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Biomedical subjects

R Levey

Publications and source records attributed to R Levey.

At least 19 recordsLinked to original sources
PubMed2000

Hind limb malformations in free-living northern leopard frogs (Rana pipiens) from Maine, Minnesota, and Vermont suggest multiple etiologies.

BACKGROUND: Reports of malformed frogs have increased throughout the North American continent in recent years. Most of the observed malformations have involved the hind limbs. The goal of this study was to accurately characterize the hind limb malformations in wild frogs as an important step toward understanding the possible etiologies. METHODS: During 1997 and 1998, 182 recently metamorphosed northern leopard frogs (Rana pipiens) were collected from Minnesota, Vermont, and Maine. Malformed hind limbs were present in 157 (86%) of these frogs, which underwent necropsy and radiographic evaluation at the National Wildlife Health Center. These malformations are described in detail and classified into four major categories: (1) no limb (amelia); (2) multiple limbs or limb elements (polymelia, polydactyly, polyphalangy); (3) reduced limb segments or elements (phocomelia, ectromelia, ectrodactyly, and brachydactyly; and (4) distally complete but malformed limb (bone rotations, bridging, skin webbing, and micromelia). RESULTS: Amelia and reduced segments and/or elements were the most common finding. Frogs with bilateral hind limb malformations were not common, and in only eight of these 22 frogs were the malformations symmetrical. Malformations of a given type tended to occur in frogs collected from the same site, but the types of malformations varied widely among all three states, and between study sites within Minnesota. CONCLUSIONS: Clustering of malformation type suggests that developmental events may produce a variety of phenotypes depending on the timing, sequence, and severity of the environmental insult. Hind limb malformations in free-living frogs transcend current mechanistic explanations of tetrapod limb development.

Animals↗
PubMed2000

Strategies for assessing the implications of malformed frogs for environmental health.

The recent increase in the incidence of deformities among natural frog populations has raised concern about the state of the environment and the possible impact of unidentified causative agents on the health of wildlife and human populations. An open workshop on Strategies for Assessing the Implications of Malformed Frogs for Environmental Health was convened on 4-5 December 1997 at the National Institute of Environmental Health Sciences in Research Triangle Park, North Carolina. The purpose of the workshop was to share information among a multidisciplinary group with scientific interest and responsibility for human and environmental health at the federal and state level. Discussions highlighted possible causes and recent findings directly related to frog deformities and provided insight into problems and strategies applicable to continuing investigation in several areas. Possible causes of the deformities were evaluated in terms of diagnostics performed on field amphibians, biologic mechanisms that can lead to the types of malformations observed, and parallel laboratory and field studies. Hydrogeochemistry must be more integrated into environmental toxicology because of the pivotal role of the aquatic environment and the importance of fates and transport relative to any potential exposure. There is no indication of whether there may be a human health factor associated with the deformities. However, the possibility that causal agents may be waterborne indicates a need to identify the relevant factors and establish the relationship between environmental and human health in terms of hazard assessment.

Animals↗
PubMed1989

Regional brain glucose metabolism in neuroacanthocytosis.

Two brothers with neuroacanthocytosis had [18F]-2-fluoro-2-deoxyglucose PET scans showing marked glucose hypometabolism of the caudate and putamen. MRIs showed no evidence of atrophy or modification of signal intensity in these structures. Decreased glucose utilization of the striatum can underlie hyperkinetic movement disorders of various etiologies.

Acanthocytes↗
PubMed1986

Severe primary hyperparathyroidism in a neonate with two hypercalcemic parents: management with parathyroidectomy and heterotopic autotransplantation.

A neonate with severe primary hyperparathyroidism was successfully managed by parathyroidectomy and heterotopic autotransplantation (one third of one gland of the infant was implanted in the forearm). In vitro studies of parathyroid tissue from the infant revealed a severe defect in parathyroid suppressibility. Postoperatively, the infant had modest hypercalcemia, normal serum immunoreactive parathyroid hormone levels, hypermagnesemia, and relative hypocalciuria. The parents were related and both had asymptomatic hypercalcemia with mean serum immunoreactive parathyroid hormone levels that were within the normal range. Similar to the findings in the infant postoperatively, relative hypocalciuria in the presence of hypercalcemia was found in the mother; in contrast, the father had hypercalciuria. The presumed dominantly transmitted hypercalcemia in this kindred is consistent with familial hypocalciuric hypercalcemia with a confounding factor of ethanol possibly accounting for the hypercalciuria in the father.

Acute Disease↗
PubMed1985

Stage IV-N: a favorable subset of children with metastatic neuroblastoma.

Among children over 1 year of age with Evans Stage IV neuroblastoma, there appears to be a small group with a relatively favorable prognosis. These patients have extensive lymph node metastases (cervical/axillary/thoracic/abdominal/pelvic), but no extranodal metastases. Three of six such patients (50%) are long-term disease-free survivors, compared with none of 40 patients with extranodal metastatic disease (p less than 0.0002). Patients with only lymph node metastases (Stage "IV-N") may have a biologically more favorable tumor that is curable with conventional, intensive multimodality therapy.

Abdominal Neoplasms↗
PubMed1984

Influence of local-regional lymph node metastases on prognosis in neuroblastoma.

Data relative to the prognostic and therapeutic significance of lymph node metastases in regionally confined neuroblastoma (Evans stages II-III) are scant. We have analyzed lymph node status in order to assess the significance of nodal involvement. Disease-free survival (minimum follow-up of 2 years) was 84% (21/25) among node-positive patients compared with 95% (18/19) for node-negative patients (P greater than 0.1, two-tailed test). These results contrast with the results from two other centers in which lymph node involvement was a significant adverse prognostic indicator. The use of intensive multimodal therapy including surgical resection of the primary tumor, wide-field radiation therapy to the tumor bed and regional lymph nodes, and chemotherapy may have accounted for the better survival in our node-positive patients.

Combined Modality Therapy↗
PubMed1984

Improved survival in neuroblastoma using multimodality therapy.

One hundred and thirty-six patients with neuroblastoma have been treated at our center from 1970 to 1982, using various combinations of surgery, radiation therapy, and chemotherapy. Choice of therapy was individualized but depended primarily on age and stage. The overall disease-free survival was 60% (minimum follow-up of one year). Patients with stage I disease and younger patients with stage II disease usually received less intensive therapy and fared extremely well (100% survival). Patients with stage III disease and older patients with stage II disease also did extremely well (survival of 85% and 90%, respectively). These patients may have benefited from intensive treatment with all three modalities. Patients under one year of age with stage IV neuroblastoma were treated with surgery and multiagent chemotherapy, and 92% (11/12) survived free of disease. Patients over one year old with stage IV disease represented the only group for which therapy was unsuccessful (10% survival). With combination approaches and with more effective multiagent chemotherapeutic regimens, a real impact on the survival of older stage II patients, stage III patients, and younger stage IV patients appears to have been made. However, older stage IV patients are rarely cured with conventional therapy, and better approaches will be needed for this group.

Adolescent↗
PubMed1984

Prognostic significance of complete surgical resection of pulmonary metastases in patients with osteogenic sarcoma: analysis of 32 patients.

Between 1972 and 1981, 93 patients with extremity osteogenic sarcoma without detectable metastatic disease were treated with surgery and adjuvant chemotherapy. Fifty-two patients remain continuously free of disease. Thirty-two of the 41 patients who relapsed had pulmonary metastases only and 26 underwent thoracotomy to remove all metastatic disease. Complete resection was possible in 11 of 26 patients as defined by the removal of all macroscopic disease, no microscopic disease at resection margins, and no histologic evidence of pleural disruption by tumor. Nine of 11 patients are currently free of disease with a median duration of most recent remission of 42 months (range, 3-72 months). Four of these nine patients have had only one relapse. Only two of 15 patients with incomplete resection of metastatic disease defined by the above criteria are currently free of disease for 57 and 101 months. A significant difference in survival from initial relapse for patients made surgically free of disease using this stringent criteria was observed even when the result is stratified for time to first relapse and number of pulmonary nodules (p = 0.005). A subgroup of patients within the group undergoing thoracotomies who can be expected to have an improved survival has been defined.

Adolescent↗
PubMed1984

Neuroblastoma: the Joint Center for Radiation Therapy/Dana-Farber Cancer Institute/Children's Hospital experience.

The treatment results for 118 patients with neuroblastoma seen at the Joint Center for Radiation Therapy/Dana-Farber Cancer Institute/Children's Hospital from 1970 to 1980 were analyzed. Patients were treated with a combination of surgery, radiation therapy, and chemotherapy depending on stage and age. Disease-free survival was excellent in all patient groups except those over one year of age with stage IV disease, a group for which currently available therapy cures only a small proportion of patients. Patients with stage III disease and older patients with stage II disease did extremely well (survival of 81% and 89%, respectively) and may have benefited from intensive treatment with all three modalities. Survival for infants (under one year) with stage IV neuroblastoma (90%) has clearly improved with intensive combination chemotherapy. With combination approaches and newer, more effective systemic regimens, a real impact on survival appears to have been made in the last decade. Better approaches will be necessary to cure more than an occasional older patient with stage IV disease.

Abdominal Neoplasms↗
PubMed1984

Improved prognosis for infants with stage IV neuroblastoma.

From 1970 to 1982 11 infants with Evans stage IV neuroblastoma who were 11 months of age or less at diagnosis were treated. All but one were treated with intensive multiagent chemotherapy; eight had attempted surgical resection; only one received radiotherapy to the primary tumor. Ten of the 11 infants remain free of disease from 2 1/2 to 13 years (median, four years). Multiagent chemotherapy has clearly improved the outcome for infants with stage IV neuroblastoma.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1983

Tumors of the exocrine pancreas in children and adolescents. A clinical and pathologic study of eight cases.

Eight patients with a tumor of the exocrine pancreas were treated or seen in consultation at the Children's Hospital Medical Center over the last 30 years. There were five girls and three boys ranging in age from 15 months to 18 years (average age: 8 years). Tumors were surgically resectable in six of eight cases--three by modified Whipple procedure and three by local resection. The average diameter of tumor was 13.6 cm (range: 3.8-20 cm). There were three adenocarcinomas of duct cell type, two acinar cell carcinomas, two acinar cell adenomas, and a papillary-cystic tumor of low-grade malignancy. One of the adenocarcinomas arose in a field of orthovoltage radiation and another occurred in a patient with tuberous sclerosis. Five of eight patients died, four with regional or distant metastases documented at autopsy. The patient with the papillary-cystic tumor experienced several local recurrences but was alive 14 years after initial surgery. Data from the literature indicate that acinar cell tumors are proportionately more common in children than in adults and have a somewhat better prognosis than tumors of duct cell type. Further reporting of cases with long-term follow-up is encouraged in order to gain clearer perspective of nonendocrine tumors of the pancreas in childhood.

Adenocarcinoma↗
PubMed1983

Long-term results of the APO protocol (vincristine, doxorubicin [adriamycin], and prednisone) for treatment of mediastinal lymphoblastic lymphoma.

Twenty-one patients with biopsy-proven mediastinal lymphoblastic lymphoma were treated with the APO protocol (vincristine, doxorubicin, and prednisone). Treatment consisted of two years of therapy with a modified doxorubicin-containing acute lymphoblastic leukemia regimen with preventive cranial irradiation and intrathecal methotrexate. The median age in the group was 13 years (range, 2.5-22 years). Complete remission was obtained in 20 of 21 patients. Three patients required mediastinal irradiation for successful remission induction. Six patients have subsequently relapsed: two in the central nervous system, one in the central nervous system and testicle, one in the testicle, one in the pleura, and one in the abdomen. The median follow-up is six years (range, 16 months to 9.5 years) and a Kaplan-Meier estimate of disease-free survival at three years is 58% +/- 23% (2 SE).

Adolescent↗
PubMed1981

Histiocytosis-X.

Twelve of 17 patients with histiocytosis-X were immunologically abnormal, as shown by the presence of circulating lymphocytes spontaneously cytotoxic to cultured human fibroblasts or of antibody to autologous erythrocytes. The patients also had a notable lack of histamine H2 surface receptors on their T lymphocytes, suggesting a suppressor-cell deficiency. The lymphocyte abnormalities were reversed in vitro after incubation in a crude extract of calf thymus gland, and therefore all 17 patients were treated with daily intramuscular injections of this extract. With this therapy, 10 patients entered complete remission -- a response at least as good as that observed in historical controls treated with chemotherapy. A positive clinical response was associated with an increase in the number of T-cell histamine H2 receptors to normal levels and with correction of the other immunologic abnormalities. The results of this preliminary study justify a larger prospective clinical trial of thymic extract and further investigation of the immunoregulatory mechanisms in histiocytosis-X.

Cell Membrane↗
PubMed1980

Synthesis of human plasminogen by the liver.

Genetic types of plasminogen were determined from a donor and a recipient before and after hepatic homotransplantation. Examination of the plasminogen types demonstrated that the liver is the principal site of synthesis of human plasminogen.

Female↗
PubMed1978

Complete correction of the Wiskott-Aldrich syndrome by allogeneic bone-marrow transplantation.

Two patients with the Wiskott-Aldrich syndrome had complete donor lymphoid and hematopoietic engraftment after successful allogeneic bone-marrow transplantation. One patient had had only a temporary donor T-lymphocyte graft after a previous transplantation, for which he had been prepared with cytarabine and cyclophosphamide; the patient's own T lymphocytes returned six months later. A repeat transplant, for which the patient was prepared with anti-human thymocyte serum, total-body irradiation and procarbazine, resulted in complete donor engraftment. The second patient underwent a successful transplantation after similar preparation, except that procarbazine was omitted. At 11 and five months after transplantation both had normal hematopoiesis and no evidence of graft-versus-host disease. This treatment of the Wiskott-Aldrich syndrome may be a model for the correction of other genetically determined immune and hematologic bone-marrow disorders.

Antilymphocyte Serum↗
PubMed1976

Hyperlipidemia after renal transplantation in children.

A cross-sectional survey of 32 children who received renal allografts was undertaken to evaluate lipid profiles in a pediatric transplant population. Ages ranged from 8 to 18 years, and serum creatinine concentrations varied from 0.5 to 5.6 mg/100 ml (mean, 1.4 mg/100 ml). Fifty percent of patients showed an abnormal lipoprotein electrophoresis, and these were evenly divided between type II and type IV patterns. The data suggest that patients with type II pattern tend to be receiving higher doses of prednisone, and increasing levels of cholesterol and triglyceride are also associated with higher corticosteroid dosages. In contrast to the observations of others in dialysis patients, measurements of glucose metabolism such as fasting blood sugar and fasting insulin levels were not associated with lipid abnormalities in this population. Lipid abnormalities following renal transplantation in children are similar to those described in adults, and may contribute to morbidity in the years following successful renal transplantation.

Adolescent↗