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Biomedical subjects

R Paradis

Publications and source records attributed to R Paradis.

12 recordsLinked to original sources

New active paclitaxel glucuronide derivative with improved water solubility.

Poor solubility of paclitaxel constitutes an important limitation to its administration to cancer patients. In order to increase solubility, while preserving cytotoxicity, a new paclitaxel derivative substituted at the 2' position of the side chain was prepared. The first step consisted in the introduction of a glutaryl group at the 2' position by esterification of the free hydroxyl followed by an amidation with 6-amino hexanol previously attached to a glucuronide group. The new water soluble derivative was cytotoxic in vitro against an ovarian teratocarcinoma cell line.

Antineoplastic Agents, Phytogenic↗

Octogenarian with a congenital bronchoesophageal fistula.

Bronchoesophageal fistula are commonly caused by a lung or esophageal malignancy eroding into the neighboring structure. Benign forms of bronchoesophageal fistula are less common and may have a congenital nature. Congenital bronchoesophageal fistula usually present in adult life with chronic symptoms of lung suppuration. We present a case of congenital bronchoesophageal fistula in an octogenarian and review the literature on this subject. We also suggest an extrapleural approach to the fistula to lessen the possibility of postoperative empyema.

Aged↗

Effect of diabetes on the healing process of synthetic grafts implanted in dogs: a preliminary study.

The deleterious effects of diabetes in peripheral vascular surgery and blood access are generally considered to be associated with the greater failure rate of vascular prostheses. To understand better these phenomena, we investigated the healing characteristics of an ePTFE graft in dogs. The animals were made diabetic after total pancreatectomy and the grafts implanted for scheduled periods of 24 h, 48 h, 1 wk and 1 month, either as thoracic (series I) or abdominal (series II) aortic substitutes. The same implantations were performed in non-diabetic dogs used as controls. The luminal surfaces of grafts implanted in diabetic dogs, either as thoracic or abdominal bypasses, proved to be more invaded by platelets as a result of the blood's increased platelet aggregation properties. The presence of endothelial-like cells spreading over the pannus after 1 month implantation was strikingly different in diabetic versus non-diabetic dogs. In the first group, the cells were fragile and less abundant, whereas in the second they were more adhesive, elongated and orientated in the direction of the blood flow.

Animals↗

A survey of the anemia status of preschool age children and pregnant and lactating women in Jamaica.

An island-wide anemia survey was conducted in Jamaica on pregnant and lactating women and preschool age children. The results indicate that anemia is a serious public health problem in Jamaica. Of pregnant women, 61.6% had Hb levels below 11.0 g/dl. Of lactating women 58.7% had Hb levels below 12.0 g/dl. Of preschool age children 69.1% had Hb levels below 11.0 g/dl. Public health and fortification programs for the control of anemia have been implemented by the government and are currently being reviewed.

Anemia↗

New active paclitaxel amino acids derivatives with improved water solubility.

Paclitaxel shows interesting clinical activity against several tumors. However, its poor solubility is an important limitation: Cremophor EL used for intravenous administration is responsible for hypersensitivity reactions. In order to improve solubility while preserving the activity, we have synthesized new paclitaxel amino acid derivatives substituted with a glutaryl group at the 2' position followed by the reaction of a peptide link between the carboxyl and the amino terminal group of the amino acid. The derivatives were cytotoxic in vitro against many sensitive cell lines. They also increased G2+M phase arrest. Moreover, these derivatives were stable for over a year and showed a better solubility in water than the parent compound. The ester linkage is hydrolysed in slightly acid lysosomal conditions to free paclitaxel which binds to tubulin.

Amino Acids↗