RESUMEN
The Blairex Water Purifier is designed to make tap water into purified water that can be used to make saline solution for soft contact lens disinfection and rinsing. The micropore filters of eight Purifiers were perforated to allow a controlled contamination by either Pseudomonas aeruginosa or Serratia marcescens. The bacterial growth was evaluated in these altered Blairex Water Purifiers under refrigerated and unrefrigerated conditions. Those Purifiers that were refrigerated showed significantly less bacterial growth than those Purifiers that were kept at room temperature between samplings. Our findings imply that soft contact lens wearers may reduce the level of microbial growth in undamaged Purifiers by refrigerating the Purifiers between uses.
Asunto(s)
Lentes de Contacto Hidrofílicos , Desinfección/instrumentación , Contaminación de Equipos , Pseudomonas aeruginosa/crecimiento & desarrollo , Refrigeración , Serratia marcescens/crecimiento & desarrollo , Esterilización/instrumentación , TemperaturaRESUMEN
The Blairex Water Purifier (previously called The Blairex Deionizer) is a filtration unit designed to purify tap water for uses that require distilled or deionized water. The unit is intended to offer soft contact lens wearers a more convenient and safe method of obtaining distilled water when using salt tablets or enzymatic cleaning tablets. In this study, the safety of these units was analyzed from a microbiological point of view. The microbial starting state of 18 factory sealed Blairex Water Purifiers was evaluated by filtering sterile water through each unit and enumerating the organisms in the effluent. Then a known number of specific microorganisms was filtered through each unit. For the next 30 days, subsequent sterile distilled water filtrations were done each day. The effluent was collected with each filtration and enumerated for microorganisms. The results indicated that the majority of Blairex units tested were not sterile from the onset. Several Blairex units evaluated did support bacterial growth, as the bacteria that were passed through the unit on day 1 of the study were found in the effluent in increasing numbers with use. The clinical implications of our findings are discussed. Each time Blairex units were obtained for evaluation, the units appeared different in either filter attachments, plastic composition, or shape. The results varied according to which type of Blairex unit was tested.
Asunto(s)
Filtración/instrumentación , Técnicas Microbiológicas , Microbiología del Agua , Agua , Estudios de Evaluación como AsuntoRESUMEN
The structure of the potent inflammatory mediator, platelet-activating factor, is 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine (AGEPC, PAF-acether). Human sera contain an acid labile factor (ALF) that is a Ca+2-independent 2-acylhydrolase-specific for AGEPC and AGEPC-like molecules. The enzyme functions by catalytically removing the sn-2 acetyl moiety from AGEPC, producing the biologically inactive sn-2 hydroxy form or 2-lyso-GEPC. Incubation of ALF with sn-2 acyl PAF analogs indicated that the enzyme hydrolyzes the sn-2 fatty acid only if the chain length is five carbons or less, the sn-1 position fatty acid length is greater than 10 carbon units, and at least one methyl group is present on the terminal amine of the choline group. The enzyme was active with either an ether or ester linkage at the sn-1 position. ALF is inactivated by heating to 65 degrees C for 30 min. It is pronase and trypsin sensitive but resistant to papain and papain with dithiothreitol. Further characteristics of human ALF indicated a broad pH range of activity with an optimum of pH 6.2 and an isoelectric point of 6.2 to 6.7. The specificity and Ca+2 independence of human ALF sets it apart from phospholipase A2. It is proposed that human ALF be called human serum PAF-acylhydrolase to distinguish it from other hydrolases currently known to exist.
Asunto(s)
Fosfolipasas A/sangre , Fosfolipasas/sangre , Factor de Activación Plaquetaria/metabolismo , 1-Alquil-2-acetilglicerofosfocolina Esterasa , Animales , Calcio/metabolismo , Fenómenos Químicos , Química Física , Calor , Humanos , Ácido Clorhídrico/farmacología , Concentración de Iones de Hidrógeno , Péptido Hidrolasas/farmacología , Fosfolipasas A/inmunología , Fosfolipasas A/fisiología , Fosfolipasas A2 , Conejos , Especificidad por SustratoRESUMEN
Platelet-activating factor (PAF) is a phospholipid that activates platelets, induces inflammation, and causes profound alteration in the cardiopulmonary system. PAF from rabbit basophils and hog leukocytes is 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine (AGEPC). Human and other mammalian serums contain an acid-labile factor (ALF) that rapidly inactivates AGEPC. ALF is associated with low-density lipoproteins but can be dissociated from the lipoproteins with detergent followed by ultracentrifugation. Delipidated ALF has an isoelectric point of approximately 7.1, its molecular weight is unknown, and it will not react with goat anti-whole human serum, antialbumin, anti-alpha- or anti-beta-lipoproteins, or antiapolipoproteins A or B. ALF has the following characteristics: 1) is acid labile; 2) is Ca2+ independent; 3) has a pH optimum of 6.2; 4) can hydrolyze a four-carbon but not a six-carbon or longer chain fatty acid at the sn-2 position; 5) is independent of an ester or ether linkage at the sn-1 position; 6) is incapable of hydrolyzing sn-2-acetylphosphatidylethanolamine, which indicates the need for at least one methyl group on the choline moiety of AGEPC; 7) requires between 5 and 16 carbons at the sn-1 position to remove a three- or four-carbon fatty acid on the sn-2 position; 8) is inactivated by heating to 65 C for 30 min; 9) is pronase and trypsin sensitive but papain resistant; and 10) is a hydrophobic molecule and thus behaves like a membrane-associated enzyme. Thus, ALF is a specific phosphatide 2-acylhydrolase.
Asunto(s)
Fosfolipasas A/fisiología , Fosfolipasas/fisiología , Factor de Activación Plaquetaria/metabolismo , 1-Alquil-2-acetilglicerofosfocolina Esterasa , Calcio/fisiología , Humanos , Fosfolipasas A/metabolismo , Factor de Activación Plaquetaria/antagonistas & inhibidoresRESUMEN
Mycoplasma pneumoniae was grown on Formvar- and carbon-coated electron microscope grids and treated with the nonionic detergent Triton X-100 to gently remove the membrane and cytoplasm. The detergent mixture was composed of 0.5% Triton X-100 in SSR-2 broth base. After this treatment, the grids were rinsed in a mixture of 0.1 M KCl, 5 mM MgCl2, and 6 mM potassium phosphate buffer (pH 7.05) and negatively stained with uranyl acetate. The Triton X-100-resistant remains of M. pneumoniae after gentle removal of the membrane and cytoplasm consisted of fibrous structures oriented similarly to the undisrupted cells. The thin fibers displayed a negative staining quality and diameter analogous to that of rabbit muscle F-actin. The fibrous moieties ended in rodlike condensations which appeared striated in negatively stained and shadowed preparations. These striations were regular, and the majority of rod structures had lengths of 220 to 300 nm and widths of 50 to 80 nm. Specific antibody to rabbit muscle actin, produced in guinea pigs, was used in indirect immunofluorescence of the M. pneumoniae colonies. Fluorescence was detected, with concentrations at the colony center and at the tips of filamentous cells.