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M A Friedman

Publications and source records attributed to M A Friedman.

At least 55 records · Page 3Linked to original sources
PubMed1994

Toxic neurofilamentous axonopathies and fast axonal transport. V. Reduced bidirectional vesicle transport in cultured neurons by acrylamide and glycidamide.

Fast axonal transport deficiencies as mechanisms of action of acrylamide in producing axonal degeneration are under evaluation. The current study determines the effects of acrylamide and several analogues on the number of vesicles moving within the neurite processes of cultured rat embryonic neurons. Acrylamide produced severe, concentration-dependent (0.25-1.0 mM) and time-dependent (0-60 min) reduction in the quantity of vesicles translocated in both the anterograde and retrograde directions. Glycidamide, a potential neurotoxic metabolite of acrylamide, produced a time-dependent but not a concentration-dependent (in the 0.25-1.0 mM range) reduction in bidirectional transport. Based on inhibition at 60 min, glycidamide was estimated to be 4 times more potent than acrylamide in altering transport. Propionamide, a C1-C2 saturated nonneurotoxic acrylamide analogue, had no effect on axonal transport. While a tendency for methylene bisacrylamide (MbACR) to reduce vesicle transport was noted, at the concentration used no statistically significant differences from control were observed. The data support the correlation between toxicant-induced fast anterograde and retrograde axonal transport reductions and axonal degeneration produced by acrylamide and its analogues.

Acrylamide↗
PubMed1994

New directions for Medicare payment systems.

This overview discusses articles published in this issue of the Health Care Financing Review, entitled "Medicare Payment Systems: Moving Toward the Future." These articles focus on the ongoing development of Medicare payment methodologies, their adoption by non-Medicare payers, and issues to be addressed in the development of all-payer systems based on these methodologies.

Long-Term Care↗
PubMed1994

Paclitaxel (Taxol) in breast cancer.

Paclitaxel (Taxol) is a diterpine plant compound that was isolated initially from the bark of the western yew tree, Taxus brevifolia, but can now be produced by semisynthesis from a renewable source. Paclitaxel is the first new agent in the past decade to have confirmed single agent activity in breast cancer in excess of 50%. A 28% response rate has been reported in doxorubicin-refractory patients. Ongoing studies include attempts to combine paclitaxel with other drugs used for breast cancer treatment and with radiation.

Breast Neoplasms↗
PubMed1994

1991 national survey of carcinoma of the breast by the Commission on Cancer.

A nationwide survey of patterns of care for carcinoma of the breast was conducted by the Commission on Cancer of the American College of Surgeons. Information regarding patient history, diagnostic tests, treatment, survival and disease status was obtained for 17,295 patients treated during 1983 and 24,356 patients treated during 1990. The results indicate that patients diagnosed in recent years (1990) are being treated at an earlier stage of the disease compared with the 1983 survey and the findings of earlier years, probably because of the use of mammography. Surgical treatment for conservation of the breast is being used more frequently, but modified radical mastectomy remains the most commonly used surgical treatment.

Aged↗
PubMed1994

New directions for breast cancer therapeutic research.

For the past two decades, attempts to improve chemotherapy for patients with breast cancer have emphasized the use of currently available agents. Research by drug discovery programs of the National Cancer Institute has identified a number of clinically promising novel agents. Conceivably, within the next several years there could be a doubling of the chemotherapy armamentarium for breast cancer--more than 30 active cytotoxic agents.

Antineoplastic Agents↗
PubMed1993

Neoadjuvant therapy in cancer treatment.

Neoadjuvant therapy has come to play an increasingly prominent role in the treatment of cancer. Originally defined as systemic therapy given before local treatment, the concept has been extended to include radiation therapy given before surgery. Potential advantages include improved local and distant control, direct evaluation, and organ-sparing treatment. Potential disadvantages include increased toxicity and cost, potential delay in effective treatment, and obscuring of pathologic staging. Neoadjuvant therapy in cancer treatment may be viewed in three categories: tumors in which neoadjuvant treatment has been shown effective, thus becoming standard therapy; tumors in which it has been shown to facilitate organ-sparing, and tumors in which its utility has not been shown. For patients with osteogenic sarcoma, for example, preoperative chemotherapy and limb salvage therapy have become the standard of care. Response to chemotherapy, ascertained by histologic review of the surgical specimen, can be used to tailor postoperative chemotherapy. In patients with advanced laryngeal squamous cell carcinoma, neoadjuvant chemotherapy followed by radiation has permitted laryngeal preservation in a majority of patients without compromising overall survival. Phase II and III studies conducted in women with breast cancer have demonstrated promising results for neoadjuvant chemotherapy given before radiation therapy and/or surgery. Phase III studies to compare neoadjuvant therapy to standard therapy in patients with breast cancer are underway. For neoadjuvant therapy, as with other innovations in cancer treatment, it is crucial that a new strategy must be compared closely to standard therapy in terms of recurrence, survival, and impact on organ sparing, as well as quality of life and treatment costs.

Antineoplastic Agents↗
PubMed1993

Neurotoxicity of glycidamide, an acrylamide metabolite, following intraperitoneal injections in rats.

Acrylamide (2-propenamide) monomer produces central-peripheral distal axonopathy in humans and some animal species. Its neurotoxicity is characterized by abnormal sensation, decreased motor strength, and ataxia. Acrylamide forms adducts with glutathione, proteins, and DNA. Recent studies demonstrated that acrylamide is metabolized to its epoxide, glycidamide (2,3-epoxy-1-propanamide). We studied the neurotoxicity potential of glycidamide in male Sprague-Dawley rats. Animals (groups of 6) were injected ip daily with either aqueous acrylamide or glycidamide at an acrylamide-equivalent dose of 50 mg/kg (0.70 mmol/kg). Both treatments resulted initially in the rats circling, which was followed by the onset of ataxia at 7-9 d and hindlimb paralysis at 12-14 d. Treated animals showed muscle wasting. At termination, acrylamide- and glycidamide-treated rats weighed 105% and 86% of initial weight, respectively, compared to 145% for controls. Animals were anesthetized and perfused with 10% neutral phosphate-buffered formalin 12 or 14 d after beginning of treatment. Both treatment groups exhibited similar neuropathologic changes in the central and peripheral nervous systems. More severe lesions were produced by glycidamide. A marked increase in the number of affected Purkinje cells in the cerebellum, which exhibited changes ranging from pyknosis to cell death, were present. The brainstem exhibited axonal degeneration with chromatolytic necrosis in midbrain medial and lateral reticular nuclei. The spinal cord was characterized by spongy form changes with vacuoles of different sizes in various levels. These results suggest that glycidamide is an active neurotoxic metabolite of acrylamide.

Acrylamide↗
PubMed1993

Inhibition of the scarlet fever exanthem in concurrent varicella and group A streptococcus infection.

An atypical scarlet fever exanthem was noted in a 5-year-old child with varicella complicated by secondary group A beta-hemolytic streptococcus pneumonia and empyema. The rash consisted of symmetrical, concentric, circular exanthem-free zones surrounding individual varicella vesicles. The possible role of virus-induced interferon in locally modifying the effect of streptococcal pyrogenic exotoxin is explored.

Chickenpox↗
PubMed1993

Paclitaxel for platinum-refractory ovarian cancer: results from the first 1,000 patients registered to National Cancer Institute Treatment Referral Center 9103.

PURPOSE: To provide an investigational drug, paclitaxel, now commercially available, to women with refractory ovarian cancer and to evaluate response and toxicity in these patients. PATIENTS AND METHODS: Patients with platinum-refractory ovarian cancer, Eastern Cooperative Oncology Group (ECOG) performance status 0 to 3, at least three prior chemotherapy regimens, adequate hepatic and renal function, and no significant cardiac history were eligible. Patients were treated with paclitaxel 135 mg/m2 administered by 24-hour continuous intravenous infusion every 3 weeks. RESULTS: Leukopenia was the most frequent toxicity, with 78% of patients experiencing grade 3 or 4 toxicity. Other grade 3 and 4 toxicities were less common: fever (33%), infection (12%), thrombocytopenia (8%), vomiting (7%), cardiac (2%), neurologic (2%), and mucositis (1%). Fifteen treatment-related deaths (1.5%) were reported. The objective response rate was 22% (4% complete response [CR], 18% partial response; 95% confidence interval [CI] for overall response, 19% to 25%). The median time to progression from treatment initiation was 7.1 months in responding patients and 4.5 months for all patients. The median survival duration was 8.8 months. CONCLUSION: Paclitaxel has shown activity in women with platinum-refractory ovarian cancer, and it can be administered with an acceptable safety profile. Further research is needed to determine the optimal role of paclitaxel in the primary and salvage treatment of ovarian cancer.

Adult↗
PubMed1993

Clinical development of Taxol.

Taxol is the first of a novel class of anticancer drugs, the taxanes. Taxol's unique effects include its ability to polymerize tubulin into stable microtubules in the absence of cofactors and to induce the formation of stable microtubule bundles. During its development, formidable challenges were overcome: a suitable formulation was developed, an adequate supply was ensured, severe hypersensitivity reactions were diminished in incidence and severity, and clinical efficacy was demonstrated. Phase II evaluation is still underway; to date, clinical efficacy has been demonstrated in ovarian, breast, non-small-cell lung, and head and neck cancer. Response rates were low in early studies in melanoma, prostate, colon, cervix, and renal cancer, but for these tumors, additional evaluation is ongoing with a higher Taxol dose or different schedule. In December 1992, Food and Drug Administration approval was granted for use of Taxol as second-line therapy in ovarian cancer patients. Nevertheless, important questions regarding optimal use of this important new drug remain. These include determination of optimal dose and schedule and development of suitable combination chemotherapy regimens. The clinical development of Taxol and current status of phase I, II, and III clinical trials are reviewed.

Animals↗
PubMed1992

Retinoids in the lateral eye of Limulus: evidence for a retinal photoisomerase.

The lateral eyes of the horseshoe crab Limulus contain about 80 pmoles of retinal, 30 pmoles of retinol, and 4 pmoles of retinyl esters. More all-trans than 11-cis isomer was found in each category of retinoid. No consistent changes were observed in the amounts of retinal, retinol, or retinyl esters as a function of time of day. No 3,4-dehydro- nor hydroxyretinoids were found. Aqueous extracts of the eye support the stereospecific formation of 11-cis retinal from all-trans retinal when irradiated with light. The reaction requires a protein that is apparently recognized by polyclonal antibodies raised against the retinal photoisomerase extracted from honeybee eyes. The isomerase is able to use as substrate either endogenous all-trans retinal in the extract of retinal supplied in vesicles of phospholipid. The spectral efficiency of this isomerization has lambda max at 550 nm, but the spectrum appears too narrow compared with the absorbance spectrum of retinoid-binding proteins, probably because of inadequate correction for nonspecific isomerization at short wavelengths.

Animals↗
PubMed1992

Retinoids in cancer therapy.

PURPOSE: Recent reports of the dramatic antitumor effect of all-trans retinoic acid (RA) in patients with acute promyelocytic leukemia (APL) have generated renewed enthusiasm for clinical studies of retinoids for oncologic therapeutic indications. Here we provide an overview of relevant aspects of retinoid physiology and molecular biology, review preclinical studies indicating antitumor activity for retinoids, and summarize the current status of clinical investigations of retinoid use for the treatment of adult and pediatric tumors. DESIGN: The published literature was reviewed with attention to areas of retinoid research that would shed insight into the oncologic uses of retinoids. RESULTS: Retinoids play critical roles during normal fetal development and induce differentiation (and/or growth inhibition) in a variety of tumor-cell lines. Retinoid effects seem to result from changes in gene expression mediated via specific nuclear receptors (termed retinoic acid receptors, RAR-alpha, -beta, and -gamma), and a specific chromosomal translocation involving the RAR-alpha gene occurs in APL patients. In addition to the very high clinical response rate for RA in patients with APL, significant clinical responses have been observed for patients with cutaneous T-cell malignancies, juvenile chronic myelogenous leukemia, and dermatologic malignancies. Additionally, the combination of 13-cis-retinoic acid (cRA) with interferon alpha (IFN alpha) has produced high objective response rates for patients with squamous cell carcinomas of the head and neck and of the cervix. CONCLUSIONS: The antitumor activity demonstrated for retinoids (especially RA) alone and in combination with other agents supports the need for targeted phase II trials to define the spectrum of responsive tumors and for laboratory studies to further delineate the biologic mechanisms associated with therapeutic responses. High priority should then be given to phase III trials to delineate optimal strategies for improving outcome by combining retinoid-based treatments with conventional chemotherapy and radiotherapy regimens.

Animals↗