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Biomedical subjects

A E Lichtin

Publications and source records attributed to A E Lichtin.

12 recordsLinked to original sources
PubMed1998

2',5'-Oligoadenylate-antisense chimeras cause RNase L to selectively degrade bcr/abl mRNA in chronic myelogenous leukemia cells.

We report an RNA targeting strategy, which selectively degrades bcr/abl mRNA in chronic myelogenous leukemia (CML) cells. A 2', 5'-tetraadenylate activator (2-5A) of RNase L was chemically linked to oligonucleotide antisense directed against either the fusion site or against the translation start sequence in bcr/abl mRNA. Selective degradation of the targeted RNA sequences was demonstrated in assays with purified RNase L and decreases of p210(bcr/abl) kinase activity levels were obtained in the CML cell line, K562. Furthermore, the 2-5A-antisense chimeras suppressed growth of K562, while having substantially reduced effects on the promyelocytic leukemia cell line, HL60. Findings were extended to primary CML cells isolated from bone marrow of patients. The 2-5A-antisense treatments both suppressed proliferation of the leukemia cells and selectively depleted levels of bcr/abl mRNA without affecting levels of beta-actin mRNA, determined by reverse transcriptase-polymerase chain reaction (RT-PCR). The specificity of this approach was further shown with control oligonucleotides, such as chimeras containing an inactive dimeric form of 2-5A, antisense lacking 2-5A, or chimeras with altered sequences including several mismatched nucleotides. The control oligonucleotides had either reduced or no effect on CML cell growth and bcr/abl mRNA levels. These findings show that CML cell growth can be selectively suppressed by targeting bcr/abl mRNA with 2-5A-antisense for decay by RNase L and suggest that these compounds should be further explored for their potential as ex vivo purging agents of autologous hematopoietic stem cell transplants from CML patients.

Adenine Nucleotides↗
PubMed1997

Hematologic complications of rheumatic disease therapies.

Hematologic side effects of rheumatic disease therapies are generally mild and reversible; however, the clinician must be alert for potential profound and life-threatening toxicities. A knowledge of the toxicity patterns for the individual drugs is necessary to anticipate potential complications. Management of acute leukemias and lymphomas arising in patients with connective tissue disorders is particularly challenging. Further data are needed to define the best treatment options and thus enrollment in clinical trials is encouraged for these patients.

Anemia↗
PubMed1996

Antithrombotic, anticoagulant, and thrombolytic agents.

There are a growing number of clinical indications for the use of antithrombotic, anticoagulant, and thrombolytic agents. Clinicians must recognize that these patients require multidisciplinary treatment and coordination of care, and an assessment of the patient's level of anticoagulation is imperative to ensure values that may preclude problematic bleeding during dental procedures, yet maintain therapeutic anticoagulation.

Anticoagulants↗
PubMed1995

High-dose busulfan and cyclophosphamide followed by autologous bone marrow transplantation and/or peripheral blood progenitor cell rescue for metastatic breast cancer.

High doses of combination alkylating agents have shown promise in the treatment of breast cancer but are complicated by significant toxicity. Busulfan and cyclophosphamide (BuCy) is a high-dose combination alkylating agent regimen that is well-tolerated when given for hematologic malignancy. We prospectively studied the effects of BuCy followed by autologous bone marrow transplant (ABMT) or peripheral blood progenitor cell (PBPC) rescue in 21 patients with metastatic breast cancer who had responded to either standard chemotherapy or radiotherapy. The mean patient age was 44 years. Nine patients were either estrogen- or progesterone-receptor positive, ten were negative, and two were unknown. Fourteen patients had local recurrence, ten had bone metastases, six had visceral disease, and two had a nonlocal soft tissue recurrence. Busulfan 16 mg/kg and cyclophosphamide 120 mg/kg (BuCy2) was given and followed by either ABMT, PBPC rescue, or both. Grade III to IV extramyeloid toxicity occurred in 6 (29%) patients. One patient died of hepatic venoocclusive disease but there was no other treatment-related mortality. Pulmonary infiltrates with hypoxia of uncertain origin developed in 2 patients after discharge. Of the 10 patients with measurable disease, 4 had complete responses, and 3 had partial responses to high-dose therapy for a total response rate of 70%. The estimated 2-year disease-free survival is 25% (95% CI = 6% to 44%). Our study found BuCy to be a well-tolerated preparative regimen for ABMT in the treatment of patients with metastatic breast cancer.

Adult↗
PubMed1993

G-CSF primed peripheral blood progenitor cells in autologous bone marrow transplantation: parameters affecting bone marrow engraftment.

G-CSF and GM-CSF enhance the rate of neutrophil engraftment in autologous bone marrow transplantation (ABMT) without significantly affecting platelet engraftment. Peripheral blood progenitor cells (PBPC) may enhance rates of engraftment of both neutrophils and platelets. We treated 49 patients undergoing ABMT with a course of G-CSF to obtain PBPC and infused these cells post-transplant with G-CSF in an attempt to determine factors which might correlate with enhanced BM engraftment. Forty-nine patients with Hodgkin's disease, non-Hodgkin's lymphoma or breast cancer undergoing unpurged ABMT were studied. G-CSF priming consisted of an outpatient 8 day course of 5 micrograms/kg/day followed by three leukaphereses (on day 5, 7 and 8) to collect PBPC. Patients then received a chemotherapeutic BMT preparative regimen followed by an infusion of PBPC, autologous BM and the reinstitution of G-CSF (16 micrograms/kg/day). BM engraftment was rapid. The median time to achieve 0.5 x 10(9)/l neutrophils was 10 days compared with a historical BMT control patient population receiving the same preparative regimens of 19 days (p = 0.001). Time to achieve a platelet count of 20 x 10(9)/l was 16 days compared with a historical control of 22 days (p = 0.001). Neutrophil engraftment occurred in all patients by day +14. Marrow engraftment correlated with the total number of CD34+ cells infused as well as the total number of mononuclear cells infused but not the total number of CD34+/CD33- cells infused. The amount of total blood volume pheresed significantly correlated with yield of total mononuclear cells. Prior exposure to radiation therapy negatively correlated with progenitor cell yield.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Precursor Langerhans cell histiocytosis. An unusual histiocytic proliferation in a patient with persistent non-Hodgkin lymphoma and terminal acute monocytic leukemia.

BACKGROUND: Langerhans cell precursors are considered to be identical to their mature counterparts except for the lack of Birbeck granules. Proliferations composed of such histiocytes appear to be uncommon. METHODS: Standard immunophenotypic, molecular genetic, and DNA content studies were used to characterize various hematopoietic disorders, including a proliferation of precursor Langerhans cells, which arose sequentially in a patient. RESULTS: The patient studied initially had a low-grade, B-cell, non-Hodgkin lymphoma and subsequently had an unusual histiocytic proliferation (precursor Langerhans cell histiocytosis) in cutaneous and lymph node sites. The patient eventually died of acute myelogenous leukemia (FAB, M5). CONCLUSIONS: A larger series is required to determine the significance of the precursor Langerhans cell phenotype, particularly with respect to the development of acute myelogenous leukemia.

Adult↗
PubMed1992

Incidence of mixed chimerism using busulfan/cyclophosphamide containing regimens in allogeneic bone marrow transplantation.

The incidence of mixed chimerism (MC) following allogeneic bone marrow transplantation (allo-BMT) is in part a measure of the marrow ablative effect of preparative regimens. Although the incidence of MC has been reported for many patients treated with total body irradiation (TBI), limited data for busulfan/cyclophosphamide (BU/CY) recipients have been examined. We performed restriction fragment length polymorphism (RFLP) analysis on 68 peripheral blood samples from 26 patients treated with BU/CY prior to allo-BMT for chronic myelogenous leukemia or acute myeloid leukemia. MC was detected in four of 26 patients for an overall incidence of 15.4%. Three of four MC patients are alive with no evidence of disease at 263 to 795 days post-transplantation. A fourth patient is alive at day 501 but developed CNS relapse at day 274. The level of recipient origin cells was less than 10% in all samples and detectable MC was transitory with an RFLP pattern that reverted to full chimerism. These results are comparable to those reported for TBI-containing regimens in patients receiving non-T cell-depleted bone marrow. The efficacy of BU/CY in conjunction with a T cell depletion still requires exploration.

Adult↗
PubMed1992

Pseudo-gamma heavy chain (IgG4 lambda) deposition disease.

Two patients with Ig deposition disease presented with acute renal failure, moderate proteinuria, and hematuria. A plasmacytoid lymphocytic infiltrate was identified in bone marrow that produced IgG4 lambda and free lambda light chains. One patient developed an anaplastic plasmacytoma (secreting only lambda light chains) 1 yr after renal biopsy. Renal biopsy in both patients demonstrated a nodular intercapillary glomerulopathy and electron dense granular deposits, associated with a linear pattern of IgG4 heavy chain deposition in vascular, tubular, and glomerular basement membranes (VBM, TBM, and GBM). In one patient this entrapped IgG4 was unassociated with detectable kappa or lambda light chains. In the second patient, lambda light chains (1+) were detected only in the GBM, but IgG4 (4+) was identified in GBM/TBM. Neither circulating (peripheral blood and bone marrow serum) nor cellular free gamma chains were present. We propose the term "pseudo-gamma heavy chain deposition disease" for the process.

Aged↗
PubMed1987

Efficacy of intensive plasmapheresis in thrombotic thrombocytopenic purpura.

Forty-one patients with thrombotic thrombocytopenic purpura were treated at the Hospital of the University of Pennsylvania, Philadelphia, between 1975 and 1985. Initially, early splenectomy was performed. However, since 1981, more intensive plasma exchange therapy (increase in frequency and size of exchange) has been used as the primary modality of treatment for this disorder. A reduction of the mortality rate over time has been observed. For the period 1975 to 1980, the mortality rate was 41% (seven of 17). In contrast, for the period 1981 to 1985, the mortality rate decreased to 17% (four of 24). These observations support the concept that the initial management of thrombotic thrombocytopenic purpura with intensive daily plasma exchange is associated with improved survival. The role of platelet inhibitors and corticosteroids needs yet to be defined.

Adrenal Cortex Hormones↗