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Biomedical subjects

R Simon

Publications and source records attributed to R Simon.

At least 451 records · Page 25Linked to original sources
PubMed1979

Distribution, frequency, and quantitative analysis of estrogen, progesterone, androgen, and glucocorticoid receptors in human breast cancer.

The distribution and frequency of steroid hormone receptors are described 329 patients with breast cancer. The distribution of each of the steroid hormone receptors is unimodal with a progressive increase in the proportion of patients positive at lower receptor values. Receptor values expressed as fmol/mg cytoplasmic protein are well correlated with values expressed as fmol/mg breast tumor. Estrogen receptor was positive in 53% of the patients; progesterone receptor was positive in 38% of the patients; glucocorticoid receptor was positive in 52% of the patients; and androgen receptor was positive in 31% of the patients. The type of tissue assayed did not affect steroid hormone receptor positivity. For primary tumors, there was no correlation between steroid hormone receptor positivity and location of the tumor in the breast, size of the tumor, or extent of the disease. Each of the steroid hormone receptors was positively associated with each of the other steroid hormone receptors. Estrogen receptor was correlated with menopausal status and axillary nodal status, but these correlations did not exist for the other steroid hormone receptors. Estrogen receptor was not correlated with age after adjustment for menopausal status. The other steroid hormone receptors were not correlated with age.

Adult↗
PubMed1979

Association between steroid hormone receptor status and disease-free interval in breast cancer.

The possibility of an association between steroid hormone receptor status and disease-free interval was examined in 292 patients with breast cancer. Estrogen receptor positivity was associated with a prolonged disease-free interval. This association was independent of age, menopausal status, tumor size, or nodal status. There was no association between the presence or absence of progesterone, androgen, or glucocorticoid receptor and disease-free interval.

Adult↗
PubMed1979

Restricted randomization designs in clinical trials.

Though therapeutic clinical trials are often categorized as using either "randomization" or "historical controls" as a basis for treatment evaluation, pure random assignment of treatments is rarely employed. Instead various restricted randomization designs are used. The restrictions include the balancing of treatment assignments over time and the stratification of the assignment with regard to covariates that may affect response. Restricted randomization designs for clinical trials differ from those of other experimental areas because patients arrive sequentially and a balanced design cannot be ensured. The major restricted randomization designs and arguments concerning the proper role of stratification are reviewed here. The effect of randomization restrictions on the validity of significance tests is discussed.

Clinical Trials as Topic↗
PubMed1978

The relation between estrogen receptors and response rate to cytotoxic chemotherapy in metastatic breast cancer.

In a retrospective study we determined the relation between estrogen receptors and the response rate to cytotoxic chemotherapy in 70 patients with metastatic breast cancer. Thirty-four of 45 patients with low or absent estrogen-receptor values (less than 10 fmol per milligram of cytoplasmic protein) had objective responses to chemotherapy, whereas only three of 25 patients with higher values (greater than 10 fmol per milligram of cytoplasmic protein) responded (P less than 0.0001). There were no statistically significant differences between the two groups in age, menopausal status, disease-free interval, Karnofsky index or prior therapy. Differences in sites of involvement or type of chemotherapy did not account for the increased response rate in receptor-negative patients. We conclude that estrogen-receptor values are an important predictor of response to cytotoxic chemotherapy in metastatic breast cancer.

Adult↗
PubMed1978

A randomized comparative trial of adriamycin versus methotrexate in combination drug therapy.

A prospective randomized trial was conducted comparing the clinical response of 78 previously untreated patients with advanced metastatic breast cancer to a combination of cyclophosphamide, methotrexate, and 5-fluorouracil (CMF) or to a combination of cyclophosphamide, adriamycin, and 5-fluorouracil (CAF). Sixty-two percent of the patients receiving CMF responded to treatment compared to an 82% response rate for the patients receiving CAF. Although within acceptable limits, hematologic and GI toxicity was greater with CAF. There was no significant difference in the duration of response to the two regimens. Therefore, the therapeutic difference between the two therapies is a higher initial response rate to the adriamycin containing regimen.

Breast Neoplasms↗
PubMed1978

A high-humidity circle system for infants and children.

A scaled-down version of a modified adult circle system capable of increasing normal humidity output 300% was constructed for pediatric use. The moisture content of the gases leaving the system was tested and found to be superior to that of any pediatric circle system commercially available that does not incorporate an electrically heated water vaporizer.

Anesthesia↗
PubMed1978

Clinical prognostic factors in osteosarcoma.

Clinical characteristics thought to be of prognostic importance for patients with osteosarcoma are reviewed. The importance of considering prognostic factors in the evaluation of new therapies when no concurrent control group is available is emphasized.

Adult↗
PubMed1978

The intraocular lens: preliminary results in southwestern Indians.

We implanted Copeland iris plane lenses in 15 Navajo and Pueblo Indians. Visual results were gratifying. Complications have been minimal to date due to adherence to certain technical points and the use of postoperative steroids. The technique using standard intracapsular extraction is relatively simple. It is easier than the extracapsular technique or tying sutures inside the anterior chamber. The implant is certainly valuable in our population who uniformly fail with contact lenses. The mediocre acceptance and tolerance of aphakic spectacles, which is more common in Indian patients, is likewise overcome by the implant. Patients who have advanced unilateral cataract can now be operated upon and visually rehabilitated. More observation time is needed to evaluate the potential problems of cystoid macular edema and poor pupil dilatation complicating retinal detachment surgery.

Aged↗
PubMed1978

Sample size requirements for evaluating a conservative therapy.

Determination of an adequate sample size for a clinical trial has traditionally involved the specification of type I (false positive) and type II (false negative) error rates, and a difference that one wishes to detect. Because newer therapy has generally been more invasive or more toxic, it is conventional for the type I error to be 0.05 in order that new therapy not be accepted as superior unless its advantages are definitively established. Recently, many new trials have been directed toward showing that a more conservative treatment is equivalent in efficacy to a standard intensive therapy. In this paper, we provide formulas which prescribe the sample size necessary to meet certain criteria specified by the investigator for this alternative type of clinical trial. In addition, the percent increase in total sample size is described when more patients are allocated to one treatment than the other.

Biometry↗
PubMed1978

Association between steroid hormone receptors and response rate to cytotoxic chemotherapy in metastatic breast cancer.

The influence of steroid hormone receptors on response rate to cytotoxic chemotherapy in 70 patients with metastatic breast cancer was determined in a retrospective study. We have previously reported that 34 of 45 patients with tumors containing low or absent estrogen-receptor values had objective responses to chemotherapy while three of 25 patients with positive estrogen-receptor tumors responded. In the present study, 22 of 34 patients with low or absent progesterone-receptor tumors had an objective response to cytotoxic chemotherapy, while none of eight patients with a positive progesterone-receptor tumor responded (P less than 0.05). Patients having tumors with a negative estrogen receptor and a negative progesterone receptor had a response rate of 88% (21 of 24 patients). There were three patients whose tumors were estrogen-receptor negative but progesterone-receptor positive; none had a response to chemotherapy. Chemotherapy response was not associated with the presence or absence of either androgen or glucocorticoid receptor. We conclude that progesterone-receptor values in addition to estrogen-receptor status may prove to be important correlates of response to cytotoxic chemotherapy in metastatic breast cancer. Androgen- and glucocorticoid-receptor analyses are not helpful in predicting response to chemotherapy.

Adult↗
PubMed1978

[Pressure-flow relations of artificial valves in the mitral position (author's transl)].

Hemodynamic studies in pts. with Starr-Edwards disc valves (SE), Lillehei-Kaster valves (LK) and normal mitral valves (N) were performed to compare pressure gradient (deltaP) and volume flow (V). Therefore, synchronous pressure-volume measurements at a diastolic filling time of 500 ms and 250 ms were done. The results show that deltaP in SE valves is much higher than in LK-valves, but this exists only at the beginning of volume acceleration whereas at the end of diastolic time deltaP is similar to that of LK valves. In normal mitral valves initial pressure gradients are also present. Maximum volume flow in SE valves occurs at the end of diastole, but in normal mitral valves and in LK valves, however, it is reached already at the beginning. The studies showed a substantial obstacle to volume flow in SE-disc valves while LK-valves are similar to normal mitral valves.

Blood Pressure↗
PubMed1977

[Study of systolic ventricular volume changes by means of current measurement of contrast media].

Systolic changes of left ventricular volume were estimated after left ventricular contrast injections in dogs by roentgen-videodensitometry with adjustable windows. Good correlations were found between densitometric volume changes and the integral of electromagnetic aortic flow, as measured every 20 msec (r greater than or equal to 0.95 in 118 of 124 systoles analyzed). Videodensitometry avoids the time consuming frame-to-frame analysis with the errors inherent in geometric assumptions in ventricular volume measurements.

Animals↗