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Biomedical subjects

D G Poplack

Publications and source records attributed to D G Poplack.

At least 199 records · Page 11Linked to original sources
PubMed1979

Intraventricular versus intralumbar methotrexate for central-nervous-system leukemia: prolonged remission with the Ommaya reservoir.

Ten children had recurrence of central-nervous-system (CNS) leukemia despite monthly injections of methotrexate into their lumbar cerebrospinal fluid. Each child was then reinduced into remission and maintained with intraventricular methotrexate administered via an Ommaya reservoir and the length of this remission was compared with the duration of the child's previous intralumbar-treated remission. Of eight evaluable patients, seven had longer CNS remissions with intraventricular therapy than with intralumbar therapy (P less than 0.02). The median CNS remission duration in all patients was 475 days with intraventricular and 286 days with intralumbar therapy (P less than 0.05). The rate of CNS relapse was reduced from 2.94 relapses per thousand days at risk during intralumbar therapy to 0.93 relapse per thousand days of intraventricular therapy. We conclude that intraventricular chemotherapy is significantly more effective against CNS leukemia than the same therapy given by lumbar puncture.

Adolescent↗
PubMed1979

Hypothalamic-pituitary dysfunction following CNS prophylaxis in acute lymphocytic leukemia: correlation with CT scan abnormalities.

In an attempt to identify possible adverse effects of CNS prophylaxis (cranial radiation and intrathecal chemotherapy), we examined hypothalamic-pituitary function in 23 patients with acute lymphocytic leukemia (ALL). Of 18 patients who had received both cranial radiation and intrathecal chemotherapy, nine had abnormally low growth hormone responses to insulin-induced hypoglycemia (less than 7.0 ng/ml). Seven of the nine patients with abnormally low growth hormone responses also manifested ventricular dilatation on computed tomography (CT) brain scans, whereas only one of the nine patients with normal growth hormone responses demonstrated this CT scan finding (P = 0.015). The remaining patients, who had not received cranial radiation, had normal growth hormone responses and normal CT scans. There is significant correlation between ventricular dilatation on CT and abnormally low peak growth hormone responses following CNS prophylaxis in ALL.

Adolescent↗
PubMed1979

Methotrexate-induced oral mucositis and salivary methotrexate concentrations.

We examined the plasma and saliva levels of methotrexate (MTX) achieved during the treatment and rescue periods of ten patients receiving 42-h MTX infusions followed by citrovorum rescue. Saliva MTX levels were generally 1%--2% of the simultaneous plasma levels. Four patients developed severe oral mucositis; three patients developed mild to moderate oral toxicity, and three others had no evidence of mucositis. MTX levels in the patients with severe mucositis were not higher and did not persist longer than the levels achieved in patients with mild or absent toxicity. Attempts at reducing the severity of oral mucositis with topical citrovorum mouthwashes or with atropine to suppress salivation were unsuccessful. MTX-induced oral mucositis is not related to salivary MTX concentrations, and the use of topical citrovorum therapy or the suppression of salivation does not appear to ameliorate this toxicity.

Humans↗
PubMed1979

Experimental approaches to the treatment of CNS leukemia.

Some of the current experimental approaches to the treatment of CNS leukemia are reviewed. While small animal models have provided a basic understanding of the pathophysiology of meningeal leukemia, large animal models, particularly the subhuman primate, allow a more detailed examination of the complex dynamics of CNS pharmacokinetics. Principles derived from these models have provided a rational basis for the development of new approaches to the treatment of meningeal leukemia in man.

Animals↗
PubMed1979

Characterization of lymphoblast Fc receptor expression in acute lymphoblastic leukemia.

Lymphoblasts from 18 patients with untreated acute lymphoblastic leukemia were investigated for the presence of conventional cell surface markers (spontaneous sheep red blood cell rosette formation, complement receptors, and surface immunoglobulin). The expression of Fc receptors for both IgG and IgM was investigated using indicator bovine erythrocytes coated with rabbit anti-BRBC (IgG and LgM fractions). The leukemic cells of all patients in this tudy expressed Fc receptors for both IgC and LgM. In contrast with previous reports, null (non-T non-B) lymphoblasts as well as T lymphoblasts demonstrated Fc-IgG and Fc-IgM receptors. However, these two immunologic subclasses of leukemic cells demonstrated significantly different patterns of Fc receptor distribution. These data suggest that expression of Fc receptors is an early event in cellular differentiation in this lymphoid malignancy.

Adolescent↗
PubMed1979

Neurotoxicities of current leukemia therapy.

While major advances have been made in the treatment of acute leukemia, complications of therapy are significant. One of the most worisome complications is the neurotoxicity which is related to both central nervous system prophylaxis (cranial irradiatif neurotoxicity may be acute or delayed, and may range in severity from mild headaches ann of treatment-related neurotoxicity is important since this may permit amelioration of otherwise irreversible neurological sequelae in some patients. We review the clinical, phyh irradiation and chemotherapy, and offer recommendations for monitoring, evaluating and treating patients with potential or proven neurotoxicity.

Antineoplastic Agents↗
PubMed1979

Bacillus Calmette-Guérin enhancement of colony-stimulating activity and myeloid colony formation following administration of cyclophosphamide.

Pretreatment of mice with Bacillus Calmette-Guérin (BCG) enhances recovery of the peripheral granulocyte count from cyclophosphamide (CTX)-induced leukopenia. In the present study, in vitro bone marrow culture was used to assess the effect of BCG pretreatment on serum levels of myeloid colony-stimulating activity and on regeneration of bone marrow myeloid colony-forming units (CFU-c) following CTX. C57BL/6 mice received either BCG or 0.9% NaCl solution i.p. 8 days prior to the administration of CTX (300 mg/kg i.p.). Following CTX, peak serum levels of myeloid colony-stimulating activity were strikingly higher in the BCG-pretreated mice [1320 +/- 30 (S.E.) units] than in the 0.9% NaCl solution-pretreated mice (764 +/- 37 units). BCG pretreatment also resulted in higher numbers of marrow CFU-c during recovery from CTX (e.g., 43.9 +/- 1.8 versus 20.0 +/- 0.9 myeloid colonies/10(5) marrow cells, Day 3 post-CTX). However, neither the rate of decline nor the absolute nadir of CFU-c, nor CFU-c cell cycle characteristics were affected by the pretreatment. The initial effect of i.p. BCG pretreatment on recovery from CTX-induced granulocytopenia is an augmentation of serum myeloid colony-stimulating activity which precedes the enhanced regeneration of CFU-c and the accelerated recovery of the peripheral granulocyte count.

Animals↗
PubMed1979

ADCC against human erythrocyte target cells: role of the anti-target cell antibodies in determining lymphocyte killer activity.

Studies were undertaken to investigate the role of anti-target cell antibodies in determining whether lymphocytes can mediate antibody-dependent cellular cytotoxicity (ADCC) in vitro. Trinitrophenyl (TNP) modified Chang liver cells and human erythrocytes were employed as target cells and were coated with xenogeneic and allogeneic antibodies against TNP and natural cell surface antigens. Two cytotoxic effector cell populations were used: human peripheral blood mononuclear cells (PBMC) containing both lymphocytes and monocytes, and monocyte-depleted peripheral blood lymphocytes (PBL). With Chang targets, both PBMC and PBL mediated ADCC with xenogeneic anti-Chang and xenogeneic anti-TNP sera. With human erythrocyte targets, PBMC but not PBL mediated ADCC with human anti-blood group B serum, while both PBMC and PBL mediated ADCC with xenogeneic anti-TNP sera and also with a human anti-CD serum. These results demonstrate that the source of anti-target cell antibodies employed in ADCC reactions may determine whether or not lymphocytes are capable of mediating cytotoxicity.

Antibodies↗
PubMed1979

The mononuclear phagocyte system: role in expression of immunocompetence in neonatal and adult life.

The cells of the mononuclear phagocyte system are critical elements in host defense. They are essential to many specific immune processes in addition to their well-recognized role in nonspecific resistance. In this report we describe studies of the influence of the maturation of this system of cells on the capacity of the neonatal rat to generate specific immune responses. In addition, studies of human cord blood monocyte function are presented along with data demonstrating a previously unrecognized synergistic action between monocytes and a heat labile, nonantibody, serum factor which may play an important role in host defense. Finally, data are presented demonstrating that one of the recognition processes used by monocytes for cellular interaction is dependent upon a system of natural lectin-like receptors on the monocyte cell surface which recognize membrane-bound oligosaccharides on other cells.

Animals↗
PubMed1978

Acute encephalopathy after initiation of cranial irradiation for meningeal leukaemia.

Five patients experienced severe encephalopathy within hours of receiving their initial dose of cranial irradiation for the treatment of central-nervous-system leukaemia. Neurological findings included cranial-nerve palsies, seizures, ataxia, depressed consciousness, increased intracranial pressure, and signs of herniation. Symptoms developed within 3-30 hours of the first radiation treatment of 50-200 rad. Each patient had also received one or more injections of intrathecal chemotherapy before encephalopathy developed. The aetiology of this syndrome is uncertain but may involve transient cerebral oedema and/or an altered blood-brain barrier produced by the combination of intrathecal chemotherapy and cranial irradiation.

Acute Disease↗
PubMed1978

Abnormal CT scans of the brain in asymptomatic children with acute lymphocytic leukemia after prophylactic treatment of the central nervous system with radiation and intrathecal chemotherapy.

Thirty-two asymptomatic patients with acute lymphocytic leukemia, who had received prophylactic cranial radiation (2400 rads) and either intrathecal methotrexate or cytosine arabinoside were studied by computed tomography of the brain 19 to 67 months after initiation of prophylaxis. Seventeen of 32 (53 per cent) had one or more abnormal findings. Dilatation of the ventricles (eight patients) and widening of the subarachnoid spaces (nine patients) were equally distributed among patients in both intrathecal-chemotherapy groups. Areas of decreased attenuation coefficient (hypodense, abnormally radiolucent regions) (four patients) and intracerebral calcification (one patient)--lesions previously described in methotrexate leukoencephalopathy--were found only in those who had received intrathecal methotrexate. Mild central-nervous-system dysfunction was detected in seven patients but did not correlate with the presence of tomographic abnormalities. Nevertheless, these tomographic findings may represent preclinical lesions. The unexpectedly high prevalence of such abnormalities contrasts with the essentially normal tomographic findings in a control group with acute lymphocytic leukemia who received no central-nervous-system prophylaxis. These results suggest that alternative approaches to such prophylaxis be considered.

Adolescent↗
PubMed1978

Immunodeficiency in familial erythrophagocytic lymphohistiocytosis.

4 children with familial erythrophagocytic lymphohistiocytosis and hyperlipidaemia were found to have a previously unrecognised immunological deficiency syndrome which included defects in both humoral and cellular immunity and a plasma inhibitor of in-vitro lymphocyte blastogenesis. The inhibitory activity was proportional to the increase in the triglyceride concentration in the patients' plasma. Immunological deficiency, to which hyperlipidaemia may be a contributing factor, appears to be a significant feature of familial erythrophagocytic lymphohistiocytosis.

Antibody-Dependent Cell Cytotoxicity↗
PubMed1978

Prolonged complete remission following high dose chemotherapy of Burkitt's lymphoma in relapse.

Fourteen patients with American Burkitt's lymphoma resistant to conventional chemotherapy were treated with high-dose combination chemotherapy and intensive supportive care. Four patients died shortly after chemotherapy, 3 of an acute carditis. All ten remaining patients demonstrated tumor regression and 3 remain in prolonged complete unmaintained remission 29+, 19+, and 9+ months after treatment. These findings demonstrate that high-dose chemotherapy will benefit some patients with Burkitt's lymphoma unresponsive to conventional chemotherapy, but the medullary and extramedullary toxicity of this treatment strategy remains a formidable obstacle.

Adolescent↗
PubMed1978

The Ommaya reservoir: newly recognized complications and recommendations for insertion and use.

Two of 27 patients treated with intraventricular chemotherapy via an Ommaya reservoir developed unusual life-threatening complications attributable to the reservoir. In one patient treated for meningeal Burkitt's lymphoma, the cause of death was a large mass of tumor cells growing around the cannula. Also the tip of the cannula was found in the contralateral cerebral peduncle. In the other patient, the tip of the cannula apparently perforated the ventricular wall postoperatively and migrated into the contralateral thalamus. In both cases evidence for methotrexate-associated leukoencephalopathy was present at autopsy. Based on the experience with these two patients, we offer specific recommendations for reservoir insertion and use.

Adult↗
PubMed1978

Correlation of adenosine deaminase activity with cell surface markers in acute lymphoblastic leukemia.

Adenosine deaminase (ADA) activity has been measured in the lymphoblasts of 23 untreated patients with acute lymphoblastic leukemia and related to the presence or absence of immunologic cell surface markers. The mean ADA activity in the acute lymphoblastic leukemia population as a whole was increased fourfold over that in normal lymphocytes. 9 of the 23 patients were classified as thymus-derived (T-) cell acute lymphoblastic leukemia on the basis of erythrocyte rosette positivity; the remaining 14 patients had null-cell leukemia. The mean ADA activity (ADA U/mg protein) of T-cell lymphoblasts (102 U) was 3 times higher than the mean of null lymphoblasts (30 U). This difference is statistically significant (P less than 0.02). Measurement of ADA activity offers a biochemical method of distinguishing between immunological subtypes of lymphoblasts which may be of prognostic and therapeutic value.

Adenosine Deaminase↗