Advances on structuring, integration and magnetic characterization of molecular nanomagnets on surfaces and devices.

This critical review represents a concise revision of the different experimental approaches so far followed for the structuration of molecular nanomagnets on surfaces, since the first reports on the field more than ten years ago. Afterwards, a presentation of the different experimental approaches followed for their integration in sensors is described. Such work involves mainly two families of sensors and devices, microSQUIDs sensors and three-terminal devices for single-molecule detection. Finally the last section is devoted to a detailed revision of the different experimental techniques that can be used for the magnetic characterization of these systems on surfaces, ranging from magnetic circular dichroism to magnetic force microscopy. The use of these techniques to characterize other nanostructured magnetic materials, such as nanoparticles, is also revised. The aim is to give a broad overview of the last advances achieved with these techniques and their potential and evolution over the next years.

Limbic encephalitis secondary to neuro-Behcet disease: an uncommon presentation. / Encefalitis límbica secundaria a neuro-Behçet: una presentación insólita.

INTRODUCTION: Limbic encephalitis (LE) can have a wide range of etiologies, most frequently infectious (especially viral) or autoimmune. Behcet's disease (BD) can present with heterogeneous neurological manifestations. However, LE is not considered a typical presentation of neuro-Behcet's disease (NBD). CASE REPORT: A 40-years-old male presented with new-onset subacute headaches, memory problems and apathy. A review of systems revealed an unrecorded past history of recurrent oral sores for years, recent malaise and fever, as well as an episode of bilateral panuveitis four months before presentation. His general and neurologic examination revealed slight fever, an isolated oral aphtha, anterograde amnesia and signs of bilateral retinal vasculitis. Brain magnetic resonance imaging displayed a pattern of limbic meningoencephalitis, and his cerebrospinal fluid showed mononuclear inflammation. The patient met BD diagnostic criteria. Considering LE is a very rare presentation of NBD, alternative etiologies were thoroughly assessed and excluded, including infectious, autoimmune and paraneoplastic encephalitis. Therefore, he was diagnosed with NBD, and he recovered well after immunosuppression. DISCUSSION: Only two cases of NBD presenting with LE have been previously reported. We report a third case of this rare presentation and compare it with the previous two. We aim to highlight this association and contribute to enlarge the rich clinical spectrum of NBD.

TITLE: Encefalitis límbica secundaria a neuro-Behçet: una presentación insólita.Introducción. La encefalitis límbica (EL) puede tener un amplio abanico de etiologías, más frecuentemente la infecciosa (sobre todo viral) o autoinmune. La enfermedad de Behçet (EB) puede presentarse con manifestaciones neurológicas heterogéneas. Sin embargo, la EL no se considera una presentación típica del neuro-Behçet (NB). Caso clínico. Varón de 40 años que consultó por cefalea de novo subaguda, problemas de memoria y apatía. La anamnesis por sistemas reveló una historia no conocida previamente de aftas orales recurrentes durante años, fiebre y afectación general reciente, así como un episodio de panuveítis bilateral cuatro meses antes de la presentación. Su exploración general y neurológica reveló febrícula, una afta oral aislada, amnesia anterógrada y signos de vasculitis retiniana bilateral. La resonancia magnética mostró un patrón de afectación de meningoencefalitis límbica y su líquido cefalorraquídeo presentaba inflamación mononuclear. El paciente cumplía los criterios diagnósticos de la EB. Considerando que la EL es una presentación muy rara del NB, se buscaron exhaustivamente y se excluyeron otras etiologías alternativas, incluyendo las encefalitis infecciosas, autoinmunes y paraneoplásicas. En consecuencia, el paciente se diagnosticó de NB y mostró una buena recuperación con tratamiento inmunosupresor. Discusión. Sólo dos casos de NB con presentación en forma de EL se han publicado previamente. Comunicamos el tercer caso de esta rara manifestación clínica de la EB y lo comparamos con los dos anteriores, con el objetivo de destacar dicha asociación y contribuir a expandir el rico espectro clínico del NB.

[Management of neurogenic bladder patients in France: a survey carried out by the French-speaking neurourology study group (GENULF)]. / Prise en charge des patients ayant une vessie neurologique en France: une enquête du groupe d'études de neuro-urologie de langue française (GENULF).

OBJECTIVE: To design and run a survey aiming at investigating urologists' and physiatrists' clinical practices in France when managing neurogenic bladder patients. PATIENTS AND METHODS: Three thousand one hundred and eighty questionnaires were sent to the members of four French societies involved in treating neurogenic bladder dysfunction. Questions were focused on consultations, clinical follow-up and patient management. RESULTS: Two hundred and seventy-four urologists and 109 physiatrists completed the questionnaire. The frequency of systematic follow-up differed between urologists (6 months) and physiatrists (12 months). Upper urinary tract imaging and systematic urodynamic follow-up were usually performed yearly. The latter was carried out by 56% urologists and 83% physiatrists. Urinary retention was essentially treated by intermittent catheterization. Less than 15% of urologists and physiatrists were treating bacteriuria. Symptomatic urinary infections were treated for 11 to 12 days (men) and for 8 to 9 days (women). To treat their patients, both specialists used self-catheterization education and botulinum toxin A injections. CONCLUSION: Our survey showed differences in approach between urologists and physiatrists in the management of patients with neurogenic bladder dysfunction. Their clinical practice was most of the time in line with national and international guidelines.

Spanish translation and linguistic validation of the North Star Ambulatory Assessment for Duchenne muscular dystrophy functional evaluation. / Traducción al español y validación lingüística de la escala North Star Ambulatory Assessment para la evaluación funcional de la distrofia muscular de Duchenne.

INTRODUCTION: There is a need for reliable and properly validated outcome measures in Duchenne muscular dystrophy, both to monitor functional impairment and to assess the impact of new therapies. OBJECTIVE: We aimed to perform a translation of the North Star Ambulatory Assessment scale into Spanish and a linguistic validation of the resulting Spanish version. MATERIALS AND METHODS: A structured multistage process based on international guidelines was used, with the following steps: translation (preparation, forward translation, reconciliation, back translation, back translation review, clinicians' review), linguistic validation though pilot testing (cognitive interviewing, medical review, review of results and final changes), and finalization (proofreading, final report). RESULTS: No major difficulties were found during translation steps. Few changes were needed to reconcile forward translations. The linguistic validation process required several meetings to solve comprehension difficulties due to subtle nuances in the meaning of some words. The pilot study was carried out in 10 practitioners from different places in Spain, including both physiotherapists and specialists and registrars in physical medicine and rehabilitation. A total of 6 comments were obtained, including 2 comments on starting positions for items 4-5 (stand on one leg) and item 10 (stand on heels) and 2 comments on scoring instructions for item 3 (stand up from chair) and item 14 (jump). CONCLUSION: Our study has resulted in a convenient and reliable instrument for the quantification of functional abilities in boys with Duchenne muscular dystrophy in Spain. Our innovations in methods and our results could be used as a suggested template for the North Star Ambulatory Assessment linguistic validation in other languages.

TITLE: Traducción al español y validación lingüística de la escala North Star Ambulatory Assessment para la evaluación funcional de la distrofia muscular de Duchenne.Introducción. En la distrofia muscular de Duchenne son necesarias medidas de evaluación fiables y validadas para el seguimiento del deterioro funcional y de los efectos de los nuevos tratamientos. Objetivo. Se realizó una traducción, seguida de validación lingüística, de la escala North Star Ambulatory Assessment al español. Materiales y métodos. Se utilizó un proceso estructurado, de múltiples etapas, basado en las guías internacionales, con los siguientes pasos: traducción (preparación, traducción directa, reconciliación, retrotraducción, revisión de la retrotraducción y revisión por médicos clínicos), validación lingüística mediante una prueba piloto (entrevista cognitiva, revisión médica, revisión de resultados y ajustes finales) y finalización (revisión de pruebas e informe final). Resultados. No surgieron dificultades importantes durante los pasos de traducción. La reconciliación de las traducciones directas requirió pocos cambios. En la validación lingüística fueron precisas varias reuniones para resolver dificultades de comprensión, en matices sutiles, en el significado de algunas palabras. El estudio piloto se realizó con 10 especialistas clínicos de diferentes lugares de España (fisioterapeutas y especialistas o residentes de medicina física y rehabilitación). Hubo seis comentarios, dos de ellos sobre las posiciones de partida en los ítems 4-5 (de pie sobre un solo pie) y 13 (de pie sobre los talones), y dos sobre las instrucciones de puntuación para los ítems 3 (levantarse de la silla) y 14 (saltar). Conclusión. Nuestro estudio ha proporcionado un instrumento cómodo y fiable para cuantificar las capacidades funcionales en niños con distrofia muscular de Duchenne en España. Las innovaciones en el método y nuestros resultados podrían usarse como modelo para la validación lingüística en otros idiomas.

Flood analysis in mixed-urban areas reflecting interactions with the complete water cycle through coupled hydrologic-hydraulic modelling.

The potential devastating effects of urban flooding have given high importance to thorough understanding and management of water movement within catchments, and computer modelling tools have found widespread use for this purpose. The state-of-the-art in urban flood modelling is the use of a coupled 1D pipe and 2D overland flow model to simultaneously represent pipe and surface flows. This method has been found to be accurate for highly paved areas, but inappropriate when land hydrology is important. The objectives of this study are to introduce a new urban flood modelling procedure that is able to reflect system interactions with hydrology, verify that the new procedure operates well, and underline the importance of considering the complete water cycle in urban flood analysis. A physically-based and distributed hydrological model was linked to a drainage network model for urban flood analysis, and the essential components and concepts used were described in this study. The procedure was then applied to a catchment previously modelled with the traditional 1D-2D procedure to determine if the new method performs similarly well. Then, results from applying the new method in a mixed-urban area were analyzed to determine how important hydrologic contributions are to flooding in the area.

The anionic peptide fraction is present on the gallbladder apical epithelium and favours biliary cholesterol absorption.

BACKGROUND/AIMS: We investigated (a) in vitro and in vivo the changes of biliary mass of the anionic peptide fraction, apolipoproteinA-I, immunoglobulin-A, albumin and cholesterol over time in the excluded gallbladder and (b) in vivo the localization in the gallbladder epithelium of the anionic peptide fraction and cholesterol absorbed from bile. METHODS: Native bile was substituted with pig bile containing radiolabeled cholesterol in the in vitro isolated intra-arterially perfused pig gallbladder (n=9) and in vivo in anestethized pigs with excluded gallbladders (n=6). The amount of cholesterol (scintillation counting) and proteins (enzyme-linked immunosorbent assay) in gallbladder bile were measured over time. The localization of the anionic peptide fraction and cholesterol absorbed from bile in the gallbladder epithelium was studied in vivo by immunohistochemistry and fluoro-phospho-imager analysis. RESULTS: The rate of biliary cholesterol disappeared from bile was a function of the initial concentration and of the biliary mass changes over time of the anionic peptide fraction, but not of that of the other biliary proteins. The anionic peptide fraction colocalized with biliary cholesterol absorbed by the gallbladder on the apical side of gallbladder epithelial cells. CONCLUSIONS: These data indirectly suggest that biliary anionic peptide fraction could favour biliary cholesterol absorption by the gallbladder epithelium.

Domain wall magnetoresistance in BiFeO3 thin films measured by scanning probe microscopy.

We measure the magnetotransport properties of individual 71° domain walls in multiferroic BiFeO3 by means of conductive-atomic force microscopy (C-AFM) in the presence of magnetic fields up to one Tesla. The results suggest anisotropic magnetoresistance at room temperature, with the sign of the magnetoresistance depending on the relative orientation between the magnetic field and the domain wall plane. A consequence of this finding is that macroscopically averaged magnetoresistance measurements for domain wall bunches are likely to underestimate the magnetoresistance of each individual domain wall.

Output of liver fatty acid-binding protein (L-FABP) in bile.

Liver fatty acid-binding protein (L-FABP) is a small cytoplasmic molecule highly expressed in the liver. Since L-FABP exhibits affinities for several biliary components, its presence in bile was explored by Western blotting and competitive ELISA in various mammalian species. A L-FABP-like immunoreactivity was consistently found in both hepatic and gallbladder bile. A close molecular identity between this 14 kDa biliary protein and the purified L-FABP was assessed by immunological analyses and high performance capillary electrophoresis. Pharmacological induction of hepatic L-FABP biosynthesis led to a similar increase in biliary L-FABP levels showing a close relationships between the cytosolic and biliary contents of this protein. Finally, a correlation between the presence of L-FABP in bile and both bile flow and bile acid release was found. These data suggest an output of L-FABP in bile in normal conditions which might be coupled with the physiological release of biliary components.

Effect of beta-cyclodextrin dietary supplementation on biliary proteins and their resulting cholesterol nucleating activity in pigs.

We explored the possibility that the biliary protein fraction may support part of the variation in the nucleating activity previously measured in gallbladder biles of pigs. Eighteen gallbladder aspirates freshly obtained from three dietary groups (0, 5, or 10% beta-cyclodextrin) of six pigs were chromatographed to purify their total protein fraction. Proteins were quantified, and analysed through electrophoresis and immunoblotting or enzyme-linked immunosorbent assay for albumin, and five putative effectors of cholesterol crystallisation, mucins, immunoglobulin A, 130 kDa, apolipoprotein A-I, and anionic polypeptide fraction. Each total protein fraction was also assayed for its ability to influence cholesterol precipitation, when added to supersaturated model bile. The current data provided evidence that the cholesterol crystallisation-promoting activity of biliary proteins in model biles increased with the beta-cyclodextrin dietary content. This occurred without any significant change in the total biliary protein content, but was associated with a significant decrease in the concentration of albumin and apolipoprotein A-I, resulting in changes in the overall balance of proteins in bile. Comparison of these results with the crystallisation figures previously obtained from the corresponding native biles led us to conclude that biliary proteins might influence the outcome of the crystallisation process, namely the final crystal concentration at equilibrium, but would not systematically represent a major driving force for determining the velocity of crystal formation in native bile of pigs.

Detection and characterization of anionic polypeptide fraction binding sites in rat liver plasma membranes and cultured hepatocytes.

The binding of human 125I-labeled 'anionic polypeptidic fraction' (APF) to purified rat liver plasma membranes was studied. The dissociation constant for this binding was 3.0 micrograms protein/mg membrane protein. Binding was competitively inhibited by unlabeled human APF, but not by human LDL (low density lipoproteins). When unlabeled HDL3 was added, binding of labeled APF was competitively reduced to a level between that of unlabeled APF and unlabeled LDL. Experiments with cultured rat hepatocytes confirmed those obtained with liver membranes and suggested the presence in rat liver of saturable APF-binding sites which seem to be specific for APF. The physiologic significance of these APF binding sites is discussed in relation to the fate of cholesterol in the liver.

Evidence for the synthesis and secretion of APF--a bile lipid associated protein--by isolated rat hepatocytes.

Bile lipids are thought to be secreted in a lipoprotein complex in which they are associated with cholesterol and a protein called the anionic polypeptidic fraction (APF). APF is present in both bile and serum HDL. The association of APF with both bile and lipoprotein strongly suggests that hepatocytes may be responsible for the synthesis and secretion of this protein. In the present work we attempted to verify this by studying the incorporation of [14C]leucine into APF in isolated rat hepatocytes and by immunolocalization in cell cultures. Results obtained showed that synthesis of APF by cells follows the same kinetic pattern as albumin and that it was the third most abundant protein in the bile secretion. Immunolocalization confirmed that APF is synthesized in the endoplasmic reticulum of hepatocytes. This protein which appears to be rapidly secreted could be of great value for the specific detection of the lipids destined for bile secretion.

Determination of physicochemical parameters of liposomes from concentration data.

Determination of the physicochemical parameters of unilamellar and multilamellar liposomes from concentration data in light of a recent quantitative biodynamic concept which strictly adheres to the CGS unit system (cm, g, s) and the mass/volume chemical unit, mol.cm-3.

A quantitative dynamic concept of the interphase partition of lipids: application to bile salt-lecithin-cholesterol mixed micelles.

A system is proposed for a quantitative classification of lipids, based on interphase partition coefficients. This system enables calculation of exchanges of lipid molecules between phases. The mass/volume chemical unit mol X cm-3, strictly derived from the CGS system, is used, thus simplifying mathematical relations. Applied to bile salt-lecithin-cholesterol mixed micelles, this dynamic concept gives new insight into the variations of physico-chemical parameters. Experimental results obtained with the glycodesoxycholate and the taurocholate show a striking difference in partition coefficients between aqueous and mixed bile salt-lecithin interfacial phases. A new model applying triangular co-ordinates to a bile salt-lecithin-cholesterol mixed lipid phase is described.

Interaction of immunoglobulins and lipids in human gallbladder bile.

The lipoprotein complex from human gallbladder bile was challenged with anti-IgA and anti-IgG antisera in order to determine whether the apolipoprotein complex isolated from the detergent-free form of bile lipoprotein contains IgA and IgG. The apolipoprotein complex indeed crossreacts with anti-IgA and anti-IgG. In addition, the interactions of IgA and IgG with lipids were studied by ultracentrifugation and gel chromatography to determine whether these interactions occur in human bile.

Zone electrophoresis study of the bile lipoprotein complex.

Sucrose gradient column electrophoresis was performed with human hepatic and gallbladder bile. It is shown that bile phosphatidylcholines exhibit a more rapid anodic mobility than do bile salts and serum albumin. This high mobility of bile phosphatidylcholines is not due to the negatively charged lipids which are present in bile, i.e. bile salts or free fatty acids. It is demonstrated that phosphatidylcholines are associated with anionic polypeptides. Electrophoresis of reassociations between these purified polypeptides and dilaurylphosphatidylcholine showed that these anionic polypeptides are primarily responsible for the high anodic mobility of the bile lipoprotein complex. This work describes a procedure for the purification of the bile lipoprotein complex which can be useful for the study of other kinds of lipid-polypeptide associations.

The apoprotein fraction of the bile lipoprotein complex: isolation, partial characterization and phospholipid binding properties.

A bile apoprotein fraction (Apo BLC) was isolated by preparative isoelectric focusing (I.E.F.) from the detergent-free form of the bile lipoprotein complex (BLC). Analytical I.E.F. of Apo BLC yields a characteristic and reproducible pattern of two narrow acidic bands (pI 4,8-5,0). This apoprotein presents a strong tendency to undergo self-aggregation in aqueous buffer. A low molecular weight constituent of Apo BLC has been isolated after gel filtration, its mean Mw is estimated by SDS-PAGE at 7,500 daltons. The binding capacity of Apo BLC for phospholipids was investigated on dimyristoylphosphatidylcholine liposomes by gel filtration and zone electrophoresis. The resulting structures, larger than the original single-shelled vesicles, acquire and anodic electrophoretic mobility. Apo BLC has a weaker affinity for lysophosphatidylcholines: these phospholipids decrease the degree of aggregation of the apoprotein. These studies contribute additional data concerning the high affinity of Apo BLC for phosphatidylcholines, which are the major phospholipid constituents of bile. The discussion deals with the fact that association of Apo BLC with bile phosphatidylcholines may present some implications in the pathogeny of LpX and in the process of intestinal fat absorption.

Differences in hypolipidaemic effects of two statins on Hep G2 cells or human hepatocytes in primary culture.

1. The objective of this study was to compare in cultured human hepatocytes or Hep G2 cells, changes in the fate of unesterified low density lipoprotein (LDL)-cholesterol induced by crilvastatin, a new cholesterol lowering drug and a reference statin, simvastatin. 2. The experiments were carried out for 20 h, each well contained 4.2 x 10(5)/cm2 Hep G2 cells or 0.5 x 10(5)/Cm2 human hepatocytes, 130 microM ursodeoxycholate, 0.68 microCi or 1.59 microCi unesterified human [14C]-LDL-cholesterol, crilvastatin or simvastatin at 0 or 50 microM (both cell types) or 300 microM (Hep-G2 cells). Incubation with the two drugs resulted in increased amounts of unesterified [14C]-LDL-cholesterol taken by the two cell types, compared to control. 3. Crilvastatin 50 microM led to significantly higher quantities of [14C]-glyco-tauro-conjugated bile salts, compared to simvastatin. Statins reduced the apo B100 level secreted by the two cell types (simvastatin) or human hepatocytes (crilvastatin). Crilvastatin enhanced both the level of apo A1 secreted by the Hep G2 cells and the level of APF, a high density lipoprotein (HDL) and biliary apoprotein. 4. Crilvastatin not only acts by stimulating LDL-cholesterol uptake by hepatocytes, but also by enhancing the catabolism of LDL-cholesterol in bile salts and probably by stimulating HDL and/or bile component secretion. Such a mechanism was not previously described for HMG CoA reductase inhibitors. Our results on APF show that this apoprotein could be considered also as an indicator of changes in bile and/or HDL compartments. 5. The human hepatocyte model appeared to be a suitable and relevant model in the pharmacological-metabolic experiments carried out in this study. It led to more consistent data than those obtained with Hep G2 cells.

Dietary soybean phosphatidylcholines lower lipidemia: mechanisms at the levels of intestine, endothelial cell, and hepato-biliary axis.

The beneficial metabolic effects of dietary soybean lecithin on lipid metabolism are now more clearly established. The intestinal absorption of cholesterol is decreased by soybean phosphatidylcholine-enriched diet and results in a cholesterol-lowering effect. There is an enhancement of the cholesterol efflux by endothelial cells incubated with soybean phosphatidylcholines, and a stimulation of the reverse cholesterol transport by high density lipoprotein-phosphatidylcholines. As a result of all these processes, phosphatidylcholines provided by the soybean lecithin metabolism appear to be key molecules controlling the biodynamic exchanges of lipids. They regulate homeostasis of cholesterol and fatty acids by decreasing their synthesis and promoting cholesterol oxidation into bile salts. Finally, the outcome is the increase in bile secretion of these lipids and/or their metabolite forms. Such findings constitute promising goals in the field of nutritional effects of soybean lecithin in the treatment or prevention of hyperlipidemia and related atherosclerosis.

Intralipid 10%: physicochemical characterization.

OBJECTIVES: Parenteral fat emulsions contain two populations of particles: artificial chylomicrons rich in triacylglycerols (TAG), and liposomes (bilayer of phospholipids [PL] enveloping an aqueous phase). Centrifugation permits isolating the liposomes in the infranatant called mesophase. The aim of the present work was to better characterize this mesophase chemically and to view the particles it contains by electron microscopy. METHODS: Electron microscopy (Philips 410) was performed after cryofracture on native 10% Intralipid, mesophase (centrifugation for 1 h at 27 000 g), and a liposome-enriched fraction (ring of density 1.010-1.030 g/l obtained after centrifuging mesophase in a KBr density gradient at 100 000 g for 24 h). The TAG and protein content of the mesophase was analyzed and the proteins partially characterized by immunodetection (Western-blot). RESULTS: This electron microscope study of 10% Intralipid gives evidence for the coexistence of artificial chylomicrons (mean diameter, 260 nm) and liposomes (43 nm), the latter being smaller than expected and containing 8% w/w TAG after purification. The solubilization of TAG in PL bilayers (reported to be < or = 3.1% w/w) might have been increased in parenteral emulsions by the manufacturing process or/and the high TAG/PL ratio. Minute amounts of proteins have also been detected and partially characterized using a specific antibody raised against the human 7 kDa Anionic Polypeptide Factor (APF), known to strongly interact with PL in bile. CONCLUSIONS: This work has shown that the size (mean diameter, 43 nm) of the liposomes present in 10% Intralipid is smaller than that usually assumed. Traces of hydrophobic proteins in the emulsion may account for certain allergic reactions sometimes observed in infused patients.

Bile formation and hepatic plasma membrane composition in guinea-pigs and rats.

We compared bile formation, and biliary and liver plasma membrane composition in guinea-pigs and rats in an attempt to explain the observation that the bile flow rate and the bile acid independent fraction of bile flow (BAIF) in guinea-pigs is about five to seven times higher than in rats. Analysis of electrolytes in bile showed that bicarbonate was significantly [acid] higher in guinea-pigs while Cl-, phosphate and Ca2+ were markedly lower than in rats. High bile independent secretion in guinea-pigs was associated with a significantly lower concentration of total bile acid, phospholipid and cholesterol than in rats. Bile acid distribution studies showed that glycine conjugated chenodeoxycholate and ketolithocholate were the main bile acids in guinea-pigs, while taurine conjugated cholate and muricholate were the predominant bile acids in rats. Total fatty acid analysis of bile indicated that in rats the major fatty acids were palmitic acid (C16:0) and linoleic acid (C18:2, n-6). In guinea-pigs, the contribution of these fatty acids was lower than in rats and compensated with a significantly higher percentage of oleic acid (C18:1, n-9). Concentrations of anionic polypeptide fraction (APF), an acidic calcium binding apoprotein closely associated with biliary phospholipid and cholesterol secretion was also significantly lower in guinea-pigs. Canalicular plasma membrane analysis showed that as compared with rats, specific activities of Na+,K+ ATPase, and cholesterol and phospholipid content were markedly lower in guinea-pigs.(ABSTRACT TRUNCATED AT 250 WORDS)