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Biomedical subjects

D Anbar

Publications and source records attributed to D Anbar.

7 recordsLinked to original sources
PubMed1985

Clinical effects of gonadotropin-releasing hormone analogue in metastatic carcinoma of prostate.

Leuprolide is a new, potent analogue of gonadotropin-releasing hormone which, after an initial transient stimulation, causes a profound suppression of serum gonadotropins and testosterone. One hundred eighteen patients with advanced carcinoma of the prostate have undergone treatment with leuprolide in a multi-institutional trial. Minimal evidence of objective response was seen in patients who had failed prior endocrine therapy with orchiectomy or estrogens. In patients without previous hormonal treatment, leuprolide induced an objective disease response (72%) comparable to alternative primary endocrine therapy. Considering the lack of significant side effects seen with long-term GnRH agonists, compounds such as leuprolide may prove to be the preferred initial endocrine therapy for selected patients with metastatic carcinoma of the prostate.

Adenocarcinoma↗
PubMed1983

The relative efficiency of Zelen's prerandomization design for clinical trials.

The prerandomization design due to Zelen (1979, New England Journal of Medicine 300, 1242-1245), for comparing an experimental treatment with a standard, is studied and compared with the traditional randomization scheme. Two models for estimating the treatment effect are considered: one applies when the response variables are continuous and normal, and the other when they are binary. Relative efficiencies are computed and lower bounds, expressed in terms of the probabilities of consent under the two schemes, are given.

Clinical Trials as Topic↗
PubMed1983

On estimating the difference between two probabilities, with special reference to clinical trials.

The problem of estimating the difference between the probabilities of 'success' for two binomial experiments is considered. Confidence intervals based on large-sample theory are constructed and some of their properties are compared with those of a simple technique based on exact distributions. It is shown that the former method is superior to the latter, both theoretically and practically.

Biometry↗
PubMed1982

Visual masking: a unified approach.

The suppression effect observed in masking is assumed to be due to neural inhibition between two stimuli that interact spatially or within a narrow span of time in the fashion demonstrated in simultaneous brightness-contrast experiments. Three principles are brought together in a comprehensive mathematical model of visual masking. The three principles are: lateral inhibition, the integrated visual response function (VRF), and stimulus decay after its offset over a limited period of time (up to about 100 ms). Block's law is extended to apply to the integration of the VRF, including decay. The three principles combined are sufficient to explain well-known masking phenomena such as metacontrast, and forward and backward masking. The mathematical model presented demonstrates clearly the common underlying basis of all masking. The validity of the lesser documented decay after stimulus offset, a necessary assumption to explain masking effects with stimuli that are delayed relative to each other, is demonstrated with experimental evidence.

Humans↗