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J Raskova

Publications and source records attributed to J Raskova.

At least 19 recordsLinked to original sources
PubMed1992

IL-2 responsiveness of lectin-induced lymphoblasts: soluble IL-2 receptor release and differential in vitro effects of immunosuppressants.

We examined the mode of action of different immunosuppressants on the responsiveness of phytohemagglutinin (PHA)-induced lymphoblasts further stimulated by recombinant interleukin-2 (rIL-2). The stimulation of PHA blasts with rIL-2 resulted in an enhancement of tritiated thymidine ([3H]TdR) incorporation and of soluble interleukin-2 receptor (sIL-2R) release. Cyclosporin A (CsA) and prednisolone inhibited in different ways the responsiveness of PHA pre-stimulated blood mononuclear cells (PBMC) to rIL-2, as measured by [3H]TdR incorporation. The addition of CsA resulted in considerable enhancement of the release of sIL-2R, whereas the addition of prednisolone was associated with a similar enhancement only when the higher concentrations of rIL-2 were employed. EGTA, a calcium (Ca2+) chelator, and verapamil, a Ca2+ channel blocker, inhibited [3H]TdR incorporation in a concentration-dependent manner. EGTA inhibited sIL-2R release in the same manner when used alone, and reversed the CsA- and prednisolone-induced enhancement of sIL-2R release by rIL-2 induced lymphoblasts, when used in combination with CsA or prednisolone. Verapamil had a similar but less striking effect. The effects of CsA and prednisolone were also studied in PHA-induced blasts originating from purified CD4+ or CD8+ lymphocytes. Stimulation of these blasts with rIL-2 resulted in higher [3H]TdR incorporation by CD8+ blasts than by CD4+ blasts: however, no sIL-2R release was detected in supernatants of either CD4+ or of CD8+ blasts. Both CsA and prednisolone inhibited the rIL-2-induced enhancement of [3H]TdR incorporation by both T-cell subsets.(ABSTRACT TRUNCATED AT 250 WORDS)

CD4 Antigens↗
PubMed1992

Uremic serum effects on peripheral blood mononuclear cell and purified T lymphocyte responses.

We have studied the effects of uremic serum on the activation state and function of normal lymphocytes in vitro, by examining both accessory cell-dependent and accessory cell-independent responses. Uremic serum was obtained from patients on conservative treatment and from the same patients after they have undergone six months of maintenance hemodialysis. Uremic serum inhibited the proliferative responses to mitogens and to recombinant IL-2 (rIL-2) of both peripheral blood mononuclear cells (PBMC) and purified T cell populations. However, the responsiveness to IL-2 of pre-formed lymphoblasts, obtained from both PBMC and purified T cells, in the presence of uremic serum was similar to that obtained in the presence of normal serum, or was even enhanced. Uremic serum did not affect the cellular IL-2 receptor alpha (IL-2R) generation though it inhibited significantly the release of soluble IL-2 receptor (sIL-2R) and the production of IL-2 after mitogenic stimulation. Uremic serum from patients after six months of hemodialysis enhanced, but did not completely restore, proliferative responses and IL-2 production by control PBMC. Neither IL-1 nor IL-2R, which are present at elevated concentrations in uremic serum, appeared to be responsible for serum effects on in vitro responses of control lymphocytes. In conclusion, our results indicate that uremic serum affects both accessory cell-mediated and accessory cell-independent normal T cell responses. Uremic serum inhibition of T cell proliferation is associated with down-regulation of IL-2 synthesis by lymphocytes and the induction of an abnormal state of activation of lymphoblasts which is further enhanced following chronic hemodialysis.

Cell Division↗
PubMed1992

Binding of phycoerythrin-conjugated interleukin-6 to in vitro-activated human peripheral blood mononuclear cells--effect of immunosuppressive agents and of a calcium channel blocker.

We studied the effect of cyclosporine A, prednisolone, and the Ca2+ channel blocker verapamil on interleukin-6 binding to mitogen-activated peripheral blood mononuclear cells, using a flow cytometric technique and phycoerythrin-conjugated IL-6. All mitogenic stimuli up-regulated IL-6 binding to a variable degree. PHA alone or in combination with PMA was the most effective stimulant in up-regulating IL-6 binding in all the experiments performed. The main changes in IL-6 binding were seen in the large cell cluster, which consisted mainly of lymphoblasts. PHA and PHA/PMA, however, also up-regulated the mean fluorescence intensity on the small cell cluster, which consisted mainly of quiescent lymphocytes. The overall effect of the three pharmacological agents on mitogen-up-regulated IL-6 binding was minimal; most significant were a down-regulation by all three agents of IL-6 binding by small lymphocytes in PHA/PMA cultures, a down-regulation of IL-6 binding by CsA in PHA/PMA-induced large PBMC, and an up-regulation by verapamil of PMA-induced IL-6 binding in large PBMC. Measurements of IL-2 binding and of IL-6 production in the same cultures showed a different pattern than that seen with IL-6 binding, as well as different CsA, prednisolone, and verapamil action. In conclusion, by using a new flow cytometric technique providing information both about the quantity of bound cytokine and about the proportion of IL-6-binding cells, we have demonstrated that IL-6 receptor expression in vitro by PBMC can be up-regulated by the use of stimulants differing in the signal transduction pathways they activate. In addition, by using different pharmacological agents and stimuli to dissect different activation pathways of the in vitro immune response, we conclude that IL-6R generation is regulated differently from IL-6 production. Furthermore, since CsA and prednisolone are known inhibitors of in vitro IL-2 production, our results indicate that IL-6R generation does not rely exclusively on the presence of IL-2.

Calcium↗
PubMed1992

Effects of hemodialysis on activation of lymphocytes: analysis by an in vitro dialysis model.

Patients undergoing maintenance hemodialysis have impaired immune responsiveness, which appears to deteriorate progressively with the duration of the replacement treatment. It has been suggested that it is caused by a chronic preactivation state of T cells caused by hemodialysis. Each treatment session has been compared with a recurring "acute-phase" inflammatory reaction. In this study, the acute effects of hemodialysis on the activation state and functional responsiveness of normal peripheral blood mononuclear cells have been evaluated by use of an in vitro dialysis model. The dialysis was carried out with either cuprophan or polysulfone membranes, with or without sodium acetate in the dialysis fluid. It was observed that a single session of in vitro dialysis did not induce production of interleukin-2 (IL-2) and did not alter the expression of IL-2 receptor (IL-2R) on the cytoplasmic membrane and the secretion of soluble IL-2R, whereas it induced transcription of mRNA for IL-2R. The proliferative response of lymphocytes to phytohemagglutinin or IL-2 in vitro also did not change after a single dialysis session. There was only a slight decrease of the release of soluble IL-2 receptor by phytohemagglutinin-stimulated cells after dialysis. Dialysis induced an active synthesis of IL-1 by peripheral blood mononuclear cells, even in the absence of sodium acetate in the dialysate bath, but there was no release of IL-1 to the circulating medium. The results show that a single dialysis encounter can acutely prime the activation of human peripheral blood mononuclear cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗
PubMed1992

Teaching pathology without lectures through computer-based exercises, small-group discussions and reading.

The Department of Pathology at Robert Wood Johnson Medical School teaches a 205-hour, one semester course to 150 second-year students in the fall semester of the second year. The course begins with General Pathology (4 weeks) and continues with Systemic Pathology (12 weeks). In 1986, lectures were eliminated as a means of conveying the course content. Students were expected to read the textbook and to participate in obligatory small group discussions. Extensive computer based self-learning materials were provided in both MS/DOS and Macintosh formats. In 1991, these computer resources included the full text of Robbins Pathologic Basis of Disease, extensive question banks and a guide through the Slice of Life Videodisc. Over the past 6 years this modified curriculum has been enthusiastically received by the students and faculty. Student performance on internal and external examinations has been excellent. Approximately 4% of the graduating students select pathology for their post-graduate training.

Computer-Assisted Instruction↗
PubMed1991

Cyclosporine A and prednisolone inhibit lectin- and alloantigen-induced release of sCD8: correlation with proliferative responses.

It has been shown previously that there is a strong correlation between the in vitro release of soluble CD8 glycoprotein (sCD8) and CD8+ T lymphocyte activation. In the present study, the lectin stimulation of peripheral blood mononuclear cells (PBMC) induced a dose-dependent release of sCD8 which correlated with the magnitude of CD8 lymphocyte activation as measured by the expression of the interleukin 2 (IL-2) receptor and HLA-DR antigen and of the T cell proliferative responses. Both the proliferative responses and the release of sCD8 were inhibited by cyclosporine A (CyA) and prednisolone (PRED) in a concentration-dependent manner. When the immunosuppressants were present for only 60 min before the initiation of the cultures, an inhibitory effect was also seen, but this was maximal only when the agents were added at the initiation of the culture period; when the addition of CyA or PRED was delayed for either 24 or 48 hr after the initiation of the culture, the degree of inhibition of the proliferative response was greatly reduced. However, there was a significant inhibition of sCD8 release by CyA even when it was added 48 hr after the culture initiation. The addition of recombinant IL-2 did not affect the lectin-induced sCD8 release. The inhibition of the lectin-induced proliferative response and sCD8 release by PRED, but not that by CyA, was reversed by the recombinant IL-2. Alloantigen stimulation also induced sCD8 release and this release was inhibited both by CyA and by PRED. These data, together with the known effects of CyA on differentiation, clonal amplification, and activation of CD8 T lymphocytes, suggest that in vitro sCD8 release occurs during the early stages of activation of CD8+ cytotoxic T cells.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1991

Mixed lymphocyte reaction-induced release of soluble IL-2 receptor.

We studied the release of soluble interleukin 2 receptor (sIL-2R) by PBMC in mixed lymphocyte reaction (MLR) in order to clarify the significance of high plasma levels of sIL-2R in transplant patients undergoing rejection. Levels of sIL-2R were shown to increase progressively after the first day of the MLR and reached their peak on day 5. This pattern of sIL-2R correlated with the incorporation of [3H]thymidine. CsA and prednisolone (PRED) were added at the beginning of the MLR and were shown to inhibit the release of sIL-2R. This inhibition correlated with an inhibition of the [3H]thymidine incorporation. When CsA and PRED were added 24 hr after the initiation of the MLR, a similar inhibition of sIL-2R release was observed, but when they were added 48 hr after the initiation or in the last day of the MLR little or no effect was observed. Incubation of responder or stimulator-responder cells with either CsA or PRED before the initiation of MLR showed that only CsA preincubation was accompanied by decreased [3H]thymidine incorporation. Preincubation with CsA inhibited the release of sIL-2R, whereas PRED had a variable effect. Recombinant IL-2 was shown to augment the release of sIL-2R even at very low doses, but it did not alter significantly MLR-induced [3H]thymidine incorporation. The addition of rIL-2 at the initiation of the MLR was also shown to reverse completely the PRED inhibition of the MLR-induced release of sIL-2R and of the [3H]thymidine incorporation. Addition of rIL-2 reversed only partially CsA-induced inhibition. Addition of different concentrations of sIL-2R at the initiation of the MLR were not shown to affect incorporation of [3H]thymidine. We conclude that the release of sIL-2R in response to alloantigens is an IL-2-dependent phenomenon, and determination of its levels might be a useful indicator of either in vitro or in vivo alloantigen responses and of the effectiveness of immunosuppressive treatment.

Cells, Cultured↗
PubMed1991

Production and kinetics of interleukin-1 in hemodialysis. In vivo and in vitro study.

Interleukin-1-beta (IL-1-beta) was measured in the plasma and peripheral blood mononuclear cell lysates of uremic patients undergoing maintenance hemodialysis by means of either cuprophane or polysulfone membranes. Basal plasma levels of IL-1-beta in hemodialyzed patients were strikingly higher than those of uremic patients on conservative treatment or of healthy subjects. Plasma levels of IL-1-beta in uremic patients increased significantly after 3 and 6 months of hemodialysis. The study of the kinetics of IL-1-beta concentration during a single hemodialysis session revealed that the concentration of IL-1-beta fell to 21 and 22% of the predialysis level with cuprophane and polysulfone, respectively. Hemodialysis patients also had a significantly higher intracellular IL-1-beta level than normal controls. During the hemodialysis session, an increase in cell-associated IL-1-beta was seen regardless of the membrane employed. In a parallel study, normal mononuclear cells were subjected to closed-loop in vitro dialysis with either cuprophane or polysulfone membranes, with or without acetate buffer. After 120 min of recirculation, an increase in cell-associated IL-1-beta was detected, but no changes were seen in the circulating medium. IL-1-beta production was not significantly influenced by either membrane or the dialysate composition. Hemodialysis has been associated with high plasma- and cell-associated IL-1 levels. The kinetics of intradialytic changes of IL-1-beta levels make IL-1 an unlikely cause of acute complications in hemodialysis. On the other hand, a chronic elevation of IL-1 in plasma of patients on maintenance hemodialysis may contribute to the development of some of the long-term complications of this treatment.

Biocompatible Materials↗
PubMed1991

Immune deficiency in uremia: interleukin-2 production and responsiveness and interleukin-2 receptor expression and release.

We have studied the role of interleukin-2 (IL-2) and its receptors in the impaired in vitro lymphocyte response characteristic of hemodialysis patients treated by means of cuprophane membranes. The proliferative response of T lymphocytes as well as T-cell-dependent B cell proliferation after stimulation with mitogens was significantly reduced in hemodialysis patients. The in vitro production of IL-2 after such stimulation in parallel cultures was found to be similar in patients and in controls. The expression of IL-2 receptor on the lymphocyte cellular membrane in the hemodialysis group was also similar to controls. The in vitro proliferative response of uremic lymphocytes to exogenous IL-2, however, was significantly depressed suggesting a reduced availability of biologically active IL-2 receptor. The release of soluble IL-2 receptor by lectin-stimulated lymphocytes in culture was also significantly lower in the patient group; yet, hemodialysis patients has a strikingly elevated level of plasma soluble IL-2 receptor, and similar high levels were also found in three other groups of end-stage renal disease patients dialyzed by means of cellulose acetate, polysulfone and polyacrylonitrile membranes, as well as in a group of uremic patients on conservative treatment. In the hemodialysis patient group a significant positive correlation between levels of soluble IL-2 receptor and the duration of hemodialysis was found. Since soluble IL-2 receptor has been reported to down-regulate lymphocyte responses, the elevation in plasma levels of soluble IL-2 receptor in hemodialysis patients may be a pathogenetic factor in the progressive development of impaired immunity associated with end-stage renal disease.

Aged↗
PubMed1990

Soluble interleukin-2 receptors in patients with systemic sclerosis. Clinical and laboratory correlations.

Plasma levels of soluble interleukin-2 receptors (sIL-2R) were measured by an enzyme-linked immunosorbent assay in 79 patients with systemic sclerosis (SSc). These levels were significantly elevated in SSc patients, compared with normal controls (mean +/- SEM 866.0 +/- 63.6 units/ml versus 293.0 +/- 20.5; P less than 0.001). Soluble IL-2R levels were highest in patients with generalized disease, were strongly associated with mortality (P less than 0.001) and inversely correlated with disease duration (P = 0.003), but were not related to sex, age, specific visceral involvement, serologic status, peripheral lymphocyte count, or therapy. Levels of sIL-2R in the supernatants of peripheral blood mononuclear cells were low in patients and controls, and showed comparable increases following phytohemagglutinin stimulation. Exposure of peripheral blood mononuclear cells to laminin did not induce sIL-2R release. Circulating IL-2 levels were comparably low in patients and controls. Our findings suggest the presence of lymphocyte activation in SSc, and further suggest that measurement of sIL-2R may prove to be a useful laboratory technique for assessing disease activity.

Adult↗
PubMed1990

Soluble and cellular markers of immune activation in patients with systemic sclerosis.

The peripheral blood lymphocyte pattern, the lymphocyte responses in vitro, as well as the soluble markers of immune activation were studied in 24 patients with systemic sclerosis (SSc patients). The proportions of total T cells (CD3), their CD4 subset, as well as B lymphocytes were within the normal range. The relative proportion of CD8 lymphocytes, however, was significantly reduced. Patients with SSc had a slightly lower percentage of CD4/4B4+ cells, whereas their proportion of CD4/2H4+ cells was elevated as compared to healthy controls. The proportion of lymphocytes expressing the interleukin-2 receptor (IL-2R) was significantly higher in SSc patients. The proliferative responses of peripheral blood mononuclear cells to PHA stimulation were reduced in the patient group, while expression of IL-2R on lymphocytes after such in vitro stimulation was comparable to that of controls. Expression of IL-2R on patient but not control lymphocytes was increased after in vitro exposure to laminin. Such exposure failed to induce IL-2 production or cell proliferative responses. Soluble plasma IL-2R level (sIL-2R) and soluble CD8 (sCD8) molecule levels in SSc patients were significantly elevated. These results indicate the presence of an ongoing lymphocyte activation in this disease process.

Adult↗
PubMed1990

Normal T lymphocyte function in patients with end-stage renal disease hemodialyzed with 'high-flux' polysulfone membranes.

T lymphocyte function was analyzed in patients hemodialyzed with 'high-flux' polysulfone membranes, which have been reported to improve the patients' overall clinical condition and well-being. For comparison purposes, patients treated by the use of 'low-flux' cuprophane membranes were also studied. Peripheral blood white cell counts, numbers of lymphocytes as well as the numbers of T cells and their CD4 and CD8 subsets were within normal range in both patient groups. The absolute number of B cells was slightly decreased in cuprophane-membrane- but not polysulfone-membrane-treated patients. The proliferative response of T lymphocytes after stimulation with optimal concentration of phytohemagglutinin (PHA) was normal in patients treated with 'high-flux' membrane dialysis but significantly reduced in those treated with cuprophane membranes. The generation of interleukin-2 (IL-2) receptor on T lymphocytes after PHA stimulation was normal in the polysulfone-membrane-treated group and slightly impaired in the cuprophane-membrane-dialyzed patients. Production of both IL-2 and interleukin-1, as well as the natural killer cell activity, in patients treated by 'high-flux' membrane dialysis were also comparable to controls. The levels of serum beta 2-microglobulin were significantly elevated in patients-maintained on 'high-flux' dialysis membranes but did not reach the levels seen in patients dialyzed by cuprophane membranes. The beta 2-microglobulin at levels seen in patients on cuprophane dialysis had no effects on activation and proliferation of control lymphocytes in vitro. These results suggest that impaired functional responses of T lymphocytes seen in end-stage disease patients on prolonged hemodialysis with cuprophane membranes are not seen in similar patients hemodialyzed with polysulfone membranes.

Biocompatible Materials↗
PubMed1989

C-terminal domain of the adenovirus E1A oncogene product is required for induction of cytotoxic T lymphocytes and tumor-specific transplantation immunity.

Adenovirus genes required for the elicitation of adenovirus group C-specific cytolytic T lymphocytes (CTLs) and for the induction of adenovirus-specific transplantation antigen (TSTA) were identified by immunization with a library of adenovirus mutants. The group C Ad-specific CTL response was elicited by immunization with wild-type adenovirus type 5 (Ad5) or with recombinant adenoviruses containing Ad5 E1A gene. The specific CTL response was also elicited by Ad5 virus constructs which express only the 12 S or 13 S E1A early mRNA, but not with viruses unable to express E1A protein sequences normally encoded by the E1A early messages. The induction of transplantation immunity against tumorigenic Ad-transformed cells was studied next. The product encoded by either 13 S and 12 S E1A mRNA alone was sufficient for strong TSTA activity. A series of viruses with mutations within the first exon of the E1A message also induced strong TSTA, while Ad5 mutants with lesions within the second exon failed to induce syngraft immunity. These results provide strong evidence that amino acid sequence encoded by the second exon of the Ad5 E1A message is required, either directly or indirectly, for the induction of both Ad-specific CTL and Ad TSTA.

Adenovirus Early Proteins↗
PubMed1989

Human immunodeficiency virus (HIV) infection in haemophiliacs: long-term prognostic significance of the HIV serologic pattern.

To identify markers of prognostic value in the course of HIV disease, immunologic parameters and profiles of HIV antibodies and antigen were studied in 60 haemophiliacs. The 43 HIV-seropositive subjects were followed prospectively over a 4 year period with a retrospective analysis as well of their frozen plasma for HIV markers. This group had a significant decrease in number of helper/inducer T lymphocytes as compared with 17 HIV seronegative subjects. The degree of changes correlated with the stage of disease, with the most severe depletion of CD4 cells in those who developed AIDS. Counts of B cells and platelets were also lower in HIV-infected haemophiliacs. Ten out of 12 AIDS patients had undetectable antibodies to HIV p24 antigen; low levels of p24 antibody were also seen in six out of 15 subjects with lymphadenopathy (CDC stage III), but in only two out of 16 asymptomatic subjects (CDC stage II). Sustained HIV p24 antigenaemia (greater than 30 pg/ml) was seen in 10 AIDS patients, in five subjects with lymphadenopathy and in two asymptomatic haemophiliacs. Initial HIV serologic profiles, obtained when all patients were asymptomatic, were highly predictive for progression of the HIV infection: the initial pattern of low anti-p24 antibody and positive p24 antigenaemia conferred the worst prognosis, with all patients in this group developing ARC or AIDS within 36 months, whereas an initial high level of anti-p24 without p24 antigenaemia was associated with relatively the best prognosis. Of such subjects, 58% have remained clinically asymptomatic after 48 months of the study (P less than 0.00001). The serologic profile of HIV antibody pattern and HIV antigen in haemophilic patients thus already provides important prognostic information at an early stage of HIV infection.

AIDS Serodiagnosis↗
PubMed1989

Independent learning in pathology. Does it work?

The sophomore pathology course at the University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway, was substantially modified with the intention of promoting guided, independent learning. The emphasis has been shifted from lectures to other modalities of instruction. This article delineates the curricular changes made, describes the instructional modalities used, and reports student performance after two year's experience with the new curriculum.

Education, Medical, Undergraduate↗
PubMed1986

Adenovirus tumor-specific transplantation antigen is a function of the E1A early region.

Viable recombinant adenoviruses that carry a portion of the type 12 E1A and E1B transcription units in a type 5 background were used to identify genes controlling expression of the adenovirus tumor-specific transplantation antigen (TSTA). The TSTA immunity is not crossreacting between the group A and group C adenovirus serotypes. Viruses carrying the E1A region (sub370-12E1A), or both E1A and E1B (sub370-12E1AB) regions of Ad12, induce a strong transplantation immunity against tumors induced by syngeneic cells transformed with adenovirus 12, but fail to induce any protection against syngeneic cells transformed with adenovirus 2. Immunization with the virus carrying only the E1B region (sub370-12E1B) of adenovirus 12 induces no immunity to adenovirus 12 transformed cell line, but confers a strong protection against cells transformed with adenovirus 2. These results provide strong evidence that the adenovirus tumor-specific transplantation antigen is a function of the E1A early region.

Adenovirus Early Proteins↗
PubMed1986

T cells in patients undergoing chronic hemodialysis: mitogenic response, suppressor activity, and interleukin-2 production and receptor generation.

The functional response of peripheral blood T lymphocytes was studied in patients with end-stage renal disease treated by chronic hemodialysis for over 1 year. Proliferation after phytohemagglutinin stimulation of patients' peripheral blood mononuclear cells and of T lymphocyte fractions isolated by either sheep erythrocyte rosetting or by use of a nylon wool column was significantly reduced as compared with that of corresponding fractions from healthy control subjects (P less than 0.001). The induction of suppressor cell activity by concanavalin A in rosetted T cell fractions was higher with cells of hemodialyzed patients than with control cells (P less than 0.025). The expression of class II MHC antigen (HLA-DR) by the T8 lymphocyte subset after concanavalin A induction, as determined by staining with monoclonal antibodies and two-color fluorescence analysis by flow cytometry, was also higher in hemodialyzed subjects (P less than 0.025). Since contamination by non-T cells in such cell fractions and increases in proliferation after indomethacin treatment of peripheral blood mononuclear cells were similar in hemodialyzed and control subjects, it is unlikely that the depressed T lymphocyte responses and the increased suppressor cell activity can be attributed to increased peripheral blood monocyte counts observed in patients undergoing hemodialysis. Studies of the biological events associated with the activation of lymphocytes of hemodialyzed patients revealed a reduction in expression of interleukin 2 receptor in the plasma membrane of phytohemagglutinin-stimulated lymphocytes as determined by staining with monoclonal antibody (P less than 0.01). In addition, a very low secretion of interleukin 2 by stimulated peripheral blood mononuclear cell populations was observed in about one-half of patients receiving hemodialysis.

Adult↗