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Biomedical subjects

R Or

Publications and source records attributed to R Or.

At least 163 records · Page 9Linked to original sources

Ganciclovir for the treatment of disseminated CMV disease without pneumonia in allogeneic T-lymphocyte depleted bone marrow transplantation.

Treatment with ganciclovir was assessed in 13 patients who underwent allogeneic T-lymphocyte depleted bone marrow transplantation (BMT) for a variety of malignant hematological disorders and subsequently developed severe cytomegalovirus (CMV) disease without pneumonia. The manifestations of CMV disease appeared on days 23-105 (median 51) post BMT, and included gastrointestinal symptoms, weight loss, fever, disturbed liver function, leukopenia and thrombocytopenia. Ganciclovir was administered for 14 days, without the addition of intravenous immunoglobulins. Following therapy, the clinical manifestations subsided in most of the patients, while leukopenia, thrombocytopenia and liver dysfunction resolved in about half of the patients. One patient who experienced recurrent CMV disease responded to a second course of ganciclovir. Poor response to ganciclovir treatment was observed in 2 of the 3 patients with grade 4 graft-versus-host disease (GVHD). Our experience suggests that a 2-week course of ganciclovir may be effective in BMT recipients who develop severe CMV-associated disease without lung involvement, especially when there is no concomitant severe GVHD.

Adolescent↗

Sudden onset deafness as a presenting manifestation of chronic lymphocytic leukemia.

An unusual patient with typical Rai Stage 2 (Binet Stage A) chronic lymphocytic leukaemia (CLL), who presented with sudden onset deafness as the initial manifestation of disease is reported. This sensorineural hearing loss improved dramatically after the administration of chemotherapy. This unique observation was also associated with reduction of the circulating B-CLL cells and with the achievement of a partial response, lasting for almost three years. Recently there was another episode of sudden deafness, associated with a rising leukocyte count, and disease activity followed once again by recovery after chemotherapy. Audiograms were recorded showing positive findings on presentation and recovery after therapy. This very rare manifestation of CLL was presumed to be due to infiltration of the cochlear duct or the 8th cranial nerve although all imaging techniques were negative, because of the rapid relief and recovery achieved after specific chemotherapy. The importance of early diagnosis and therapy is stressed in the light of the rapid clinical recovery observed here.

Adult↗

Prevention and treatment of relapse by bone marrow transplantation.

High, myeloablative doses of chemoradiotherapy represent the treatment of choice for a large number of malignant hematological diseases that cannot be successfully treated with conventional chemotherapy. Residual tumor cells following high dose chemotherapy represent the most common treatment failure, resulting in frequent relapse following autologous bone marrow transplantation (ABMT) and even allogeneic bone marrow transplantation (BMT). Graft vs leukemia (GVL) effects mediated by immunocompetent donor lymphocytes represent a major therapeutic potential of allogeneic BMT which results in reduced rate of relapse, especially when immune interactions between immunocompetent donor's T lymphocytes and host allogantigens is apparent, a reaction which might result in graft vs host disease (GVHD). Recent experiments in animal models of murine leukemias suggest that post-transplant immunotherapy may be successfully accomplished by lymphokine-mediated immunotherapy (LMI) and cell-mediated immunotherapy (CMI). Following allogeneic BMT, provided GVHD can be prevented by T-cell depletion, CMI may be amplified by repeated administration of immunocompetent donor's lymphocytes in graded increments following successful induction of chimerism and sustained hematopoiesis. GVL effects induced by CMI may be further potentiated by in-vivo administration of a short course of recombinant human interleukin-2 (rhIL2). Taken together, our data suggest that post-transplant immunotherapy by cytokines and adoptive cell therapy may successfully prevent relapse in patients at high-risk and even result in complete elimination of tumor cells following overt relapse. Thus, immunotherapy may represent an optimal approach for prevention and treatment of minimal residual disease.

Animals↗

Invasive fungal sinusitis in patients undergoing bone marrow transplantation.

Invasive fungal sinusitis is becoming increasingly common in patients undergoing BMT. This study was undertaken to evaluate the incidence, presenting symptoms, diagnosis procedures, treatment and outcome of invasive fungal sinusitis. The study population comprised 423 consecutive BMT patients at Hadassah University Hospital from January 1986 to August 1992. Eleven patients (2.6%) developed invasive fungal sinusitis, 8 had underlying hematologic malignancies and 3 severe aplastic anemia (SAA). Median interval between BMT and fungal sinusitis was 22.5 days (range 2-106 days). Eight of 11 patients had protracted neutropenia (median 8 days with median neutrophil count at the time of fungal sinusitis diagnosis of 0.25 x 10(9)/l). Four patients developed GVHD before fungal sinusitis was diagnosed. Presenting symptoms were fever (100%), orbital swelling (63%), facial pain (54%) and nasal congestion (36%). In 8 patients Aspergillus species were isolated (A. flavus in 7, A. quadrilineatus in 1); in 1 patient Candida albicans was isolated and in the other 2 fungal elements were detected histologically (Fusarium and Mucor, respectively). Six of the patients underwent surgical debridement at diagnosis. Three received granulocyte transfusions. All patients received systemic amphotericin B (7 conventional and 4 amphotericin B colloidal dispersion (ABCD)). Only 2 of the 11 patients responded completely to therapy with a follow-up of 15 months. It appears that invasive fungal sinusitis is a potentially fatal complication in immunocompromised patients post-BMT. Current treatment approaches are largely ineffective and new methods of management of this serious problem are needed.

Adolescent↗

Cutaneous hypersensitivity to co-trimoxazole after autologus bone marrow transplantation and immunotherapy with interferon alpha-2A and interleukin-2.

Typical cutaneous hypersensitivity reaction to co-trimoxazole was seen in a woman after autologous bone marrow transplantation and immunotherapy. She had developed no such reaction during chemotherapy prior to the transplant or immediately after the transplant. The immunoperturbed state that exists for a period of time after bone marrow transplantation, especially in the presence of immunomodulation caused by combined therapy with recombinant human interferon alpha and interleukin-2, with exposure to potentially reaginic agents may have contributed to the development of the hypersensitivity reaction in this patient.

Adult↗

Adoptive transfer of immunity to hepatitis B virus after T cell-depleted allogeneic bone marrow transplantation.

Recipients of allogeneic bone marrow transplantation are pancytopenic for several weeks and immunosuppressed for many months as a result of myeloablative therapy required to eliminate the basic disease and to prevent allograft rejection. After bone marrow transplantation, these patients remain profoundly immunosuppressed by the chemotherapy and immunotherapy used as prophylaxis against graft-vs.-host disease, treatment of established disease or both. These patients are usually dependent on multiple blood products and are therefore at risk for hepatitis B virus infection, which may run a fulminant course. Active immunization against hepatitis B virus in the immediate pre-bone marrow transplantation and post-bone marrow transplantation periods was found to be ineffective, probably because of the absence of T cell-dependent B-cell responses, which persists for approximately 1 yr after bone marrow transplantation. We studied adoptive transfer of immunity to hepatitis B virus through bone marrow transplantation in two populations of patients. The first group (A) consisted of 12 pairs of BMT donors and recipients, in which all bone marrow donors were positive for antibodies to HBc and HBs as a result of previously acquired hepatitis B virus infection and resolution; all recipients were negative to antibodies to HBc and HBs. The second group (B) consisted of eight pairs of donors and recipients in which all the donors were actively immunized against hepatitis B virus before bone marrow transplantation; all recipients were negative for all hepatitis B virus markers. All bone marrow transplantation recipients were monitored for antibodies to hepatitis B virus antigens.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

Optimization of conditioning therapy for leukemia prior to BMT. I. Optimal synergism between cyclophosphamide and total body irradiation for eradication of murine B cell leukemia (BCL1).

The doses of chemotherapy and radiotherapy and the sequence-dependent influence of CY administration and total body irradiation (TBI) on the eradication of murine B cell leukemia (BCL1) were investigated. Tumor-bearing BALB/c mice were treated with either CY followed by TBI (CY/TBI) or in the reverse (TBI/CY) at different time intervals after injection of 10(6) BCL1 cells. The presence of residual tumor cells after cytoreduction was assessed in secondary BALB/c recipients by monitoring leukemia-free survival. The anti-leukemic effect of CY followed by TBI was significantly better than TBI followed by CY. The survival of secondary adoptive recipients inoculated with 10(5) spleen cells obtained from mice treated with CY/TBI was 54% (57 of 105) compared with 25% (25 of 98) of recipients inoculated with 10(5) spleen cells obtained from mice treated with TBI/CY (p = 0.0001).

Animals↗

Inappropriate antidiuretic hormone secretion (SIADH) preceding skin manifestations of disseminated varicella zoster virus infection post-BMT.

We report the syndrome of inappropriate antidiuretic hormone secretion (SIADH) preceding the development of skin lesions of varicella zoster virus (VZV) infection in a patient with CML 5 months post-allogeneic BMT. This is the first report of SIADH complicating disseminated VZV infection in a BMT patient. SIADH is an unusual complication that may precede VZV infection post-BMT.

Adult↗

Transcription of IL-2 and IL-4 genes is not inhibited by cyclosporin A in competent T cells.

Cyclosporin A (CsA) inhibits T-cell proliferation primarily by blocking the transcription of several early activation genes, especially those of the important T-cell growth factors IL-2 and IL-4. This effect seems to be mediated through inhibition of the activity of the transcription factor NF-AT which is essential for IL-2 and probably for IL-4 gene transcription. However, once T cells are rendered "competent" to proliferate following a brief exposure to the phorbol ester, phorbol 12,13-dibutyrate (PDBu), and the calcium ionophore, ionomycin, CsA no longer inhibits cell cycle progression supported by the presence of PDBu alone. Here it is shown that transcription of the IL-2 and IL-4 genes occurs normally throughout this "progression" phase, even in the presence of CsA. However, further production of functional NF-AT, which began during the competence phase of the cell cycle, is inhibited. These data indicate that, although the primary initiation of transcription of IL-2 and IL-4 mRNA during induction of competence may be NF-AT-dependent and CsA-sensitive, the augmentation in the progression phase is both NF-AT-independent and CsA-resistant.

Base Sequence↗

Low molecular weight heparin for Hickman catheter--induced thrombosis in thrombocytopenic patients undergoing bone marrow transplantation.

BACKGROUND: Patients with an indwelling central venous catheter are prone to development of thrombotic complications. Thrombocytopenia in patients undergoing bone marrow transplantation (BMT) generally is protracted. The management of thrombosis in thrombocytopenic patients is difficult because heparin and warfarin are relatively contraindicated because of the high risk of major bleeding. Low molecular weight heparin (LMWH) is a new class of antithrombotic drug. Enoxaparin (Rhone Poulenc Rorer, Antony, France) is an LMWH that has been shown to be effective in the treatment and prophylaxis of venous thrombosis. Enoxaparin, with its high antithrombotic to anticoagulant ratio, may be safer than standard heparin in patients at high risk of hemorrhagic complications. METHODS: The authors report the cases of five thrombocytopenic patients, undergoing autologous BMT, in whom venous thrombosis developed related to a Hickman catheter. RESULTS: All the patients were treated with Enoxaparin and recovered promptly without hemorrhagic complications. CONCLUSIONS: The authors suggest that Enoxaparin is an effective drug in treating thrombocytopenic patients in whom acute venous thrombosis develops.

Adult↗

Enhanced marrow recovery by short preincubation of marrow allografts with human recombinant interleukin-3 and granulocyte-macrophage colony-stimulating factor.

We studied an alternative method of using hematopoietic growth factors (HGFs) to enhance hematopoietic recovery in patients undergoing bone marrow transplantation (BMT), by short in vitro preincubation. Twenty consecutive patients with leukemia received T-cell-depleted allografts using Campath-1G. Two thirds of the marrow was infused on the scheduled day of transplant and one third of the marrow following preincubation with granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-3 (IL-3) on day 4. Engraftment parameters and duration of hospitalization were compared by actuarial analysis to those of 40 historical controls. Patients receiving the incubated boost had significantly faster platelet recovery (P = .017) and shorter hospitalization period (P = .001) when compared with the control subjects. Platelet count reached greater than 25 x 10(9)/L on day 17 (median) in the study group and on day 23 in the controls. The median duration of hospitalization was 20 and 36 days, respectively. In the early posttransplantation follow-up, two of four patients in the study group died as a result of graft rejection, while all 13 deaths in the control group resulted from complications associated with marrow suppression. We suggest that pretransplant in vitro activation of bone marrow cells with IL-3 and GM-CSF may prove to be an efficient method for enhancing marrow recovery after BMT.

Adult↗

Effects of changes in membrane potential on the cyclosporin-induced inhibition of T-cell proliferation.

Cyclosporin A (CsA) exerts its major immunosuppressive effect by inhibition of T-lymphocyte proliferation. The precise mechanism and target of its action has not yet been completely identified. CsA is also known to induce a rapid membrane depolarization in T lymphocytes. We have tested the role of CsA-dependent depolarization in the inhibition of T-cell proliferation by the drug. In these studies, induced membrane depolarization (in the presence of gramicidin or by replacing the Na+ content of the medium with K+) or hyperpolarization (in the presence of valinomycin) had no influence on the induction of T-cell competence by phorbol dibutyrate/ionomycin or by submitogenic concentrations of PHA, a target for CsA immunosuppression. However, regardless of the state of membrane potential during the induction of T-cell competence, the inhibition by CsA was the same as seen in normally polarized cells. We conclude that the depolarization induced by CsA is not a critical element in its inhibitory effect on T-cell proliferation.

Cell Division↗

Superoxide dismutase inhibits radiation-induced lung injury in hamsters.

An animal model of pulmonary radiation-induced lung injury was established in the hamster and the effects of pretreatment with recombinant human CuZn superoxide dismutase (SOD) on the development of the lesion were evaluated. Hamsters exposed to a single irradiation dose of 2000 cGy delivered to the thorax were treated with 150 mg/kg body weight of SOD or an equivalent volume of saline intraperitoneally 75 min and subcutaneously 5 min before receiving irradiation. At 4, 8, and 16 weeks following irradiation, pulmonary injury was evaluated by the grading of morphologic changes semiquantitatively, measurement of lung hydroxyproline content, and analysis of bronchoalveolar lavage fluid for total and differential cell counts and total protein concentration. Radiation-induced lung injury in saline-pretreated animals was documented at 16 weeks by histologic morphology and increased protein in bronchoalveolar lavage fluid. SOD protected against radiation-induced pulmonary injury as indicated by the absence of severe histopathologic changes and prevention of elevation in bronchoalveolar lavage protein levels. The beneficial effects of SOD in preventing radiation-induced pulmonary toxicity suggests that this recombinant enzyme may play a role in protection against radiation-induced pulmonary injury in humans.

Animals↗

Essential fatty acids and iron are involved at distinct stages of the proliferative cycle but not in the activation of human T cells.

In the absence of serum, optimal lymphocyte proliferation is obtained when cultures are supplemented with transferrin and an essential fatty acid (EFA). In order to study the effects of iron in conjunction with EFA on T-cell proliferation, we have utilized a chemically defined serum-free culture system to achieve better control of the variables involved. This system includes three different serum-free media (SFM) that differ in total iron content and source of iron: (i) transferrin-free medium containing a high concentration (500 microns) of a soluble iron salt in the form of ferric citrate (Fe-SFM); (ii) iron-saturated human transferrin (5 micrograms/ml) (T-SFM); and (iii) iron-free medium (SFM(-Fe)) without any apparent source of iron. None of these SFM supported proliferation of T cells stimulated by the combination of phorbol 12,13-dibutyrate/ionomycin or phytohemagglutinin. Restoration of the proliferative response was only observed following supplementation of the iron-containing media with linoleic acid (complexed to bovine serum albumin (LA/BSA)). In cultures containing LA/BSA, the addition of iron alone in the absence of transferrin (Fe-SFM) resulted in similar responses to the transferrin-containing medium (T-SFM). Low levels of RNA synthesis in mitogen-stimulated T cells could be demonstrated in the presence or absence of iron and the addition of LA/BSA resulted in marked enhancement of RNA synthesis, regardless of the availability of iron. Cell cycle analysis showed that 91-94% of the cells cultured in SFM were arrested in G0/G1. These cells could progress through the cell cycle following the addition of LA/BSA, but only in the iron-containing media. Unlike DNA or RNA synthesis, activation of T cells could be demonstrated in SFM with or without iron as shown by the normal induction of c-fos and early growth response gene mRNA, normal expression of IL2 and transferrin receptors, and normal IL2 production, despite the arrest of cells in G0/G1. These results suggest that although human T-cell growth is iron and EFA dependent, the early events of T-cell activation are both iron and EFA independent.

Cell Cycle↗

IL-4 and IL-2 promote human T-cell proliferation through symmetrical but independent pathways.

The role of IL-4 and IL-2 on normal human T-cell activation and proliferation was studied. Both IL-2 and IL-4 were unable to induce proliferation of resting T cells. Therefore, we investigated their effect and the regulation of the T-cell proliferative response in competent T cells. T cells were rendered competent following incubation with PDB/ionomycin for 30 min or suboptimal concentrations of PHA for 60 min. Cells were then washed and recultured with PDB, IL-2, or IL-4 in the second or progression phase of the culture. Cells cultured in medium alone in this phase did not proliferate. IL-2 and IL-4 independently promoted competent T cells to proliferate to a similar degree as the response to PDB and the combination of IL-2 and IL-4 was not additive. The induction of competence and subsequent responsiveness to IL-2 and IL-4 could be maintained for about 24 hr after which time they become gradually less responsive to the interleukin in the progression phase. Addition of anti-IL-2R mAb or anti-IL-2 mAb resulted in selective inhibition of IL-2-mediated proliferation only. Similarly, addition of anti-IL-4 mAb resulted only in inhibition of IL-4-mediated proliferation. Addition of IL-2 during the progression phase led to an enhancement of IL-2R (TAC) expression while IL-4 did not affect IL-2R expression. The production of IL-2 and IL-4 by competent T cells could not be enhanced by the noncorresponding lymphokine. These results on the protein level were confirmed at the mRNA level as well and demonstrated that only PDB and IL-2 could induce IL-2 mRNA and PDB and IL-4 enhanced IL-4 mRNA. The immunosuppressive drug, cyclosporin A, failed to inhibit progression triggered by PDB, IL-2 or IL-4 in competent T cells. These findings suggest that IL-2 and IL-4 trigger T-cell proliferation through symmetrical, but independent pathways.

Antibodies↗

Reciprocal regulatory effects of IL-4 on cell growth and immunoglobulin production in Ig-secreting human B-cell lines.

The effects of interleukin-4 (IL-4) on cell proliferation and immunoglobulin (Ig) production from three different Ig-secreting B-cell lines (U266, IgE; HSCE-, IgG; LA 350, IgM) were analyzed. Addition of IL-4 increased Ig production by the IgE- and IgG-secreting cell lines and this was paralleled by an inhibition of cellular proliferation. In contrast, the addition of IL-4 to LA 350 cells stimulated cellular proliferation but a decrease in IgM secretion. With each cell line, the IL-4 effects were both dose- and time-dependent and effects were maximal in the presence of 400 U/ml. Further analysis of the mechanism of IL-4 action on Ig production at the single B-cell level using an ELISA spot assay revealed a dualistic effect: increased Ig levels in culture supernatants reflected both an enhancement of single-cell Ig production as well as an increase in numbers of Ig-secreting B cells (IgE and IgG). In LA 350 cells the number of IgM-secreting B cells was suppressed as well as the amount of Ig released by single cells. These data on Ig production were supported by determination of mRNA amounts for the epsilon, gamma, and mu gene transcripts. Addition of IL-4 enhanced the levels of epsilon and gamma message in U266 and HSCE- cells, respectively, and reduced the amount of mu mRNA in LA 350 cells. In the IgE- and IgG-secreting cell lines, the IL-4 effect also correlated with enhanced expression of IL-4 receptor (IL-4R) mRNA levels, whereas IL-4R mRNA levels were unchanged in IgM-producing cells after IL-4 treatment. Incubation of cells with IL-4 and interferon-gamma abolished the stimulatory activities of IL-4 on either cell proliferation (LA 350 cells) or Ig production (HSCE- and U266); but did not influence the inhibitory activities of IL-4 on the cell lines. The immunosuppressive drug cyclosporin A (CsA) inhibited both cell proliferation and Ig production in all three cell lines to a similar degree. Furthermore, in U266 and HSCE- cells, CsA inhibition could not be overcome by IL-4. These data support the conclusion that on Ig-secreting human B-cell lines, IL-4 regulates cell proliferation and Ig production in a reciprocal fashion.

Antibody-Producing Cells↗