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D S Snyder

Publications and source records attributed to D S Snyder.

At least 73 records · Page 4Linked to original sources
PubMed1989

Autoimmune sequence of streptococcal M protein shared with the intermediate filament protein, vimentin.

The crossreactivity of antibodies against a renal autoimmune epitope of Streptococcus pyogenes M protein with glomerular mesangial cells was investigated. The antibodies directed against the amino acid sequence Ile-Arg-Leu-Arg of the nephritogenic type 1 M protein reacted in a fibrillar pattern with mesangial cells cultured from isolated glomeruli. In Western blots of urea-extracted mesangial proteins, the antibodies reacted with a 56-kD protein. Monoclonal and polyclonal antibodies identified the 56-kD mesangial protein as vimentin. Two synthetic peptides of human vimentin containing the sequence Arg-Leu-Arg reacted with the autoimmune antibodies raised against a streptococcal M protein peptide. These results provide evidence that the intermediate filament protein vimentin shares autoimmune epitopes with streptococcal M protein.

Amino Acid Sequence↗
PubMed1989

Activation of astrocytic lysosomal proteinases by factors released by mononuclear leukocytes.

Lysosomal proteinases are increased in the tissue lesions of experimental allergic encephalomyelitis and have been implicated in the degradation of myelin proteins. The cellular origins of the increased proteinases are not known but reactive astrocytes found in areas of increased activity are candidate cells. To evaluate the potential of astrocytes as the source of these proteinases, cathepsin B (CB) and cathepsin D (CD) levels were measured in lysates of cultured astrocytes from neonatal rats. Because astrocytes are activated by inflammatory mediators in demyelinating lesions the effect of activation on proteinase levels was examined. Culture supernatants from mononuclear leukocytes stimulated with either concanavalin A or phytohemagglutinin (PHA) induced significant increases in the astrocytic proteinases. Neither PHA alone, interleukin-1, interleukin-2, nor gamma-interferon induced significant increases. Fractions of the supernatant from PHA stimulated mononuclear leukocytes were tested and activity was found in fractions corresponding to a molecular weight of 45-50,000. These studies demonstrate that astrocytes contain significant amounts of CB and CD activity which can be increased by a factor or factors released by activated mononuclear leukocytes.

Animals↗
PubMed1989

Antiproliferative effects of lipoxygenase inhibitors on malignant human hematopoietic cell lines.

Eicosanoids regulate a wide spectrum of cellular processes including cell proliferation. We have shown previously that lipoxygenase metabolites of arachidonic acid modulate normal human hematopoiesis by in vitro colony assays. In this study we investigated the role of lipoxygenase metabolites in regulating the proliferation of several malignant hematopoietic cell lines, including K562 and EM-2 (chronic myelogenous leukemia blasts), HL-60 (promyelocytic leukemia cells), and U937 (malignant histiocytes). Piriprost, a specific inhibitor of 5-lipoxygenase, inhibits proliferation of these cell lines up to 95% with 50% cell inhibition at approximately 3 x 10(-5) M. Other less specific lipoxygenase inhibitors such as caffeic acid, nordihydroguaiaretic acid, and BW755C have similar activity in a [3H]-thymidine incorporation assay. In contrast, indomethacin, which is a cyclooxygenase inhibitor, has no suppressive effect in these assays. Inhibition by these drugs is completely reversible. Several nonhematopoietic malignant cell lines do not appear to be affected by these drugs. Two specific lipoxygenase metabolites, leukotriene B4 and leukotriene D4, stimulate leukemia cell line proliferation to 150% of control levels when added directly to cell cultures. These data suggest that certain lipoxygenase products, perhaps leukotrienes, are critical for the proliferation of malignant hematopoietic cells in vitro.

Arachidonate 5-Lipoxygenase↗
PubMed1988

Alterations of the posttranslational processing of a lysosomal enzyme in C6 glioma cells.

Cathepsin D was assessed in C6 glioma cells grown in medium with an intermediate- or low-percent composition of serum. The amount, form, and subcellular location of cathepsin D differed after treatment with cyanate or monensin in cells grown in a low-serum, growth-factor-supplemented medium. Immunoblotting showed that cathepsin D in the lysosomal fraction of the C6 cell line had a molecular weight (Mr) of 42 kD, whereas that in the microsomal fraction had Mr's of 42, 47, and 78 kD. After treatment for 1 to 16 hr with 4 mmol/L cyanate and subcellular fractionation, the molecular weight of lysosomal cathepsin D was the same in treated and untreated cells, but more enzyme was found in lysosomes of treated cells at 8 and 16 hr. In the microsomal fraction, the amounts of both the 42 and 47 kD forms were increased after 1 to 16 hr of treatment. When exposed to 20 mmol/L cyanate, C6 cells remained viable, but compared with untreated cells, they showed 25% less lysosomal cathepsin D, with increased amounts found in the microsomal fraction. The 78 kD protein detected by immunoblotting was present in both the lysosomal and microsomal fractions but was predominant in the latter. The apparent molecular weight of this protein was the same after cyanate but differed with monensin, where Mr's of 39, 42, and 73 kD were found. Monensin-treated cells had less lysosomal cathepsin D and relatively more microsomal enzyme. The differing molecular weights of cathepsin D from cyanate- and monensin-treated cells suggest that their inhibitions occur at different processing loci in distal elements of the Golgi stacks. The differences in the pI of cathepsin D and the number of its forms from cyanate- and monensin-treated cells are also consistent with interference in the late stages of glycoprotein maturation. In this paper we show that the amount, molecular form, and consequent intracellular location of cathepsin D in cells of the C6 line can be affected by agents that selectively disrupt stages in Golgi-related protein modification and transport.

Animals↗
PubMed1988

Fractionated total body irradiation and high dose cyclophosphamide: a preparative regimen for bone marrow transplantation for patients with hematologic malignancies in first complete remission.

We treated 73 patients with hematologic malignancies in first complete remission (acute lymphoblastic leukemia = 23 patients; acute non-lymphoblastic leukemia = 25 patients; chronic myelogenous leukemia in first chronic phase = 20 patients, and high grade lymphoma = five patients) with a uniform preparative regimen consisting of fractionated total body irradiation (1,320 cGy) and high dose cyclophosphamide (100 mg/kg), followed by allogeneic bone marrow transplantation. By radiation dosimetry we demonstrated that the calculated doses were delivered accurately and reproducibly. Actuarial survival rates (+/- SEM) in complete remission were as follows: Acute lymphoblastic leukemia = 74 +/- 9%; acute nonlymphoblastic leukemia = 50 +/- 11%; and chronic myelogenous leukemia = 55 +/- 11%. Actuarial relapse rates for these three diagnoses were 19 +/- 9%, 17 +/- 11%, and 0% respectively. Three of the five lymphoma patients are alive in complete remission at 22+, 28+, and 54+ months. Overall probability of survival for the 73 patients was 59 +/- 7%. Interstitial pneumonia, usually associated with cytomegalovirus infection and graft-versus-host disease, and relapse of the underlying malignancy were the major causes of death.

Adolescent↗
PubMed1987

Allogeneic bone marrow transplantation for high risk non-Hodgkin's lymphoma during first complete remission.

Allogeneic bone marrow transplantation from histocompatible sibling donors was performed in six patients with extranodal involvement of high grade lymphoma during first complete remission. Five patients had lymphoblastic lymphoma and one had diffuse undifferentiated lymphoma. The cytoreductive/immunosuppressive regimen consisted of total body irradiation and high dose cyclophosphamide. Four patients are alive in complete remission at 8 months, 14 months, 21 months and 47 months post transplantation. One patient who relapsed 7 months after his initial transplantation underwent a second transplantation but another relapse 17 months later led to his death. One patient died of chronic graft-versus-host disease and at autopsy there was no evidence of lymphoma. These data demonstrate that allogeneic bone marrow transplantation can produce durable remissions in patients with high grade lymphoma who present with bone marrow, central nervous system and/or skin involvement.

Adolescent↗
PubMed1987

Allogeneic bone marrow transplantation for acute lymphoblastic leukemia during first complete remission.

Patients with acute lymphoblastic leukemia who have poor prognostic features at diagnosis usually have a short disease-free survival in spite of successful remission induction. Those poor risk features are: age over 30 years, a white blood cell count over 25,000/microliter, certain translocations of chromosomes, and requirement for more than six weeks of induction chemotherapy to attain a complete remission. We have used high-dose radiochemotherapy to prepare 39 patients with acute lymphoblastic leukemia in first complete remission (1 infant and 38 adults; median age 23 years) for bone marrow transplantation from histocompatible sibling donors. Thirty-one of the 39 patients in this study had one (n = 23) or more (n = 8) poor risk features: age (n = 7); high white blood cell count (n = 19); translocations (n = 4), or resistance to initial induction therapy (n = 11). Currently, 26 patients are surviving for 4-72 months (median 18 months) following marrow grafting and are in complete remission. One of the surviving patients had two marrow transplant procedures because of recurrent leukemia. Actuarial survival in complete remission is 63% for the entire group of 39 patients and is 60% if the eight patients who had no poor risk features are excluded from analysis. The following causes for failure were observed: leukemic relapse was encountered in four patients between 3 and 17 months after BMT for an actuarial relapse rate of 16%; bacterial sepsis was the cause of death in two patients; graft-versus-host disease and/or interstitial pneumonia led to the demise of seven patients, and one patient died with leukoencephalopathy. It appears that high-dose radiochemotherapy followed by bone marrow transplantation from a histocompatible sibling donor during first complete remission can result in a high disease-free survival rate for younger adults with poor-risk acute lymphoblastic leukemia. This concept needs to be tested in prospective trials comparing bone marrow transplantation with chemotherapy.

Adolescent↗
PubMed1987

Bone marrow transplantation for acute nonlymphoblastic leukemia during first complete remission. An analysis of prognostic factors.

Sixty-nine patients with acute nonlymphocytic leukemia in first remission received total-body irradiation and chemotherapy followed by allogeneic bone marrow transplantation from histocompatible sibling donors. Patient age was between 1 and 41 years: 20 patients 1-19 years (group 1); 27 patients 20-29 years (group 2); and 22 patients 30-41 years (group 3). Two pretransplant radiochemotherapy regimens were employed: The first 45 patients received total-body irradiation (in a single dose) with cytosine arabinoside and cyclophosphamide; the next 24 patients received total-body irradiation (in a fractionated schedule) with cyclophosphamide alone. For all patients, actuarial disease-free survival is 51% (37 of 69 patients are alive and in continuous remission between 5 months and 9.3 years, median 3.7 years). For group 1 actuarial survival is 56%, group 2 48%, and group 3 48%. When analyzed for pretransplant factors that might predict disease-free survival after bone marrow transplantation neither patient age, white cell count at the time of diagnosis, FAB leukemic subtype, length of time before achieving remission, nor length of time between remission and bone marrow transplantation were established as prognostic.

Acute Disease↗
PubMed1987

Inhibition of human monocyte antigen presentation, but not HLA-DR expression, by cyclosporine.

The effects of cyclosporine (CsA) on antigen-dependent human T cell proliferation have been studied using tetanus toxoid as the antigen. CsA significantly inhibited antigen-dependent T cell proliferation at concentrations as low as 0.1 microgram/ml. In dissecting this system we found that preexposure of separated monocytes to CsA during the period of antigen processing led to a marked inhibition of proliferation of T cells added subsequently to the monocytes. We investigated whether this suppressive effect on monocyte antigen presentation was related to monocyte HLA-DR expression, interleukin 1 (IL-1) production, or prostaglandin (PG) secretion. None of these functions seemed to be affected by CsA. In particular, human monocyte HLA-DR expression was not inhibited by CsA, even at concentration of 10 micrograms/ml. The addition of exogenous IL-1 or indomethacin did not reverse the inhibitory effects of CsA. These experiments demonstrate that CsA inhibits antigen-dependent human T cell proliferation, at least in part by acting directly on human monocytes to inhibit antigen presentation. The mechanism of action seems to be independent of IL-1 production, PG secretion, and HLA-DR expression.

Antigen-Presenting Cells↗
PubMed1987

Bone marrow transplantation for myelodysplastic and myeloproliferative syndromes.

Twenty patients (age range, 4 to 48 years; median age, 36 years) with de novo or drug-induced myelodysplastic syndromes or myeloproliferative disorders were treated with myeloablative immunosuppressive therapy followed by bone marrow transplantation (BMT). Four preparative regimens were used; three regimens consisted of combined total body irradiation (TBI) and chemotherapy and one of combination chemotherapy only. One patient received marrow from his identical twin brother, whereas the other 19 patients were grafted with marrow from histocompatible siblings. In 19 patients the abnormal clone was at least temporarily ablated, while in one patient the congenital myelodysplasia persisted. Eight patients are alive and well for +108 to +3,359 days post-transplantation. Nine patients died of transplant-related complications (six of interstitial pneumonia, two of gastrointestinal bleeding, and one of fungal sepsis) and three patients died with persisting or recurring disease. One patient with a late recurrence has undergone a second successful bone marrow transplant procedure. Outcome of BMT was not related to French-American-British (FAB) type, marrow fibrosis, cytogenetic abnormalities, or preparation regimen. Marrow transplantation as a means of providing long-term disease-free survival and possible cure should be considered in patients if a suitable donor is available.

Adolescent↗
PubMed1987

Bone marrow transplantation for patients with Philadelphia chromosome-positive acute lymphoblastic leukemia.

We report the treatment outcome of allogeneic bone marrow transplantation in ten patients with Philadelphia chromosome-positive acute lymphoblastic leukemia. Six patients are alive and well for 6 to 30 months (median 19 months) after transplantation. Four patients died with transplant related complications. In view of the poor prognosis associated with this disease, marrow ablation followed by allogeneic or syngeneic marrow grafting may be the preferred treatment modality if a suitable marrow donor is available.

Acute Disease↗
PubMed1987

Total body irradiation and high-dose etoposide: a new preparatory regimen for bone marrow transplantation in patients with advanced hematologic malignancies.

In a phase I/II study, 47 patients (median age, 24 years) with hematologic malignancies (33 patients with acute leukemia not in first remission and 14 patients with other advanced malignant hematologic disorders) were treated with total body irradiation and high doses of etoposide (VP16-213) followed by bone marrow transplantation. At the time of analysis, 21 patients were alive, and 19 of them were in continued complete remission for 101 days to greater than 40 months (median, 12 months). The actuarial disease-free survival rate of the 33 acute leukemia patients is 43% (2 SEM, 18%) and the actuarial relapse rate is 32% (2 SEM, 20%). Five of the 14 patients with the other hematologic malignancies are alive, and four of them continue to be free of disease for 8 to 27 months. Pharmacokinetic studies established a strong correlation between the administered drug doses and their plasma levels and also demonstrated complete drug clearance prior to marrow grafting. An etoposide dose of 60 mg/kg body weight was found to be the maximum tolerated dose. This new preparatory regimen was well tolerated and was not associated with specific acute or long-term regimen-related toxicities. Our data suggest that total body irradiation with high-dose etoposide presents a viable alternative to other preparatory regimens. The role of this novel combination remains to be defined by future prospective randomized trials.

Acute Disease↗
PubMed1986

Long-term follow-up of previously separated pigtail macaques: group and individual differences in response to novel situations.

A follow-up study of monkeys who experienced maternal separations as infants 2.5-4.9 years earlier was performed. Matched pairs of previously separated and nonseparated control monkeys were observed individually in four unfamiliar situations, and their behavioral responses and plasma cortisol levels were measured. Results indicated that previously separated animals displayed more disturbance than did their matched controls, and levels of disturbance were significantly correlated with the degree of behavioral and physiological disturbance displayed during the original maternal separations. The results support the idea that the perception of the maternal separation may be a significant factor in whether long-term behavioral deficits exist in social and emotional functioning.

Affective Symptoms↗
PubMed1986

Bone marrow transplantation for hematologic malignancies in patients aged 30 years or older.

During the past 10 years, 86 patients 30 to 54 years of age with hematologic malignancies were prepared with high-dose radiochemotherapy and received histocompatible bone marrow grafts. Thirty-four of these patients are surviving for 4 months to 9 years (median, 26 months) following marrow transplantation and 32 of them are in continuing complete remission (CR). Disease-free survival is 44% for 37 patients who were in first remission of acute leukemia or in the chronic phase of chronic granulocytic leukemia (CGL), 23% for 39 patients whose leukemia had relapsed at least once before transplantation or who had advanced stages of CGL, and 60% for ten patients who had hematologic malignancies other than leukemia. The median age of the surviving 34 patients is 36 years (range, 30 to 43 years). The incidence of moderate to severe acute graft-v-host disease (GVHD) was 48% and of chronic GVHD, 26%. The major causes of failure were interstitial pneumonia in 31 patients (24 of whom had antecedent acute GVHD) and recurrent leukemia in 12 patients (11 of whom had either never entered a CR or had relapsed at least once with acute leukemia or had progressive CGL before transplantation). Our data warrant further prospective studies in patients with hematologic malignancies who are older than 30 years.

Actuarial Analysis↗