Spa Region Research Articles

Development of a Binational Framework for Active and Healthy Ageing (AHA) Bridging Austria and Slovenia in a Thermal Spa Region.

In view of ongoing demographic developments resulting in a longer life expectancy of the European population, the creation of “age-friendly” environments represents an initiative picked up by the European Union and its Member States to enable active and healthy ageing. The present study aims at the co-creation of a cross-border framework model to deploy a healthy ageing region linking Austria and Slovenia, building on previous work dealing with the development of an integrated regional ecosystem for active and healthy ageing. A qualitative, community-based action research method based on focus group discussions allowed the development of an exemplary framework model for active and healthy ageing building on cross-border collaboration in the region of Promura. Within the project group, twelve cross-border regional key assets were identified. In the course of further open discussions, an exemplary model for the deployment of a cross-border healthy ageing region was developed, comprising underlying fundamental environmental aspects, regional structures in the field of health and care as well as crosscutting features spreading across all levels. This article presents a promising, strategic co-creation approach on how to span a model on active and healthy ageing across two cross-border regions with similar characteristics and assets.

Mobile genetic elements responsible for discordant Staphylococcus aureus phenotypes and genotypes in the same blood culture bottle

Approximately 15–20% of the S. aureus genome contains mobile genetic elements that can cause discrepancies between phenotypic and genotypic identification methods. Three blood culture bottles (each from a different patient) that showed discordant results, were shown to contain 2 S. aureus isolates after additional subcultures. One bottle had MRSA and MSSA that by DNA sequence analysis differed only by 31 kb; however, the deletions encompassed parts of SCCmec including mecA and SCCM1. The second bottle contained MRSA and MSSA that differed by 124 kb; the MSSA was missing the entire SCCmec and spa regions. The last bottle contained 2 MRSA, one with ACME II disrupting SCCmec and a 24 bp spa deletion. The deletions in SCCmec and the other elements gave rise to the discrepancies between molecular and the original culture results. Such discrepancies should prompt a search for additional strains in the blood culture bottle.

Individual rationality and differences in Taiwanese spa hotel choice

This study explored a systematic framework to understand the dynamic relationships of individual rationality in spa hotel choice. Taking a relational perspective, we examined the process of net value perception linking the antecedents (i.e. quality, price and risk) and consequence (i.e. willingness to buy (WTB)), along with the moderating effects of demographic variables on the links. A survey was conducted at spa hotels in four major spa regions of Taiwan. The findings indicated that the immediate situational factors of quality and price contribute to the net value perception, which in turn leads to the WTB. Oppositely, the long-term factor of risk does not have either direct or indirect effect when making such an infrequent decision. The contrarily moderating effects of demographic variables (e.g. gender, living region and consumptive frequency) on the decision paths present managers with directions to offer proper packages to reach their target customers.

A Conception of a Mountain Geopark in a SPA region; example of a projected Geopark „Wisłok Valley - The Polish Texas”, in the Krosno region.

The Polish Geological Institute – National Research Institute (PGI – NRI), in cooperation with AGH University of Science and Technology in Krakow carried out the project of new geopark in Poland – “Wislok Valley – The Polish Texas”. It is located in the Polish Outer Carpathians (SE part of Poland). Oil fields, mineral water, nappe tectonics and other geological components of the Outer Carpathians constitute important elements of the geodiversity of this region. The area is located in the Krosno neighbourhood and encloses a zone of about 1000 km2. The Iwonicz-Zdroj – Rymanow-Zdroj SPA region is also included in the research area. It covers 20 municipalities of the Podkarpackie province. For the project of the Geopark, a geotouristic map, geosites, geological-educational paths, website, advertising brochures, geological-educational tables and a movie were made, which promote geotourism. The final product will be targeted at regional and local public administration bodies, national and landscape Parks, the State Forests National Forest Holding and local tourist organizations. // Panstwowy Instytut Geologiczny – Panstwowy Instytut Badawczy we wspolpracy z Akademią Gorniczo-Hutniczą w Krakowie zrealizowal projekt nowego geoparku w Polsce „Dolina Wisloka – Polski Teksas”. Ma sie on znajdowac w Karpatach zewnetrznych. Zloza ropy naftowej, wody mineralne, tektonika plaszczowinowa i inne geologiczne cechy Karpat zewnetrznych skladają sie na georoznorodnośc tego rejonu. Obszar tego opracowania obejmowal ponad 1000 km2 w rejonie Krosna wlączając w to rowniez teren uzdrowisk Iwonicza-Zdroju i Rymanowa Zdroju. Projekt ten objąl swym zasiegiem 20 gmin wojewodztwa podkarpackiego. W ramach projektu wykonano mape geologiczno-turystyczną, udokumentowano ponad 150 geostanowisk i zaprojektowano dziewiec ściezek geologiczno-edukacyjnych. Przygotowano tez dwa foldery, 12 tablic geologiczno-edukacyjnych, zaprojektowano strone internetową o projekcie oraz nakrecono film promocyjny. Produkt koncowy skierowany jest do wykorzystania w promocji regionu do samorządow lokalnych, parkow krajobrazowych i narodowych, lasow panstwowych oraz lokalnych organizacji turystycznych.

New <i>Spa</i> Types among MRSA and MSSA Isolates in North of Iran

Staphylococcus aureus typing using gene encoding protein A (spa typing) seems to have a high potential discriminatory power for typing this bacterium. This study was designed based on spa typing method to compare the S. aureus types among healthy carrier vs patients, and MRSA vs MSSA isolates. Method: This study was carried out on 182 spa typeable S. aureus isolates, including 52 MRSA. DNA was extracted by phenol chloroform-isoamyl alcohol method and it was amplified by specific primer of polymorphic X region of spa. Spa types were determined by Ridom Staph Type software. The spa types distribution among MRSA vs MSSA and healthy carrier vs patients, isolates were statistically compared by X2 method and P < 0.05 was considered as significant. Result: The most common types of spa in our region were t037 (18.3%) and t937 (13.9%) from 50 spa types which were identified in this study. spa types in this study were isolated from various age groups but t660 spa types were only isolated from children. Distribution of all spa types among MRSA and MSSA isolates was 16 and 38 types, respectively which is significant. In this study we found seven new spa types (belong to twelve isolates) which are reported for the first time. In 5 out of the above 7 new types the 24 bp repeated sequences in spa gene X region were already recognized but their 24 bp arrangement is introduced in our present investigation. In the remaining 2 new types we found new 24 bp nucleotide sequences which are also introduced for the first time in our present study. Conclusion: The distribution of spa types in MSSA strains was significantly higher than MRSA isolates, but there are not any specific spa types for discrimination between MRSA and MSSA. The novelty of our study is the introducing 7 new spa types including 2 new 24 bp repeated sequences in the X region of spa gene.

Decision-making Framework of Customer Perception of Value in Taiwanese Spa Hotels

In this study we examined the framework linking antecedents of perceived value and willingness to buy in the Taiwanese spa hotel industry. We developed 6 hypotheses to identify the factors that are evaluated by customers. Hierarchical multiple regression analysis of data collected from hotels in 4 major spa regions in Taiwan revealed that the source of multicollinearity among the antecedents resulted in perceived value, which was positively associated with willingness to buy, being assigned varying levels of importance. The results also confirmed the 2 distinct and different effects of perceived price to perceived value and perceived quality in the service domain. Our findings could be used for comparative studies of value perception in other service industries and cultural settings.

Assessment of recharge and flowpaths in a limestone thermomineral aquifer system using environmental isotope tracers (Central Portugal)

We conducted chemical and isotopic analyses to develop and test a hydrogeological model of thermomineral water circulation in a limestone aquifer system at Caldas da Rainha (Central Portugal), contributing to future borehole-drilling and development strategies, with the aim of extracting waters with the best possible flow and/or temperature. The thermomineral waters (T ≈ 33 °C) discharge from springs and boreholes located close to a locally N–S-oriented oblique fault (60°E) that places loamy and detritic Upper Jurassic rocks and Hettangian-Rhaetian marls (and evaporitic deposits) in contact. 14C determinations indicate a pmC content between 29.33±0.14 and 44.39±0.20 pmC. The presence of HCO, Ca2+ (and Mg2+) are ascribed to water–limestone interactions, while Na+, Cl− and SO concentrations are mainly associated with the dissolution of halite and gypsum lenses found along the regional syncline structure. The δ18O values of Caldas da Rainha thermomineral water were slightly lower than those of shallow groundwater from the Upper Jurassic rocks, suggesting the existence of two distinct aquifer systems. The different isotopic composition of water also indicates that the main recharge of the thermomineral waters likely occurs in the Middle and Lower Jurassic limestone formations of the Candeeiros Mountains. The presence of 3H (from 1.1 to 2.8 TU) in some thermomineral borehole waters (showing rather similar geochemical signatures) suggests mixing of small amounts of shallow groundwater with thermomineral waters, as a result of leaking borehole casing construction or a recharge when the 3H content in the atmosphere was higher than that at present. Caldas da Rainha thermomineral waters having δ34Ssulphate and δ18Osulphate values between+14.9 and+19.1 ‰ and+11.1 and+16.2 ‰, respectively, indicate that the sulphate is the result of water–rock interaction with evaporitic formations. The obtained chemical and isotopic data have informed the further development of a hydrogeological model that will be used by decision-makers, in order to contribute to the socio-economic development of the spa region.

Tourist phenomenon in Geoagiu Spa region within the Central Metaliferi Mountains

Tourist phenomenon in Geoagiu Spa region within the Central Metaliferi Mountains

Stan i perspektywy rozwoju bazy noclegowej w obwodzie lwowskim

Lviv Oblast can be proud of most favourable conditions for the development of various forms of tourism. It is a region of unique environmental features, characterized both by lowlands and mountain ranges with large share of protected areas. Tourist functions of the region are proven by numerous cultural heritage sites, especially in such a centre as the city of Lviv. In Lviv there are over three thousand monuments, which makes it a unique “city – museum”, recognized by UNESCO within its list of World Heritage Sites. Lviv Oblast is one of the most important spa regions in Ukraine, with the main spa resort of Truskawiec, which has been recently undergoing a whole range of structural changes. For many years a deficit of tourist accommodation has been observed, both in Lviv itself and in other areas of the region. Another drawback is low quality of the offered services, which is caused by the low standard of available facilities.

Structural model of surfactant protein A (SP‐A) ‐‐ peroxiredoxin 6 specific interaction

Peroxiredoxin 6 (Prdx6), the only bifunctional member of the peroxiredoxin super family, exhibits both phospholipase A2 (PLA2, pH 4.0) and phospholipids hydroperoxide GSH-peroxidase (pH 7.0) activities. PLA2 activity of Prdx6 is essential for normal lung surfactant metabolism. SP-A binding to Prdx6 non-competitively inhibits its PLA2 activity although the mechanism of the SP-A-Prdx6 interaction is unknown. Prdx6 in solution is found in a monomer-homodimer equilibrium; SP-A is octadecameric with homotrimer as a major structural element. Evaluation of SP-A-Prdx6 interaction using ZDOCK (http://zlab.bu.edu/zdock/) resulted in a highly scored model indicating that monomer of the Prdx6 homodimer can interact with one homotrimeric unit of SP-A. Two structural recognition elements were found: one between α-helixes that provides electrostatic interaction between the hydrophobic stem region of SP-A (D84EELQTELYEIKHQIL99) and a short helix in the C-terminal region of Prdx6 (P194EEEAKKLFPK204), and another between adjacent β-strands of Prdx6 (179DWK182) and SP-A (180LDG183) provides hydrophobic interaction. Both sites are ~25Å apart from the PLA2 catalytic triad which is considered to be the phospholipid substrate binding site. This model is in agreement with the non-competitive inhibition of Prdx6 PLA2 activity by SP-A as reported recently. As a test of the model SP-A did not affect Prdx6's GSH-peroxidase activity towards phospholipid hydroperoxide substrate. The proposed model indicates that the two independent enzymatic activities of Prdx6 may share the same binding site for phospholid substrates.

Networking Trends of Small Tourism Businesses in Post‐Socialist Slovakia

It is argued that the development of small economic enterprises is vital for transitioning economy (Gibb 1993; Gibb and Haas 1996). Small businesses provide an outlet for many specialized workers to start their own firm, thus providing foundation for newly transitioning economy (Erutku and Vallee 1997). This philosophy has led to a very substantial growth of the micro-small business sector over the past half-dozen years (Charap, quoted in Gibb 1993, p.461), and this growth is the reason for the expansion of many new firms, particularly in the service sector (Gibb 1993). Tourism development is playing strong role in the service sector boom. Research suggests that the industry can be an area of high growth during economic transition, due to the low requirements of human capital needed to gain entry (Szivas and Riley 1999). Academics have become interested in studying the interaction among firms, both large and small. Network theory, as applied to the business world, views businesses as spatial nodes and the interactions between them as linkages. Most academic literature on this topic is focused on manufacturing. A very small literature exists on the use of networks in the service sector, and even less on the sector. The greater attention to the manufacturing sector in networking studies is probably due to the historical importance of manufacturing in global economic development (Roehl 1998). However, with the service sector playing more prevalent role in the global economy, research pertaining to service sector networks is growing (Afford 1998; Echtner 1995; Roehl 1998; Selin and Meyers 1998; Shaw and Williams 1998). Whereas manufacturing firms network mainly for the purposes of resource and product development, service firms tend to enter partnerships more for marketing and training purposes. Afford (1998), for example, focuses on how regional tourist boards seek to establish market position, and how they benefit from networking with other sectors of the industry. Selin and Meyers (1998) investigate network usage by examining regional public/private association between agencies and public land management bureau. The goal of this article is to combine the fields of small business behavior, transition economies, and development. Specifically the reorganization of the industry within transition economy and the usage of networks by small businesses will be analyzed in case study of the Slovak Republic. Geographic differences between these small businesses and their use of networks will be an underlying theme of this research. Tourism in East Central Europe in the 20th Century East Central Europe is currently in political and economic transition. The post-WW2 adoption, and in most cases the recent dismissal, of communist ideology, will be briefly discussed within framework. The century will be divided into three periods: pre-social tourism, tourism, and post-social tourism. According to Vuoristo (1981), demand for in East Central Europe was relatively low before the 1950s. This was in part due to low disposable income among the local population and lack of interest from outside the region. A few exceptions existed, however, such as the isolated spa resorts found in East Central Europe that catered to the wealthy west Europeans and nobility. Thus, during this period domestic was almost nonexistent, and international tourists were few and spatially concentrated in spa regions. During the communist era, tourism's potential was eventually realized, demanding need for the formation of state-controlled agencies to administer activities (Kreck 1998). Domestic tourism, which was stressed over international tourism, was seen as necessary activity for the working masses, and has been dubbed social tourism in the literature (Allcock and Przeclawski 1990; Hall 1993, 1991). …

Importance of the carboxy-terminal 25 amino acid residues of lung collectins in interactions with lipids and alveolar type II cells.

Surfactant proteins A and D (SP-A and SP-D) are structurally related members of the collectin family found in the alveolar compartment of the lung. SP-A binds dipalmitoylphosphatidylcholine (DPPC) and galactosylceramide (GalCer), induces liposome aggregation, and regulates the uptake and secretion of surfactant lipids by alveolar type II cells in vitro. SP-D binds phosphatidylinositol (PI) and glucosylceramide. The purpose of this study was to identify a critical stretch of primary sequence in the SP-A region Cys(204)-Phe(228) and the SP-D region Cys(331)-Phe(355) that is involved in protein-specific lipid and type II cell interactions. Chimeras ad1 and ad2 were constructed with rat SP-A/SP-D splice junctions at Cys(218)/Gly(346) and Lys(203)/Cys(331), respectively. Chimera ad1 but not ad2 retained DPPC liposome binding activity. Both chimeras retained significant binding to GalCer liposomes. Chimera ad1 did not bind to PI, whereas chimera ad2 acquired a significant PI binding. Both chimeras failed to induce liposome aggregation and to interact with alveolar type II cells. In addition, monoclonal antibody 1D6 that blocks specific SP-A functions did not recognize either chimera. From these results, we conclude that (1) the SP-A region Leu(219)-Phe(228) is required for liposome aggregation and interaction with alveolar type II cells, (2) the SP-A region Cys(204)-Cys(218) is required for DPPC binding, (3) the SP-D region Cys(331)-Phe(355) is essential for minimal PI binding, and (4) the epitope for mAb 1D6 is located at the region contiguous to the SP-A region Leu(219)-Phe(228).

Survival and Detection of Shigella flexneri in Vegetables and Commercially Prepared Salads

The normal bacterial microflora of 4 commercially prepared salads (coleslaw, crab salad, carrot salad, and potato salad) and 3 vegetables (green pepper, onion, and cabbage) were evaluated. Twenty-eight species of bacteria, including potential pathogens, were isolated. The foods were artificially inoculated with an avirulent mutant strain of Shigella flexneri 5 (pHS1059) to develop a method for the rapid detection of Shigella spp. Bacteria were separated from insoluble and particulate salad ingredients by filtration through shark skin filter paper and by low speed centrifugation. S. flexneri survived at 4 degrees C in all salads for at least 11 days and up to 20 days in crab salad. The polymerase chain reaction (PCR), using primers for amplification of a 118-base pair DNA fragment from the virulence-associated spa region, present in all Shigella spp., was used to detect S. flexneri in filtrates from salads inoculated with S. flexneri 5 (pHS1059). DNA was amplified from all of the artificially contaminated salads and vegetables except green pepper. After 3-5 days of storage, the PCR also amplified S. flexneri DNA from salads that had been enriched with nutrients to increase the number of bacteria. Green peppers contained a PCR inhibitory substance that was attenuated by dilution and enrichment before the PCR. No amplification of DNA was observed in foods to which S. flexneri had not been added.

Evaluation of Natural Radiation in Kestanbol Spa Region

Gamma background radiation measurements were made in the region of Kestanbol Spa, the outdoor and indoor air radon concentrations were measured in Kestanbol spa and in about 50 houses of Koruktasi village, which is located at 1 km from the Spa. The results were evaluated from a radiological point of view. The total annual effective dose received from natural sources by the inhabitants of the village and the workers at the Spa were calculated and compared with the total annual effective dose received by the inhabitants of Istanbul.

Indoor Radon and Radon Emanation in the Herculane Spa (Cerna Valley) Area - Romania

Recent investigations have shown a connection between high indoor levels of radon and lung cancer risk. The main source of the radon is the emanation from soil and ground water. A study has been carried out in the Herculane Spa region, where the highest level of radioactivity (226Ra and 222Rn) from geother mal waters in Romania has been measured. This paper presents data about the radon emanation rate and indoor radon concentrations measured in the area studied. Only 20% of the measurements of indoor radon concentrations were values above 200 Bq·m-3 (average 98 Bq·m-3) when the weather was warm but in the cold season 40% of the radon levels indoors (average 185 Bq·m-3) exceeded this value. For radon emanation rates we generally found values in the range 13-70 mBq·m-2·s-1 although they were significantly higher in the vicinity of the geological faults found in the area.

Radon in various environmental samples in the Herculane Spa, Cerna Valley, Romania

Early measurements in the Herculane Spa region showed high helium content (6 mL/L) and high radon concentrations (up to 7.4 MBq m −3) for the emanated gases which accompany geothermal waters originating in the hydrogeothermal deposit existing in this area. This paper presents new data on the radon exhalation rate from soil, and indoor radon in some buildings in this resort. The greater values obtained in two places for radon flux are probably caused by transversal faults in this area. In the winter, the indoor radon mean value is two times greater than the summer value. The Ra, U, Th, and K content for six soils sampled in the vicinity of the site of radon flux measurement were also determined. The values obtained are somewhat higher than the values expected as a consequence of surface granitic rocks in this region. Large 137Cs deposits were found (up to 950 Bq kg −1).

Surveys of concentration of radon isotopes in indoor and outdoor air in Japan

A series of radon and 220Rn surveys using passive radon 220- Rn discriminative dosimeters were conducted in the Masutomi radium spa region, Yamanashi Prefecture, and at several subway stations in Metropolitan Tokyo. In Masutomi, the highest outdoor radon concentration was 569.8 ± 59.5 (SE) Bq m −3 and the lowest, 7.4 ± 0.1 (SE) Bq m −3, while the highest outdoor 220 Rn concentration was 142.8 ± 52.7 (SE) Bq m −3 at 0.04 m above the ground. The outdoor 220Rn concentrations at some survey sites increased as the ground surface approached. The highest radon and 220Rn concentrations in the public bathhouse were 530.2 ± 74.4 (SD) Bq m −3 and 592.0 ± 226.8 (SD) Bq m −3, respectively. Average indoor radon concentrations in the two houses in Masutomi, were 35.9 ± 2.9 (SE) Bq m −3 and 14.2 ± 1.4 (SE) Bq m −3, respectively. Indoor and outdoor radon and 220Rn concentrations within a square kilometer region in Masutomi showed the irregular distributions, which might be easily influenced by the local geology and meteorology at each survey site. Average radon concentrations at several subway stations in Metropolitan Tokyo were 10.9 ± 1.1 (SE) Bq m −3, which was unexpected. Significant 220Rn concentrations were not observed at all survey sites (except some platforms, where values ranged from 11–12 Bq m −3) since the ventilation system of all subway stations exchanged the stale air with the fresh air above ground entirely.

Enteropathogenic Escherichia coli contains a putative type III secretion system necessary for the export of proteins involved in attaching and effacing lesion formation.

Enteropathogenic Escherichia coli (EPEC) causes a characteristic histopathology in intestinal epithelial cells called the attaching and effacing lesion. Although the histopathological lesion is well described the bacterial factors responsible for it are poorly characterized. We have identified four EPEC chromosomal genes whose predicted protein sequences are similar to components of a recently described secretory pathway (type III) responsible for exporting proteins lacking a typical signal sequence. We have designated the genes sepA, sepB, sepC, and sepD (sep, for secretion of E. coli proteins). The predicted Sep polypeptides are similar to the Lcr (low calcium response) and Ysc (yersinia secretion) proteins of Yersinia species and the Mxi (membrane expression of invasion plasmid antigens) and Spa (surface presentation of antigens) regions of Shigella flexneri. Culture supernatants of EPEC strain E2348/69 contain several polypeptides ranging in size from 110 kDa to 19 kDa. Proteins of comparable size were recognized by human convalescent serum from a volunteer experimentally infected with strain E2348/69. A sepB mutant of EPEC secreted only the 110-kDa polypeptide and was defective in the formation of attaching and effacing lesions and protein-tyrosine phosphorylation in tissue culture cells. These phenotypes were restored upon complementation with a plasmid carrying an intact sepB gene. These data suggest that the EPEC Sep proteins are components of a type III secretory apparatus necessary for the export of virulence determinants.

Survival of Shigella flexneri on Vegetables and Detection by Polymerase Chain Reaction

Commercially prepared and packaged fresh vegetables were tested to determine the types and levels of indigenous microflora. Sixteen species of bacteria from 11 genera were identified and titers of up to 1 × 1010 cells per gram of vegetable were observed. To evaluate the survival of Shigella spp. on packaged vegetables, an avirulent insertion mutant of Shigella flexneri 5 (pHS 1059) was added to vegetables. This strain survived in phosphate-buffered saline at pH 7.3 at 5 to 10°C for more than 3 months. It also survived for several days at both ambient and refrigerator temperatures when inoculated onto various commercially prepared vegetables. A rapid method for detecting Shigella spp. on vegetables was developed by using the polymerase chain reaction (PCR) to amplify a 118-base-pair DNA fragment from the S. flexneri virulence-associated spa region. The PCR also generated the corresponding fragments from S. sonnei, S. boydii, and Shigella sp. This fragment was also observed when S. flexneri cells were used to artificially contaminate sterile and nonsterile vegetables, but no amplified fragment was observed when the normal microflora of the vegetables were eluted and tested by PCR.

Binding of calcium to SP-A, a surfactant-associated protein

SP-A is a lung-specific pulmonary surfactant-associated protein containing a calcium-dependent carbohydrate recognition domain and collagen-like sequence. The protein is a major component of the extracellular form of surfactant known as tubular myelin. SP-A is thought to influence the surface properties of surfactant lipids and regulate the turnover of extracellular surfactant through interaction with a specific cell-surface receptor. These properties of SP-A are dependent on the presence of calcium. We have estimated calcium binding parameters for SP-A from binding data obtained by equilibrium dialysis and gel permeation chromatography. Our results suggest that each SP-A monomer binds two to three calcium ions in conditions chosen as similar to those found in the alveolar lumen. The binding data are best fit to a model incorporating two calcium binding sites with different affinities. Studies with a fragment of SP-A generated by limited proteolysis suggest the higher affinity site for calcium is located in the noncollagenous carboxy-terminal end of SP-A. This region of SP-A contains a carbohydrate recognition domain homologous to other C-type lectins. The binding of calcium to this region of SP-A causes a conformational change as assessed by a small change in the intrinsic fluorescence spectrum and a marked change in the susceptibility to proteolysis. At physiological calcium concentrations, intact SP-A aggregates in a reversible fashion, a property that may be relevant to the formation of tubular myelin.