Organ donation: a portrait of family refusal in Québec.

Many studies from around the world have reported different reasons why families refuse organ donation. In Quebec, however, there are no known data on the subject. To enable us to better communicate with families, a research project was conducted from January to December 2007 in hospital centers with personnel who specialize in supporting families. Our objective was to identify the reasons why Quebecers refuse a request for organ donation. The findings demonstrate that knowing the express wishes of the deceased person about organ donation and end-of-life treatment influences the family. When these wishes are not known, the partners of older donors refuse in greater numbers, primarily for familial or circumstantial reasons. Refusal based on religion or ethnicity is rare. Some families approached before neurologic death is diagnosed do not wish to wait until all the criteria for neurologic death are met.

Double immunohistochemical labeling technique applied to different types of cytokeratins in epithelial proliferations of the breast.

The double labeling technique using peroxidase and alkaline phosphatase for immunohistochemistry is well known, but must be adapted according to the antibodies used, fixation, and technical conditions. The technique allows identification on one slide of two antigens that are localized in the same or different cells of the same lesion. The aim of this paper is to describe the adaptation of this technique to cytokeratins of normal mammary tissue and proliferative lesions of the breast.

Aristolochic acid impedes endocytosis and induces DNA adducts in proximal tubule cells.

BACKGROUND: Aristolochic acid (AA), present in Aristolochia plants, appears to be the toxin responsible for Chinese herbs nephropathy (CHN), a rapidly progressive tubulointerstitial nephritis. One of the earliest sign of CHN is the urinary excretion of low-molecular-weight proteins (LMWP), suggesting that AA is toxic to proximal tubules (PT). METHODS: The effects of AA on PT functions including reabsorption of LMWP were investigated on the well-established opossum kidney (OK) cell line, a model for PT, and compared with those of the classical PT toxin cadmium chloride (CdCl2). RESULTS: OK cell monolayers internalized albumin and beta2-microglobulin by receptor-mediated endocytosis, both proteins apparently competing for the same receptor, a complex of megalin and cubulin. The process was significantly impaired by 24-hour preincubation with AA (10 or 20 micromol/L) or CdCl2 (15 micromol/L). Furthermore, 24-hour exposure to AA followed by its removal during one to six days led to a persistent inhibition of the uptake of albumin, in contrast to the substantial recovery observed after CdCl2 removal. Neither AA nor CdCl2 affected cell viability, Na+-glucose cotransport or total rate of protein synthesis. AA significantly decreased megalin expression and formed specific DNA adducts in OK cells, similar to those found in kidneys from CHN patients. CONCLUSIONS: The present data support the involvement of AA in the early PT dysfunction found in CHN; furthermore, they suggest a causal relationship between DNA adduct formation, decreased megalin expression, and inhibition of receptor-mediated endocytosis of LMWP.

[In vitro sensitivity of Plasmodium falciparum isolates from Gabon to chloroquine and cycloguanil]. / Sensibilité in vitro d'isolats gabonais de Plasmodium falciparum vis-à-vis de la chloroquine et du cycloguanil.

The in vitro susceptibility of 91 Plasmodium falciparum isolates obtained from malaria-infected children living near Libreville (Gabon) was evaluated against chloroquine and cycloguanil (biologically active metabolite of proguanil), using an isotopic micro-drug susceptibility test. In vitro resistance to chloroquine and cycloguanil was observed in 83% (35/42) and in 38% (30/78) of the patients, respectively. Our data showed that 41% (16/39) of Gabonese field isolates were resistant both to chloroquine and cycloguanil. These findings are of great importance because they might indicate imminent chloroquine-proguanil failure, and there are not many affordable antimalarial drugs to replace chloroquine-proguanil combination.

In vitro susceptibility of African isolates of Plasmodium falciparum from Gabon to pyronaridine.

The in vitro activity of pyronaridine was evaluated against 62 isolates of Plasmodium falciparum from Libreville, Gabon using an isotopic, drug susceptibility microtest and was compared with amodiaquine, chloroquine, quinine, and halofantrine activities. The mean 50% inhibitory concentration (IC50) values of the 62 isolates from Gabon to pyronaridine was 3.0 nM (95% confidence interval [CI] = 2.1-3.9). Pyronaridine was less potent against chloroquine-resistant isolates than chloroquine-susceptible isolates but more potent than chloroquine against chloroquine-resistant parasites. The cut-off value for in vitro reduced susceptibility to pyronaridine was an IC50 > 15 nM. Two isolates (3%) showed an IC50 > 15 nM. A significant positive correlation was found between the activities of pyronaridine and chloroquine (r2 = 0.26, P < 0.001), pyronaridine and quinine (r2 = 0.36, P < 0.001), pyronaridine and amodiaquine (r2 = 0.55, P < 0.001), and pyronaridine and halofantrine (r2 = 0.50, P < 0.001). This correlation suggests in vitro cross-resistance or at least in vitro cross-susceptibility, which is not necessarily predictive of cross-resistance in vivo. The present in vitro findings require comparison with those of clinical studies.

Contribution of Na/Ca exchange to Ca2+ outflow and entry in the rat pancreatic beta-cell: studies with antisense oligonucleotides.

To characterize the role played by Na/Ca exchange in the pancreatic beta-cell, phosphorothioated antisense oligonucleotides (AS-oligos) were used to knock down the exchanger in rat pancreatic beta-cells. Na/Ca exchange activity was evaluated by measuring cytosolic free Ca2+ concentration ([Ca2+]i) in single cells using fura-2. Exposure of beta-cells to 500 nmol/l of the AS-oligos for 24 h inhibited Na/Ca exchange activity by approximately 77%. In contrast, control oligonucleotides (scrambled and mismatched) did not affect Na/Ca exchange activity. In AS-oligo-treated cells, the increase in [Ca2+]i induced by membrane depolarization (K+ or the hypoglycemic sulfonylurea, tolbutamide) was reduced by 28 or 40%, respectively. Likewise, the rate of [Ca2+]i decrease after K+ or tolbutamide removal was reduced by 72 or 40%, respectively. AS-oligos treatment also abolished the nifedipine-resistant increase in [Ca2+]i induced by K+ and profoundly altered the oscillatory or sustained increases in [Ca2+]i induced by 11.1 mmol/l glucose. The present study shows that AS-oligos may specifically inhibit Na/Ca exchange in rat pancreatic beta-cells. In those cells, Na/Ca exchange appears to mediate Ca2+ entry in response to membrane depolarization and to be responsible for up to 70% of Ca2+ removal from the cytoplasm upon membrane repolarization.

In vitro susceptibility of Gabonese wild isolates of Plasmodium falciparum to artemether, and comparison with chloroquine, quinine, halofantrine and amodiaquine.

The in vitro activity of artemether against 63 African isolates of Plasmodium falciparum from Libreville, Gabon was evaluated using an isotopic drug susceptibility semi-microtest. The 50% inhibitory concentration (IC50) values for artemether were in a narrow range from 0.8 to 34.8 nM (mean IC50 5.0 nM) and the 95% confidence interval (CI95%) was 3.6-6.3 nM. In vitro decreased susceptibility or resistance were observed with artemether (14%), to chloroquine (90%), to quinine (32%). Isolate susceptibility to amodiaquine and halofantrine was high i.e. 100% and 98%, respectively. There was a significant positive correlation between responses to artemether and amodiaquine (r2 = 0.45, P < 0.001), artemether and chloroquine (r2 = 0.36, P < 0.001), artemether and quinine (r2 = 0.31, P < 0.001), and artemether and halofantrine (r2 = 0.19, P < 0.01). Positive correlation between these drugs suggests in vitro cross-resistance or at least common features in drug uptake and/or mode of action or resistance.

Expression of p53 in oesophageal squamous epithelium from surgical specimens resected for squamous cell carcinoma of the oesophagus, with special reference to uninvolved mucosa.

Accumulation of p53 protein has been considered an intermediate biomarker in multistage oesophageal carcinogenesis. The aim of the present study was to investigate p53 expression by immunohistochemistry in 13 thoroughly sampled oesophagectomy specimens from a geographical area with a high oesophageal cancer incidence (Basse Normandie, France). Expression of p53 was looked for in tissue samples of cancer, intraepithelial neoplasia, and uninvolved mucosa. The streptavidin biotin peroxidase complex method was used for p53 immunostaining. p53 expression was found in invasive squamous cell carcinoma in 8 out of 11 cases and in intraepithelial neoplasia in 10 out of 11 cases. In all 13 cases, in uninvolved oesophageal mucosa, expression of p53 was focally present in areas of chronic oesophagitis. Chronic oesophagitis has been regarded by epidemiologists as a precursor lesion for squamous cell carcinoma of the oesophagus. Since oesophageal carcinogenesis is a multistage process, the study of precursor lesions could provide information on the timing of p53 gene abnormalities during oesophageal carcinogenesis. These preliminary data require to be confirmed by molecular analysis of the p53 gene.

Coagulase expression in Staphylococcus aureus is positively and negatively modulated by an agr-dependent mechanism.

Expression of staphylocoagulase by agr+ Staphylococcus aureus depends on the growth phase, being maximal during exponential growth and decreasing sharply postexponentially, while an agr-deleted strain continuously expresses an intermediate level of coagulase. Therefore, coagulase expression appears to be both positively and negatively modulated by an agr-dependent mechanism.

Coagulase deficiency in clinical isolates of Staphylococcus aureus involves both transcriptional and post-transcriptional defects.

The molecular basis of the non-expression of coagulase was investigated for 14 coagulase-negative isolates of Staphylococcus aureus obtained from different clinical samples. These isolates had typical S. aureus characteristics such as production of clumping factor, DNAase and protein A, but, with one exception, failed to produce detectable amounts of alpha-haemolysin. All 14 strains had DNA homologous to the coagulase gene (coa), but a coa-specific transcript was found in only seven of them. alpha-Haemolysin mRNA was detected in only eight strains without direct correlation to coa-mRNA expression. Thus, coagulase and alpha-haemolysin deficiencies in S. aureus may involve either transcriptional or post-transcriptional alterations although additional regulatory factors may influence the expression of both genes.

Clotting activity in Staphylococcus schleiferi subspecies from human patients.

Staphylococcus schleiferi subsp. schleiferi is a coagulase-negative staphylococcus, usually present as a contaminant in human specimens. A near relative, S. schleiferi subsp. coagulans, possesses coagulase activity but has not been reported from humans. We here describe three isolates of pseudocoagulase-positive S. schleiferi subsp. schleiferi and one isolate of S. schleiferi subsp. coagulans from human patients. The pseudocoagulase from the S. schleiferi subsp. schleiferi isolates differs from S. aureus staphylocoagulase by being sensitive to a combination of protease inhibitors (aprotinin, N-ethylmaleimide, and heparin). These isolates could all easily be confused with S. aureus in a typical clinical laboratory, since they all possess a heat-stable DNase and promote clotting formation. Moreover, S. schleiferi subsp. coagulans produces protein A, and S. schleiferi subsp. schleiferi expresses a clumping factor (fibrinogen affinity factor). Southern blot hybridization with an S. aureus coa-specific probe revealed no sequence related to the coa gene in any of the S. schleiferi isolates, and their riboprobe profiles and biochemical characteristics were typical of S. schleiferi subspecies, not of S. aureus. This study demonstrates that both subspecies of S. schleiferi can promote clotting of rabbit plasma in the standard tube test for coagulase.

[Absence of distinctive characteristics between Staphylococcus epidermidis strains responsible of non-hospital infectious endocarditis and commensal strains]. / Absence de caractères distinctifs entre des souches de Staphylococcus epidermidis responsables d'endocardites infectieuses non hospitalières et des souches commensales.

In order to recognize particular characteristics of pathogenic strains, epidemiologic markers of 27 Staphylococcus epidermidis strains (9 pathological and 18 commensal) were studied. Nine strains were responsible of infective endocarditis (8 on native valves, and 1 on prosthetic valve). No case occurred after admission to hospital or surgery. Eighteen commensal strains were isolated from control subjects who had had no contact with the hospital environment and who had not received a recent antibiotic treatment. The microbiological characteristics were so diverse that no differentiation between the pathogenic strains and commensal strains could be done and no particular pathogenic clone was recognized.

Inhaled terbutaline administered via a spacer fully prevents exercise-induced asthma in young asthmatic subjects: a double-blind, randomized, placebo-controlled study.

The effects of inhaled terbutaline, a beta 2-adrenergic agonist, administered via a 750-ml spacer device were studied in young asthmatic subjects with exercise-induced asthma. A double-blind, randomized, placebo-controlled study of the effects of inhaled 0.5 mg terbutaline and placebo was conducted in 10 asthmatic children (age range 6-16 years) with documented exercise-induced asthma. Forced expiratory volume in 1 s (FEV1) was measured at baseline, 15 min after inhaling terbutaline or placebo, and at intervals up to 60 min after exercising. Subjects exercised using a cycle ergometer for 5 min at a submaximal, constant work-load while breathing dry air at room temperature. Terbutaline induced bronchodilation at rest in all subject and fully prevented exercise-induced asthma in nine out of the 10 subjects; the exercise-induced fall in FEV1 was markedly reduced in the remaining subject. It is concluded that exercise-induced asthma can be inhibited by pretreatment with inhaled terbutaline, administered via a spacer, in a majority of young asthmatics.

Lung transfer factor for CO at rest in normal children by a steady-state method.

Lung transfer for CO (TLCO) was measured at rest in 94 normal children (47 boys and 47 girls) whose ages ranged from 3.5 to 16 years. A steady-state method, using a technique of alveolar sampling based on the equality of the mean expiratory and alveolar respiratory quotients, was employed. Highly significant correlations, statistically different for boys and girls, were fond between TLCO and standing height. TLCO was also linearly correlated with the functional residual capacity--the only pulmonary volume measurable in very young children--but without any sex difference. A multiple linear regression relates TLCO to FRC and height. Variance analysis shows the preponderant influence of FRC.