Stereoselective metabolism of tazofelone, an anti-inflammatory bowel disease agent, in rats and dogs and in human liver microsomes

Incubation of (R)-tazofelone and (S)-tazofelone in rat, dog, and human liver microsomes demonstrated that the (R)-tazofelone enantiomer was more rapidly metabolized, with two diastereomeric sulfoxides as the major metabolites formed in all three species. The two diasteresomers epimerized at physiological pH, therefore total sulfoxide formation rates were measured. The formation of the total sulfoxide metabolites followed Michaelis-Menten kinetics. The K(m), Vmax, and intrinsic formation clearance (Vmax/K(m)) values were determined in rat, dog, and human liver microsomes. The intrinsic formation clearance of sulfoxide from (R)-tazofelone exceeded that of (S)-tazofelone in all three species. In vivo studies in rats and dogs dosed orally and intravenously confirmed the stereoselective metabolism of tazofelone observed in vitro. Plasma concentrations of (S)-tazofelone exceeded (R)-tazofelone in rats and dogs by a factor of 3 to 4. In rat portal plasma, both enantiomers were of approximately equal concentration after oral dosing, indicating similar absorption. The half-lives of tazofelone and total sulfoxides in rats were 3.5 and 2.8 h, respectively. In dogs, the half-lives of tazofelone and total sulfoxides were 2.2 and 5.5 h, respectively. Plasma clearance was 2.3 l/h in rats and 1.4 l/h in dogs, and the volumes of distribution were 12 and 4.5 l, respectively, in rats and dogs. Both enantiomers were highly bound to plasma proteins to a similar extent in both species.     

Memory and effector T cells modulate subsequently primed immune responses to unrelated antigens

Memory and effector T cells modulate subsequently primed T cell responses to the same antigen. However, little is known about the impact of pre-existing memory and effector T cell immunity on subsequently primed immune responses to unrelated antigens. Here, we show that an antigen-primed first wave of Th1 and Th2 immunity enhanced or inhibited the subsequently primed T cell immunity to an unrelated antigen, depending on whether the second antigen was administered in the same or opposite type of adjuvant. The regulatory effects of the first wave of T cell immunity on the subsequent T cell responses to an unrelated antigen attenuated over time. Notably, following challenge with the second antigen, there was a mutual cross-regulation between the first and second wave of humoral responses to unrelated antigens. Thus, immunization with one antigen not only primes immune responses to that antigen, but also influences subsequently primed immune responses to unrelated antigens.     

Monosaccharides and monosaccharide derivatives in human seminal plasma

Gas chromatography—mass spectrometry with an on-line data system was used to identify monosaccharides and monosaccharide derivatives in human seminal plasma. The carbohydrates were converted into the methoxime—trimethylsilyl derivatives before separation in open tubular glass capillary columns coated with SE-30. Twenty-one different compounds were detected in the seminal fluid, of which twelve have not been recognized before. Seventeen of the monosaccharides have previously been identified in urine. Similar patterns of sugars were found both in fertile and infertile individuals, including one with azoospermia. The compounds identified are, with the possible exception of -ribose, present as free monosaccharides at the time of ejaculation, and they do not seem to be preformed by spermatozoa.     

Muscle flaps in osteomyelitis of the lower extremity: a 20-year account

Between 1977 and 1993, 64 patients had local muscle flap transposition as an integral portion of treatment for lower-extremity osteomyelitis. All muscle flaps were performed by a single surgeon. There were 54 men and 10 women with an average age of 45 years (range, 16 to 87 years). Median follow-up period was 9.3 years (range, 5 to 21 years). The muscles used included medial gastrocnemius (n = 28), soleus (n = 19), lateral gastrocnemius (n = 13), and peroneus tertius (n = 1). At final follow-up, the recurrence free rates at 5, 10, and 15 years were 94, 92.5, and 86 percent, respectively. These long-term results support the use of local muscle flap transposition as an important management method in the treatment of lower extremity osteomyelitis; however, the risk of treatment failure may arise after extended periods of time.     

DNA sequence profiles of the colorectal cancer critical gene set KRAS-BRAF-PIK3CA-PTEN-TP53 related to age at disease onset

The incidence of colorectal cancer (CRC) increases with age and early onset indicates an increased likelihood for genetic predisposition for this disease. The somatic genetics of tumor development in relation to patient age remains mostly unknown. We have examined the mutation status of five known cancer critical genes in relation to age at diagnosis, and compared the genomic complexity of tumors from young patients without known CRC syndromes with those from elderly patients. Among 181 CRC patients, stratified by microsatellite instability status, DNA sequence changes were identified in KRAS (32%), BRAF (16%), PIK3CA (4%), PTEN (14%) and TP53 (51%). In patients younger than 50 years (n = 45), PIK3CA mutations were not observed and TP53 mutations were more frequent than in the older age groups. The total gene mutation index was lowest in tumors from the youngest patients. In contrast, the genome complexity, assessed as copy number aberrations, was highest in tumors from the youngest patients. A comparable number of tumors from young (<50 years) and old patients (>70 years) was quadruple negative for the four predictive gene markers (KRAS-BRAF-PIK3CA-PTEN); however, 16% of young versus only 1% of the old patients had tumor mutations in PTEN/PIK3CA exclusively. This implies that mutation testing for prediction of EGFR treatment response may be restricted to KRAS and BRAF in elderly (>70 years) patients. Distinct genetic differences found in tumors from young and elderly patients, whom are comparable for known clinical and pathological variables, indicate that young patients have a different genetic risk profile for CRC development than older patients.     

Freeze-resistant Trichinella (Trichinella nativa) Established on the Scandinavian Peninsula

Until the 1970’s, Trichinella spiralis (Owen 1835) was considered the only species within the genus Trichinella. Then T. pseudospiralis (Garkavi 1972) was classified as a separate species on the basis of morphological and biological features. The remaining morphologically homogenous “T. spiralis-group” has been split into 4 different species (or subspecies) on the basis of their biological and biochemical characteristics; T. nativa (Britov & Boev 1972), T. nelsoni (Britov & Boev 1972), T. spiralis sensu stricto and T. britovi (Pozio et al. 1992).     

Retention and removal of the fish pathogenic bacterium Yersinia ruckeri in biological sand filters

AIMS: To investigate the retention and removal of the fish pathogenic bacterium Yersinia ruckeri in biological sand filters and effects on the microbial community composition. METHODS AND RESULTS: Sand filter columns were loaded (70 mm day(-1)) with fish farm wastewater and a suspension (10(8) CFU ml(-1)) of Y. ruckeri. Bacterial numbers and protozoan numbers were determined by plate counts and epifluorescence microscopy, respectively, and microbial biomass and community composition were assessed by phospholipid fatty acids (PLFA) analysis. Concentrations of Y. ruckeri in the filter effluent decreased from 10(8) to 10(3)-10(5) CFU ml(-1) during the experiment. Numbers of Y. ruckeri in the sand decreased from 10(6) CFU g(-1) dry weight (DW) sand to 10(4) CFU g(-1) DW sand. In contrast, microbial biomass determined with plate counts and total PLFA increased during the whole experiment. Principal component analysis (PCA) revealed a change in microbial community composition with time, with the most pronounced change in surface layers and towards the end of the experiment. Protozoan numbers increased from ca 0-600 cells g(-1) DW sand, indicating the establishment of a moderate population of bacterial grazers. CONCLUSIONS: The removal of Y. ruckeri improved during the experiment. Introduction of Y. ruckeri to the sand filter columns stimulated growth of other micro-organisms, which in turn caused a shift in the microbial community composition in the sand. SIGNIFICANCE AND IMPACT OF THE STUDY: This study increases the understanding of the dynamics of sand filters subjected to a high loading of a pathogenic bacterium and can therefore be used in future work were the overall aim is to provide a more reliable and efficient removal of pathogenic bacteria in biological sand filter systems.     

Influence of Nitrogen and Winter Climate Stresses on Calluna vulgaris(L.) Hull

Four nitrogen (N) levels, spanning those found naturally, wereestablished in Calluna vulgaris grown in containers in an oceanicclimate for 4 years on the southwest coast of Norway. EstablishedN contents of the plants were 0.7, 0.8, 1.3 and 2.5% of dryweight. Experiments comprising 5000 plants were performed inthe open and in growth chambers. In the open, dry matter accumulationand date of bud burst were recorded at the different N levels.Breaking of winter dormancy was studied under controlled conditions.In October/November, plants needed 1474 day-degrees for budburst at the lowest N level, whereas at the highest level only582 day-degrees were required. The natural start of growth inthe field was on 14 April at the highest N level and on 26 Aprilat the lowest. Freeze testing of the shoots (with the rootsprotected from frost) revealed that Calluna tolerates temperaturesas low as -15 °C as late as the beginning of April. However,plants at the two medium N levels were most tolerant of frost.During the last winter of the experiments, nearly 50% of plantsin the open died at the highest N level, whereas plants at thelower levels survived without damage. The effects of N are discussedin relation to the influence on physiological ageing of theplants, the change in nutrient balance of the plant tissue andthe subsequent increase in susceptibility to biotic and abioticstresses. Copyright 2001 Annals of Botany Company Calluna vulgaris, climate stress, growth initiation, nitrogen