Sodium Hypochlorite Treatment and Nitinol Performance for Medical Devices.

Processing of nitinol medical devices has evolved over the years as manufacturers have identified methods of reducing surface defects such as inclusions. One recent method proposes to soak nitinol medical devices in a 6% sodium hypochlorite (NaClO) solution as a means of identifying surface inclusions. Devices with surface inclusions could in theory then be removed from production because inclusions would interact with NaClO to form a visible black material on the nitinol surface. To understand the effects of an NaClO soak on performance, we compared as-received and NaClO-soaked nitinol wires with two different surface finishes (black oxide and electropolished). Pitting corrosion susceptibility was equivalent between the as-received and NaClO-soaked groups for both surface finishes. Nickel ion release increased in the NaClO-soaked group for black oxide nitinol, but was equivalent for electropolished nitinol. Fatigue testing revealed a lower fatigue life for NaClO-soaked black oxide nitinol at all alternating strains. With the exception of 0.83% alternating strain, NaClO-soaked and as-received electropolished nitinol had similar average fatigue life, but the NaClO-soaked group showed higher variability. NaClO-soaked electropolished nitinol had specimens with the lowest number of cycles to fracture for all alternating strains tested with the exception of the highest alternating strain 1.2%. The NaClO treatment identified only one specimen with surface inclusions and caused readily identifiable surface damage to the black oxide nitinol. Damage from the NaClO soak to electropolished nitinol surface also appears to have occurred and is likely the cause of the increased variability of the fatigue results. Overall, the NaClO soak appears to not lead to an improvement in nitinol performance and seems to be damaging to the nitinol surface in ways that may not be detectable with a simple visual inspection for black material on the nitinol surface.

Identification of immunologically relevant proteins of Chlamydophila abortus using sera from experimentally infected pregnant ewes.

Chlamydophila abortus is an intracellular pathogen and the etiological agent of enzootic abortion of ewes (EAE). C. abortus has a biphasic development cycle; extracellular infectious elementary bodies (EB) attach and penetrate host cells, where they give rise to intracellular, metabolically active reticulate bodies (RB). RB divide by binary fission and subsequently mature to EB, which, on rupture of infected cells, are released to infect new host cells. Pregnant ewes were challenged with 2 x 10(6) inclusion forming units (IFU) of C. abortus cultured in yolk sac (comprising both EB and RB). Serum samples were collected at 0, 7, 14, 21, 27, 30, 35, 40, and 43 days postinfection (dpi) and used to identify antigens of C. abortus expressed during disease. Additionally, sera from fetal lambs were collected at 30, 35, 40, and 43 dpi. All serum samples collected from experimentally infected pregnant ewes reacted specifically with several antigens of EB as determined by one-dimensional (1-D) and 2-D gel electrophoresis; reactive antigens identified by mass spectrometry included the major outer membrane protein (MOMP), polymorphic outer membrane protein (POMP), and macrophage infectivity potentiator (MIP) lipoprotein.

Model building and quantitative analysis of a tandem immuno-capturing assay as a screening tool for breast cancer.

The onset of breast cancer appears to occur, on average, a decade earlier in Mexican women in comparison to American or European women. Early detection and prevention of breast cancer are of crucial importance to increase survival and improve quality of life. Based on the molecular elucidation of critical events leading to breast carcinogenesis, a tandem immuno-capturing blood test was developed as a quantitative population screening assay in view of providing a cost-effective and non-invasive alternative to population screening. Clinical analysis of 63 Mexican women within an age group of 35-70, revealed that Interstron activity increases from 800+/-65 IUJPA (Interstron Units) in the asymptomatic normal women to 994+/-100 IUJPA in the symptomatic/benign group, reaching 1289+/-81 IUJPA in the cancerous group. Accordingly, activity thresholds were established at 800 and 1200 IUJPA respectively, encompassing three risk groups: (i) Healthy Otherwise Normal (<800 IUJPA); (ii) Grey Risk Area (>800 and <1200 IUJPA), and (iii) At Risk group (>1200 IUJPA). Taking into account both baseline and clinical case reports, the Healthy Otherwise Normal group and the At Risk group were mostly homogeneous in nature, comprising a population of normal and cancer patients respectively. The Grey Risk group is heterogeneous, likely reflecting a transitional nature towards a potential early stage of breast disease development. Based on these results, a screening algorithm was developed as the underlining principle for population surveillance encompassing over 30,000 Mexican women. The current screening results have enabled us to objectively prioritize medical attention to approximately 1 in 8 women out of the general population mapped within the At Risk group. Overall, our findings suggest that monitoring Interstron activity units provides a valuable quantitative screening analysis as to selectively streamline the population of women in need of early medical counseling and/or mammography, thereby enhancing both the quality and cost-effectiveness of preventative population surveillance programs targeting breast cancer.

[Sanitary quality of ham eaten in Mexico City]. / Calidad sanitaria del jamón que se consume en la ciudad de México.

Microbiological results of 2,539 hams were analyzed (counts of mesophilic aerobes, Salmonella sp. and S. aureus) at the National Public health Laboratory from 1979 to 1987. In 58.7 percent of the cases the hams were not acceptable for human consumption, due to any of the above mentioned microbiological determinations. The main cause was the finding of high levels of mesophilic aerobes (57.5%), followed by Salmonella sp (4.4%) and S. aureus (0.43%). Raw, cooked and smoked hams presented the highest counts of mesophilic aerobes. Virginia, american style and blade hams presented the most elevated frequencies of Salmonella sp. Baked ham was the one in better sanitary conditions. The conclusion is that the quality of hams in Mexico City is bad.

[Sanitary control of food in Mexico city]. / Control sanitario de alimentos en la ciudad de México.

This work was undertaken as to avoid health risks to tourism in the "XIIth Soccer World Cup, Mexico 86". The above project was carried out through proper quality control of foods, drinking water as well as a definite care of personal hygiene of all those involved in the catering business (132 restaurants were included). The mentioned report informs only of the work of the National Public Health Laboratory in the Sanitary Epidemiological Program. The following products were analyzed: 133 water samples, 272 animated and nonliving surfaces, and 399 foods. Twenty seven percent of water samples were rejected, as well as 85% of the different surfaces and 60% of the food samples. High counts of mesophilic aerobics, followed by coliforms, S. aureus and Salmonella sp., were the principal specimens encountered. Therefore, it was suggested the permanent development of a sanitary epidemiological program.

Taenia solium taeniasis and cysticercosis in a Mexican village.

One hundred and twenty-four persons, nearly the entire population of a rural village in Hidalgo State, were screened for intestinal parasites and clinical or serologic (ELISA) evidence of Taenia solium cysticercosis. Heads of households were questioned about dietary and other practices that might lead to pork tapeworm transmission, and soil samples were examined for helminth eggs. Twenty-five percent of local pigs had cysticerci visible by examination of the undersurface of their tongues. Four persons passed taeniid eggs, 7 were seropositive, and 10 gave medical histories suggestive of neurodysticercosis. Most seropositive persons were not symptomatic and the reverse was also true. The clustered distribution of infected pigs, tapeworm carriers, and persons with serologic or clinical evidence of cysticercosis suggested intrahousehold transmission. Dietary and sanitary practices were generally optimal for transmission of pork tapeworm. No cattle were kept in the village and beef was rarely eaten. This preliminary report attempts to characterize T. solium transmission in communities with endemic disease in rural Mexico and illustrates some of the methodological problems faced by epidemiologists who study this disease.