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Biomedical subjects

M E Horowitz

Publications and source records attributed to M E Horowitz.

At least 19 recordsLinked to original sources
PubMed1992

Expression of the cholecystokinin gene in pediatric tumors.

We have examined a wide range of cultured human tumor cell lines and found that a specific subset of tumors expresses the cholecystokinin (CCK) gene. All neuroepitheliomas (eight) and Ewing sarcoma (eight) cell lines that were tested express CCK RNA. In addition, two of six rhabdomyosarcoma cell lines also express the CCK gene, suggesting that rhabdomyosarcomas are probably heterogenous and that a subset may be similar to Ewing sarcoma and neuroepithelioma. Very few of the positive tumors express completely processed immunoreactive CCK. However, we have used a radioimmunoassay that detects the CCK precursor to demonstrate synthesis of CCK precursor-like peptides by all of the Ewing sarcoma and neuroepithelioma lines that were tested and by the rhabdomyosarcoma cell line that expresses CCK mRNA. These data demonstrate a consistent association of CCK gene expression with a specific group of human neoplasms. The data also add credence to the theory that Ewing sarcoma and neuroepithelioma are derived from the same transformed cell type. Finally, our results suggest that CCK gene expression may serve as a marker to distinguish these tumors, which are considered to be small-round-cell tumors of childhood, from other pediatric tumors.

Cholecystokinin↗
PubMed1992

Neuraxis dissemination in pediatric brain tumors. Response to preirradiation chemotherapy.

Of 29 consecutive children treated for malignant primary tumors of the central nervous system (CNS) at this institution, postoperative examination showed radiographic or cytologic evidence of neuraxis dissemination in 10 (34%). Given the historically poor results in disseminated CNS tumors treated with surgery and radiation therapy alone, these ten patients were treated prospectively with an investigational Phase II protocol consisting of preirradiation cisplatin (90 mg/m2 on day 1) and etoposide (150 mg/m2 on days 3 and 4). The diagnoses included medulloblastoma (n = 4), malignant glioma (n = 3), cerebral primitive neuroectodermal tumor (n = 1), pineoblastoma (n = 1), and mixed glioma of the brainstem (n = 1). Postoperative neuraxis scanning with computed tomography, magnetic resonance imaging, or spinal myelography showed measurable intracranial or spinal metastases in all children. The cerebrospinal fluid (CSF) cytologic examination was positive for tumor cells in five. The best responses, based on serial imaging of neuraxis metastases, included two complete responses, four partial responses, and three stable disease states. One patient had progressive disease at the primary site despite stable disease in the spine; progressive neuraxis disease was documented in only one patient during chemotherapy. Clearance of tumor cells from the CSF was documented in three patients. The adverse effects of chemotherapy, consisting of transient myelosuppression and mild ototoxicity, were minimal. Reversible neurologic deterioration occurred in two patients; one patient became acutely quadriplegic after a prolonged convulsive seizure without radiographic evidence of tumor progression.

Adolescent↗
PubMed1992

Cytogenetic studies in subgroups of rhabdomyosarcoma.

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma of childhood and accounts for 10% of all solid tumors in children. There are three different histologic forms of this tumor: embryonal (RMS-E), alveolar (RMS-A), and primitive (RMS-P). Among these, the embryonal form has responded well to chemotherapy. Identification of the correct subtype is important for both the management and treatment of this malignancy. However, the histopathologic classification of RMS is sometimes difficult and distinguishing between the embryonic and primitive forms can present a diagnostic dilemma. Chromosomal abnormalities have been observed in all subtypes. We present the cytogenetic findings in six cases of RMS or related sarcoma. All four cases with RMS-A had both numerical and structural abnormalities in the tumor and involved bone marrow specimens. Three patients had a common marker, t(2;13)(q37;q14), and one patient had a variant marker involving 13q14, t(1;13) (p36;q14), and double minutes (dmin). The single embryonal RMS patient had modal chromosome numbers in the hypertriploid range and extensive structural abnormalities; the t(2;13) was not present, but translocation of 13q to both 1q and 2p was observed, der(1)t(1;13)(q21;q14) and der(2)t(2;13)(p25;q14). The patient with primitive type RMS had a hypodiploid line with several markers, including a complex translocation involving chromosomes 5 and 13 with a breakpoint at 13q14, and t(11;12)(q24;q12), a chromosome marker heretofore found only in Ewing's sarcoma and related tumors. This patient had atypical RMS with mixed neural and myogenic elements. The significance of these chromosomal markers and their importance in the characterization of childhood tumors are discussed, along with a review of the literature.

Adolescent↗
PubMed1992

Pulmonary metastases: MR imaging with surgical correlation--a prospective study.

The sensitivity of magnetic resonance (MR) imaging for detection of pulmonary metastases in 11 patients scheduled for thoracotomy and curative resection of metastases was evaluated with a prospective, controlled study. MR imaging performed at 0.5 T was compared with chest radiography, computed tomography (CT), and thoracotomy in 12 cases. (One patient had two separate occurrences of pulmonary metastases.) All images were interpreted in blinded fashion. When all MR sequences were interpreted together, MR imaging enabled correct identification of all patients with pulmonary nodules (100%). CT enabled detection of at least one nodule in all 12 cases (100%) by design; the sensitivity of chest radiography was only 64%. For individual nodules, MR imaging was at least as sensitive as CT (P2 less than .25 [two-sided value]) and significantly more sensitive than chest radiography (P2 less than .01). Among all MR sequences, short inversion time inversion-recovery sequences had the highest sensitivity for detection of individual nodules (82%).

Adult↗
PubMed1992

Phase I and pharmacokinetic evaluation of all-trans-retinoic acid in pediatric patients with cancer.

PURPOSE: Recent reports of the dramatic antitumor effect of all-trans-retinoic acid (RA) in patients with acute promyelocytic leukemia (APL) have renewed interest in the oncologic indications for retinoids. Furthermore, a variety of pediatric tumors are responsive to RA in vitro, which provides additional rationale for a phase I evaluation of RA in children with cancer that is refractory to standard therapy. PATIENTS AND METHODS: A phase I trial of RA administered orally twice daily for 28-day treatment courses was performed. Cohorts of at least three pediatric cancer patients were entered at successive RA dose levels (from 45 to 80 mg/m2/d) until dose-limiting toxicity (DLT) was consistently observed. RESULTS: The maximum-tolerated dose (MTD) of RA was 60 mg/m2/d. Three of eight patients at the 80-mg/m2/d dose level developed reversible pseudotumor cerebri that necessitated discontinuation of the agent. Both patients with APL achieved complete remission (CR), whereas no patients with solid tumors had objective responses. Pharmacokinetic studies demonstrated a relatively short terminal half-life for RA (45 minutes), with diminution in plasma levels after chronic dosing. CONCLUSIONS: The MTD and recommended phase II dose for RA in children is 60 mg/m2/d given twice daily. Reversible CNS toxicity related to RA-induced pseudotumor cerebri is dose-limiting. Two children with APL achieved a CR to RA, which supports the inclusion of pediatric patients in clinical trials that evaluate the use of RA for patients with APL.

Administration, Oral↗
PubMed1991

Influence of doxorubicin dose intensity on response and outcome for patients with osteogenic sarcoma and Ewing's sarcoma.

The goal of this study was to use dose-intensity analyses of published Ewing's sarcoma and osteogenic sarcoma trials to determine which agents were most closely associated with a favorable response. The percentage of patients with more than 90% tumor necrosis following neoadjuvant chemotherapy was the end point for analysis of osteogenic sarcoma trials, and disease-free survival and percentage of patients with distant-only relapse were the end points for analysis of Ewing's sarcoma trials. The data were analyzed using logistic regression analysis to circumvent the distortion of univariate analysis resulting from the correlation between doxorubicin dose intensity and the dose intensity of other agents. Our analysis suggests that doxorubicin dose intensity is an important determinant of favorable outcome for both Ewing's sarcoma and osteogenic sarcoma and that the dose intensities of other agents do not contribute as significantly to outcome as does doxorubicin dose intensity. Increasing dactinomycin dose intensity was associated with a poorer outcome in treatment of osteogenic sarcoma and Ewing's sarcoma, most likely resulting from regimens with a higher dactinomycin dose intensity having a lower doxorubicin dose intensity. While our analysis of osteogenic sarcoma trials is consistent with significant activity for cisplatin and high-dose methotrexate (and likely ifosfamide), a rank ordering of the efficacy of these agents when given with doxorubicin in multiagent regimens is not possible. Our analysis illustrates the importance of analyzing the contributions of individual agents to combination chemotherapy regimens. In the design of future clinical trials for osteogenic sarcoma and Ewing's sarcoma, careful attention should be given to optimizing doxorubicin dose intensity in regimens to be tested.

Dose-Response Relationship, Drug↗
PubMed1991

Long-term follow-up of Ewing's sarcoma of bone treated with combined modality therapy.

Between 1968 and 1980, 107 consecutive patients with Ewing's sarcoma of bone were entered on three sequential combined modality treatment protocols (S2, S3, S4) at the National Cancer Institute (NCI). Protocol treatment involved 4 cycles of two drug [cyclophosphamide (CTX) and vincristine (VCR)] or three drug [CTX and VCR with either actinomycin-D (ACT-D) or doxorubicin (ADR)] regimens and local irradiation (50 Gy) to the involved bone. Eighty patients presented with localized disease and 27 patients had metastatic disease at presentation, including 11 patients with multiple metastatic sites. With a median potential follow-up of greater than 15 yrs (range 8-20 yrs), 28 pts (27%) remain alive. Disease-free (DFS) and overall survival (OS) decreased most rapidly during the initial 5 yrs of follow-up with 5-yr DFS of 29% and 5-yr OS of 39%. Only two patients with metastases at presentation are long term (greater than 5 yr) survivors. For localized disease patients, the 2, 5, 10, and 15 yr DFS and OS are 52%, 37%, 35%, and 33% DFS and 68%, 51%, 39%, and 34% OS, respectively. Eleven patients relapsed locally as the first site of failure. Using the Cox proportional hazards model, four significant variables for both DFS and OS were recognized, including metastatic disease at presentation, age greater than 25 yrs, high LDH in localized disease patients, and central primary tumor in localized disease patients in decreasing order of significance. We conclude that a majority of these patients with Ewing's sarcoma of bone relapsed within 5 yrs of presentation although late relapse (5-15 yrs) did occur. Local failure occurred in 20% of patients using these combined modality treatments but had no impact on overall survival.

Adolescent↗
PubMed1991

Ewing's sarcoma. Radiotherapy versus surgery for local control.

Significant strides in the treatment of Ewing's sarcoma, the second most common bone tumor of childhood, have resulted in cure for approximately 50% of patients. Successful therapy requires systemic chemotherapy for the eradication of microscopic or overt metastatic disease and surgery or irradiation therapy for control of the primary lesion. The article debates the controversy over the extent to which surgical resection should play a role in the local management of this disease.

Bone Neoplasms↗
PubMed1991

The child with recurrent solid tumor.

A significant percentage of relapse occurs in children with solid tumors despite advances in treatment. This article discusses reasons for failure of primary therapy, evaluation of the relapsed patient, treatment of the relapsed patient, as well as questionable cancer therapies and therapy cessation.

Algorithms↗
PubMed1991

Changing pattern of pulmonary metastases with adjuvant chemotherapy in patients with osteosarcoma: results from the multiinstitutional osteosarcoma study.

The multiinstitutional osteosarcoma study (MIOS), a randomized trial of adjuvant therapy for osteosarcoma with a concurrent control group, registered 113 patients from June 1982 to August 1984. Preliminary analysis of the study indicated a significant event-free survival advantage favoring immediate adjuvant chemotherapy, (P less than .001). For patients treated with surgery alone or with surgery and adjuvant chemotherapy, the lungs were involved in more than 80% of the relapses. Patients relapsing after surgery alone tended to relapse earlier (P less than .01), had more pulmonary nodules (P less than .01), and had more frequent bilateral pulmonary involvement (P less than .01) than those treated with immediate postsurgical adjuvant chemotherapy. However, patients relapsing after treatment with surgery alone experienced a significantly longer interval to further disease progression (P less than .01) and improved survival after relapse (P = .01) when compared with patients who relapsed after treatment with immediate adjuvant chemotherapy. The only factor predictive of survival after relapse was if the patient could be made surgically disease-free after initial relapse (P = .03).

Antineoplastic Agents↗
PubMed1991

Development of chemotherapy treatment for pediatric brain tumors.

Until relatively recently the standard treatment for the child diagnosed with a brain tumor was surgical resection followed by radiation therapy. If initial treatment failed patients were rarely referred for chemotherapy. This, in large part, was owing to the therapeutic nihilism that resulted from the disappointing experience with chemotherapy in the treatment of adults with glioblastoma multiforme. Following encouraging reports of clinical responses to chemotherapy in children with recurrent medulloblastoma, however, the value of adjuvant chemotherapy has become more accepted.

Antineoplastic Agents↗
PubMed1990

Preirradiation cisplatin and etoposide in the treatment of high-risk medulloblastoma and other malignant embryonal tumors of the central nervous system: a phase II study.

Medulloblastoma, pineoblastoma, and cerebral neuroblastoma are malignant embryonal tumors of the CNS that may demonstrate similar histologic features, a propensity for neuraxis dissemination and sensitivity to radiation therapy and, in certain cases, chemotherapy. To evaluate the activity of preirradiation chemotherapy in such tumors, 11 newly diagnosed children with measurable residual disease and characteristics indicative of poor prognosis were treated postoperatively with cisplatin (CDDP) and etoposide (VP-16). Responses graded on the basis of radiographic findings in areas of either macroscopic residual tumor or metastatic disease included two complete responses (CRs), eight partial responses (PRs), and one stable disease (SD). Acute and subacute toxicity consisted of high-frequency hearing loss in four patients, reversible signs and symptoms of increased intracranial pressure in two patients, and transient neutropenia. Seven of eight patients with high-risk medulloblastoma and two of two with pineoblastoma remain free of tumor progression following neuraxis irradiation at 8 to 48 months postdiagnosis (median, 18 months). CDDP and VP-16 is a highly active drug combination when given before irradiation in children with high-risk medulloblastoma and other malignant embryonal tumors of the CNS, producing objective responses in at least one site of measurable disease in 10 of 11 newly diagnosed patients, including all of five with gross neuraxis dissemination.

Adolescent↗
PubMed1990

Pediatric AIDS: a perspective for the oncologist.

By the mid 1990s the number of newly diagnosed children with HIV infections in the US may rival the 6,500 children diagnosed with cancer each year. But recent developments in therapy for the child with AIDS offer some hope. A pediatric trial at the NCI used a continuous infusion of azidothymidine in order to achieve the desired blood and cerebrospinal fluid levels. Objective and subjective evidence of response to therapy was noted in all patients who presented with neurodevelopmental deficit. Increases in appetite and weight gain and reductions in lymphadenopathy and hepatosplenomegaly, and increases in CD4 count similar to those observed in adults were apparent. Promising preliminary results have also been seen in trials of dideoxycytidine, dideoxyinosine, and recombinant CD4.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Modulation by verapamil of vincristine pharmacokinetics and toxicity in mice bearing human tumor xenografts.

The effect of the calcium channel blocker verapamil (VRP) on the accumulation and retention of vincristine (VCR) has been examined in mice bearing xenografts of human rhabdomyosarcomas. The tumors were Rh18, moderately sensitive to VCR, and its subline, Rh18/VCR3, selected in vivo for primary resistance to VCR. Administration of VRP by i.p. bolus at dose levels above 75 mg/kg was limited by acute lethality. At this dose, the maximal concentration in plasma was 24 microM, with rapid elimination such that plasma concentrations reported to modulate resistance in vitro (approximately 5-10 microM) were maintained for less than 60 min. To sustain a 10 microM plasma concentration, mice were infused with VRP at 6.25 mg/kg/hr (150 mg/kg/day) for up to 7 days using osmotic pumps implanted in the peritoneal cavity. Steady-state plasma levels were greater than or equal to 10 microM for at least 96 hr, and this schedule demonstrated minimal toxicity. Administration of VCR 20 hr after the start of VRP infusion produced significant lethality, requiring an 8-fold reduction in the VCR dose. Pharmacokinetic studies showed that VRP markedly increased the uptake and retention of VCR in small intestine, liver and kidney of mice. In small intestine, 8-fold greater levels of VCR were determined 24 hr after VCR administration, and this was associated with in increase in T1/2 for elimination from 350 to 913 min. HPLC analysis of extracts from small intestine showed that greater than 90% of the radiolabel eluted with VCR or 4-desacetyl-VCR. Modulation of VCR retention was also related to the dose of VCR administered. The VRP-sensitive efflux pathway appeared more effective in certain tissues only at higher concentrations of VCR. In contrast, VRP did not alter significantly the uptake and retention of VCR in either the parent or VCR-resistant human xenografts. The data demonstrated that, in the mouse, VRP modulates the uptake and retention of VCR in several tissues, and this may indicate that drug efflux mediated by a VRP-sensitive mechanism (e.g. GP-170, associated with the multiple drug resistance phenotype) has a protective function against xenobiotics in these tissues.

Animals↗
PubMed1989

Phase I study of 4'-deoxydoxorubicin (esorubicin) in children with malignant solid tumors.

4'-Deoxydoxorubicin was given to 15 patients with drug-resistant pediatric malignant solid tumors with the objectives of determining the maximum tolerated dosage and dose-limiting toxicity. Maximum tolerated dosage was 36 mg/m2 given IV once every 3 weeks. Dose limiting toxicity was myelosuppression, which was severe and prolonged. Therapeutic benefits were not observed for these patients.

Adolescent↗