A novel S-nitrosothiol (RIG200) causes prolonged relaxation in dorsal hand veins with damaged endothelium

BACKGROUND: Reduced nitric oxide bioavailability caused by endothelial dysfunction or damage is a contributory factor in the initiation and progression of a number of cardiovascular diseases. Delivery of exogenous nitric oxide is an attractive therapeutic option, but current agents lack selectivity for areas of endothelial damage. We tested the hypothesis that a novel nitric oxide donor drug, N-(S-nitroso-N-acetylpenicillamine)-2-amino-2-deoxy-1,3,4,6-tetra-O-acet yl-P-glucopyranose [RIG200], which has selective effects in endothelium-denuded isolated arteries in vitro, would exert similar effects in dorsal hand veins with experimentally damaged endothelium in vivo. METHODS: Venodilator responses to sodium nitroprusside and RIG200 were compared in two groups of healthy volunteers (age range, 18 to 63 years; n = 7 for each group) in norepinephrine 70% maximum effective concentration (EC70) preconstricted hand veins with use of the Aellig technique. In this doubleblind study, subjects were randomly assigned to receive either sodium nitroprusside or RIG200 (infusions of 0.06 and 6 nmol/min into the hand vein) before and 2 days after 15 minutes of local venous irription with distilled water. Endothelial function was assessed in all subjects on both visits with use of the endothelium-dependent vasodilator acetylcholine (1 nmol/min). RESULTS: Irrigation of hand veins with distilled water abolished endothelium-dependent dilatation in response to acetylcholine in both study groups (n = 14) but did not affect the amplitude or duration of responses to the conventional nitric oxide donor sodium nitroprusside (P = .87; n = 7). However, responses to RIG200 were significantly prolonged during the washout phase (30 minutes) in veins after water irrigation (P = .02; n = 7). CONCLUSION: These studies confirm that RIG200 has prolonged effects in veins with damaged endothelium, a characteristic that might be exploited therapeutically to target nitric oxide delivery to damaged blood vessels.     

Antibiotic prophylaxis in “clean” surgical procedures

The incidence of infection for clean surgical procedures should be less than 2%. The majority of infections are exogenous from Staphylococcus aureus.These exogenous sources of bacteria include the ward, the theater environment, medical personnel, bed linen, and other infected patients. Endogenous infections may arise from the patient's own nose and skin; and although the majority of bacteria are staphylococcal, gram-negative intestinal bacteria may colonize the skin around the perineum and are, therefore, important pathogens in hip replacement and aortobifemoral grafts. Methods of reducing exogenous infection include theater discipline, ultra clean air, surgical scrub, and isolating infected patients on the ward. Endogenous infections may be minimized by avoiding prolonged preoperative hospital stay, careful shaving only around the incision, and skin preparation with iodophors or chlorhexidine in alcohol. There is no place for antibiotic prophylaxis in clean surgical operations, provided the patient has a normal defense mechanism and provided a foreign body is not being implanted into bone or the circulation. Because of the morbidity and potential mortality of infected implants, antibiotics should be used in clean prosthetic surgery.

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Résumé Le taux d'infection chirurgicale ne soit pas dépasser 2% lorsqu'il s'agit d'interventions dites aseptiques. La cause la plus fréquente en est lestaphylococcus aureus. Les sources exogènes de l'infection se situent au niveau des salles d'hospitalisation des annexes du bloc opératoire, du personnel médical, du linge et des malades déjà infectés. Les sources endogènes sont représentées par la peau et les orifices naturels du patient lui même. Bien que dans la majorité des cas le staphylocoque soit en cause des germes grams négatifs situés au niveau de la région périnéale peuvent être à l'origine de l'infection chirurgicale, en particulier lors des arthroplasties de la hanche et des greffes aortobifémorales.Pour réduire l'infection de cause exogène il convient d'observer une stricte discipline au niveau du bloc opératoire, de disposer d'air absolument pur, de respecter les règles d'asepsie avec rigueur et d'isoler tous les malades infectés. L'infection d'origine endogène peut être réduite en écourtant le séjour du malade à l'Hôpital avant l'intervention, en rasant soigneusement les téguments au niveau de la zone opératoire, en préparant la peau avec des solutions antiseptiques (solutés alcooliques d'iodophores ou de chlorexidine).Il est inutile de donner des antibiotiques à titre préventif dès lors que l'intervention à entreprendre est considérée comme aseptique, que le malade en bon état général possède un bon système de défense, et que l'opération ne consiste pas en la pose d'une prothèse au niveau de la coxofémorale ou d'un greffon aorto-bi-iliaque.

     

Multiple sample flow through immunomagnetic separator for concentrating pathogenic bacteria

The standard method of immunomagnetic separation for isolating pathogenic bacteria from food and environmental matrices processes 1 ml volumes. Pathogens present at low levels (<0.5 pathogenic bacteria/g) will not be consistently detected by this method. Here a multiple sample flow through immunomagnetic separator has been designed and tested to process large volume samples (50 to 250 ml). Preliminary results show >97% recovery of polydisperse magnetic particles (diameter range 1 to 8 microm) containing 29-33% w/w Fe3O4 content. Between 70 and 130 times more of the pathogenic bacteria Escherichia coli O157 is recovered from PBS compared with the standard 1 ml method. Also, the recovery of E. coli O157 from beef mince homogenates, after a 4 h incubation at 42 degrees C, is between 80 and 180 times higher than the standard 1 ml method.     

Periorbital swelling: the important distinction between allergy and infection

Orbital cellulitis and abscess formation are rare complications of sinusitis, however acute orbital inflammation is secondary to sinusitis in about 70% of cases. Delay in diagnosis must not occur to avoid serious complications such as blindness and life threatening intracranial sepsis. A case is reported in which despite late referral, emergency surgical intervention was sight saving.