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This Letter introduces a new circuit topology of the simple electronically controllable voltage‐mode bilinear two port (BTP) employing two operational transconductance amplifiers. The proposed two‐port circuit is completely resistorless and contains only a grounded capacitor. It has a high‐impedance input (a simple cascading of sections is possible) and allows an independent electronic adjusting of zero and pole frequency of the transfer function. The operation of the BTP circuit is demonstrated for two different locations of the pole and zero frequency coordinates. Moreover, a direct application of four BTPs in fractional‐order integrators (order −0.11 and −0.33) with phase shifts −10° and −30° is shown. Design specification is verified by experimental measurements. [ABSTRACT FROM AUTHOR]

Different lymphocyte subpopulations were prepared from lymph nodes and spleen obtained from 2.4-dinitrofluorobenzene/Freund's complete adjuvant (DNFB/FCA) sensitized guinea-pigs. The capacity to react in vitro to secondary antigenic (dinitrophenyl- modified syngeneic macrophages, DNP-Mø) stimulation by an increased DNA synthesis, appeared to be restricted to those T cells which lack receptors for lgG-Fc (Tγ- ). We confirmed the existence in this species of an IgG-Fc receptor-positive T-cell subset, which is particularly represented in the spleen (up to 56%). These Tγ+ cells apparently are not of monocyte lineage as they show strong PHA-responsiveness and a lack of non-specific esterase staining, whereas the majority of these cells form RRBC-rosettes. Neither B nor Tγ+ cells appeared to act as suppressor cells in the secondary DNP-Mø-driven proliferative response. [ABSTRACT FROM AUTHOR]

Investigates the effect of elimination of suppressor cells on the development of dinitrochlorobenzene (DNCB) contact sensitivity in guinea-pigs. Finding that impulses activating the formation of effector cells also activate suppressor cells; Observation that under conditions of conventional immunization, suppressor cells are activated later than effector cells; Conclusion that elimination of suppressor cells results in an increase in the intensity and duration of specific skin reactions.

Lymph nodes-and to a lesser extent spleen cells-from guinea-pigs tolerant to DNCB contact sensitivity, when injected into normal syngeneic guinea-pigs, decrease the ability of the recipients to become sensitized to contact with DNCB. The difference between the complete tolerance transferred by parabiosis with tolerant partners and the partial tolerance induced by transfer of tolerant cells can be explained by the different numbers of cells homing in the recipients. The tolerogen does not play any role in the transfer of tolerance. [ABSTRACT FROM AUTHOR]

Tolerance to DNCB induced by feeding guinea-pigs with the same hapten has been reversed by a single treatment with cyclophosphamide. This is paralleled by a return of the ability of T cells to proliferate in the draining lymph node following sensitization. Certain quantitative differences between this system and that previously described using intravenous DNBSO3 have been revealed. These may indicate some difference between these two mechanisms of tolerance induction. [ABSTRACT FROM AUTHOR]

The frequency of DNP-binding T and B lymphocytes was studied in various states of sensitization and unresponsiveness to DNCB contact sensitivity In guinea-pigs, where unresponsiveness to DNCB had been established with DNBSO3 by pretreatment or during the primary response, no increase in antigen-binding cell frequency was found after antigenic stimulation. On the contrary, DNCB-sensitive guinea-pigs, later desensitized with DNBSO3, showed the same frequency of antigen-binding cells as sensitized animals, although they were unable to react to DNCB. [ABSTRACT FROM AUTHOR]

Immunological unresponsiveness to DNP--guinea-pig skin protein conjugate (DNP--GPSP) was induced by intravenous injections of dinitrobenzenesulphonic acid (DNBSO3) given before, simultaneously, or after sensitization with DNP-GPSP. The increased DNA synthesis in vitro by lymph node or peritoneal exudate lymphocytes from unresponsive guinea-pigs was suppressed only in animals tolerized by pretreatment with DNBSO3. The majority of guinea-pigs with the other two types of unresponsiveness showed an increased [³H]thymidine incorporation into lymph node--but not into peritoneal exudate lymphocytes. From these results two conclusions may be drawn: (1) the mechanism of unresponsiveness induced during the primary response is similar to that of desensitization and different from that of `classical' tolerance; (2) tolerogen given before the sensitization prevents both the increased DNA synthesis by lymph node and peritoneal exudate lymphocytes and the skin reaction. Tolerogen given during the primary response or after the sensitization prevents increased DNA synthesis by peripheral lymphoid cells (peritoneal exudate lymphocytes) and the skin reaction, whereas lymph node lymphocytes showed increased DNA synthesis. [ABSTRACT FROM AUTHOR]

To study the effect of suppressor cells, the Effect of elimination of suppressor cells on the development of flare-up reaction. Lenged on day 3 and the skin reactions (flare-up) evaluated daily without further applications The absence of suppressor cells the skin Cells limit the generation of effector cells. [Extracted from the article]

Contact sensitivity and production of anti-DNP-antibodies induced by epicutaneously applied dinitrochlorobenzene (DNCB) can be permanently suppressed by a previous intravenous injection of a high dose of dinitrobenzene- sulphonate (DNBSO3). The animals fail to develop a paracortical area rich in pyroninophilic cells, in lymph nodes regional to the local application of hapten, characteristic of sensitized controls. Following the injection of lymphoid cells from normal syngeneic donors into these unresponsive animals, large pyroninophilic cells develop in the paracortical area 4 days after sensitization and in some cases antibody production is restored. However, contact sensitivity remains suppressed. If a high dose of DNBSO3 (600 mg/kg) is injected intravenously on the same day as DNCB is applied locally, or when a low dose of DNBSO3 (60 mg/kg) is administered 12 weeks before DNCB, contact sensitivity and production of anti- DNP-antibodies are also suppressed but in such animals the development of a paracortical area containing large pyroninophilic cells is not inhibited. In both cases an immune reaction can be suppressed in the presence of a paracortical area containing large pyroninophilic cells. Therefore it appears that this state of unresponsiveness is not exclusively conditioned by the absence of large pyroninophilic cells in paracortical areas and may be associated with other factors. [ABSTRACT FROM AUTHOR]

By determining the time and dose dependence of immuno-tolerance to dinitrochlorobenzene (DNCB) induced in guinea-pigs by previously injecting dinitrobenzenesulphonate (DNBSO3), it was found that smaller doses of DNBSO3 injected at short time intervals before the epicutaneous application of DNCB induced tolerance in fewer animals than higher doses. However, with small doses of DNBSO3, the percentage of tolerant animals increased the longer the time intervals between both hapten applications. A working hypothesis for this unexpected finding is proposed. [ABSTRACT FROM AUTHOR]

An abstract of the study "Serum NT-ProBNP Measured 4-5 Days After ST-Elevation Myocardial Infarction Is the Best Marker of Early Left Ventricular Dysfunction in Patients Treated With Primary Coronary Angioplasty," by I. Koska et al. is presented.