Primary neurogenic tumors of the lateral neck.
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Adolescent↗
Biomedical subjects
R Lawrence
Publications and source records attributed to R Lawrence.
Utilization of ambulance services in a rural community.
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Ambulances↗
Apartheid medicine. Health and human rights in South Africa.
Human rights and health care under apartheid in South Africa were studied. Human rights violations, such as detention without charge or trial, assault and torture in police custody, and restriction orders, have had devastating effects on the health of persons experiencing them. These violations have occurred in the context of a deliberate policy of discriminatory health care favoring the white minority over the black majority. South Africa's medical societies have had mixed responses to the health problems raised by human rights violations and inequities in the health care system. The amelioration of health care for all and prevention of human rights violations depend on ending apartheid and discrimination and greater government attention to these problems.
Delivery of Health Care↗
Empirical findings relating sample volume size to diagnostic accuracy in pulsed Doppler cerebrovascular studies.
Ultrasonic duplex scanning has a sensitivity of 97% in detecting disease of the carotid bulb. However, the specificity is much less, being 37%. The error in distinguishing normal arteries from those with minimal disease appears to be in part related to the size of the sample volume of the pulsed Doppler. This paper addresses the importance of the features of scan head design in relation to distinguishing normal and diseased arteries.
Blood Flow Velocity↗
Sources of variability in carotid duplex examination: a prospective study.
Interobserver and intraobserver variability of ultrasonic, duplex carotid artery examinations was studied in a prospective, randomized, and blinded clinical trial. Forty-eight patients were examined by two technologists, yielding 96 carotid artery examinations. The kappa statistic was calculated to determine the degree of agreement corrected for chance. The kappa value between examinations by different technologists was 0.476. Variability occurred at both steps in the examination procedure: (1) obtaining the velocity waveforms (kappa = 0.536); and (2) using these waveforms to classify the extent of carotid disease (kappa = 0.609 for interobserver variability in reading waveforms). Minimal to moderate disease categories accounted for most of the variability. There was little disagreement in categorizing lesions as greater than or less than 50% diameter reduction. Intraobserver variability in rereading spectral waveforms was minimal (kappa = 0.842 and 0.894). Recognition of disturbed flow patterns in normal carotid bulbs may reduce variability.
Carotid Artery Diseases↗
Glioblastoma multiforme: treatment by large dose fraction irradiation and metronidazole.
In an attempt to overcome the possible radioresistance of glioblastoma multiforme related to the large shoulder on the in vitro survival curves and to sensitize hypoxic tumor cells, a treatment protocol was instituted at Yale University Medical Center and affiliated hospitals, using large dose fraction irradiation therapy in conjunction with the hypoxic cell sensitizer metronidazole. Nineteen patients with biopsy-confirmed, previously untreated, cerebral grade IV glioblastoma multiforme were, following surgery, irradiated once a week at 600 rad per fraction, 3.5 to 4 hours after ingestion of metronidazole, 6 gm/m2. A total of 7 treatments were employed, with all patients maintained on antiseizure medications and corticosteroids. Metronidazole levels were determined prior to each treatment and patients were followed closely clinically and with serial computerized tomography (CT) scans. The treatment was well tolerated, in general, with no untoward side effects related to the high dose fraction irradiation. The majority of the patients experienced varying degrees of gastrointestinal upset lasting up to several hours following metronidazole administration. Three patients died of pulmonary emboli. One patient experienced moderately severe ototoxicity. A median survival of 9.4 months was obtained for all 19 patients, suggestive of a prolongation of survival compared to historical controls treated with conventionally fractionated radiation or with unconventional radiation fractionation schemes and metronidazole or misonidazole.
Adolescent↗
Effects of SW 33377, SW 68210 and SW 71425 thioxanthones on in vitro colony formation of freshly explanted human tumor cells.
Thioxanthones are aromatic hydrocarbons with cytotoxic activity against several tumor models. Potential mechanisms of action may include DNA intercalation, inhibition of nucleic acid biosynthesis, and topoisomerase inhibition, as well as formation of intracellular DNA single strand breaks. Such a broad spectrum of expected antitumor activity makes this class of compounds particularly interesting and worth pursuing in clinical studies. SW 33377 (Win 33377, SR 233377) was so promising in vitro that it was taken into Phase I clinical trials for further evaluation. The compound had undesirable cardiac effects, so new analogs were sought that would have similar antitumor effects without the undesirable side effects. In the present study, two new analogs SW 68210 (WIN 68210), and SW 71425 (WIN 71425) are compared to the antiproliferative action of SW 33377 against a variety of freshly explanted human tumor specimens using an in vitro soft agar cloning system. All compounds were more effective with continuous exposure than 1 hour exposure and a concentration-response effect was evident with all compounds. SW 68210 with continuous exposure showed similar activity to SW 33377 at all concentrations. SW 71425 with continuous exposure was less effective at the lower concentrations but was nearly as effective at 10 microg/ml as the other two compounds and was highly effective at 50 microg/ml. At the 10 microg/ml concentration all compounds were similarly effective against breast, colon, non-small cell lung, and ovarian tumors. The two new analogs, SW 68210 and SW 71425 have activity similar to SW 33377 and are both likely candidates for further development.
Antineoplastic Agents↗
The influence of charting upon liability determinations.
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Child↗
Cytotoxic effects of MGI 114 are independent of tumor p53 or p21 expression.
MGI 114, an analog of illudin S, shows potent activity against a broad range of human tumors in vitro and in vivo, including drug resistant tumors. In this study we examined cytotoxicity of MGI 114 against human tumor cell lines (MCF7, MDA.MB.468, EJ1, J82, SCaBER, KG-1, HL60, and IMR-90) with differing expression of p53 and/or p21 (WAF1) tumor suppressor genes. Only MCF7 and IMR-90 express the wild type p53, WAF1 is present in high levels in MCF7 and SCaBER. WAF1 expression can be induced in KG-1, HL60, and IMR-90. The cells were treated with MGI 114 at 0.1, 1.0 and 10 micrograms/ml in 1 h exposure and with 0.01, 0.1 and 1.0 microgram/ml MGI 114 in a continuous exposure. Cell numbers were measured at days 2, 4, and 7. MGI 114 suppressed growth in all cell lines at day 2 after 1 h exposure at the two highest concentrations and at all concentrations in a continuous exposure. Some cells partly recovered from the inhibition by day 4. Expression of WAF1 had no apparent effect on growth suppression by MGI 114, however, cells with inducible WAF1 showed slower recovery from MGI 114 inhibition in comparison with the cells under non-permissive conditions. Overall, MGI 114 effectively inhibited growth of human cancer cells regardless of their p53 and WAF1 status.
Antineoplastic Agents↗
Combination chemotherapy for advanced ovarian cancer: a prospective randomized trial comparing hexamethylmelamine and cyclophosphamide to doxorubicin and cyclophosphamide.
Forty-three patients with advanced stage III and IV epithelial cancers of the ovary were entered in a prospective randomized study comparing doxorubicin and cyclophosphamide to hexamethylmelamine and cyclophosphamide chemotherapy. No statistical difference in the overall response rates or survival times was demonstrated. However, the combination of doxorubicin and cyclophosphamide was more effective in inducing a response in histologically poorly differentiated cancers than in well-differentiated and moderately differentiated cancers, and the therapeutic implications of this observation are discussed.
Adenocarcinoma↗
Development and comparison of iron dextran products.
Iron dextran complex has existed as a parenteral drug formulation for forty years. Two new formulations of this prodrug became available after an older form was withdrawn from distribution in the United States. Molecular weight, lot-to-lot consistency and thermal stability were examined among these three complex formulations using HP-GPC analysis. Also, particle size measurements using transmission electron microscopy and reduction degradation kinetics were determined. In each mode of analysis, substantial differences were observed among the three preparations with variability and sensitivity to stress (either thermal or acid) decreasing from the oldest form (no longer available) to the next offered complex (Mw of 90 kd +/- 7.5%) to the most recently approved complex (Mw of 265 kd +/- 1.5%). These findings support an iron dextran complex produced by improved techniques and higher manufacturing quality standards with less variability and more reproducibility.
Iron-Dextran Complex↗