PubMed Health⌕ Search

Biomedical subjects

C J Fryer

Publications and source records attributed to C J Fryer.

At least 37 records · Page 2Linked to original sources
PubMed1995

Steroid hormone receptor status defines the MMTV promoter chromatin structure in vivo.

The ability to respond to small signalling molecules such as steroid hormones is important for many physiological processes. Steroid hormones act through a group of high affinity receptors that regulate transcription by binding to hormone response elements (HREs) located within the promoters of target genes, which themselves are organized with nuclear proteins to form chromatin. To dissect the mechanisms(s) of steroid hormone action we have used the steroid inducible mouse mammary tumor virus (MMTV) promoter as a model system. The MMTV promoter is assembled into a phased array of nucleosomes that are specifically positioned in rodent cells. Induction of transcription by glucocorticoids is accompanied by the appearance of a hypersensitive region in the proximal promoter which allows the hormone dependent assembly of a preinitiation complex including transcription factors such as nuclear factor 1 (NF1) and the octamer transcription factor (OTF). Surprisingly, when introduced by transient transfection, the progesterone receptor (PR) is unable to activate this promoter in vivo, a finding that may result from its inability to alter MMTV promoter chromatin. In an attempt to investigate the failure of the PR to activate the promoter, we have stably introduced the MMTV promoter into human T47D breast cancer cells that express high levels of the PR. In contrast to what has been observed previously in rodent cells, the MMTV templates resident in human breast cancer cells adopt a novel and constitutively open chromatin structure. The constitutively open chromatin structure is accompanied by the hormone independent loading of transcription factors including the PR and NF1. In T47D cells that stably express the glucocorticoid receptor, the MMTV promoter responds to glucocorticoids, but not progestins, and displays glucocorticoid induced restriction enzyme hypersensitivity and transcription factor loading. These findings suggest that the organization of the MMTV chromatin structure is dependent upon the cell type and receptor status of the recipient cell into which the MMTV promoter is stably introduced.

Animals↗
PubMed1993

Central neurocytoma: report of 2 cases and literature review.

Two cases of central neurocytoma are presented. This is a rare CNS tumour affecting, predominantly, young individuals. There is enough evidence in the literature now to distinguish this entity clinically, radiologically and histologically. Much less is known about the management of patients with this tumour, because most of the reports are in pathological literature. Using our two cases and reviewing the available literature, we are endeavouring to shed light on the clinical aspects and management of central neurocytoma. In particular, we attempted to evaluate the role of surgical excision and radiation therapy in the management of this tumour.

Adolescent↗
PubMed1992

An evaluation of abdominal staging procedures performed in pediatric patients with advanced Hodgkin's disease: a report from the Childrens Cancer Study Group.

Forty-nine children and adolescents underwent staging laparotomy in the course of a cooperative group (CCG) study of advanced Hodgkin's disease (HD). The purpose of the study was to evaluate the toxicity of a regimen of 12 cycles of doxorubicin, bleomycin, vinblastine, and imidazole carboxamide (ABVD) plus 2,100 cGy regional irradiation in patients with stage III-IV disease. Review of the biopsies and specimens from these 49 laparotomies identified distinct patterns of abdominal involvement and permitted an evaluation of the importance of different aspects of the staging procedure and an assessment of the value of non-invasive techniques in determining the extent of abdominal disease. The major observations from these studies were: (1) computed tomography (CT) and gallium 67 scans (GA) were specific (few false positives), but not sensitive, indicators of abdominal disease; (2) negative findings at laparotomy in 29 patients permitted a contraction of the abdominal radiation fields with no subsequent abdominal recurrence in these patients; (3) in five patients, stage IV status was established only by laparotomy and open hepatic biopsy; (4) all patients with lower abdominal or pelvic involvement also had upper abdominal node or splenic involvement; (5) involvement of splenic hilar nodes was a sensitive predictor of splenic involvement; (6) disease in the inferior paraaortic nodes accurately predicted the presence of more distal disease, ie, in the iliac or pelvic node groups; and (7) in a limited experience, transposition of the ovaries protected ovarian function from the effects of pelvic irradiation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Breast metastases after bone marrow transplantation for rhabdomyosarcoma.

Two adolescent females with metastatic alveolar rhabdomyosarcoma underwent intensive chemoradiotherapy and bone marrow transplantation, one autologous and one allogeneic. Recurrence was detected in the breasts of both patients, the first at autopsy and the other as the only site of treatment failure. Breast masses after bone marrow transplantation should be thoroughly investigated for metastatic disease in patients with rhabdomyosarcoma.

Adolescent↗
PubMed1990

Modification of the 8 drugs in 1 day regimen: feasibility of substitution of other agents.

Six children (ages 2 to 14 years) with recurrent or poor risk primary brain tumors were treated with the '8 drugs in 1 day' chemotherapy regimen. As renal function deteriorated (median after five cycles), carboplatin was substituted in place of cisplatin at a median dose of 300 mg/m2 as a one hour infusion at hour three. Four patients also had their lomustine deleted and replaced by etoposide 100 mg/m2 at hour four. Compared to earlier cycles of chemotherapy, there was a moderate increase in transfusion requirement (especially platelets) but the incidences of fever and neutropenia were unchanged. Glomerular function as measured by nuclear glomerular filtration rate (GFR) remained unchanged or improved at the end of therapy. The severity of nausea and vomiting after substitution was markedly improved. Four of the six patients are still in complete remission 19 to 41 months after diagnosis or recurrence. It is feasible to substitute carboplatin and etoposide into the '8 drugs in 1 day' regimen when extramedullary toxicity is found.

Adolescent↗
PubMed1990

Efficacy and toxicity of 12 courses of ABVD chemotherapy followed by low-dose regional radiation in advanced Hodgkin's disease in children: a report from the Children's Cancer Study Group.

Sixty-four patients aged 2 to 18 years with advanced-stage Hodgkin's disease (HD) were treated on a Children's Cancer Study Group (CCSG) pilot toxicity study (521-P). Therapy consisted of 12 courses of Adriamycin (doxorubicin; Adria Laboratories, Columbus, OH), bleomycin, vinblastine, and dacarbazine (ABVD), followed by low-dose (2,100 cGy in 12 fractions) regional irradiation (RT). All patients were monitored for toxicity with particular attention to the pulmonary system. Six patients (9%) developed grade 3 or 4 pulmonary toxicity. Three had grade 3 toxicity based solely on changes in carbon monoxide diffusing capacity (DLCO) and remained well for more than 3 years after diagnosis. There was one fatality among the three symptomatic cases. In five cases, toxicity occurred prior to RT. One occurred after seven courses of ABVD, one after nine courses, and three after 10 courses. In one of these five cases, ABVD was stopped. The patient was given nitrogen mustard (mechlorethamine), vincristine, prednisone, and procarbazine (MOPP). This patient subsequently developed recurrence of HD and died of overwhelming sepsis. The other four continued on study and completed their chemotherapy. Three patients had no further bleomycin, and one continued bleomycin at 50% of the assigned dose. They all received mantle RT following chemotherapy, one with a boost dose to the mediastinum to 3,800 cGy and one with added RT to both lungs (1,050 cGy). In the sixth case of pulmonary toxicity, symptoms were first noticed 2 weeks after mantle RT to 3,500 cGy. This patient died of progressive respiratory failure. The event-free survival (EFS) and overall survival is 87% at 3 years. These early results indicate that this therapy is effective in advanced HD in children but has a 9% incidence of acute pulmonary toxicity.

Adolescent↗
PubMed1988

The relationship of various aspects of surgical management to outcome in childhood nonmetastatic osteosarcoma: a report from the Childrens Cancer Study Group.

Recently, much attention has been focused on the role of adjuvant chemotherapy in the treatment of osteosarcoma. Surgery, however, remains the primary modality for the ablation of this disease. In this report, we examine the relationship of various aspects of surgical management of osteosarcoma to prognosis for disease-free survival (DFS) in a randomized study of 234 pediatric patients. Attention is restricted to 166 patients with nonmetastatic disease confined to an extremity and who were randomized to receive one of two chemotherapeutic regimens. No advantage with respect to DFS was attributable to the various aspects of surgical management considered: interval from first symptoms to definitive surgery, surgical sequence, and type of surgery. Only two local recurrences were seen. One occurred in an above knee amputation stump and the other occurred in a patient receiving a tibial allograft. One of these patients died of pulmonary metastases within 6 months of recurrence; the other patient is alive without evidence of disease at last contact after resection of the recurrence followed by chemotherapy.

Adolescent↗
PubMed1987

A randomized study comparing high-dose methotrexate with moderate-dose methotrexate as components of adjuvant chemotherapy in childhood nonmetastatic osteosarcoma: a report from the Childrens Cancer Study Group.

Methotrexate (MTX) has demonstrated significant activity against relapsed and metastatic osteosarcoma. However, there is little published data to indicate the appropriate dose for MTX when given as a component of a multidrug regimen for the treatment of osteosarcoma. Therefore, the investigators at the Childrens Cancer Study Group undertook a randomized clinical trial that compared Adriamycin and vincristine given with either high-dose methotrexate or moderate-dose methotrexate as postoperation chemotherapy in the treatment of childhood osteosarcoma. We report here the results for 166 patients with completely resected nonmetastatic disease of an extremity. The two therapies demonstrated equivalent disease-free survival (DFS). Further, no therapy prejudices survival after relapse. Approximately 38% of patients remain disease free 4 years after diagnosis. Two relapses occurred in patients free of disease at least 36 months after initiation of treatment. Some factors found by other investigators to be prognostic of poorer DFS, namely, male sex, primary tumor in the humerus or femur, and larger primary tumors, demonstrated similar though not statistically significant trends. The presence of spontaneous necrosis in the tumor sample from the definitive surgery was associated with poor prognosis for DFS. We postulate that this feature represents rapidly growing tumors with increased potential for metastases.

Adolescent↗
PubMed1987

Allogeneic bone marrow transplantation using partially-matched related donors.

Six patients with advanced leukemia and one with severe combined immunodeficiency syndrome received allogeneic bone marrow transplantation (BMT) from HLA haploidentical donors who were compatible for one or two loci on the non-shared chromosome. Methotrexate was used for prophylaxis against acute graft-versus-host disease (GVHD). All patients engrafted but developed moderate to severe acute GVHD, and three patients died. Two leukemic patients relapsed but two others survived and were free of disease 403 and 936 days post-transplant. BMT using related partially matched donors may result in durable engraftment and long-term survivors. The implications of using such donors in expanding the application of BMT are discussed.

Bone Marrow Transplantation↗
PubMed1986

Advances in pediatric radiotherapy in the last ten years and future proposals.

Advances made can be divided into five main categories. Firstly, the problem of geographic miss which has been reduced by delivering effective radiation doses with greater precision. This has been accomplished with more sophisticated diagnostic and therapeutic equipment, immobilization techniques and computerized treatment planning. Second is the recognition of the interplay of radiation and chemotherapy on normal tissue tolerance and local tumor control. This interaction has necessitated reduction in both dose and volume of irradiation. Third is the use of wide field irradiation as a systemic treatment. Fourthly, the utilization of cooperative group trials to define the role of irradiation. Finally, with the improvement in survival has come the recognition of late effects of irradiation in the growing child and the means of reducing such effects. The current role of radiation therapy in childhood malignancies is summarized, controversies are identified, and future prospects explored.

Brain Neoplasms↗
PubMed1986

Primary Ewing's sarcoma of the base of the skull.

The authors report a case of primary Ewing's sarcoma of the petrous bone. The radiological features, including the computed tomographic scan and angiographic findings, are described in detail.

Cerebral Angiography↗
PubMed1986

Minoxidil for control of acute blood pressure elevation in chronically hypertensive children.

Twenty-three episodes of acute elevation of BP related to renal disease in 13 chronically hypertensive children 2 to 18 years of age were treated with a single oral dose of minoxidil. All except one patient were receiving a diuretic and all but one a beta-blocking agent at the time of minoxidil treatment. The goal of lowering BP to or below the 95th percentile for age within four hours of minoxidil administration was achieved in 14 of 23 treatment episodes. The goal was achieved in nine of 11 (82%) when the dose of minoxidil was greater than or equal to 0.2 mg/kg and in five of 12 (42%) when the dose was less than 0.2 mg/kg (P less than .05). In patients treated with greater than or equal to 0.2 mg/kg of minoxidil, mean systolic and diastolic BP decreased significantly from pretreatment values within one hour. In patients receiving less than 0.2 mg/kg, mean systolic BP was never significantly reduced and mean diastolic BP did not change significantly for two hours. Adverse effects were minimal. The results indicate that minoxidil in a dose of 0.2 mg/kg in combination with a diuretic and beta-blocking agent will lower BP to safe levels in most patients with severe hypertension related to renal disease within four hours with minimal side effects.

Adolescent↗
PubMed1985

Sudden cerebral death in malignant presacral teratoma.

A three-year-old girl with disseminated malignant teratoma was treated by palliative radiotherapy to her pulmonary metastases. She developed seizure followed by absence of cerebral function and death ensued in 36 hours. Computerized scan of brain was negative prior to death. The main finding at autopsy was occlusion of the carotid and cerebral arteries by necrotic tumour. Widespread cerebral tumour embolization may be an unusual terminal event in cancer patients with pulmonary metastases.

Brain Death↗
PubMed1980

Neuroblastoma: influence of age at diagnosis, stage, tumor site, and sex on prognosis.

A study of a consecutive series of 99 children with neuroblastoma seen at two major Toronto hospitals between 1951 and 1971 is reported. The children who were aged 24 months or less at diagnosis showed an overall two-year survival rate of 59 percent. Analysis, including fitting of a log-linear model, showed that increased probability of survival was associated with younger age at onset, nonadrenal site, and lower staging and the each of these factors acted independently. The sex of the child had no prognostic effect. This study thus extends earlier work by demonstrating the independent prognostic influence of site of tumor. The implications for treatment policy are discussed.

Actuarial Analysis↗