Prospective, double-blind, randomized trial of equimolar mixture of nitrous oxide/oxygen to prevent pain induced by insertion of venous access ports in cancer patients

BACKGROUND: To assess the efficacy of equimolar mixture of nitrous oxide/oxygen (EMNO) to prevent pain induced by venous access ports (VAPs) implantation in cancer patients. PATIENTS AND METHODS: In a randomized, double-blind study on an adult population not knowing the effects of EMNO, cancer patients were randomly assigned to breath via a facial mask, EMNO or a placebo mixture comprising 50% oxygen and 50% nitrogen. The primary end-point was the patients' assessment of the severity of pain evaluated using a visual analog scale (VAS, 0 to 100) and the proportion of patients suffering pain in each group. The secondary criteria were side effects, tolerability of EMNO, and the level of satisfaction of both the patients and the medical team. RESULTS: Eighty-three adults (42 in the EMNO group and 41 in the placebo group) were included. VAPs were implanted in the jugular vein in 95% of patients. In the placebo group, 78% of the patients declared that they found VAP implantation painful vs. 34% in the EMNO group (p=0.001). The severity of the pain was reduced by 50% in the EMNO group in comparison with placebo (p=0.0125). Although the median time to perform implantation was strictly identical in both groups (20 min), the estimated duration of surgery seemed longer to patients in the control group. Patient and investigator satisfaction indexes were >90% in both groups. CONCLUSION: EMNO provides an effective solution for the prevention of pain during placement of VAPs.     

Age-specific analysis of normal cytokine levels in healthy infants.

While pathophysiology of elevated cytokines is well delineated, reference values for children are unknown, although they may vary physiologically with age and differ from those of adults. Between June and November 2001, interleukin (IL)-6, IL-10 and tumor necrosis factor-alpha (TNF-alpha) concentrations from blood samples of 79 healthy children in six different age groups (group I: 0-3 months; group II: 4-12 months; group III: 13-24 months; group IV: 25-36 months; group V: 37-48 months; group VI: 49-60 months) were measured with ELISA. TNF-alpha was within 2.2-3.5 pg/ml in all groups with a trend toward higher values in groups II and III (p = ns). IL-6 was significantly lower in group III than in groups IV (p = 0.0165) and VI (p = 0.0147). IL-10 was within 3.3-5.5 pg/ml in all groups (p = ns). In regression analysis no correlation between age and cytokine concentrations was found. Although not statistically significant, IL-6 was lower and TNF-alpha higher than the adult reference values provided by the kit manufacturer. Although reference cytokine levels seem not age-related during early infancy, IL-6 is significantly lower during the second year of life than later. In infants aged 5 years or younger, reference levels of IL-6 should be chosen lower, and those of TNF-alpha higher, than the adult reference values.     

Source monitoring deficits in hallucinating compared to non-hallucinating patients with schizophrenia.

In two source memory tests, hallucinating patients with schizophrenia (N=30), compared to non-hallucinating (N=31), are impaired in recognizing internal self-generated items and misattribute them to an external event. They are not impaired in recognizing events from two internal sources. Results support a selective source-monitoring deficit in the occurrence of auditory hallucinations.     

Routine use of mupirocin at the peritoneal catheter exit site and mupirocin resistance: still low after 7 years.

OBJECTIVE: The purpose of this study (the third in a series of similar studies) is to evaluate the prevalence of Staphylococcus aureus (SA), methicillin-resistant SA (MRSA) and mupirocin-resistant SA (MuRSA) carriers in a peritoneal dialysis centre where patients have been instructed to use prophylactic mupirocin ointment at the catheter exit site over the last 7 years. METHODS: Swabs were taken from catheter exit site, nares, axillae and groin in 147 chronic peritoneal dialysis out-patients between November 2003 and January 2004. Axillae/groin and nasal samples were pooled and cultured in the same medium, whereas exit site swabs were cultured separately. All SA isolated were tested for methicillin and mupirocin resistance using oxacillin screening plates and E-test strips. RESULTS: Sixteen of 147 patients (10.9%) were found to be SA carriers: of these 13 (8.8%) had a positive nasal/axillae/groin culture; two (1.4%) had both nasal/axillae/groin- and exit site-positive culture; and one (0.7%) had only exit site-positive culture. In these 16 SA carriers, we found mupirocin-resistant strains (MuRSA) in four patients (25%) and MRSA in two patients (12.5%). Among the four MuRSA carriers, one had both nasal/axillae/groin- and exit site-positive culture and three had only nasal/axillae/groin-positive culture. Three high-level resistance and one low-level resistance MuRSA carriers were isolated. One MuRSA strain was also methicillin resistant. All MRSA strains were sensitive to vancomycin and rifampicin. CONCLUSION: After 7 years' routine use of prophylactic mupirocin ointment at the catheter exit site in non-selected chronic peritoneal dialysis patients, MuRSA was found in 25% of SA strains isolated or in 2.7% of the patients. Compared with our previous study, 3 years earlier, there is no significant increase in the MuRSA prevalence in peritoneal dialysis patients who routinely apply mupirocin ointment at the catheter exit site.     

On the calculation and interpretation of signal intensity in echo-shifted sequences.

Echo-shifted sequences have been shown to be useful in applications where strong T*2-weighting and short repetition times are wanted, such as BOLD-contrast fMRI, MR thermometry, and perfusion studies. However, a full understanding of signal formation with such methods, which is mandatory to optimize sequence parameters for particular applications, has still not been achieved. Here, two methods are proposed to calculate the steady-state signal intensity in coherent TR-periodic and TR-shifted gradient-echo sequences. The integration method, which consists of averaging the steady-state magnetization over all isochromats in a voxel, is shown to be a particularly efficient way of obtaining the analytical expression of the measurable signal. The partition method, based on a physical decomposition of the steady-state magnetization into a sum of contributions from past excitation pulses, reveals that the net transverse magnetization results from a destructive interference between the wanted component and a series of stimulated echoes. The analysis includes off-resonance effects and is illustrated by phantom measurements. Relationships with previous publications on this subject are discussed.     

Development of an in vitro screening model for the biosynthesis of acyl glucuronide metabolites and the assessment of their reactivity toward human serum albumin.

An in vitro screening model was developed to determine the reactivity of acyl glucuronide metabolites from carboxylic drugs. This assay is composed of two phases. The first is a phase of biosynthesis of acyl glucuronides by human liver microsomes (HLM). The second, during which acyl glucuronides are incubated with human serum albumin (HSA), consists of assessing the reactivity of acyl glucuronides toward HSA. Both phases are performed successively in the same experiment. This model was validated using eight carboxylic drugs that were well known for their reactivity, their extent of covalent binding, and their immunological potential. These products were representative of the scale of reactivity. Each compound was incubated with HLM at 400 microM and metabolized into acyl glucuronide to different extents, ranging from 5.6% (tolmetin) to 89.4% (diclofenac). The first-order aglycone appearance rate constant and the extent of covalent binding to proteins were assayed during the incubation of acyl glucuronides formed with HSA for 24 h. Extensive isomerization phenomenon was observed for each acyl glucuronide between the two phases. An excellent correlation was observed (r(2), 0.94) between the extent of drug covalent binding to albumin and the aglycone appearance constant weighted by the percentage of isomerization. This correlation represents an in vitro reactivity scale, which will be helpful in drug discovery support programs to predict the covalent binding potential of new chemical entities. This screening model will also allow the comparison of acyl glucuronide reactivity for related structure compounds.     

Compte-rendu de la première journée de réflexion sur l’endoscopie digestive en France organisée par la SFED — Le 16 janvier 1999

Acta Endoscopica - En préambule, Jean-Marc Canard, organisateur de cette première journée de réflexion sur l’endoscopie digestive, en expose les objectifs. Il s’agit...     

Evolutionary lability of odour-mediated host preference by the malaria vector Anopheles gambiae

Many species of disease‐vector mosquitoes display vertebrate host specificity. Despite considerable progress in recent years in understanding the proximate and ultimate factors related to non‐random host selection at the interspecific level, the basis of this selection remains only partially understood. Anopheles gambiae sensu stricto, the main malaria vector in Africa, is considered a highly anthropophilic mosquito, and host odours have been shown to play a major role in the host‐seeking process of this species. Studies on host preference of An. gambiae have been either conducted in controlled conditions using laboratory reared mosquitoes and worn stockings as host‐related stimuli, or have been done in the field with methods that do not account for internal (e.g. age of sampled mosquitoes) and/or environmental effects. We explored differential behavioural responses to host odours between two populations of the same sibling species, An. gambiae in semi‐field conditions in Burkina Faso. The behavioural responses (i.e. degree of activation and strength of anemotaxis) were investigated using a Y‐olfactometer designed to accommodate whole hosts as a source of odour stimuli. Two strains of An. gambiae (3 to 4‐day‐old female) from laboratory Kisumu strain, and from field‐collected individuals were confronted to combinations of stimuli comprising calf odour, human odour and outdoor air. In dual‐choice tests, field mosquitoes chose human odour over calf odour, outdoor air over calf odour and responded equally to human and outdoor air, while laboratory mosquitoes responded equally to human and calf odour, human odour over outdoor air and calf odour over outdoor air. Overall, no effect of CO₂ exhaled by humans and calves neither on the proportion of activated mosquitoes nor on the relative attractiveness to odour stimuli was found. We report for the first time an intraspecific variation in host‐odour responses. This study clearly suggests that there may be genetic polymorphism underlying host preference and emphasizes that the highly anthropophilic label given to An. gambiae s.s. must be carefully interpreted and refer to populations rather than the whole sibling species.