Enantioselective analysis of albendazole sulfoxide in plasma using the chiral stationary phase

We present a method for the enantioselective analysis of albendazole sulfoxide (ABZSO) in plasma for application in clinical pharmacokinetic studies. ABZSO enantiomers were separated on a 5-μm Chiralcel OB-H® column (4.6 × 150 mm) using hexane:ethanol (93:7, v/v) as the mobile phase and fluorescence detection. ABZSO was extracted with chloroform:isopropanol (8:2, v/v) from 500-μl aliquots of acidified plasma, with full drug recovery. The proposed method presented quantitation limits of 20 ng/ml for (−)ABZSO and 50 ng/ml for (+)ABZSO and was linear up to a concentration of 5,000 ng/ml of each enantiomer. Chirality 9:722–726, 1997. © 1997 Wiley-Liss, Inc.     

Pincer-like claws in centipedes (Chilopoda): multiple evolutionary origin of similar form and serial pattern

In most Chilopoda, the walking legs end in a single-tip claw usually accompanied by short accessory spines. Instead, in all species of three small and only distantly related geophilomorph taxa (Diphyonyx, Neogeophilidae, Eucratonyx), the claws of an anterior set of leg pairs are unusually pincer-like. By integrating different microscopic techniques, including confocal laser scanning microscopy, we found that these modified claws are very similar in form, internal structure, and pattern of variation in shape along the trunk in all three taxa: the claws are distinctly swollen and bent, provided with peculiar bulges, and flanked by a conspicuous additional branch, either cylindrical or flattened, which overreaches the tip of the claw; instead, the internal cuticular features are not modified with respect to the condition in the other centipedes, claiming against the possibility of controlled abduction/adduction between claw and branch. Irrespective of the total number of leg pairs (63–129), the claws change gradually from pincer-like to usual shape invariantly in the range spanning between the 34 and the 45% of the total number of leg pairs. Despite these similarities, pincer-like claws originated independently in the three taxa, and by way of fundamentally different changes, either by the dramatic modification of the already existent anterior accessory spine (Diphyonyx, Neogeophilidae) or by the production of a novel cuticular projection (Eucratonyx). Moreover, their shared pattern of variation along the body was most probably constrained by already operating developmental processes controlling the longitudinal patterning of the trunk.     

A highly sensitive LC-MS-MS assay for analysis of midazolam and its major metabolite in human plasma: applications to drug metabolism

Betamethasone is a synthetic corticosteroid designed to exert a marked glucocorticoid activity. As the free alcohol, betamethasone finds widespread clinical applications related to its anti-inflammatory and immunosuppressant activity. In the present study, a fast, sensitive, robust method was developed for the determination and quantification of betamethasone in human plasma by liquid chromatography coupled with tandem mass spectrometry, using photospray ionization in negative mode. Betamethasone was extracted from 0.5 ml human plasma by liquid-liquid extraction (LLE) using chloramphenicol as internal standard. The method has a chromatographic run of 2.5 min using a C(18) analytical column (100 mm x 2.1 mm i.d.) and the linear calibration curve over the range was linear from 0.05 to 50 ng ml(-1) (r(2)>0.993). The between-run precision, based on the relative standard deviation replicate quality controls was 94.1% (0.15 ng ml(-1)), 90.7% (4.0 ng ml(-1)) and 97.2% (40 ng ml(-1)). The between-run accuracy for the above-mentioned concentrations was 11.9, 9.0 and 9.8%, respectively. The method herein described was employed in a bioequivalence study of two formulations of dexchlorpheniramine/betamethasone 2 mg/0.25 mg tablets.     

Fish oil supplementation in F1 generation associated with naproxen, clenbuterol, and insulin administration reduce tumor growth and cachexia in Walker 256 tumor-bearing rats

Weanling female Wistar rats were supplemented with fish oil (1 g/kg body weight) for one generation. The male offspring received the same supplementation until to adult age. Rats supplemented with coconut fat were used as reference. Some rats were inoculated subcutaneously with a suspension (2 x 10(7) cells/mL) of Walker 256 tumor. At day 3, when the tumor was palpable, rats were treated with naproxen (N) (0.1 mg/mL), clenbuterol (Cb) (0.15 mg/kg body weight), and insulin (I) (10 U/kg body weight). At day 14 after tumor inoculation, the animals were killed. Tumor was removed and weighed. Blood, liver, and skeletal muscles were also collected for measurements of metabolites and insulin. In both tumor-bearing untreated rats and tumor-bearing rats supplemented with coconut fat, tumor growth, triacylglycerol, and blood lactate levels were higher, and glycogen content of the liver, blood glucose, cholesterol and HDL-cholesterol levels were lower as compared with the non-tumor-bearing and fish oil supplemented groups. Fish oil supplementation of tumor-bearing rats led to a partial recovery of the glycogen content in the liver and a full reversion of blood glucose, lactate, cholesterol, and HDL-cholesterol levels. The treatment with N plus Cb plus I attenuated cancer cachexia and decreased tumor growth in both coconut fat and fish oil supplemented rats. In conclusion, chronic fish oil supplementation decreased tumor growth and partially recovered cachexia. This beneficial effect of fish oil supplementation was potentiated by treatment with naproxen plus clenbuterol plus insulin.     

Survival of enterococcal species in aquatic environments

Analysis of the survival ability of faecal streptococci/enterococci in the environment has almost invariably been conducted using the standard culture method (CFU counts) despite the demonstration that these microorganisms are capable of entering a viable but nonculturable (VBNC) state. In this study we evaluated the fate, in terms of culturability and viability, of different enterococcal species under laboratory stress conditions mimicking those of the aquatic environment. The results indicate that enterococcal species may activate two different survival strategies, namely starvation and the VBNC state, depending on the specific environmental condition. Moreover, the different enterococcal species can be divided into three groups on the basis of the time needed to activate the VBNC state and the resuscitation capability. The differences in activation of the two survival strategies and the different kinetics observed among the enterococcal species reaching the VBNC state should be taken into consideration when the microbiological quality of waters has to be evaluated and because of their role as faecal contamination indicators.     

Molecular vs culture methods for the detection of bacterial faecal indicators in groundwater for human use

AIMS: The current standard culture methods are unable to detect nongrowing bacteria and, thus, might not be sufficient for precise monitoring of the microbiological quality of waters. The use of a molecular method such as PCR could be a valid alternative to detect bacterial faecal contamination indicators such as Escherichia coli and Enterococcus faecalis and reveal the presence of culturable and nonculturable bacterial forms. METHODS AND RESULTS: The presence of E. coli and Ent. faecalis cells in 30 groundwater samples was evaluated with the standard culture method and compared with a specific PCR protocol. A substantial percentage (50%) of the samples not containing culturable cells proved positive in the search for Ent. faecalis DNA by PCR. Quantification by competitive PCR (cPCR) of the DNA detected allowed us to calculate the number of nonculturable cells present in water samples: the number varied from 2 to 120 cells ml(-1). Only four samples were positive for E. coli DNA and the corresponding nonculturable cells varied from 24 to 70 ml(-1). CONCLUSIONS: This study demonstrates that the standard culture methods in use are unable to detect a substantial proportion of the bacterial population which is nonculturable but, as previously demonstrated, potentially still viable and able to express those pathogenic factors needed for causing infections in humans. SIGNIFICANCE AND IMPACT OF THE STUDY: To protect human health it is necessary to develop and use methods which detect the nonculturable as well as culturable bacteria present in water.     

Thermo-search: lifestyle and thermostability analysis

Thermo-search is an online web tool for the analysis of proteomes and individual proteins according to the ratio of two couplets of preferred and avoided amino acids in hyperthermophiles, thermophiles and mesophiles. It displays the ratio between glutamic acid plus lysine (E+K) and glutamine plus histidine (Q+H), which is higher in thermophilic proteomes and thermostable proteins than in mesophilic proteomes and thermo labile proteins. Thermo-search allows a rapid screen of the CRM database for thermostable proteins in their functional categories and a visualization of the (E+K)/(Q+H) average ratio between organisms, allowing a comparison of their lifestyles.     

Brain cholecystokinin depletion in rats with acute liver failure

A decrease of both hypothalamic and cortical CCK occurred in the brain of rats killed 8 hours after hepatic artery ligation following portocaval anastomosis. Brain CCK depletion was not reproduced by exogenously provoked hyperammonemia nor by insulin-induced hypoglycemia, thus suggesting a central mechanism for the derangement of the CCKergic system in the course of acute liver failure.