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Biomedical subjects

M R Fetell

Publications and source records attributed to M R Fetell.

At least 19 recordsLinked to original sources
PubMed2007

Novel paclitaxel formulations for oral application: a phase I pharmacokinetic study in patients with solid tumours.

PURPOSE: To explore the pharmacokinetics (PKs) of paclitaxel and two major metabolites after three single oral administrations of a novel drinking solution and two capsule formulations in combination with cyclosporin A (CsA) in patients with advanced cancer. Moreover, the tolerability and safety of the formulations was studied. In addition, single nucleotide polymorphisms in the multidrug resistance (MDR1) gene were determined. PATIENTS AND METHODS: Ten patients were enrolled and randomized to receive CsA 10 mg/kg followed by oral paclitaxel 180 mg given as (1) drinking solution (formulation 1), (2) capsule formulation 2B, and (3) capsule formulation 2C on day 1, 8, or 15. RESULTS: The median C (max) of paclitaxel was 0.42 (0.23-0.96), 0.48 (0.08-0.59), and 0.39 (0.11-1.03) microg/ml and the area under the plasma concentration-time curve was 2.83 (1.69-5.12), 2.01 (1.57-3.04), and 2.67 (1.05-3.61) mug h/ml following administration of formulations 1, 2B, and 2C, respectively. The novel formulations were tolerated after single oral dose without causing relevant gastrointestinal or haematological toxicity. CONCLUSIONS: The PK and metabolism of paclitaxel were comparable between the oral formulations co-administered with CsA.

Administration, Oral↗
PubMed1999

Supratentorial ependymomas in adult patients.

OBJECTIVE: Ependymomas arise from different areas in the neuraxis and have variable outcomes that depend on tumor location and patient age at the time of presentation. The predictive value of histology for these tumors is unresolved. We report a series of adult patients with supratentorial ependymomas to characterize the roles of surgery, histology, ploidy, and proliferation index in tumor control. METHODS: Fourteen of the 23 supratentorial ependymomas were in the region of the third ventricle and the remainder were located in the hemispheres. Resections were gross total in 12 patients, subtotal in 8, and biopsy in 3. A single pathologist reviewed all slides and quantitated the deoxyribonucleic acid. The mean follow-up duration was 95 months (+/-75 mo). RESULTS: All of the malignant ependymomas were hemispheric (n = 4). Mortality occurred only in patients with third ventricular tumors; two patients died as a result of surgical complications and three as a result of tumor progression. Kaplan-Meier estimates of 5- and 10-year survival rates were 100% for hemispheric and 72.5% for third ventricular tumors (62.5% including the two perioperative deaths). The median time to recurrence was 53 months, with a 10-year progression-free survival rate of 27%. Univariate analysis revealed that recurrence was associated with malignant histology, including mitoses, cellularity, and aneuploidy. For nonmalignant ependymomas, recurrence was associated with subtotal resection and metastases. S-phase fraction did not correlate with recurrence. Only malignant histology correlated with recurrence on multivariate analysis. CONCLUSION: Although the numbers are too small to draw any definite conclusions, treatment of ependymomas that arise in the supratentorial compartment in adult patients results in excellent outcomes despite frequent recurrences. Association with the third ventricle and metastases seem to have a negative impact on survival, whereas malignant histology, subtotal resection, and metastases may be predictors of recurrence.

Adolescent↗
PubMed1998

Disparity in expression of protein kinase C alpha in human glioma versus glioma-derived primary cell lines: therapeutic implications.

Intracellular signal transduction by the protein kinase C (PKC) family of enzymes plays a critical role in carcinogenesis and cellular growth regulation. Recent studies have suggested that the PKC isoform alpha may be a critical target for antiglioma therapy in humans (G. H. Baltuch et al., Can. J. Neurol. Sci., 22: 264-271, 1995). We studied the expression and subcellular distribution of the PKC alpha isoform in human high- and low-grade gliomas and also in glioma-derived cell lines with immunoblot analyses. Cell lines derived from high-grade gliomas expressed higher levels of PKC alpha than did cell lines derived from low-grade gliomas. In glioblastoma-derived cell lines, PKC alpha was mainly expressed in the soluble (cytosolic) fraction, indicating an inactive state of the enzyme. When analyzed in freshly frozen samples from human gliomas, the expression of PKC alpha was at similar levels in high- and low-grade tumors and was also similar to the levels in normal brain tissue controls. The PKC partial antagonist bryostatin 1, currently undergoing Phase II testing in patients with malignant gliomas, was capable of specifically down-regulating PKC alpha in vitro in glioblastoma-derived cell lines. However, this was not associated with significant growth inhibition. We conclude that the observed overexpression of PKC alpha in glioblastoma-derived cell lines may be an artifact of in vitro growth. Furthermore, we conclude that expression of PKC alpha in glioma-derived cell lines is not essential for cellular growth in vitro because down-regulation of PKC alpha following treatment with bryostatin 1 was not associated with growth inhibition.

Antineoplastic Agents↗
PubMed1997

Thiotepa and etoposide treatment of recurrent malignant gliomas: phase I study.

PURPOSE: To determine: (1) the maximum tolerable dose (MTD) of thiotepa (TT) that can be administered with etoposide without stem cell support; (2) whether this regimen is active against recurrent malignant gliomas. BACKGROUND: Although several chemotherapeutic agents show minor activity against recurrent brain tumors, there is no consensus about the most effective regimen. The alkylating agent TT has excellent central nervous system (CNS) penetration and is synergistic with the topoisomerase II inhibitor etoposide. DESIGN/METHODS: Fifteen patients with recurrent malignant gliomas (14 glioblastomas, 1 anaplastic astrocytoma) received intravenous etoposide 100 mg/m2 on days 1, 2, and 3, and intravenous TT (40, 50, 60, or 70 mg/m2) on day 2. All had received irradiation, and eight BCNU. Chemotherapy was repeated every 3-4 weeks, with stepwise TT dose increments of 10 mg/m2, provided toxicity was less than grade III. RESULTS: The major toxicity was dose-limiting leukopenia. The MTD of TT in cycle 1 was 60 mg/m2. All patients died of progressive disease and none died of chemotherapy-related complications. CONCLUSIONS: The MTD of TT in this regimen for recurrent malignant gliomas is 60 mg/m2. Higher doses of TT would require colony-stimulating factors or stem cell support.

Adolescent↗
PubMed1997

Preirradiation paclitaxel in glioblastoma multiforme: efficacy, pharmacology, and drug interactions. New Approaches to Brain Tumor Therapy Central Nervous System Consortium.

PURPOSE: The purpose of this study was to determine the response rate of paclitaxel administered at maximal tolerated doses (MTD) in patients with newly diagnosed glioblastoma multiform. PATIENTS AND METHODS: All patients in this multicenter study were 45 years or older and had measurable residual tumor on postoperative MRI scans. Up to 3 cycles of paclitaxel were administered as a continuous 96-hour intravenous infusion prior to radiation, provided that the tumor did not enlarge on serial MRIs. The initial 10 patients were treated with the previously recommended phase II dose of 140 mg/m2. Less than anticipated toxicity led to the development of a phase I/II study in 24 patients in which paclitaxel doses were escalated separately in patients receiving (+EIAED) or not receiving (-EIAED), concomitant enzyme-inducing antiepileptic drugs. Paclitaxel plasma steady-state concentrations (Css) were measured during the first cycle of chemotherapy. Response was the primary efficacy endpoint for this study, although survival was also assessed. RESULTS: The MTD was 140 mg/m2 in the -EIAED, and 200 mg/m2 in the +EIAED patient groups. The mean Css for the -EIAED patients treated at 140 mg/m2 was 38 nM, whereas the mean Css for +EIAED patients were 17 nm at 140 mg/m2, 27 nM at 175 mg/m2, 46 nM at 200 mg/m2, and 51 nM at 230 mg/m2. One patient, who had a verified partial response, had his diagnosis changed to an anaplastic oligodendroglioma on subsequent central neuropathologic review. None of the 15 assessable glioblastoma patients treated at or above the MTD doses showed a radiographic response to paclitaxel. The median survival of eligible patients on this protocol was 355 days (95% CI, 255 to 485 days), which is similar to the survival of comparable patients treated with conventional therapy. CONCLUSIONS: These results suggest that (1) paclitaxel given as a 96-hour infusion at the MTD has minimal activity in patients with untreated glioblastoma, (2) the concomitant administration of EIAEDs alters the pharmacology of paclitaxel, resulting in a lower Css, reduced systemic toxicity, and higher dose requirements, (3) this study design, in which a new agent is given prior to radiation therapy (with serial monitoring of MRI), did not adversely affect survival in this patient population.

Aged↗
PubMed1996

Sentinel lesions of primary CNS lymphoma.

Some patients ultimately diagnosed with primary CNS lymphoma (PCNSL) have transient symptomatic contrast enhancing lesions. These "sentinel lesions" of PCNSL recede spontaneously or with corticosteroid treatment and present an important diagnostic dilemma because they show variable, but non-diagnostic histopathological features. Four previously healthy, immunocompetent patients aged 49 to 58 years had contrast enhancing intraparenchymal brain lesions. Before biopsy, three of the four were treated with corticosteroids. Initial biopsies showed demyelination with axonal sparing in two, non-specific inflammation in one, and normal brain in one. Infiltrating lymphocytes predominantly expressed T cell markers with rare B cells. All four patients recovered within two to four weeks after the initial biopsy and imaging studies showed resolution of the lesions. The CSF was normal in three of the four patients tested; oligoclonal bands were absent in both of the two tested. After seven to 11 months, each patient developed new symptomatic lesions in a different region of the brain, biopsy of which showed a B cell PCNSL. The mechanism of spontaneous involution of sentinel lesions is not understood, but may represent host immunity against the tumour. Sentinel lesions of PCNSL should be considered in patients with contrast enhancing focal parenchymal lesions that show non-specific or demyelinative histopathological changes. Close clinical and radiographic follow up is essential if PCNSL is to be diagnosed early in such patients.

Adrenal Cortex Hormones↗
PubMed1993

Nevus of Ota and leptomeningeal melanocytic lesions.

Two patients with congenital nevus of Ota developed intracranial malignant melanocytic tumors. One had a localized tumor that resembled a melanocytoma, but the other had a more highly malignant tumor that diffusely seeded the leptomeninges. There are 10 prior cases in the world literature. These cases are contrasted with the other disorders in which melanotic skin lesions are associated with CNS melanocytic tumors, including neurocutaneous melanosis, cellular blue nevus, and metastatic malignant melanoma. Each disorder tends to involve particular sites of the CNS. The nevus of Ota can be considered a neurocristopathy and, rarely, may give rise to malignant CNS lesions.

Adult↗
PubMed1993

Reversible dementia due to macroprolactinoma. Case report.

Subfrontal tumors are an infrequent cause of dementia. Most of those that do cause dementia are meningiomas, and the symptoms may recede when the tumor is resected. A patient with a huge prolactinoma who came to medical attention because of dementia is described. The tumor shrank dramatically after bromocriptine therapy and the patient's mental status returned to normal.

Behavior↗
PubMed1992

Induction of growth suppression and modification of gene expression in multi-drug-resistant human glioblastoma multiforme cells by recombinant human fibroblast and immune interferon.

The combination of recombinant human fibroblast (IFN-beta) and immune (IFN-gamma) interferon induces enhanced growth suppression and modifies the antigenic phenotype in parental and multi-drug-resistant (MDR) human glioblastoma multiforme (GBM) cells. The present study was conducted to explore the mechanism underlying this cooperative interaction between interferons in inducing growth suppression in MDR-GBM cells. For this analysis we have utilized 2 MDR-GBM cell lines which display a differential sensitivity to growth suppression when exposed to IFN-beta or IFN-gamma. GBM-18-B3 (MDR) cells are more sensitive to growth inhibition by IFN-gamma than by IFN-beta, whereas GBM-18-A3 (MDR) cells are inhibited to a greater degree by IFN-beta than by IFN-gamma. In both cell types, however, growth is suppressed to a greater degree by the combination of interferons than by equivalent concentrations of either type of interferon used alone. Growth suppression induced by the interferons, alone or in combination, was not associated with comparable changes in the steady-state level of MDRI mRNA. In addition, the anti-proliferative effect of interferon was similar in GBM-18 (MDR) cells grown in the presence or absence of colchicine. GBM-18-A3 and GBM-18-B3 cells differed in their de novo and interferon-inducible expression levels of IFN-beta-responsive genes, isg-15 and isg-54. In contrast, both cell types responded in a similar manner with respect to expression of the IFN-gamma-responsive gene, HLA Class II (HLA-DR beta), and HLA Class I, fibronectin and ICAM-I. No further increase in expression of any of the genes was observed which was unique to the combination of interferons.

Cell Division↗
PubMed1992

Neurolymphomatosis: a clinicopathologic syndrome re-emerges.

We describe a patient with sensorimotor peripheral neuropathy and cranial neuropathy due to autopsy-proven neurolymphomatosis defined by infiltration of peripheral nerves by tumor cells and review the findings in 39 previously reported patients. The cause of the neuropathy is not known. The association with immune-deficient states suggests virally mediated pathogenesis, possibly a retrovirus.

Adult↗
PubMed1991

Intravenous recombinant interferon beta in patients with recurrent malignant gliomas: a phase I/II study.

A multicenter phase I/II trial of a human recombinant interferon beta (Betaseron; Triton Biosciences, Alameda, CA) was conducted in patients with recurrent glioblastoma and anaplastic astrocytoma in six centers between 1986 and 1988. Betaseron was given intravenously three times per week, starting at 90 x 10(6) IU per dose and escalating by 90 x 10(6) IU every 2 weeks up to a maximum dose of 540 x 10(6) per treatment. All patients had failed prior radiotherapy, and most had failed one or more courses of chemotherapy. Of the 72 patients entered into the protocol, 65 were considered assessable. Of 65 patients, 41 had glioblastoma, and 24 had anaplastic astrocytoma. Of the 65 assessable patients, 15 (23%) had an objective response (R), and 18 (28%) had stable disease (S), with a combined R and S rate of 51%. The Kaplan-Meier median time to progression was 24 weeks for the responders, 10 weeks for the nonresponders, and 23 weeks for the whole group. These results suggest that Betaseron has definite activity in recurrent gliomas, with an R + S rate of 51%. The maximum-tolerated dose (MTD) is between 180 and 360 x 10(6) IU, with neurotoxicity being the most troublesome toxicity at higher doses. Two patients died of treatment-related complication. Since most responders showed responses at the 180 x 10(6 IU dose range, further studies using a lower dose of Betaseron aimed at decreasing toxicity and allowing chronic maintenance therapy are merited.

Adult↗
PubMed1991

Non-neoplastic pineal cysts.

We identified 53 patients with non-neoplastic cysts of the pineal gland. In contrast to patients with pineal neoplasms, pineal cysts are usually asymptomatic. They infrequently obstruct the aqueduct to cause hydrocephalus or compress the tectum to produce the neuro-ophthalmologic signs of dorsal midbrain dysfunction. Obstructive hydrocephalus was present in only five patients (9.4%); three of them showed clinical signs of Parinaud's syndrome. CT and MRI typically reveal a cystic mass that averages 1.6 cm in anteroposterior (A-P) diameter with calcification at the periphery and faint rim-like contrast enhancement. Sagittal MRI is the most useful diagnostic test because it shows the anatomic relationship of the cyst to the aqueduct. The mass may compress the tectum and distort the proximal aqueduct; occasionally a large cyst may occlude the aqueduct. All patients with obstructive hydrocephalus had cysts greater than 2.0 cm in A-P diameter. Nine patients had suboccipital craniotomy. In all of them, the cysts contained clear fluid and were easily removed. We advocate conservative management with clinical observation of these benign lesions that may be developmental variants of normal pineal gland.

Adolescent↗
PubMed1990

Intratumor administration of beta-interferon in recurrent malignant gliomas. A phase I clinical and laboratory study.

We administered doses of 5 to 180 x 10(6) IU of beta-serine-interferon (IFN-beta ser17) twice weekly to 20 patients with recurrent malignant gliomas in a Phase I study. Interferon was given through an Ommaya reservoir connected by a catheter to the tumor cavity. Side effects of interferon therapy occurred in only one patient and consisted of nausea, vomiting, fever, and chills after each treatment, presumably due to rapid diffusion of interferon into ventricular cerebrospinal fluid (CSF). Problems with the Ommaya reservoir (obstruction in two patients and infection in four patients) led to six patients being terminated from the study, and represent the major difficulty with this form of therapy. Although this was primarily a study of interferon toxicity, of 12 evaluable patients, 3 had stable disease for 148, 192, and 539 days; 9 had progressive disease. In addition, we tested the effect of IFN-beta ser17 on the growth of early passage in vitro cultures of malignant gliomas established from patients. Growth inhibition varied from 0% to more than 50%. In all cultures evaluated, the combination of recombinant gamma-interferon plus IFN-beta ser17 enhanced growth inhibition. Further clinical and laboratory study is necessary to better define the therapeutic efficacy of IFN-beta ser17 and the role of combinations of interferons in the treatment of malignant gliomas.

Adult↗
PubMed1990

B cell small lymphocytic lymphoma and chronic lymphocytic leukemia with peripheral neuropathy: two cases with neuropathological findings and lymphocyte marker analysis.

Two patients with lymphoproliferative disorders developed peripheral neuropathy and neoplastic lymphocytic nerve infiltrates. One of these patients, with B cell small lymphocytic lymphoma, presented with a chronic axonal neuropathy. CD22+, CD5- cells were identified in the epineurium. The other patient with chronic lymphocytic leukemia of 3 years duration developed a mixed axonal and demyelinating neuropathy. CD22+ and CD5+ cells were observed in the endoneurium. While the cause of the neuropathy in these two cases is unknown, intraneural or systemic autoantibody production may have led to the development of disease.

Aged↗
PubMed1986

Neuroendocrine aspects of pineal tumors.

The evaluation and treatment of pineal region tumors has changed dramatically in the past decade. New imaging techniques result in earlier diagnosis. Surgical techniques now permit removal of benign tumors (about one third of cases). Pathologic diagnosis is obtained for the remainder, and postoperative therapy can be planned rationally. Germ cell tumors pose a particularly difficult problem for the pathologist because they often contain mixed germ cell elements. Biologic markers, beta HCG and AFP, aid diagnosis and can be monitored in serum and CSF to assess response to treatment. Only boys develop precocious puberty with pineal tumors. What appears to be puberty is actually pseudoprecocious puberty, due to ectopic production of HCG by their neoplasms (choriocarcinomas or germinomas with syncytiotrophoblastic giant cells). HCG can stimulate tests to produce testosterone, but FSH is necessary (together with LH or HCG) to stimulate ovaries to produce estrogen. Diabetes insipidus with pineal tumors is usually due to spread to the hypothalamus by ventricular seeding, but we report a case of aqueductal stenosis with diabetes insipidus resulting from a massively dilated third ventricle. Rarely, hydrocephalus may trigger true precocious puberty, a syndrome easily differentiated from pseudoprecocious puberty by endocrinologic tests. There are no biologic markers to diagnose pineal parenchymal tumors. Elevation of melatonin in plasma or CSF and increased tumor biosynthetic activity has been reported in isolated cases, but the range of melatonin values in normals is very wide, and melatonin levels do not correlate with specific pathologic tumor types. Both parenchymal and nonparenchymal tumors may increase melatonin nonspecifically by interfering with regulatory mechanisms of the normal pineal gland.

Brain Neoplasms↗