Ciliated Cells of the Trachea of the Rabbit, Treated with Cis-Diamminedichloroplatinum (II) Alone, or in Combination with Ionizing Radiation

The ciliated epithelium of the rabbit trachea was irradiated with daily fractions of 2 Gy to an accumulated dose of 20 Gy (TD: 2, 6, 10, 16, or 20 Gy). Fifteen to forty-five minutes before start of the first irradiation ( treatment day 1) , 5 mg cis-DDP was given by intraperitoneal injection to each rabbit. Examination was made 1-10 days after each fractionation schedule, when specimens were ta ken for investigations. Scanning electron microscope investigations showed a gradual development of ciliary damage from blebs on the cilia to swollen tips, broken and bent cilia and finally an epithelial lining with areas free from cilia with a surface covered with microvilli-like structures. SEM also showed cell loss, and remnants of dead cells on the surface together with detritus. By transmission electron microscope ciliary damage, cell death and cell loss of the ciliated cell layer as well as exfoliation of portions of goblet-like cells on the surface could be confirmed. The irradiated ciliated epithelium and the untreated control epithelium in each animal showed no difference in this respect. Thus no enhancement of the effects of radiation could be observed. The development of ultrastructural damage may be due to a cytotoxic effect of the drug on the ciliated epithelium. However, 19 days after the start of cis-DDP injection, a hyperplasia of the basal cell layer was observed, which indicates that the observed cytotoxicity of the drug is reversible and a normalisation occurs during the last days of observation in this study

Effects of Cis-Dichlorodiammineplatinum Alone and in Combination with Ionizing Radiation on the Esophageal Mucosa: A Scanning and Transmission Electron Microscopic Study

Cis-dichlorodiammineplatinum (cis-DDP) has for more than 20 years been part of the therapeutic arsenal of oncology. Most of the knowledge about its biological action is based on clinical investigations and therefore an examination of the influence of cis-DDP at the cellular and sub-cellular level is necessary. Five mg of cis-DDP was given intraperitoneally (i.p.) to ten rabbits. Ultrastructural examinations were performed on the upper and lower parts of the esophagus each day after the injection on the following ten days. Another 50 rabbits were given 5 mg cis-DDP and were irradiated in an area just beneath the hypopharynx. They were given 2 Gy at each irradiation and were maximally treated with up to 20 Gy. Examinations were carried out from the first day after the final treatment and each day during ten consecutive days. Five animals were used as controls. Cis-DDP proved to have a deleterious effect on the epithelial layer of the esophageal mucosa with cell loss and structural disarrangement of the microridges and whorls on the surface. This finding was an early phenomenon and lasted for all ten examination days. The changes were not more exaggerated when irradiation was added to the experiments. Repopulation of new cells from the matrix was noticed about five days after the administration of cis-DDP alone

Effects of Fractionated Irradiation on the Esophageal Mucosa: A Scanning and Transmission Electron Microscopic Study

The mucosa of rabbit esophagus was irradiated with daily fractions of 2 Gy to an accumulated dose of 20 Gy. Specimens were taken for scanning electron microscopy, transmission electron microscopy and light microscopy investigations. Examination was made 1-10 days after each fractionation schedule. Light microscopy showed dose-dependent edema of the irradiated mucosa which also could be seen and scored from SEM pictures. SEM investigations showed that this was accompanied by loosening of microridges and a slightly increased cell loss. By SEM, a varying amount of bacteria could be seen which did not make intimate contact with the surface cells. During the first five days there was a steady decrease of the number of bacteria in relation to the absorbed dose. In the later period of examination, the amount of bacteria increased up to a given dose of 10 Gy. Thereafter, the number faded off to about zero when 20 Gy had been administered

Structural Elucidation of Cisoid and Transoid Cyclization Pathways of a Sesquiterpene Synthase Using 2-Fluorofarnesyl Diphosphates

Sesquiterpene skeletal complexity in nature originates from the enzyme-catalyzed ionization of (trans,trans)-farnesyl diphosphate (FPP) (1a) and subsequent cyclization along either 2,3-transoid or 2,3-cisoid farnesyl cation pathways. Tobacco 5-epi-aristolochene synthase (TEAS), a transoid synthase, produces cisoid products as a component of its minor product spectrum. To investigate the cryptic cisoid cyclization pathway in TEAS, we employed (cis,trans)-FPP (1b) as an alternative substrate. Strikingly, TEAS was catalytically robust in the enzymatic conversion of (cis,trans)-FPP (1b) to exclusively (≥99.5%) cisoid products. Further, crystallographic characterization of wild-type TEAS and a catalytically promiscuous mutant (M4 TEAS) with 2-fluoro analogues of both all-trans FPP (1a) and (cis,trans)-FPP (1b) revealed binding modes consistent with preorganization of the farnesyl chain. These results provide a structural glimpse into both cisoid and transoid cyclization pathways efficiently templated by a single enzyme active site, consistent with the recently elucidated stereochemistry of the cisoid products. Further, computational studies using density functional theory calculations reveal concerted, highly asynchronous cyclization pathways leading to the major cisoid cyclization products. The implications of these discoveries for expanded sesquiterpene diversity in nature are discussed

Digital Quantification of Human Eye Color Highlights Genetic Association of Three New Loci

Previous studies have successfully identified genetic variants in several genes associated with human iris (eye) color; however, they all used simplified categorical trait information. Here, we quantified continuous eye color variation into hue and saturation values using high-resolution digital full-eye photographs and conducted a genome-wide association study on 5,951 Dutch Europeans from the Rotterdam Study. Three new regions, 1q42.3, 17q25.3, and 21q22.13, were highlighted meeting the criterion for genome-wide statistically significant association. The latter two loci were replicated in 2,261 individuals from the UK and in 1,282 from Australia. The LYST gene at 1q42.3 and the DSCR9 gene at 21q22.13 serve as promising functional candidates. A model for predicting quantitative eye colors explained over 50% of trait variance in the Rotterdam Study. Over all our data exemplify that fine phenotyping is a useful strategy for finding genes involved in human complex traits

Prediction of irinotecan and 5-fluorouracil toxicity and response in patients with advanced colorectal cancer

Irinotecan and 5-fluorouracil (5-FU) are used to treat metastatic colorectal cancer. Irinotecan's active metabolite is inactivated by UDP-glucuronosyltransferase 1A1 (UGT1A1), which is deficient in Gilbert's syndrome. Irinotecan and metabolites are transported by P-glycoprotein, encoded by ABCB1. 5-FU targets folate metabolism through inhibition of thymidylate synthase (TYMS). Methylenetetrahydrofolate reductase (MTHFR) generates active folate necessary for haematopoiesis. We retrospectively genotyped 140 Swedish and Norwegian irinotecan and 5-FU-treated colorectal cancer patients from the Nordic VI clinical trial for selected variants of UGT1A1, ABCB1, TYMS and MTHFR. We found an increased risk of clinically relevant early toxicity in patients carrying the ABCB1 3435 T/T genotype, Odds ratio (OR)=3.79 (95% confidence interval (CI)=1.09–13.2), and in patients carrying the UGT1A1*28/*28 genotype, OR=4.43 (95% CI=1.30–15.2). Patients with UGT1A1*28/*28 had an especially high risk of neutropenia, OR=6.87 (95% CI=1.70–27.7). Patients who had reacted with toxicity during the first two cycles were in total treated with fewer cycles (P<0.001), and less often responded to treatment (P<0.001). Genetic variation in ABCB1 was associated with both early toxicity and lower response to treatment. Carriers of the ABCB1 1236T-2677T-3435T haplotype responded to treatment less frequently (43 vs 67%, P=0.027), and survived shorter time, OR=1.56 (95% CI=1.01–2.45)