Biomedical subjects

F Gentil

Publications and source records attributed to F Gentil.

8 recordsLinked to original sources

PubMed2000

Byte structure variable length coding (BS-VLC): a new specific algorithm applied in the compression of trajectories generated by molecular dynamics

Molecular dynamics is a well-known technique very much used in the study of biomolecular systems. The trajectory files produced by molecular dynamics simulations are extensive, and the classical lossless algorithms give poor efficiencies in their compression. In this work, a new specific algorithm, named byte structure variable length coding (BS-VLC), is introduced. Trajectory files, obtained by molecular dynamics applied to trypsin and a trypsin:pancreatic trypsin inhibitor complex, were compressed using four classical lossless algorithms (Huffman, adaptive Huffman, LZW, and LZ77) as well as the BS-VLC algorithm. The results obtained show that BS-VLC nearly triplicates the compression efficiency of the best classical lossless algorithm, preserving a near lossless behavior. Compression efficiencies close to 50% can be obtained with a high degree of precision, and the maximum efficiency possible (75%), within this algorithm, can be performed with good precision.

Journal Article↗

PubMed1981

Treatment of disseminated malignant melanoma with high-dose oral BCG.

Thirty patients with unresectable disseminated melanoma (Stage IV) were treated with Bacillus Calmette-Guerin (BCG) (Moreau strain--Rio de Janeiro) by mouth, with weekly doses ranging between 200 mg and 28,000 mg. Five patients died in the first two months of treatment. Of the remaining 25 patients, two (8%) showed complete regression, and one (4%) partial regression. Seven patients (28%) had stabilization of the disease for a six-month period, and 15 (60%) had progression of the disease. Complete and partial regressions were seen only in patients with extravisceral (subcutaneous) metastases, and were associated with a longer survival time. Regression of the subcutaneous metastatic nodules was always accompanied by the following local phenomena: increased temperature; local inflammation; softening, pain and pruritus at the nodule site; and a gradual decrease in size. At the site of the tumor mass, a hypochromic halo appeared. This halo remained permanently and was pathognomonic of the metastatic nodule rejection. When the halo was fully established, the inflammatory infiltrate was minimal and the malignant cells disappeared. If the area contained hairs, they underwent complete albinization. Serial biopsies of the nodules undergoing inflammatory changes and decreased consistency exhibited an intense cellular infiltration of lymphocytes, macrophages, and plasma cells around the malignant cells. This sometimes simulated lymphoid follicle formation involving the melanoma cells associated with necrosis in a centripetal way. Some patients with visceral metastases (particularly pulmonary) had an unexpectedly long survival, apparently associated with interruption of the growth rate of the masses. Eleven out of 20 deaths were due to cerebral metastases. When cerebral disease was diagnosed, BCG was discontinued and the administration of corticoids was usually associated with a disappearance of the inflammatory signs at the nodule sites, but with progression of the disease. Toxicity was minimal.

Administration, Oral↗

PubMed1980

Mammary carcinoma--multidisciplinary treatment with bilateral mastectomy and immediate reconstruction.

The classical concepts pertaining to the natural history of mammary carcinoma and its treatment must be reviewed if survival rate is to be improved. By the time diagnosis is established, a fair amount of cases of carcinoma of the breast present distant, clinically undetectable micrometastases, which will not be affected by local therapy (surgery or radiation). Increasing evidence shows that mammary carcinoma nowadays must be looked upon as a diffuse disease affecting both breasts. Postoperative radiation does not improve the 5- and 10-year survival rates and has a negative effect upon the immunological defense of the patient. Immunology plays an important role in the evolution and cure of the patient with carcinoma of the breast. The mutilation produced by radical or ultraradical mastectomy may throw the patient into mental depression which, as a consequence, may decrease the immunological competence of the patient. Multiple drug chemotherapy, started at the time of surgery and continued for several months thereafter, may kill micrometastases. Preventive immunotherapy seems to be beneficial to the patient in attempting control of metastases.

Breast Neoplasms↗

PubMed1978