator teres does not behave in the same way as anconaeus or popliteus and, above all, it is not the sole muscle active in slow movement. Thus, all the stocky mucles lying close to an articulation do not behave in the same way.     

Detection of radiolabelled bone marrow cells bearing surface ace immunoglobulins by combined autoradiography and immunoperoxidase

A method is described for the simultaneous detection of radiolabelled bone marrow cells bearing surface immunoglobulins by combined autoradiography and immunoperoxidase. Bone marrow cells from normal CBA mice prelabelled in vivo with ¹²⁵IUDR or exposed in vitro to [³H]thymidine were incubated with rabbit anti-mouse immunoglobulins under capping conditions, washed, cytocentrifuged and treated with methanol and hydrogen peroxide to destroy endogenous peroxidase. Cells were then covered with peroxidase-conjugated goat anti-rabbit immunoglobulins, washed, treated with diaminobenzidine a and hydrogen peroxide and finally covered with autoradiographic stripping film and exposed for different times. Peroxidase-positive cells were typically capped and those radiolabelled had autoradiographic silver grains overlying the nucleus.     

Pulmonary function changes in asthmatics associated with low-level SO2 and NO2 air pollution, weather, and medicine intake

This paper presents the response in subjects with asthma to gaseous air-pollution levels, weather, and medicine intake as identified by principal-component analysis and neutral network techniques. Pulmonary function measured by respiratory peak-flow rate in nonallergic asthmatics was associated with ambient, low level, air-pollution concentrations of sulphur dioxide and nitrogen dioxide, temperature, relative humidity, and medicine intake. Results from 27 nonallergic asthmatics aged 18–60 years with well-characterized bronchial asthma and regular medical treatment were analyzed from two cities. During an 8-month period, each subject kept a diary table, which included symptoms, lung function (evening peak flow), medicine intake, and tobbaco smoking.
High intake of medicine and high ambient temperatures correspondend to decreased peak flow. The changes in temperature did not occur in situations with low medicine intake. During frost periods, peak-flow values decreased independently of medicine intake and levels of so². During other times, increased levels of so² and no² increased temperature, and increased intake of medicine, and low relative humidity corresponded to synergistically to decreased peak flow at levels above 40μ/m³.     

Effects of spontaneously chosen crank rate variations on electromyographic responses in sub-maximal arm exercise in inexperienced subjects

The aim of the present study was to compare electromyographic responses during arm exercises with a crank rate chosen spontaneously (T_S) or set at 20% below or above (T_–20, T₊₂₀) the spontaneously chosen crank rate (SCCR). Ten male physical education students performed arm exercises with intensities ranging from 20% to 80% of maximal power. Muscular activity levels were analysed for the biceps brachii and the triceps brachii muscles using integrated rectified surface electromyography (iEMG). All values were presented as the mean and standard deviation. During T_S, the sum of iEMG for the two muscles studied was significantly (P<0.05) lower than during T₊₂₀ for each power output. No significant differences were observed in iEMG values between T_S and T_–20. The hypothesis that SCCR relates to a minimisation of muscle activation during an upper body exercise was not confirmed. Variations superior or inferior to a 20% increase of the iEMG responses do not influence it. Moreover, the selection of crank rates depends on the power output and the SCCR increased significantly (P<0.05) with increasing power output.     

Pigeon allergens in indoor environments: a preliminary study

BACKGROUND: Few studies have measured pigeon allergens in non pigeon coop environments. This study was conducted to determine approximate pigeon dropping allergen concentrations in indoor environments. METHODS: Polyclonal antibody serum was prepared by injecting a rabbit three times with crude wild pigeon dropping extract in 50 mM Tris buffer with Freund's adjuvant. One hundred and fifteen dust samples were collected in a pigeon-infested school, pigeon coops, homes and hospitals and analyzed by a direct competitive pigeon enzyme-linked immunosorbent assay (ELISA). RESULTS: The highest level of pigeon allergen inhibitory activity were recorded in four samples from pigeon coop bedding samples with a median activity of 11.2% relative to pigeon droppings. The second highest level of pigeon allergens was in a pigeon-infested high school with a median or 7.4% activity relative to pigeon droppings. At an entrance underneath pigeon roosts, one sample had a relative inhibitory activity of 62.3%. Pigeon allergen inhibitory levels were generally low in the home and hospital samples, but nevertheless 46 out of 89 of these samples were still above detection limit. CONCLUSIONS: This study suggests that large concentrations of pigeon allergens can be found in buildings without domestic pigeons such as the pigeon-infested high school.     

Morphologic evaluation of the liver in hereditary angioedema patients on long-term treatment with androgen derivatives

17 alpha-Alkylated androgens are highly effective in preventing attacks in HAE patients. These drugs, however, seem to be implicated in the development of cholestatic jaundice, peliosis hepatis, and liver tumors. In order to assess the risk-benefit balance of the long-term therapy with androgen derivatives, a follow-up investigation was performed in 13 HAE patients. The results of this study indicate that long-term treatment (15 to 47 mo) with low doses of danazol or stanozolol does not induce significant hepatic damage detectable by laboratory tests or liver biopsy. However, the limited number of patients, although in a rather long period of observation, still suggests a careful control and the use of minimal effective doses.     

Methods of detecting mature human Ia-like antigen and their metabolic precursors

Ia antigens were shown to be present in the cell almost exclusively as mature alpha beta dimers which split into separate alpha and beta chains after boiling in SDS. In contrast metabolically labelling the cells with [35S]methionine resulted in only free alpha and beta chains being labelled. It is concluded that this widely used type of labelling, although useful for studying intermediate synthesis, should not be used for labelling mature cell surface molecules.