Biomedical subjects

M E Horowitz

Publications and source records attributed to M E Horowitz.

At least 73 records · Page 4Linked to original sources

PubMed1988

Presentation of Pneumocystis carinii pneumonia as unilateral hyperlucent lung.

Pneumocystis carinii pneumonia (PCP) presented as unilateral hyperlucent lung in a 27-month-old patient with a brain tumor who was receiving chemotherapy. Although unilateral pneumonia is an uncommon presentation of PCP in non-AIDS patients, PCP must be suspected in any pediatric cancer patient not receiving trimethoprim-sulfamethoxazole prophylaxis and receiving intensive chemotherapy.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1987

Potentiation of ifosfamide neurotoxicity, hematotoxicity, and tubular nephrotoxicity by prior cis-diamminedichloroplatinum(II) therapy.

We investigated the relationship between prior therapy and three distinct forms of toxicity that developed during ifosfamide administration (1.6 g/m2/day for 5 days) in 36 children with malignant solid tumors. Of ten therapies that were studied by multiple regression techniques, only the number of doses of cisplatin that patients had received was significantly related to neurotoxicity, hematotoxicity, and tubular nephrotoxicity, with the more severe cases occurring after three or more doses (P less than 0.05). Increased urinary concentrations of the renal tubular enzyme N-acetyl-beta-D-glucosaminidase, measured before each course of ifosfamide, were predictive of neurotoxicity (P = 0.02) and hematotoxicity (P = 0.01). We suggest that cisplatin-induced renal tubular damage, leading to the impaired clearance of ifosfamide metabolites, may account for this added toxicity.

Acetylglucosaminidase↗

PubMed1987

Hepatic undifferentiated (embryonal) sarcoma and rhabdomyosarcoma in children. Results of therapy.

From July 1972 through September 1984, 8 of 44 children diagnosed as having primary malignant hepatic tumors, who were treated at St. Jude Children's Research Hospital, had undifferentiated (embryonal) sarcoma (five patients) or rhabdomyosarcoma (three patients). The natural history and response to multimodal therapy of these rare tumors are described. The pathologic material was reviewed and evidence for the differentiating potential of undifferentiated (embryonal) sarcoma is presented. At diagnosis, disease was restricted to the right lobe of the liver in three patients, was bilobar in four patients, and extended from the left lobe into the diaphragm in one patient. Lung metastases were present in two patients at diagnosis. All three patients with rhabdomyosarcoma had intrahepatic lesions without involvement of the biliary tree. Survival ranged from 6 to 73 months from diagnosis (median, 19.5 months); two patients are surviving disease-free for 55+ and 73+ months, and one patient recently underwent resection of a recurrent pulmonary nodule 22 months from initial diagnosis. Three patients died of progressive intrahepatic and extrahepatic abdominal tumors, and two patients, who died of progressive pulmonary tumor, also had bone or brain metastasis but no recurrence of intra-abdominal tumor. Six patients had objective evidence of response to chemotherapy. The authors suggest an aggressive multimodal approach to the treatment of these rare tumors in children.

Adolescent↗

PubMed1987

Development and characterization of human ependymoma xenograft HxBr5.

We describe the successful heterotransplantation of a human ependymoma in CBA/CaJ mice immune deprived by infant thymectomy and whole-body irradiation. The xenograft, HxBr5, was established from a fourth ventricular ependymoma, locally recurrent in an 11-yr-old girl who had been treated with radiation therapy to the posterior fossa. HxBr5 retains histological and ultrastructural fidelity to the tumor from which it was derived as does the DNA content, as confirmed by flow cytometric analysis. The karyotype of the xenograft, which is pseudodiploid and exhibits trisomy 1q and deletion of 1p, is the first human ependymoma banded karyotype to be reported. Growth rates of the xenograft tumors are similar to the primary tumor as clinically observed with a doubling time of approximately 42 days. Cell kinetic parameters indicate that this slow-growing tumor has a relatively high growth fraction of 70.8% with a high cell loss of approximately 91%. We anticipate that HxBr5 may be useful as one component of a more complex model for studying the biology and differentiation of human ependymoma.

Animals↗

PubMed1987

Challenges in the treatment of childhood fibromatosis.

Between 1968 and 1985, we treated 20 children for fibromatosis (also called desmoid tumor and aggressive fibromatosis). The primary sites included head and neck (seven patients), extremity (seven patients), and trunk (six patients). Lesions ranged from 3 to 18 cm in diameter. The tumors were smaller than 5 cm in 13 patients, and in seven patients they were larger than 5 cm. A total resection was not feasible in any of the patients with lesions larger than 5 cm. Ten of the 11 patients treated with wide local resection, in whom the margins were clearly negative or close, remained free of disease for six to 16 years. Nine patients required additional treatment with radiotherapy (nine patients) and chemotherapy (five patients). Two died of local disease progression. In the remaining seven children, the disease was controlled. We describe our strategies for managing this disease in a pediatric population.

Adolescent↗

PubMed1987

The impact of delayed surgery on radiotherapy dose and local control of rhabdomyosarcoma.

To determine if delayed surgery permits the modification of radiotherapy dose while maintaining local control in children with localized, unresectable rhabdomyosarcoma, a prospective study was launched in 1981 to test this objective. Treatment consisted of 16 weeks of preoperative chemotherapy, with or without delayed surgery, and radiotherapy using 35 to 40 Gy (3500 to 4000 rad) for microscopic and 50 to 55 Gy (5000 to 5500 rad) for gross residual tumor, plus 14 months of chemotherapy. Among 22 patients treated, surgery was feasible in 11 of 14 patients with residual tumor after chemotherapy and was performed in eight (avoiding radical surgery in three), leaving microscopic (seven patients) or gross residual (one patient) tumor. Progressive disease or amputation precluded radiotherapy in two patients. After radiotherapy local control was sustained in 12 of 14 patients with microscopic lesions vs none of six patients with gross tumor. Delayed surgery may permit the use of lower-dose radiotherapy and should be considered in the treatment plan for this subset of patients.

Adolescent↗

PubMed1987

Carboplatin (CBDCA), iproplatin (CHIP), and high dose cisplatin in hypertonic saline evaluated for tubular nephrotoxicity.

We compared the acute tubular nephrotoxicity of three platinum compounds in children and adults with solid tumors by monitoring the urinary excretion of alanine aminopeptidase, N-acetyl-beta-D-glucosaminidase, and total protein. Cisplatin (100 mg/m2) was administered with mannitol, or at a twofold larger total dosage (50 mg/m2 per day for 4 days) in a 3% saline infusion. Carboplatin (300 mg/m2) was administered in combination with 5-fluorouracil, and iproplatin was administered in dosages ranging from 216 to 388 mg/m2. Enzymuria and proteinuria induced by cisplatin at a total dosage of 200 mg/m2 on a divided schedule did not significantly differ from that observed for the single 100 mg/m2 dose. Enzymuria and proteinuria induced by carboplatin and iproplatin were significantly less than that for cisplatin; however, one patient developed chronic tubular damage after three courses of carboplatin, and the acute tubular toxicity of iproplatin in one of 15 patients was exceptional. Our findings support the value of administering cisplatin in hypertonic saline on a divided schedule as a strategy to reduce acute tubular damage. Although carboplatin and iproplatin are less nephrotoxic than cisplatin, occasionally patients experience subclinical acute or chronic tubular damage that may lead to overt nephrotoxicity with continued therapy.

Acetylglucosaminidase↗

PubMed1987

Urinary N-acetyl-beta-D-glucosaminidase and serum creatinine concentrations predict impaired excretion of methotrexate.

We determined the risk of impaired excretion of methotrexate (MTX) in children with osteosarcoma, who also were receiving cisplatin, by analyzing urinary markers of renal tubular damage, as well as serum creatinine measured before each dose of MTX. MTX clearance was impaired in seven of the ten patients studied after cisplatin therapy. Patients with a urinary N-acetyl-beta-D-glucosaminidase (NAG) concentration of greater than 1.5 U/mmol creatinine or a greater than 50% increase in serum creatinine relative to the pretherapy level were approximately 30 times more likely to have MTX half-lives greater than 3.5 hours than were patients with lower values for these markers; MTX clearance was always impaired if both markers were elevated. If neither urinary NAG nor serum creatinine concentrations increased, the risk of impaired MTX excretion was negligible. Our findings demonstrate that urinary NAG and serum creatinine levels, measured before MTX administration, can be used to identify patients who will have difficulty in clearing the drug.

Acetylglucosaminidase↗

PubMed1987

Ifosfamide-induced subclinical tubular nephrotoxicity despite mesna.

We monitored acute tubular damage in 16 patients who received a 5-day course of ifosfamide (1.6 g/m2/day) and mesna (1.2 g/m2/day) therapy. Urinary concentrations of alanine aminopeptidase, N-acetyl-beta-D-glucosaminidase, and total protein increased in every patient, but the extent of tubular toxicity varied widely among patients. Evidence of toxicity was greatest in patients whose tumors involved the kidneys. The time course of enzymuria and proteinuria indicated tubular cell necrosis. We observed this acute toxic effect despite the administration of sufficient mesna to prevent hemorrhagic cystitis. Urinary marker concentrations returned towards pre-dose levels, and there were no increases in serum creatinine concentrations measured 3 weeks after treatment.

Acetylglucosaminidase↗

PubMed1987

Phase II trial of ifosfamide in children with malignant solid tumors.

Ifosfamide was given to 61 patients with malignant solid tumors diagnosed before the age of 21 years. In this phase II study, all patients received 1.6 g/m2/day X 5 iv over 15 minutes followed by mesna at a dose of 400 mg/m2 iv at 15 minutes and 4 and 6 hours after ifosfamide. Responses were observed in five of 15 patients with osteosarcoma, two of ten with neuroblastoma, two of six with Wilms' tumor, two of five with rhabdomyosarcoma, four of eight with other soft tissue sarcomas, one of one with retinoblastoma, one of two with germ cell tumors, one of one with B-cell lymphoma, and one of one with a primitive neuroectodermal tumor. Fifty-nine of 61 patients had received prior alkylating agent therapy which included cyclophosphamide, cisplatin, mechlorethamine, melphalan, or dacarbazine. Fourteen of 19 responses developed in patients whose tumors were resistant to treatment with cyclophosphamide. A patient with malignant Schwannoma who had received no prior chemotherapy developed a complete response which lasted 12 months. A patient with brain metastases of osteosarcoma has had complete response for greater than 2 years. Complete response was also observed in a patient with B-cell lymphoma. Toxicity consisted of mild to moderate nausea and vomiting, transient reversible myelosuppression, occasional elevation of serum BUN or creatinine, and transient neurotoxicity characterized by somnolence, confusion, weakness, tremor, hallucinations, or seizures. We conclude that ifosfamide is an important alkylating agent without apparent complete cross-resistance with cyclophosphamide, and as such should be further investigated for determination of its activity in patients with pediatric neoplasms and considered for incorporation into phase II-III trials for certain tumors.

Adolescent↗

PubMed1986

Enhancement of methotrexate nephrotoxicity after cisplatin therapy.

We measured urinary levels of total protein, N-acetyl-beta-D-glucosaminidase (NAG), alanine aminopeptidase, and adenosine deaminase-binding protein in ten children with osteogenic sarcoma who were receiving combination chemotherapy that included 12 doses of methotrexate (12 g/m2). Analysis of the changes in these sensitive markers of renal tubular damage permitted detection of subclinical methotrexate-induced nephrotoxicity. In the absence of cisplatin, methotrexate therapy was associated with significant but transient increases in each of the four markers. Irreversible nephrotoxicity, indicated by persistent rises in NAG and alanine aminopeptidase as well as increased serum creatinine levels, was associated with doses of methotrexate that followed the administration of cisplatin (400 mg/m2). The biphasic pattern of total protein and NAG excretion observed in all patients suggests more than one mechanism of methotrexate-induced nephrotoxicity. Monitoring renal tubular damage in patients who are receiving methotrexate in combined-drug regimens would provide useful information for scheduling nephrotoxic drugs in clinical trials.

Acetylglucosaminidase↗

PubMed1986

Increased levels of urinary adenosine deaminase binding protein in children treated with cisplatin or methotrexate.

Levels of adenosine deaminase binding protein (ABP), a renal tubular cell antigen, were determined by enzyme immunoassay in urine specimens from seven children with solid tumors who were receiving the recognized nephrotoxins cisplatin or methotrexate. ABP excretion was uniformly increased within the first 3 days after administration of either drug. Elevated ABP levels were usually accompanied by increased excretion of the urinary enzymes N-acetyl-beta-D-glucosaminidase and alanine aminopeptidase. In alkaline urine specimens associated with methotrexate therapy, ABP levels were increased whereas enzyme activities appeared to be unstable. Hence, immunochemical measurement of urinary ABP levels may be adjunctively useful for clinical studies of renal tubular damage.

Acetylglucosaminidase↗

PubMed1986

Cumulative renal tubular damage associated with cisplatin nephrotoxicity.

We assessed the acute and chronic effect of multiple courses of cisplatin therapy on renal tubules by monitoring the urinary excretion of alanine aminopeptidase, N-acetyl-beta-D-glucosaminidase, and total protein. Urine specimens were obtained before and after doses of cisplatin (90 mg/m2) given to 12 patients. Each dose of cisplatin induced transient increases in enzyme excretion, followed by proteinuria 3-5 days later. Transient enzymuria after the last cisplatin dose was significantly greater than that after the first dose. Moreover, persistent increases in urinary N-acetyl-beta-D-glucosaminidase and serum creatinine concentrations over pretherapy levels indicated chronic renal tubular damage. Our findings disclosed striking differences between patients in susceptibility to progressive nephrotoxicity.

Acetylglucosaminidase↗

PubMed1986

Cancer chemotherapy-induced tubular nephrotoxicity evaluated by immunochemical determination of urinary adenosine deaminase binding protein.

The authors evaluated measurements of adenosine deaminase binding protein (ADB), a proximal renal tubular cell antigen, for detection of drug-induced tubular nephrotoxicity. Concentrations of ADB were determined immunochemically in serial urine specimens from 12 children who were receiving chemotherapy for malignant solid tumors. There was no indication of increased ADB excretion after administration of two nonnephrotoxic drugs, etoposide and doxorubicin, but in patients given the recognized nephrotoxins, cisplatin and methotrexate, or an investigational drug, ifosfamide, urinary concentrations of ADB increased greater than fivefold relative to baseline values. Increased ADB concentrations preceded cisplatin- or ifosfamide-induced elevations of serum creatinine. Results of the ADB assay correlated well with those obtained by enzymatic assays for N-acetyl-beta-D-glucosaminidase and alanine aminopeptidase (r = 0.76 and 0.53; n = 142, P less than 0.001) and marginally with total proteinuria (r = 0.21; P less than 0.02). Hence, serial ADB measurements may be useful in screening investigational drugs for acute subclinical nephrotoxicity.

Antineoplastic Agents↗

PubMed1986

Therapy for childhood soft-tissue sarcomas other than rhabdomyosarcoma: a review of 62 cases treated at a single institution.

The rarity and diverse characteristics of the nonrhabdomyosarcomatous soft-tissue sarcomas (NRSTS) in children have hindered study of their clinical presentations and response to therapy. Here we describe the findings of a retrospective analysis of 62 cases of NRSTS seen in a single institution from 1962 through 1983. The most common histopathologic diagnosis was synovial sarcoma, occurring in 18 patients, followed by malignant schwannoma in 12. The median age at diagnosis was 11 years (range, 2 months to 20 years). Anatomic sites of primary tumors were the trunk (28), extremity (24), and head and neck (10). Of the 31 patients whose tumors were completely resected, 26 (84%) survive with no evidence of disease. Postoperative chemotherapy, administered to nearly one half of this group, did not produce any demonstrable gains in survival. Only one of the 26 patients with local or metastatic gross tumor after resection survives. We conclude that an aggressive surgical approach is imperative in patients with NRSTS and that the contribution of other treatment modalities needs to be defined in a collaborative group trial.

Adolescent↗

PubMed1986

Central nervous system toxicity following the treatment of pediatric patients with ifosfamide/mesna.

Ifosfamide/mesna treatment of 50 patients with pediatric malignant solid tumors was associated with the development of neurotoxic signs and symptoms in 11 of these individuals who received 29 courses of treatment. Neurologic toxicity included changes in mental status, cerebellar function, cranial nerve, and cerebellar and motor system function, including seizures. All symptoms, signs, and EEG abnormalities were transient. Some of the affected individuals failed to develop acute neurotoxic signs of symptoms when retreated with ifosfamide. A grading system for scoring these neurologic abnormalities is presented for comparison of acute neurotoxic effects of other agents. Recommendations are made regarding early termination or delay of ifosfamide/mesna treatments in the presence of significant neurotoxicity.

Adolescent↗

PubMed1985

Studies with 4'-deoxyepivincristine (vinepidine), a semisynthetic vinca alkaloid.

The antitumor activity of 4'-deoxyepivincristine (vinepidine, VNP) was examined against a human rhabdomyosarcoma line, HxRh12, grown as a xenograft in immune-deprived mice. The efficacy of VNP was lower than that of vincristine (VCR) but far superior to that of vinblastine (VLB) in this model. After i.p. administration, accumulation of [G-3H]VNP in tumors was biphasic and progressive for at least 72 hr. In contrast, VCR and VLB achieved maximal tumor levels within 4 hr, after which the level of VCR was maintained but VLB levels decreased 3-fold by 72 hr. Analysis of tumor extracts by high performance liquid chromatography showed that at 72 hr after VNP injection 98% of the radiolabel chromatographed with parent compound. In normal tissues, VNP was cleared less rapidly than VCR or VLB, and analyses of tissue extracts suggested that VNP was less rapidly metabolized than VCR or VLB. This may account for why the potency of VNP is greater than that of VCR in mice.

Animals↗

PubMed1983

Increased blood-brain transfer in a rabbit model of acute liver failure.

The blood-to-brain transfer of [14C]alpha-aminoisobutyric acid was investigated by quantitative autoradiography in normal rabbits and rabbits with acute liver failure induced by the selective hepatotoxin galactosamine. The blood-to-brain transfer of alpha-aminoisobutyric acid was similar in control animals and animals 2 and 7 h after galactosamine injections, but was increased five- to tenfold in certain gray-matter areas of the brain in animals 11 and 18 h after galactosamine treatment. No detectable differences in white-matter uptake of [14C]alpha-aminoisobutyric acid were found between the control and treated groups. The increase in alpha-aminoisobutyric acid transfer within the gray-matter areas suggested that a general or nonspecific increase in brain capillary permeability occurred in these areas. No clinical signs of early hepatic encephalopathy were observed in the treated rabbits, except for 1 animal from the 18-h postgalactosamine group. Thus, enhanced blood-brain transfer of alpha-aminoisobutyric acid preceded the development of overt hepatic encephalopathy. The distribution of radioactivity after the intravenous administration of [14C]galactosamine showed that virtually none of the hepatotoxin localized in the brain, suggesting that the drug itself does not have a direct effect upon the blood-brain barrier or the brain. The increased uptake of alpha-aminoisobutyric acid at 11 and 18 h implies that the transfer of other solutes would also be enhanced, that central nervous system homeostasis would be compromised, and that the resulting changes in brain fluid composition could contribute to or cause hepatic encephalopathy.

Aminoisobutyric Acids↗