Surface antigenic specificities of human thymus-derived lymphocytes.

Surface antigenic specificities of human thymus-derived (T) lymphocytes were studied by cytotoxicity tests using a heterologous rabbit anti-human thymus serum. This serum showed higher cytotoxic titres on thymocytes by comparison with peripheral lymphocytes. After proper absorption the antiserum was non-toxic for chronic lymphatic leukaemia cells, but lysed the majority of thymocytes. It also lysed some of peripheral lymphocytes, corresponding to those lymphocytes which bound sheep erythrocytes (E) but not erythrocyte-antibody-complement complexes (EAC). Pretreatment of lymphocytes with the absorbed antiserum and complement completely abrogated rosette formation with E but spared EAC-binding lymphocytes. It also eliminated their reactivity to phytohaemagglutinin and concanavalin A. These findings indicate that the absorbed serum causes selective lysis of T cells. The results obtained from quantitative absorption studies suggest that a certain loss of T-cell antigens is brought about during the differentiation of thymocytes into peripheral T cells.     

Rhythmical contractions in pulmonary arteries of monocrotaline-induced pulmonary hypertensive rats

Rhythmical contractions accompanied by an increase in cytosolic Ca2+ concentrations were produced in ring preparations of endothelium-denuded pulmonary arteries from monocrotaline-treated rats, but not in those from vehicle-treated rats, 2-3 h after a resting tension of 15 mN (150-180% of the initial wall length of the artery) was applied. The rhythmical contractions were abolished by nicardipine and ryanodine. Cyclopiazonic acid reduced the relaxation phase of the rhythmical contractions, finally leading to a sustained contraction. Similarly, apamin caused a sustained contraction, whereas charybdotoxin increased the amplitude of the rhythmical contractions. Glibenclamide had no apparent effects on them. Indomethacin and the prostaglandin H2/thromboxane A2 receptor antagonist SQ29548 abolished the rhythmical contractions and reduced the tension, but the thromboxane synthase inhibitor ozagrel had no effect. These results suggest that optimal stretch induces rhythmical contractions in the pulmonary arteries of monocrotaline-induced pulmonary hypertensive rats, to which both Ca2+ influx through voltage-operated Ca2+ channels and Ca2+ release from the endoplasmic reticulum seem to contribute. It is also suggested that small-conductance Ca(2+)-activated K+ channels participate in the relaxation phase of rhythmical contractions. Furthermore, prostaglandin H2 released from nonendothelial cells is likely to play a pivotal role in the induction of rhythmical contractions.     

Evaluation of anti-parvovirus B19 activity in sera by assay using quantitative polymerase chain reaction

Human parvovirus B19 (B19) infects cells of erythroid lineage. Production of neutralizing antibodies (Abs) is indispensable for recovery from B19-related disease state. In this study, we used a convenient method to measure neutralizing activities in human sera by using a real-time quantitative PCR based assay. Erythroid cell line KU812Ep6 was incubated with test sera before infection with B19 virus. The copy number of B19-DNA in cultures was decreased in the presence of the sera from patients who recovered from acute B19 infection, whereas no decrease in B19-DNA was in cultures incubated with sera from healthy volunteers who had no B19 infection. The decrease in B19-DNA copy number was calculated and the inhibition percentage was expressed as neutralizing activity to B19. A clinical study showed that the levels of neutralizing ability were high in patients who recovered soon after acute B19 infection, but were low in some patients with a prolonged clinical course for recovery from B19 infection. This method is simple and convenient compared with methods described previously, showing its usefulness to evaluate the neutralizing activity to B19.     

Protodioscin isolated from fenugreek (Trigonella foenumgraecum L.) induces cell death and morphological change indicative of apoptosis in leukemic cell line H-60, but not in gastric cancer cell line KATO III

Protodioscin (PD) was purified from fenugreek (Trigonella foenumgraecum L.) and identified by Mass, and 1H- and 13C-NMR. The effects of PD on cell viability in human leukemia HL-60 and human stomach cancer KATO III cells were investigated. PD displayed strong growth inhibitory effect against HL-60 cells, but weak growth inhibitory effect on KATO III cells. Morphological change showing apoptotic bodies was observed in the HL-60 cells treated with PD, but not in KATO III cells treated with PD. Flow cytometric analysis showed that the hypodiploid nuclei of HL-60 cells were increased to 75.2, 96.3, and 100% after a 3-day treatment with 2.5, 5, and 10 microM PD, respectively. The fragmentation by PD of DNA to oligonucleosomal-sized fragments, that is a characteristic of apoptosis, was observed to be both concentration- and time-dependent in the HL-60 cells. These findings suggest that growth inhibition by PD of HL-60 cells results from the induction of apoptosis by this compound in HL-60 cells.     

Analysis of small dense LDL in patients with type 2 diabetic mellitus by the modified Krauss method using an internal standard

In patients with Type 2 diabetes mellitus (Type 2 DM), the relationship between the prevalence rate of small dense LDL (sdLDL) and parameters of lipid metabolism was analyzed using the method devised by modified Krauss method using apoferritin as an internal standard. The prevalence rate of sdLDL was 34% compared with it of normal subjects in this study. When the severity of Type 2 DM was classified into three groups of the HbA1c value, neither the sdLDL size nor its prevalence rate differed significantly depending upon the severity of the Type 2 DM. Also, when the prevalence rate of sdLDL was analyzed in relation to the severity of complications, i.e., of microangiopathy (retinopathy and nephropathy) or macroangiopathy (cerebral infarction), there was no significant difference in the prevalence rate of sdLDL depending on the severity of any of these complications. On the other hand, the prevalence rate of sdLDL was found to be correlated with the serum TG level. The serum level of TG-rich remnants (metabolites of TG) was also high in patients with sdLDL. It should take notice that the assessment of sdLDL should be used the authorized method for the evaluation. Thus it is concluded that the levels of sdLDL were important in evaluation of Type 2 DM. The prevalence rate of sdLDL did not correlate with the severity, nor the modalities for the complications of Type 2 DM.     

A critical role of sterols in embryonic patterning and meristem programming revealed by the fackel mutants of Arabidopsis thaliana

Here we report a novel Arabidopsis dwarf mutant, fackel-J79, whose adult morphology resembles that of brassinosteroid-deficient mutants but also displays distorted embryos, supernumerary cotyledons, multiple shoot meristems, and stunted roots. We cloned the FACKEL gene and found that it encodes a protein with sequence similarity to both the human sterol reductase family and yeast C-14 sterol reductase and is preferentially expressed in actively growing cells. Biochemical analysis indicates that the fk-J79 mutation results in deficient C-14 sterol reductase activity, abnormal sterol composition, and reduction of brassinosteroids (BRs). Unlike other BR-deficient mutants, the defect of hypocotyl elongation in fk-J79 cannot be corrected by exogenous BRs. The unique phenotypes and sterol composition in fk-J79 indicate crucial roles of sterol regulation and signaling in cell division and cell expansion in embryonic and post-embryonic development in plants.     

Detection of tumour necrosis factor/cachectin in pleural effusion of patients with lung cancer.

We have found that the pleural effusion obtained from a patient with lung cancer (adenocarcinoma) has cytotoxic activity against the patient's lung cancer cells. This finding occurred in the course of establishing a lung cancer cell line from the patient's pleural effusion. The cytotoxic factor was partially purified from the pleural effusion and characterized. It had cytotoxicity against L-929 mouse fibroblasts in the standard 18-h killing assay of tumour necrosis factor (TNF). By molecular sieving chromatography, the activity appeared at molecular weight of 50,000. This activity was completely blocked by a monoclonal antibody to TNF. From these results, we conclude that the cytotoxic factor in the pleural effusion is TNF. The concentration of TNF in the pleural effusion was 34.5 pg/ml by radioimmunoassay. In addition, we detected TNF activity and protein in two other cases of carcinomatous pleural effusion. Therefore, it would appear that in vivo TNF displays cytotoxic activity against cancer cells.     

A novel human B-lymphocyte antigen shared with lymphoid dendritic cells: characterization by monoclonal antibody.

A novel cell-surface antigen (L25) expressed on human B cells was identified using a B cell-reactive monoclonal antibody (TB1-4D5). This L25 antigen was expressed on most B-lineage cells but not other cell types including thymocytes, T cells, granulocytes and monocytes. Thus, L25 existed on the majority of normal B cells present in the blood and lymphoid tissues, on cultured cell lines derived from normal and malignant B cells, and on neoplastic cells isolated from patients with B cell-derived malignancies. Though L25 was persistently expressed on B cells until 7 days after their activation with pokeweed mitogen (PWM), neither normal nor neoplastic plasma cells expressed L25. Moreover, L25 was present on cultured as well as freshly isolated leukaemic cells with common acute lymphatic leukaemia (CALL) antigen, which have been thought to correspond to the early B-cell ontogeny. Besides pan-B cell reactivity of TB1-4D5 antibody, it apparently cross-reacted with so-called dendritic or interdigitating cells located in the thymic-dependent areas of peripheral lymphoid organs, which have been presumably ascribed to those associated with accessory-cell function. Functional studies showed that anti-L25 (TB1-4D5) antibody had inhibitory effect on induction of immunoglobulin synthesis by PWM-stimulated B cells.