Boldenone, testosterone and 1,4-androstadiene-3,17-dione determination in faeces from horses, untreated and after administration of androsta-1,4-diene-3,17-dione (boldione).

Faeces, which could be a potential alternative medium for doping control, have been used for the detection of 1,4-androstadiene-3,17-dione administration to the horse. Semi-quantitative analyses of 1,4-androstadiene-3,17-dione, testosterone, 17alpha- and 17beta-boldenone have been conducted in pre- and post-administration faeces, and in controls (untreated stallions, geldings and mares). Sample preparation comprised diethyl ether extraction, lipid removal, HPLC purification and derivatisation. 1,4-Androstadiene-3,17-dione, testosterone, 17alpha- and 17beta-boldenone were analysed by GC-EI/MS/MS. Quantitative limits of detection were 0.1 ng/g for 1,4-androstadiene-3,17-dione, and 0.025 ng/g for testosterone, 17alpha- and 17beta-testosterone. In post-administration samples from geldings and mares, peak levels of 1,4-androstadiene-3,17-dione, 17alpha-, 17beta-boldenone and testosterone were attained 24 h after administration. In untreated geldings and mares (in di- or anoestrus), 17alpha- and 17beta-boldenone and testosterone were not detected. Faeces from females in oestrus had detectable levels of boldenone isomers and testosterone. 1,4-Androstadiene-3,17-dione was undetectable in faeces collected from untreated horses, but the presence of this androgen was recently reported in faeces from untreated swine and it would therefore be advisable to check for its possible presence in a larger number of individual faecal samples.

Influence of vascular filling and perfusion on BOLD contrast during reactive hyperemia in human skeletal muscle.

Mechanisms generating BOLD contrast are complex and depend on parameters that are prone to large variations, in particular in skeletal muscle. Here, we simultaneously measured perfusion by ASL, and BOLD response in the calf muscle of 6 healthy volunteers during post-ischemic reactive hyperemia. We tested whether the relation between the two was altered for varying degrees of leg vascular replenishment induced by prior positioning of the leg at different heights relative to the heart. We found that the BOLD response depended on perfusion, but also on the degree of repletion of leg blood vessels. We conclude that simultaneous determination of perfusion by ASL is important to identify the mechanisms underlying BOLD contrast in the skeletal muscle.

First measurement of the velocity of slow antihydrogen atoms.

The speed of antihydrogen atoms is deduced from the fraction that passes through an oscillating electric field without ionizing. The weakly bound atoms used for this first demonstration travel about 20 times more rapidly than the average thermal speed of the antiprotons from which they form, if these are in thermal equilibrium with their 4.2 K container. The method should be applicable to much more deeply bound states, which may well be moving more slowly, and should aid the quest to lower the speed of the atoms as required if they are to be trapped for precise spectroscopy.

Evaluation and optimization of DNA delivery into gliosarcoma 9L cells by a cholesterol-based cationic liposome.

This paper reports results concerning the transfection of gliosarcoma cells 9L using an original cholesterol-based cationic liposome as carrier. This cationic liposome was prepared from triethyl aminopropane carbamoyl cholesterol (TEAPC-Chol) and a helper lipid, dioleoyl phosphatidyl ethanolamine (DOPE). The used concentration of liposome was not cytotoxic as revealed by the MTT test. TEAPC-Chol/DOPE liposomes allowed the plasmids encoding reporter genes to enter the nucleus as observed both by electron microscopy and functionality tests using fluorescence detection of green fluorescent protein (GFP) and luminometric measurements of luciferase activity. By changing the cationic lipid/DNA molar charge ratio, optimal conditions were determined. Further, improvement of the transfection level has been obtained by either precondensing plasmid DNA with poly-L-lysine or by adding polyethylene glycol (PEG) in the transfection medium. The optimal conditions determined are different depending on whether the transfection is made with cells in culture or with tumors induced by subcutaneous (s.c.) injection of cells in Nude mice. For in vivo assays, a simple method to overcome the interference of haemoglobin with the chemiluminescence intensity of luciferase has been used. These results would be useful for gaining knowledge about the potential for the cationic liposome TEAPC-Chol/DOPE to transfect brain tumors efficiently.

Post-source decay time-of-flight study of fragmentation mechanisms of protonated synthetic polymers under matrix-assisted laser desorption/ionization conditions.

Post-source decay (PSD) of three different nylon oligomers desorbed under matrix-assisted laser desorption/ionization (MALDI) conditions was studied and their fragmentation pathways were investigated. The fragmentation of the protonated oligomers is very similar to that of peptides. The b(n)(+), y(n)(+) and z(n)(+) series of ions were observed in abundance in the PSD spectrum. The end groups and the length of the spacer in the repeating unit influence the fragmentation of the different polyamides and the relative abundances of the product ions. Competitive dehydration and deamination reactions were observed, and depend on the nature of the end groups and the repeating units. The PSD spectra are very similar to collision-induced dissociation (CID) spectra obtained under low-energy conditions, implying that the selected precursor ions possess similar average internal energies. All the peaks observed in the PSD spectrum can be rationalized by reasonable fragmentation mechanisms.

Surface characteristics, equipment height, and the occurrence and severity of playground injuries.

OBJECTIVES: To evaluate whether surface characteristics (absorption level (g-max), material) and the height of play equipment are related to the occurrence and severity of injuries from falls. SETTING AND METHODS: During the summers of 1991 and 1995, conformity of play equipment to Canadian standards was assessed in a random sample (n = 102) of Montreal public playgrounds. Surface absorption (g-max) was tested using a Max Hic instrument and the height of equipment was measured. Concurrently, all injuries presenting at the emergency department of Montreal's two children's hospitals were recorded and parents were interviewed. Inspected equipment was implicated in 185 injuries. The g-max measurements (1995 only) were available for 110 of these playground accidents. RESULTS: One third of falls (35 %) occurred on a surface exceeding 200 g and the risk of injury was three times greater than for g level lower than 150 (95% confidence interval (CI) 1.45 to 6.35). On surfaces having absorption levels between 150 g and 200 g, injuries were 1.8 times more likely (95% CI 0.91 to 3.57). Injuries were 2.56 times more likely to occur on equipment higher than 2 m compared with equipment lower than 1.5 m. Analysis of risk factors by severity of injury failed to show any positive relationships between the g-max or height and severity, whereas surface material was a good predictor of severity. CONCLUSIONS: This study confirms the relationships between risk of injury, surface resilience, and height of equipment, as well as between type of material and severity of injury. Our data suggest that acceptable limits for surface resilience be set at less than 200 g, and perhaps even less than 150 g, and not exceed 2 m for equipment height. These findings reinforce the importance of installing recommended materials, such as sand, beneath play equipment.

Ion/molecule reactions with dimethyl ether and dimethyl-d6 ether: differentiation of four isomers contained in patchouli essential oil

In this study, we show that it is possible to differentiate four sesquiterpene isomers (C(15)H(24)) preliminarily separated by gas chromatography/mass spectrometry (GC/MS). Dimethyl ether is evaluated as a selective ionization reagent and the relative abundance of adducts formed with this reagent gas under positive chemical ionization conditions are compared and adduct ions are characterized using collision-induced dissociation. The mechanisms have been confirmed by achieving the same experiments with deuterated dimethyl ether. Copyright 2000 John Wiley & Sons, Ltd.

Predominance of subtype A and G HIV type 1 in Nigeria, with geographical differences in their distribution.

The purpose of this study was to generate data on the relative prevalences of the HIV-1 subtypes circulating in Nigeria. A total of 252 HIV-1-positive samples collected during an epidemiologic survey conducted in April 1996 were genetically characterized by HMA (heteroduplex mobility assay) and/or sequencing. Samples were collected in Lagos, Calabar, Kano, and Maiduguri. Overall, the predominant env subtypes were A (61.3%) and G (37.5%). Subtype A is more prevalent in the south (p < 0.001), about 70% in Lagos and Calabar, whereas a quarter of the samples was classified as subtype G in these states. In contrast, subtype G is predominant in the north ( < 0.001), representing 58% of the samples in Kano. In the northeastern region, Maiduguri, almost similar proportions of subtype A and G were seen, 49 and 47.4%, respectively. A total of 37 samples was also sequenced in the p24 region from the gag gene; 13 (35%) had discordant subtype designations between env and gag. The majority of the gag (12 of 17) and env (14 of 22) subtype A sequences clustered with the A/G-IBNG strain. Within subtype G, three different subclusters were seen among the envelope sequences. These different subclusters are observed among samples obtained from asymptomatic individuals and AIDS patients from the four Nigerian states studied. In conclusion, we observed a limited number of HIV-1 subtypes circulating in Nigeria, with subtypes A and G being the major env subtypes responsible for the HIV-1 epidemic. Nevertheless, the high rate of recombinant viruses (A/G) and the different A/G recombinant structures indicate a complex pattern of HIV-1 viruses circulating in this country.

Antimicrobial susceptibilities and serogroups of clinical strains of Clostridium difficile isolated in France in 1991 and 1997.

Glycopeptides (vancomycin and teicoplanin) and metronidazole are the drugs of choice for the treatment of Clostridium difficile infections, but trends in susceptibility patterns have not been assessed in the past few years. The objective was to study the MICs of glycopeptides and metronidazole for unrelated C. difficile strains isolated in 1991 (n = 100) and in 1997 (n = 98) by the agar macrodilution, the E-test, and the disk diffusion methods. Strain susceptibilities to erythromycin, clindamycin, tetracycline, rifampin, and chloramphenicol were also determined by the ATB ANA gallery (bioMérieux, La Balme-les-Grottes, France). The MICs at which 50% of isolates are inhibited (MIC(50)s) and MIC(90)s of glycopeptides and metronidazole remained stable between 1991 and 1997. All the strains were inhibited by concentrations that did not exceed 2 microgram/ml for vancomycin and 1 microg/ml for teicoplanin. Comparison of MICs determined by the agar dilution method recommended by the National Committee for Clinical Laboratory Standards and the E test showed correlations (+/-2 dilutions) of 86. 6, 95.9, and 99% for metronidazole, vancomycin, and teicoplanin, respectively. The E test always underestimated the MICs. Strains with decreased susceptibility to metronidazole (MICs, >/=8 microgram/ml) were isolated from six patients (n = 4 in 1991 and n = 2 in 1997). These strains were also detected by the disk diffusion method (zone inhibition diameter, /=1 microgram/ml), clindamycin (MICs, >/=2 microgram/ml), tetracycline (MICs, >/=8 microgram/ml), rifampin (MICs, >/=4 microgram/ml), and chloramphenicol (MICs, >/=16 microgram/ml) was observed in 64.2, 80.3, 23.7, 22.7, and 14.6% of strains, respectively. Strains isolated in 1997 were more susceptible than those isolated in 1991, and this trend was correlated to a major change in serogroup distribution. Periodic studies are needed in order to detect changes in serogroups and the emergence of strains with decreased susceptibility to therapeutic drugs.

Pseudomonas aeruginosa infection in human immunodeficiency virus infected patients.

OBJECTIVES: (1) To determine the incidence and outcome of Pseudomonas aeruginosa infection in HIV-infected patients. (2) To study the antimicrobial susceptibility of P. aeruginosa isolates in this particular population. (3) To identify risk factors for these infections. PATIENTS AND METHODS: A retrospective case-control study performed in a 28-bed infectious-diseases unit in a 940-bed university hospital. All cases were defined as HIV-infected patients with severe infections due to P. aeruginosa, including bacteremia, lower or upper respiratory tract infections, infections related to a central venous catheter, and cutaneous/muscular infection. Each case was matched with an HIV-seropositive control not infected by P. aeruginosa and hospitalized on the same dates as the cases. RESULTS: One thousand and thirty-five HIV-infected patients were hospitalized during the study period. A first severe P. aeruginosa infection was documented in 41 patients, giving an overall annual incidence note of 2.51 episodes per 100 admissions. Forty of the 41 case notes were available for analysis. They consisted of 17 cases of bacteraemia, four upper respiratory tract infections, 10 lower respiratory tract infections, three catheter-related infections, and six cutaneous/muscular infections. Of these 40 cases, 60% were nosocomial and the remainder were community-acquired. The overall mortality rate was 22% (47% in bacteraemic forms). Twenty five percent of patients relapsed after an average of 37 days. The case-control comparison showed that AIDS was more frequent among the cases (92% vs. 74%, P = 0.04), who also had a lower PN count (P = 0.005), and a lower CD4 cell count (15.7 +/- 18.8/mm3 vs. 118 +/- 211/mm3; P = 0.0007). The number of days spent in hospital in the previous 3 months (29.3 +/- 20.7 vs. 19.7 +/- 14, P = 0.04) was significantly higher among the cases. In a multivariate analysis, examining treatments received in the previous month, only co-trimoxazole [OR = 5.5 (1.1-26.9)], penicillins [OR = 5.2 (1.1-25.3)], steroids [OR = 5.5, (1.2-25.5)] and a CD4 cell count below 50/mm3 [OR = 13.2 (1.4-129.4)] were identified as risk factors. CONCLUSION: P. aeruginosa infection is a not frequent bacterial disease in highly immunodeficient HIV-infected patients. It is frequently fatal and must be borne in mind in the advanced stages of HIV disease, especially when patients have received co-trimoxazole (trianthoprim-sulphamethoxazole), penicillins or steroids.

Detection of renal artery stenosis with Doppler sonography before and after administration of captopril: value of early systolic rise.

OBJECTIVE: The goal of this study was to assess the value of quantitative and qualitative analysis of the early systolic rise on Doppler waveforms obtained before and after administration of captopril in patients suspected of having renal artery stenosis. SUBJECTS AND METHODS: Seventy-one hypertensive patients (135 kidneys) were studied with transrenal Doppler sonography. Ninety-six kidneys were studied again after administration of captopril. All patients also underwent renal angiography. All Doppler studies were independently reviewed by two observers. Specific criteria for Doppler waveform patterns that were applied in the detection of renal artery stenosis included acceleration, acceleration time of early systolic rise, differential velocity of systolic rise, and resistive index. These criteria were then correlated with angiography, and receiver operating characteristic curves were generated. RESULTS: On the basis of waveform pattern recognition. Doppler sonograms obtained before administration of captopril had a sensitivity of 81% and a specificity of 98% for the detection of renal artery stenosis greater than or equal to 50%. Sensitivity of Doppler sonography obtained after administration of captopril was 100%, and specificity was 100%. For renal artery stenosis greater than or equal to 70%, sensitivity was 94% and specificity was 89% before administration of captopril. The area under the receiver operating characteristic curve for the acceleration criterion was significantly larger after administration of captopril (p = .009) for the detection of renal artery stenosis greater than or equal to 50%. After captopril administration, an acceleration threshold value of 440 cm/sec2 for early systolic rise was associated with a sensitivity of 100% and a specificity of 94% for the detection of renal artery stenosis greater than or equal to 50%. CONCLUSION: Doppler sonography of the renal arteries performed before administration of captopril appears to be an excellent screening tool in the detection of severe stenosis (> or = 70%). Administration of captopril improves the detection of renal artery stenosis greater than or equal to 50% with Doppler sonography when observers use both morphologic and quantitative criteria.

Killing kinetics of RP 59500 and pristinamycin against penicillin-resistant pneumococci.

The killing kinetics of two streptogramins, RP 59500 and pristinamycin against seventeen isolates of penicillin-susceptible and resistant pneumococci were studied. The antibiotics were tested at 1x, 2x and 4x the MIC for each individual isolate. The results showed a very good and rapid bactericidal activity within 1 hour for concentrations equal or greater to the MIC. These antibiotics are very promising agents for the treatment of infections due to multiresistant pneumococci.

Killing kinetics of meropenem against penicillin-resistant pneumococci.

The killing kinetics of meropenem against sixteen clinical isolates of pneumococci (12 penicillin-resistant, three penicillin-intermediate and one penicillin-sensitive) were studied. Meropenem was tested at 1x, 2x and 4x the MIC for each individual isolate. The results showed a good bactericidal activity with rapid killing of pneumococci (killing > 3 log10 cfu/mL was obtained for nine strains). This strategy needs clinical assessment and might prove to be a suitable alternative to penicillin and cephalosporins for the treatment of mixed infections involving multiresistant pneumococci.

[In vitro study of the bacteriostatic and bactericidal activity of meropenem against strains of Pseudomonas aeruginosa multiresistant to antibiotics]. / Etude in vitro de l'activité bactériostatique et bactéricide du méropénéme sur des souches de Pseudomonas aeruginosa multirésistantes aux antibiotiques.

Meropenem is a new dehydropeptidase stable carbapenem which has an in vitro bacteriostatic activity superior to imipenem against Pseudomonas aeruginosa. Minimal inhibitory concentrations of meropenem (MEM) and imipenem (IPM) were determined on twelve strains: two were genetically characterized reference strains and ten isolated from patients. Killing curves were performed for MEM used at 1,2 and 4 fold the MIC and 32 mg/l; survivors were counted at baseline and after 5 and 24 hours of incubation by spiral plating. Five strains were susceptible to MEM and IPM; five were intermediate and two resistant to MEM; these seven strains were resistant to IPM. A weak bactericidal effect was obtained after 5 h at each concentration. Only one strain achieved a 3 log 10 reduction after 5 h at 2 x MIC. A regrowth of all the strains tested was observed after 24 h.

Bactericidal effect of sparfloxacin alone and in combination with amoxicillin against Streptococcus pneumoniae as determined by kill-kinetic studies.

Ten clinical isolates of Streptococcus pneumoniae (six intermediately penicillin-sensitive, one penicillin-resistant and three penicillin-sensitive strains) were studied by kill-kinetic experiments using sparfloxacin alone and in combination with amoxicillin. Equipotent doses of the antibiotics (1x, 2x and 4x the MIC) were used in the kill-kinetic studies. Sparfloxacin had a moderate bactericidal potential at 4x MIC after 5h and the combination with amoxicillin did not significantly increase its bactericidal activity. The clinical significance of these findings warrants further studies in vivo.

Does play equipment conform to the Canadian standard?

In the summer of 1991, play equipment in 254 playgrounds located on the island of Montreal were inspected, using a checklist made up of items drawn from the Canadian standard for the safety of children's playspaces and equipment. The results of the study, covering 605 climbers, 522 swings and 181 slides, made it possible to identify the most and least respected aspect of safety. For example, one out of two pieces of play equipment was installed on a protective surface that did not conform to the Canadian standard; seven out of ten swings had seats made of non-impact-absorbing materials; and six out of ten pieces of equipment had head entrapment openings. Knowing the physical shortcomings of play equipment is an important step in reducing injuries sustained on it. However, to be effective, the prevention of injuries related to play equipment requires a concerted effort on the part of several partners.

Comparison of two techniques for measurement of in vitro killing kinetics of five antibiotics against Pseudomonas aeruginosa.

The in vitro activity of ticarcillin, imipenem, gentamicin, amikacin and ciprofloxacin against six Pseudomonas aeruginosa isolates was evaluated by two time-killing curve methods: the conventional broth technique, and another method previously described which employs a transfer filter membrane. The patterns of the killing curves obtained over a 5 h period with the two techniques were similar. In contrast to the results obtained for beta-lactam agents, the reduction of inoculum was great and increased with the concentration for aminoglycosides and ciprofloxacin. After 5 h, regrowth of the six strains tested was observed in broth with all antibiotics, whereas a bactericidal effect was observed over 24 h with the filter membrane method. Further studies are warranted to determine the reasons for this difference.