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Biomedical subjects

P Isaac

Publications and source records attributed to P Isaac.

At least 19 recordsLinked to original sources
PubMed2005

Microsatellite markers for powdery mildew resistance in pea (Pisum sativum L.).

Powdery mildew is a common disease of field pea, Pisum sativum L., and is caused by the ascomycete fungus Erysiphe pisi. It can cause severe damage in areas where pea is cultivated. Today breeders want to develop new pea lines that are resistant to the disease. To make the breeding process more efficient, it is desirable to find genetic markers for use in a marker-assisted selection (MAS) strategy. In this study, microsatellites (SSR) were used to find markers linked to powdery mildew resistance. The resistant pea cultivar '955180' and the susceptible pea cultivar 'Majoret' were crossed and F2 plants were screened with SSR markers, using bulked segregant analysis. A total of 315 SSR markers were screened out of which five showed linkage to the powdery mildew resistance gene. No single marker was considered optimal for inclusion in a MAS program. Instead, two of the markers can be used in combination, which would result in only 1.6% incorrectly identified plants. Thus SSR markers can be successfully used in marker-assisted selection for powdery mildew resistance breeding in pea.

Ascomycota↗
PubMed2002

Construction and analysis of a microsatellite-based database of European wheat varieties.

A database of 502 recent European wheat varieties, mainly of winter type, was constructed using 19 wheat microsatellites and one secalin-specific marker. All datapoints were generated in at least two laboratories using different techniques for fragment analysis. An overall level of >99.5% accuracy was achieved. The 199 alleles detected allowed discrimination between all of the varieties except duplicates, and varieties derived from identical parents. Approximately 25% of the varieties showed some heterogeneities, with the highest level of heterogeneity in south-eastern European material. The highest genetic diversity and the highest number of rare alleles were found in varieties from southern Europe. The relative allele frequencies varied for most microsatellites in different geographical regions.

DNA Fingerprinting↗
PubMed1989

Benzodiazepine use and abuse in Canada.

Benzodiazepines are frequently prescribed, yet the extent of their use in Canada has not been described. Such data would be valuable in assessing patient exposure to benzodiazepines and would provide a context to estimate the risk-benefit ratio of these drugs. Analysis of benzodiazepine sales in 1978-87 in Canada, expressed as the defined daily dose (DDD) per 1000 inhabitants per day, showed that the use of these drugs was stable during the first half of the decade, at 33 DDD/1000 inhabitants per day, then steadily increased from 1983 to 1987, reaching 48 DDD/1000 inhabitants per day in 1987. The total use of slowly eliminated benzodiazepines declined, whereas the overall use of rapidly eliminated benzodiazepines increased linearly. In 1978-83 Canada had the second-lowest total benzodiazepine use among several Western countries. The patterns of use and abuse of rapidly eliminated benzodiazepines in 1978-84 showed a close correlation. Our findings indicate that data on drug use can be monitored and linked to clinical data, providing a mechanism for monitoring the relation between use and related illness.

Benzodiazepines↗
PubMed1972

The metabolism of 14 C-labelled -methyldopa in normal and hypertensive human subjects.

1. The fate of orally administered (14)C-labelled l-alpha-methyldopa has been examined in three normal men and in eight hypertensive patients who responded to the drug and three who did not. 2. The output of (14)C in the urine in 2 days and in the faeces in 4 days was not very different in any of the subjects. The normals excreted about 40% of the dose in the urine and 60% in the faeces, the responders 52% (range 35-60%) and 45% and the non-responders 42% and 41%. Most of the urinary (14)C radioactivity was eliminated in 24h after dosing. 3. The main metabolite in the urine was free and conjugated alpha-methyldopa (normal men, 23%; responders, 37%; non-responders, 25% of the dose). Free and conjugated 3-O-methyl-alpha-methyldopa was about 4% in all subjects, total amines (alpha-methyldopamine and 3-O-methyl-alpha-methyldopamine) about 6% and ketones (mainly 3,4-dihydroxyphenylacetone) about 3%. 4. The output of alpha-methyldopamine (2-4% of dose), 3-O-methyl-alpha-methyldopamine (0.3%) and 3,4-dihydroxyphenylacetone (3-5%) was similar in the one normal and two responders examined. 5. The faecal (14)C in all subjects was unchanged l-alpha-methyldopa. 6. In general, the amounts of the metabolites in the urine in normal men and in responding and non-responding patients were quantitatively similar, except in one non-responding patient who converted nearly two-thirds of the absorbed drug into amines and ketones. There appeared to be no correlation between metabolites in the urine and response or lack of response to the drug. 7. In two normal subjects 70-80% of d-alpha-methyldopa was excreted unchanged in the faeces. Of the absorbed compound most (9-14% of the dose) was excreted as the free and conjugated drug together with a small amount (1-2%) of 3-O-methyl-alpha-methyldopa. No amines and only traces of ketone were excreted.

Adult↗