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Biomedical subjects

E Weber

Publications and source records attributed to E Weber.

At least 505 records · Page 28Linked to original sources
PubMed1975

Radiation as primary treatment for local control of breast carcinoma. A progress report.

One hundred patients with localized breast carcinoma have been treated by radiation alone from July 1, 1968, until June 30, 1973, at the Joint Center for Radiation Therapy. Patients were referred for many reasons, including changing opinions as to the indications for mastectomy. External beam therapy to the tumor bearing volume and its regional nodal chains has been frequently supplemented by iridium 192 interstitial implantation. Local control has been excellent, particularly in early stage disease. Regionally advanced mammary carcinoma, despite apparently adequate local therapy, demonstrates a rapidly falling survival curve, suggesting the need for early systemic chemotherapy.

Adenocarcinoma↗
PubMed1975

A phase II study of methyl CCNU in the treatment of solid tumors and lymphomas: a Southwest Oncology Group study.

In March of 1972, the Southwest Oncology Group initiated a Phase II study, No. 7200, utilizing methyl-CCNU in the treatment of patients with solid tumors and lymphomas. Initially, they received 200 mg/m2 orally as a single dose every 6 weeks. The dose was subsequently reduced in poor-risk patients to 150 mg/m2. There were 69 responses noted in 675 evaluable patients (10%). The highest response rates were noted in patients with Hodgkin's disease (13/31, 35%), malignant gliomas of the brain (8/29, 28%), anaplastic carcinomas of the lung (5/20, 25%), and squamous cell carcinomas of the head and neck (5/29, 17%). Squamous cell tumors appeared to be more responsive than adenocarcinomas (15% vs. 5%, respectively). Hematologic toxicity was cumulative, and was influenced by dose and prior treatment. There appeared to be no cross-resistance in patients previously treated with alkylating agents. Methyl-CCNU is an active antineoplastic agent. Further studies are indicated in order to determine relative effectiveness.

Adenocarcinoma↗
PubMed1975

Morphology of gastrointestinal effects of aspirin.

The effect of acetylsalicylic acid (aspirin) on the ultrastructure of gastric and jejunal mucosa was investigated in patients undergoing gastric surgery and in guinea pigs. The drug caused various degrees of damage to the surface mucous cells in both species perceptible as general signs of cytolysis in situ or as desquanmation. In patients pretreated with aspirin, an increase of secondary lysosomes was noted in the gastric parietal cells but not in the animals. In the intestinal epithelial cells of both species there was a marked increase of multivesicular bodies and the occurrence of transitional stages between the two organoids suggest a functional interrelationship. Since no specific alteration of any cellular organoid was detected, the drug-induced injury is assumed to occur on a molecular level in the cytoplasm. It is concluded that the intracellular concentrations of aspirin in gastrointestinal mucosal cells mechanims but that high drug concentrations may lead to irreversible cell damage.

Animals↗
PubMed1975

Effects of seven anthracycline antibiotics on electrocardiogram and mitochondrial function of rat hearts.

Daunomycin, adriamycin and 5 semisynthetic anthracycline antibiotics inhibited oxygen consumption or ATP production of rat heart mitochondria in vitro. The no-effect levels varied depending on the substrate used and ranged from 1 nmole per mg mitochondrial protein. Mitochondrial functions were also studied in hearts of rats treated with repeated i.p. injections of the 7 antibiotics. Decrease in oxygen consumption without change in ATP production was observed with adriamycin and NSC-149584. Daunomycin, NSC-164011, NSC-143496 NSC-143114 affected primarily ATP production. The most potent compounds were daunomycin and adriamycin which damaged mitochondrial function at cummulative doses of approximately 10 mg/kg. ECGs were monitored in groups of equally treated rats. Cardiotoxicity manifested itself by progressive widening of the QRS complex often followed by the development of a S-wave trough. The most toxic compounds also induced intraventricular block, bradycardia and heart failure. The development of the ECG changes showed a good correlation with the impairment of mitochondrial function.

Adenosine Triphosphate↗
PubMed1975

An evaluation of the micronuclei test using triethylenemelamine, trimethylphosphate, hycanthone and niridazole.

To determine the feasibility of the micronuclei procedure for cytogenetic studies, a comparatively weak chromosome breaking agent, trimethylphosphate (TMP) and the potent alkylating agent, triethylenemelamine (TEM) were evaluated. The procedure followed was that of Matter and Schmid with the following modifications: (a) direct flushing of bone marrow with 0.2 ml calf fetal serum. (b) air drying slides for a period of only I h, and (c) the use of pH 6.0 phosphate buffer to dilute both Wright and Giemsa stains. With this technique a dose response curve was generated for both TMP and TEM, using mice as the experimental animal. With TMP, a doubling over background was found when a concentration of 0.5 g/kg per day for five days was administered. To establish a statistically significant doubling dose over the control, a minimum of five animals must be used with 2000 polychromatic cells being analyzed per animal. Of the two antischistosomal agents tested, hycanthone yielded an increase of 20-fold in the number of micronuclei over control at 40 mg/kg administered i.p. for five days, while with niridazole no increase in micronuclei at several concentrations tested both by single and multiple injection was found. The results obtained with these compounds compare favorably with what has been reported for the standard in vivo metaphase analysis.

Alkylating Agents↗
PubMed1975

[Regulation of age-dependent phenomena. Influence of C6-substituted purines on cell aggregation and cell migration in primary cultures of lense epithelial cells].

The existence of an age dependent latent period of cell emigration has been proved in the primary culture of epithelial cells of bovine lenses. The previously described aggregation phenomenon as well as the latent period of the cell emigration increase with the age of the sponsor animals. Extracellular adenine and other C6-substituted purines, isolated from the cells themselves and added to the medium, act the same way on the lens cells in the primary culture as the increasing age of the sponsor animals. Adenine stimulates cell aggregation and inhibits the adhesion of the cells to the substratum, the cell flattening and the cell migration. The adenine action has been proved down to a concentration of 3 X 10(-6) M. During the primary culture, the lens cells gradually los the adenine sensitivity. The adenine action also occurs on single cells, isolated by trypsination, it differs from the reaction of ouabain and can be removed at low concentration by washing procedures. The results favour the suggestion C6-substituted purines to be involved in cell ageing.

Adenine↗
PubMed1975

[Biological availability].

The term "bioavailability" is used to describe the actual percentage of a drug released from the dosage form, which reaches the receptor site in sufficient quantity to induce a biological effect. In this connection there are many problems arising in conjunction with the formulation of the preparation, as well as through the interaction of physiological and pathological factors. Prerequisite to the bioavailability of an orally administered preparation is, firstly, the quick disintegration of the dosage form, and secondly, the release and dissolution of the active substance. No in vitro methods for the examination of these factors have as yet been evolved which would allow a reliable prediction of bioavailability in man. Animal experiments only permit limited prognoses, since numerous influential factors, such as absorption from the intestine, metabolism and metabolic rates, influence of physical and mental stress, etc., strongly dependent upon the species. Bioavailability is determined using pharmacokinetical techniques on the area affected by the dose-response curve, or a combination of these methods.

Administration, Oral↗