Induction of lymphosarcoma in sheep inoculated with bovine leukaemia virus

Five sheep were experimentally inoculated with BLV in order to study the humoral immune response in animals infected with bovine leukaemia virus (BLV). During experimental periods of 46 months, 2 sheep died with leukaemia and one sheep showed splenomegaly and proliferation of tumour cells. The other 2 sheep were clinically normal. All of the inoculated sheep developed antiviral antibodies 1 month after inoculation and BLV could be re-isolated in lymphocytes 2 to 3 months after inoculation. Antibody against glycoprotein antigen (gp51) of BLV appeared earlier than the antibody against protein antigen (p24) and antibody titres of the former were higher than those of the latter during the course of the experiment. The complement dependent antibody cytotoxicity test was performed for the detection of antibody against BLV-related cell membrane antigen with 2 different kinds of target cells; FLK cells which are foetal lamb kidney cells chronically infected with BLV and SF-28 cells which are sheep fibroblasts transformed with BLV in vitro. All 5 sheep developed cytotoxic antibodies against both types of cells. In sera from two leukaemic sheep, cytotoxic antibody titres against SF-28 cells gradually decreased 30 months after inoculation and finally became negative one to 3 months before they died of leukaemia. However, these leukaemic sheep persistently produced antibodies against gp51 and p24.     

Activities of single precentral neurons of the monkey during different tasks of forelimb movements

The neuronal activity in the motor cortex of the rhesus monkey was investigated in three different tasks performed with finger, wrist, and arm movements. A total of 125 neuronal activities were analysed. They were classified into five groups in terms of muscular contractions provoked by intracortical stimulation; neurons related to contractions of finger, wrist, elbow, shoulder, or trunk muscles. The neuronal activities in three tasks performed with finger, wrist, or arm movements were investigated for each group. Most of the neurons related to the contractions of elbow, shoulder, or trunk muscles were associated solely with arm movement. Smaller numbers of neuronal activities changed their firing frequencies in association with two or three tasks. Neurons related to the contractions of finger and wrist muscles showed various firing patterns in the three tasks; some responded to a single task with wrist or arm movement, while others changed their activities in association with more than one task. The presence of multi-task related neurons is discussed with respect to the multisegmental termination of corticospinal axons in the spinal cord.     

Antidromic latency of the monkey pyramidal tract neuron related to ipsileteral hand movements

During three different motor tasks of finger, wrist and arm movements on either side, 80 pyramidal tract neuron (PTN) activities were recorded in the monkey motor cortex. They were divided into three groups; PTNs related to controlateral movement (contra-PTNs), those related to ipsilateral movementt lateral movement (bilaterai-PTNs) and those related to ipsilateral movement (ipsi-PTNs). The latency histogram of the antidromic activation was similar for contra-PTNs as well as ipsi- and bilateral-PTNs in the fast PTN group, but most of slow PTNs appeared among contra-PTNs. Intracortical microstimulation (ICMS) was delivered to correlate muscular contraction with PTN acticity. Most of slow PTNs were related to proximal muscular contraction and PTNs related to proximal muscles appeared more in ipsi- and bilateral-PTNs than in contra-PTNs.     

Effects of symmetry groups on complexity and goodness in visual pattern

Two experiments were performed to investigate stimulus determinants of pattern complexity and pattern goodness. Two hundred and ninety-six undergraduates rated complexity and goodness of two-dimensional patterns, which consisted of solid and/or open circles. The patterns were invariant under transformations of reflection or rotation, and they formed cyclic groups or dihedral ones. The results were summarized as follows. (1) Goodness of patterns increased with the order of cyclic and dihedral groups with different weights. (2) Complexity of patterns having line-segments decreased with the order of cyclic and dihedral groups with equal weights, whereas that of patterns having no line-segments was medium regardless of the order. (3) Simplicity and goodness of patterns with a vertical axis of reflection were higher than those with the other orientation axes. (4) Patterns consisting of solid circles were rated more complex than those of open ones. (5) Complexity increased as a positively accelerated function of the number of circles, whereas goodness increased as a negatively accelerated function. It was concluded that complexity and goodness were determined by compound factors, which are processed at different stages of human visual system.     

Effect of stimulated neutrophils from the synovial fluid of patients with rheumatoid arthritis on lymphocytes—A possible role of increased oxygen radicals generated by the neutrophils

Neutrophils from the synovial fluid (SFN) of 10 patients with active rheumatoid arthritis (RA) were investigated to determine the generation of oxygen intermediates (OI) (O2-, H2O2, OH .), chemiluminescence, and lysosomal enzymes (lysozyme and beta-glucuronidase). Lymphocytes from healthy individuals were cocultured at 37 degrees C for 17 hr with SFN from the patients and the number of OKT4+, OKT8+, and OKT3+ cells and the response to mitogens were determined. A markedly increased OI and slightly elevated lysosomal enzyme levels were observed in SFN from patients. Coculture of lymphocytes with SFN resulted in a decreased number of OKT4+ and OKT8+ cells and a greatly reduced response to Con A and mildly diminished response to PHA, while OKT3+ cells were not affected. The simultaneous addition of superoxide dismutase and catalase restored the impairment of monoclonal antibody reaction and lymphocyte responsiveness almost to control levels. It is suggested that the disturbed immunoreactivity of synovial fluid lymphocytes from RA patients may be due to increased OI generated by stimulated neutrophils.     

Reduced NR2A expression and prolonged decay of NMDA receptor-mediated synaptic current in rat vagal motoneurons following axotomy

To elucidate characteristic changes in the N -methyl- d -aspartate (NMDA) receptor on neurons following axotomy, subunit expressions and functional features of the NMDA receptor were examined in the dorsal motor nucleus of vagus (DMV) of rats receiving vagal axotomy at the neck. Western blotting analysis demonstrated that the expression of NR2A decreased 2–3 days after in vivo axotomy, while expression of NR1 and NR2B, NR2C and NR2D subunits did not change significantly. To examine the functional changes, patch clamp recordings in whole-cell mode were employed on the axotomized DMV neurons identified by retrograde labelling with fluorescent dye. The amplitude ratios of ifenprodil-sensitive components of NMDA response and d , l -2-amino-5-phosphovaleric acid (APV)-sensitive evoked postsynaptic current increased after axotomy. In addition, APV-sensitive postsynaptic currents exhibited a longer decay time in identified axotomized vagal motoneurons than in control neurons. No significant differences in the current density of the NMDA response and the peak amplitude of APV-sensitive synaptic currents were observed between axotomized and intact DMV neurons. In conclusion, a decrease in NR2A expression results in the appearance of functional characteristics of the NMDA receptor predominantly containing the NR2B subunit. This might lead to a long-term increase of the susceptibility of neurons to excitotoxicity.     

Changes in the tumorigenic and metastatic properties of tumor cells treated with quercetin or 5-azacytidine

The effect of quercetin, a flavonoid derivative, on the transplantability (tumorigenicity) and metastatic behavior of mouse tumor cells was studied. BMT-11 c1-9 fibrosarcoma cells were treated in vitro with quercetin, and after cloning by limiting dilution, cell suspensions of each clone were injected subcutaneously (s.c.) into syngeneic C57BL/6 mice at a dose of 2 X 10(5) cells per mouse. Out of 17 clones examined, 8 were nontumorigenic in normal mice ("regressor" clones), whereas these clones were able to grow in immunosuppressed (600-rad-irradiated) mice. Furthermore, 1 out of 9 tumorigenic clones metastasized spontaneously to the lungs despite the very low metastatic potential of the parent BMT-11 c1-9 cells. In contrast, all 15 clones selected from the untreated parental line grew progressively in normal mice with no evidence of metastases. The appearance of both regressor and metastatic clones was also observed after treatment with a DNA hypomethylating agent, 5-azacytidine. These altered phenotypes resulting from treatment with both chemicals, however, were not necessarily stable if maintained in culture for several months. The data suggest that quercetin may be a useful new material for obtaining regressor or metastatic clones from parental tumor lines.