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PubMed1998

Capillary electrophoresis of phospholipids with indirect photometric detection.

The capillary electrophoresis (CE) separation of different anionic phospholipid classes including phosphatidic acids (PA), phosphatidylserine, phosphatidylinositol, phosphatidylglycerol (PG), and cardiolipin using indirect detection with adenosine monophosphate (AMP) is described. A standard mixture of PAs (C14, C16, and C18) can be separated in 10 min by CE using 5 mM AMP and 100 mM boric acid in 10% water--80% methanol--10% acetonitrile. Although nonionic surfactants such as Brij 35 can improve the CE resolution of PAs, the separation time and the baseline noise are both increased. Optimization of the organic solvent in the running electrolyte is important. Methanol provides faster electroosmotic flow than propanol, and 10% acetonitrile effectively reduces migration time further by a factor of 1.4-2.2, depending on the phospholipid. The concentration limit of detection ranges from approximately 2 to 6 mg/L, and the mass limit of detection is as low as 21 pg. Linearity from 19 to 100 mg/L is established for cardiolipin and C16-PG. Phospholipids in soybean and brain extract samples could be profiled.

1-Propanol↗
PubMed1994

Prevalence, significance, and specificity of antibodies to phospholipids in Q fever.

A cross-sectional study of the prevalence, significance, and specificity of antibodies to phospholipids (aPL) in patients with Q fever was undertaken in a university-based tertiary care medical center. The results of the lupus anticoagulant (LA) test, VDRL test, fluorescent treponemal antibody absorption test, and ELISA with different phospholipid antigens were determined for 26 patients with Q fever diagnosed by clinical and serological criteria. Plasma from four patients with Q fever and antibodies to cardiolipin (aCL) was purified by affinity chromatography in a cardiolipin column and tested against all phospholipids. For 17 patients with high levels of aCL, a modified ELISA without fetal calf serum was performed to determine if the serum cofactor was needed for a CL activity. Fisher's exact test was used for the statistical analysis. From the results of our study we conclude the following: patients with Q fever have a high incidence of aPL, with techniques with aCL or LA being the most sensitive to determine aPL (these antibodies can help diagnose Q fever presenting only as a fever); antibodies (phase II) to Coxiella burnetii and aCL are different antibodies; and the aCL activity in patients with Q fever is cofactor-independent.

Adolescent↗
PubMed1984

Effect of dietary fat level and polyunsaturated fatty acid content on the phospholipid composition of rat cardiac mitochondrial membranes and mitochondrial ATPase activity.

Weanling rats were fed either high fat diets containing 40% of calories as fat or low fat diets containing 15% of calories as fat for 14 days. All diets were formulated to contain equivalent essential nutrients per calorie content for the nonfat components. For both dietary fat levels, the polyunsaturated to saturated fatty acid (P/S) ratio was adjusted by substitution of beef tallow for soybean oil to provide a dietary P/S ratio of 2.0 or 0.25. After feeding, hearts were removed from six replicate groups of animals per diet treatment, and mitochondria were isolated. Phospholipids were extracted from the mitochondrial membranes, and cardiolipin, phosphatidylcholine and phosphatidylethanolamine content were quantitatively analyzed using an iatroscanner. In addition, fatty acyl tail composition of each purified phospholipid was determined. Mitochondrial ATPase was also assessed by ATP-32Pi exchange assay. Feeding high fat diets increased phosphatidylcholine content of the mitochondrial membrane. High fat diets resulted in a relative increase in mitochondrial cardiolipin content that was apparently unaffected by the P/S ratio of the diet fed. Both the fat level in the diet and the P/S content altered ATPase activity. This composition to those potentially consumed by humans can result in alterations in membrane structural constituents of cardiac mitochondria and have potential to alter lipid-dependent functions of integral membrane proteins.

Adenosine Triphosphatases↗
PubMed1996

Defective maternal-fetal interaction in a murine autoimmune model.

Anti-cardiolipin antibodies (ACA) are associated with recurrent fetal loss, but their role in this pathological condition is unknown. We recently developed an experimental mouse model of the anti-phospholipid syndrome, in which immunization of female mice with a monoclonal anti-cardiolipin antibody resulted in substantial failure of pregnancy. We observed that pre-implantation embryos derived from ACA-injected mothers exhibited morphological abnormalities and failed to implant in vitro. In the present study, we designed embryo transfer experiments to determine whether defective embryonic development originated as a maternal defect, an embryonic defect or both. Embryos (3.5 day old), taken from ACA- and control-immunized mothers were transferred into either an ACA- or a control-treated uterine environment (day 2.5 pseudopregnant females). On day 14 of gestation the incidence of pregnancy, the average number of fetuses per female and fetal resorptions were assessed. The ACA-treated uterine environment was found to be non-supportive for the development and implantation of normal embryos. Moreover, embryos derived from ACA-immunized mothers, even after their removal from the ACA-environment and transfer to a normal uterus, remained deficient. These results demonstrate that both the maternal and the embryonic compartments were defective, as a result of previous exposure to the ACA.

Animals↗
PubMed1991

Anti-phospholipid antibodies and pregnancy loss.

Anti-phospholipid antibodies such as the lupus anticoagulant and anti-cardiolipin antibodies, are antibodies directed at negatively charged phospholipids and have received much attention in the last decade. Their presence has been associated with a thrombotic tendency, leading to a variety of clinical symptoms. In the pregnant woman, the presence of these antibodies may have consequences for management, since retrospective reports have established a correlation between the lupus anticoagulant or anti-cardiolipin antibodies with intrauterine fetal death, probably due to placental thrombosis. This article reviews current knowledge on anti-phospholipid antibodies in relation to pregnancy loss, focusing on clinical aspects.

Antibodies↗
PubMed1986

Membrane phospholipid synthesis in Escherichia coli: alteration by glycerol and physiological consequences in a pss mutant.

Escherichia coli mutants harboring the pss-1 allele (coding for a temperature-sensitive phosphatidylserine synthase) are temperature sensitive for growth and synthesize less phosphatidylethanolamine at higher temperatures, giving rise to abnormal membrane phospholipid compositions. To obtain information concerning the determinant for the phospholipid polar headgroup composition and the lethal factor in the defective membranes, we have examined the effect of increased supply of sn-glycerol 3-phosphate on the phospholipid synthesis and the growth ability of a pss-1 mutant. For this purpose, a pair of E. coli K-12 derivatives isogenic except for the pss-1 allele was constructed from strain BB26-36 to harbor the mutations related to glycerol metabolism (glpD3, glpR2, glpKi, and phoA8). Pulse- and uniform-labeling of phospholipids with 32P at 42 degrees C in a synthetic medium with (0.2%) or without glycerol showed that glycerol further lowered the temperature-sensitive formation of phosphatidylethanolamine, removed the phosphatidate and CDP-diacylglycerol accumulated in the absence of glycerol, and resulted in an increase in cardiolipin content in the pss-1 mutant. The phospholipid synthesis and contents in the pss+ strain were not significantly affected by glycerol. Glycerol in the medium markedly enhanced the growth defect of the pss-1 mutant, which was remediable by sucrose. The results indicate that the intracellular pool of sn-glycerol 3-phosphate is the limiting factor for acidic phospholipid synthesis in the pss-1 mutant, and cardiolipin unusually accumulated is injurious to the functional E. coli membranes. Possible determinants for the phospholipid composition of the wild-type E. coli cells are also discussed on the basis of the present observations.

CDPdiacylglycerol-Serine O-Phosphatidyltransferase↗
PubMed1993

Cognitive impairment and autoantibodies in systemic lupus erythematosus.

Nervous system involvement in systemic lupus erythematosus (SLE) includes a wide array of manifestations some of which have been associated with specific autoantibodies. These include reactivity to surface neuronal and lymphocyte antigens, ribosomal P and cardiolipin. The aim of the present study was to examine the association between cognitive abnormalities and these autoantibodies in an unselected female population of SLE patients. Using a battery of standardized neuropsychological tests, cognitive impairment was identified in 15/70 (21%) SLE patients compared to 1/25 (4%) patients with rheumatoid arthritis and 1/23 (4%) healthy subjects (P = 0.04). Circulating antineuronal antibodies were measured by indirect immunofluorescence using human neuroblastoma cell lines IMR-6 and SK-N-SH. Lymphocytotoxic antibodies were measured by microcytotoxicity. Antibodies to ribosomal P and cardiolipin were measured by ELISA. Antineuronal antibodies were detected in 34%, lymphocytotoxic antibodies in 47%, anti-P antibodies in 17% and anticardiolipin antibodies in 24% of patients. In the cognitively impaired and unimpaired SLE patients there was no significant difference in the prevalence of antineuronal antibodies (33 vs 35%), lymphocytotoxic antibodies (40 vs 50%), anti-P antibodies (20 vs 17%) or anticardiolipin antibodies (7 vs 29%). The titre and isotype of autoantibodies were also similar in both groups. These results suggest that autoantibodies which have previously been associated with nervous system manifestations of SLE are not likely to be directly involved in the pathogenesis of cognitive dysfunction.

Antibodies, Anticardiolipin↗
PubMed2004

Autoantibodies, lupus and the science of sabotage.

Anti-double-stranded DNA antibodies (anti-dsDNA) and antiphospholipid antibodies (APL) are important in the pathogenesis of systemic lupus erythematosus (SLE) and the antiphospholipid syndrome (APS) respectively. Not all anti-dsDNA or APL antibodies can cause clinical effects. Those that are particularly likely to cause tissue damage tend to be of IgG isotype and to possess particular binding properties. Rigorous statistical analysis of published sequences of human monoclonal anti-DNA and APL antibodies showed that IgG antibodies with binding properties characteristic of pathogenicity tend to have multiple somatic mutations in their variable regions. The distribution of these mutations suggests that they have been selected by antigen. This leads to accumulation of certain residues at the antigen-binding sites of these antibodies. Arginine residues are especially important. A computer-generated model of the pathogenic human monoclonal anti-DNA antibody B3 predicted that arginines in the heavy and light chain complementarity-determining regions (CDRs) would interact with dsDNA. We expressed cloned sequences encoding the B3 heavy and light chains in vitro to produce whole IgG. The cloned sequences of the heavy and light chains were manipulated to express a range of variant IgG antibodies. Binding assays on the expressed antibodies showed that altering specific arginine residues reduced binding to dsDNA in a way consistent with computer generated structural models. Changing the pattern of somatic mutations in the light chain altered binding to both dsDNA and histones, but in different ways. A single arginine-to-serine mutation in light-chain CDR1 of B3 reduced binding to both those antigens and may also have reduced the pathogenicity of the expressed antibodies in severe combined immunodeficiency (SCID) mice. Monoclonal human APL were expressed using the same system. Nineteen different heavy-light combinations were expressed. The ability to bind cardiolipin correlated well with the presence of exposed arginine residues in the heavy- and light-chain CDRs. The heavy chain of the pathogenic APL antibody IS4 contains four exposed arginines in CDR3. The results of mutagenesis studies suggested that two of these promote binding to cardiolipin whereas the other two have no such effect.

Animals↗
PubMed1993

Modulation of doxorubicin resistance in multidrug-resistant cells by liposomes.

In this study, we have confirmed the ability of liposome-encapsulated doxorubicin to modulate drug resistance, as previously observed in CH LZ cells (Thierry et al., Cancer Commun. 1, 311-316, 1989), in two human multidrug-resistant (MDR) cell lines, the breast cancer MCF-7/ADR cell line, and the ovarian carcinoma SKVLB cell line. This effect was specific to MDR cells, as liposomally encapsulated doxorubicin did not enhance cell sensitivity to the drug in the parental cell lines. Cytotoxicity assays demonstrated that empty liposomes in the presence of free doxorubicin (Dox) reversed resistance to the drug at a level that may be higher than that observed when liposome-encapsulated Dox is used. This effect seems to be due to the high affinity of Dox for cardiolipin, one of the liposome components, which leads to the association of the drug and the cardiolipin-containing liposomes in the culture medium before entry into the cells. Neither pretreatment of empty liposomes before drug treatment nor combined incubation of vincristine and empty liposomes alter MDR in CH LZ cells, suggesting that the drug must be encapsulated or complexed to the liposomes to overcome MDR. Because MDR in CH LZ cells does not seem to be related to GSH level, MDR modulation by liposome-encapsulated Dox apparently may not be effected by altering the GSH function. These results suggest that the enhancement of sensitivity of MDR cells using Dox encapsulated in liposomes or complexed with liposomes may be explained by an increase in cell drug incorporation and by an intracellular drug redistribution. Fluorescence confocal microscopy study indicated that Dox is transported and distributed mainly in intracytoplasmic vesicles in SKVLB and MCF-7/ADR cells, whereas in parental cells the drug is located mainly in the nucleus. In addition, presentation of Dox in liposomes modifies the drug distribution pattern in MDR cells by partially shifting the drug to nuclear compartments. Thus, liposome-associated Dox may bypass the vesicular drug transport in MDR cells, resulting in the enhancement of the drug biological activity.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1994

Idiotypic induction of autoimmunity: a new aspect of the idiotypic network.

Three different experimental models of autoimmune diseases were induced in naive mice after idiotypic immunization. 1) systemic lupus erythematosus (SLE) after injection of anti-DNA antibodies carrying the pathogenic Id-16/6; 2) anti-phospholipid syndrome (APLS) after immunization with anti-cardiolipin antibodies (having the pathogenic H-3 and MIV-7 Ids); and 3) Wegener's granulomatosis (WG) induced with anti-neutrophile cytoplasmic antibodies (ANCA). In all three experiments the mice developed the respective anti-Id antibodies (Ab2), and, after a follow-up period of 4-8 months anti-anti-Id (Ab3) were generated by the immunized mice. The latter antibodies (Ab3) had the binding characteristics of the respective autoantibodies (Ab1) used in the first immunization. The appearance of auto-antibodies in the sera of the mice was associated with emergence of all the typical clinical and laboratory findings seen in patients with SLE, APLS, and WG, respectively. We suggest that in some autoimmune diseases, especially in those in which the presumed autoantigen is not immunogenic (e.g., DNA, cardiolipin), the disease may follow a common infection: The antibodies against the infecting agent may carry a pathogenic idiotype of a specific autoantibody. In a subject prone to autoimmunity (genetic, hormonal, immunologic factors), the pathogenic idiotype will progress in dysregulating the immune system to evolve into a clinical overt autoimmune disease.

Animals↗
PubMed1997

Clinical implications of autoantibodies in HIV infection.

OBJECTIVE: To study the frequency and specificity of autoantibodies in HIV-infected subjects and their association with rheumatic manifestations, immunodeficiency, and prognosis. DESIGN: Prospective study of sequentially selected HIV-infected patients. Indirect immunofluorescence reading was performed by two independent observers blinded for the patient diagnosis. Enzyme-linked immunosorbent assay (ELISA) was performed using coded serum samples. SETTING: The study was performed at the Infectious Disease and Rheumatology Divisions of a tertiary care university hospital. PATIENTS: One hundred sequentially selected HIV-infected patients formed group A. Controls included 80 non-HIV-infected high-risk individuals (group B), 20 herpesvirus-infected patients (group C), and 30 healthy blood donors (group D). MAIN OUTCOME MEASURES: Patients were followed for 2 years and evaluated for the presence of immunodeficiency, rheumatic manifestations, circulating autoantibodies and total CD4+ cell count. Indirect immunofluorescence was used to investigate antinuclear antibodies, antibodies to native DNA, smooth muscle, parietal cell, glomeruli, thyroid, and neutrophil cytoplasm. Agglutination was used to detect antibodies to erythrocytes and rheumatoid factor. ELISA was used to determine antibodies to cardiolipin and denatured DNA. CD4+ lymphocytes were counted by flow cytometry. Immunoglobulin (Ig) G, IgM and IgA serum levels were determined by radial immunodiffusion. RESULTS: HIV-infected patients presented higher overall frequency of autoantibodies than the other groups. No difference was observed between immunodeficient and asymptomatic HIV-infected patients. The most frequent specificities were antibodies to cardiolipin and to denatured DNA. Ig serum levels did not correlate with the occurrence of autoantibodies. The presence of autoantibodies was associated with lower CD4+ cell counts and with higher mortality within 2 years. Rheumatic manifestations were observed in 35 HIV-infected patients and were not associated with the occurrence of autoantibodies or the presence of immunodeficiency. CONCLUSIONS: HIV infection is associated with an increased incidence of autoantibodies. Although not related to the occurrence of rheumatic manifestations, the presence of autoantibodies was significantly associated with lower CD4+ lymphocyte counts and increased mortality, which implies prognostic significance to this phenomenon in the context of HIV infection.

Adolescent↗
PubMed2006

Systemic lupus erythematosus in Asturias, Spain: clinical and serologic features.

Asturias is an autonomous region in the north of Spain with historical and anthropologic peculiarities. In the current report, we examine the main clinical and immunologic features of 363 patients with systemic lupus erythematosus (SLE), virtually the entire population of SLE patients in Asturias. We constructed a database with the clinical and immunologic features of all patients fulfilling the American College of Rheumatology criteria, based on the review of hospital records corresponding to blood samples received for antinuclear antibodies testing since 1992. Arthritis was the most frequently observed main clinical feature and neuropathy was the rarest. Male patients had a disease more frequently characterized by serositis (p<0.05) and neurologic disorder (p<0.01) than females, while children presented malar rash (p<0.05), fever (p<0.05), and kidney involvement (p<0.01) more often than adults. Late-onset patients were characterized by lower frequencies of malar rash (p<0.01), neurologic disorder (p<0.05), alopecia (p<0.01), and lymphadenopathy (p<0.05) than young adults. Numerous direct and inverse significant associations were found among clinical and immunologic features. The most relevant significant associations were neurologic disorder with lupus anticoagulant (p<0.01); kidney involvement with serositis (p<0.01) and DNA antibodies (p<0.05); and thrombosis with DNA antibodies (p<0.05), cardiolipin antibodies (p<0.01), and lupus anticoagulant (p<0.01). A low mortality was found in our series, although kidney involvement (p<0.05) and cardiolipin antibodies (p<0.05) are factors associated with poor survival.

Adolescent↗
PubMed1986

Isolation and characterization of the tubular organelles induced by fumarate reductase overproduction in Escherichia coli.

Strains of Escherichia coli amplifying the intrinsic membrane enzyme fumarate reductase accommodate the overproduced enzyme by increasing the amount of membrane material, in the form of intracellular tubular structures. These tubules have been observed in strains harbouring multicopy frd plasmids and in ampicillin hyper-resistant strains. A procedure has been developed for isolation of tubules nearly free of cytoplasmic membrane. Using protein A-gold labelling and optical diffraction of electron micrographs, a model for tubule structure is proposed. The tubules have a lower lipid/protein ratio than the cytoplasmic membrane, with the enzyme accounting for greater than 90% of the protein in the tubules. Both cytoplasmic membranes and tubules from amplified strains are enriched in cardiolipin and have a more fluid fatty acid composition than wild-type strains. Mutants defective in cardiolipin synthesis produce tubules in response to excess fumarate reductase, but these tubules have an altered appearance, indicating that lipid-protein interactions may be important for tubule assembly.

Bacterial Proteins↗
PubMed1992

Autolysis of Clostridium acetobutylicum ATCC 824.

The optimum conditions for autolysis of Clostridium acetobutylicum ATCC 824 were determined. Autolysis was optimal at pH 6.3 and 55 degrees C in 0.1 M-sodium acetate/phosphate buffer. The ability of cells to autolyse decreased sharply at the end of the exponential phase of growth. Lysis was stimulated by monovalent cations and compounds that complex divalent cations, and inhibited by divalent cations. The autolysin of C. acetobutylicum, which was mainly cytoplasmic, was purified to homogeneity and characterized as a muramidase. The enzyme was identical to the extracellular muramidase in terms of M(r), isoelectric point and NH2-terminal amino acid sequence. The autolysin was inhibited by lipoteichoic acids and cardiolipin but not by phosphatidylethanolamine and phosphatidylglycerol. A mechanism of regulation and fixation involving lipoteichoic acid, cardiolipin and divalent cations is proposed.

Amino Acid Sequence↗
PubMed1993

Are immunoglobulins with lupus anticoagulant activity specific for phospholipids?

Recent studies have suggested that the lupus anticoagulant (LA) may be specific for prothrombin, prothrombin-phospholipid complexes, or beta 2 glycoprotein 1 (beta 2GP1) rather than phospholipids. We performed a series of experiments to determine whether LA is indeed phospholipid specific. IgG was purified from sera of six patients with the antiphospholipid syndrome (APS) and 10 healthy controls. The six IgG-APS preparations had both LA and anticardiolipin (aCL) activity. Incubation of the six IgG-APS preparations with cardiolipin (CL), phosphatidylserine (PS), phosphatidylcholine (PC), or PS/PC (20:80) liposomes in Tris-buffered saline, resulted in loss of LA activity from the supernatant. We postulated that loss of activity might have resulted from absorption of IgG LA antibodies by phospholipids, a dilutional effect, or the presence of phospholipids in the supernatant causing 'by-pass' of IgG LA inhibitory activity. To distinguish between these possibilities, we re-isolated IgG from the supernatants and re-tested them for LA activity. IgG re-isolated from the PS. CL and PS/PC supernatants had no LA activity, but LA activity remained in the PC supernatant. This suggested that IgG with LA activity was absorbed by negatively charged but not by zwitterionic phospholipids. In like manner, PS, CL and PS/PC, but not PC liposomes, absorbed IgG with aCL activity. Mixtures of the phospholipid liposomes with beta 2GP1 did not modify the absorption of IgG with LA or aCL activity. Finally, we demonstrated that IgG eluted from immunoglobulin-cardiolipin liposome complexes had LA activity. Based on these findings, we conclude that at least one population of antibodies with LA activity is phospholipid specific.

Antibodies, Anticardiolipin↗
PubMed2006

Association of apoptosis-related microsatellite polymorphisms on chromosome 1q in Taiwanese systemic lupus erythematosus patients.

Apoptosis is important in the pathogenesis of systemic lupus erythematosus (SLE). Several genome-wide scan studies have suggested chromosome 1q as a genetic susceptibility locus for SLE. This study investigated the association of apoptosis-related genes on chromosome 1q, Fas ligand (FasL), interleukin (IL)-10 and poly(ADP-ribose) polymerase (PARP), promoter microsatellite multi-allelic polymorphisms with SLE susceptibility and clinical characteristics in Taiwan. This study recruited 237 SLE patients and 304 healthy controls. FasL, IL-10 and PARP promoter microsatellite polymorphisms were genotyped employing gene scan. IL-10, located on 1q31-32, emerged as a significant susceptibility gene locus in Taiwanese SLE (T4 statistic = 0.01). IL-10 CA21 allele was the most common allele of 15 identified in Taiwanese, displaying skewed distribution of susceptibility in Taiwanese SLE patients. Conversely, the IL-10 CA20 allele showed a protective effect of SLE susceptibility. Additionally, the IL-10 CA26 allele displayed a negative significant association with ascites and IL-10 CA25 allele increased the occurrence of the anti-cardiolipin IgM antibody. This study identified five alleles of FasL and nine alleles of PARP of microsatellite polymorphisms in Taiwanese patients. FasL and PARP alleles displayed no skewing distribution between Taiwanese SLE patients and controls. However, FasL GT15 and PARP CA17 allele demonstrated a high discoid rash presentation (T4 statistic 0.01 and 0.03, respectively) and PARP CA12 allele displayed a significant association with anti-cardiolipin IgM antibody production (T4 statistic 0.02). IL-10, FasL and PARP microsatellite polymorphisms exhibited significant associations with SLE susceptibility and/or clinical characteristics in Taiwanese patients. Thus, SLE is a complex and multiple genetics determined autoimmune disease. Chromosome 1q23-42 is an important genetic locus for further SLE subphenotype susceptibility study.

Adolescent↗
PubMed1990

Acetylcholine receptor antibodies in primary biliary cirrhosis: characterization of antigen and idiotypic specificity.

Auto-antibodies against the acetylcholine receptor of skeletal muscle are considered to be the cause of the neuromuscular dysfunction in myasthenia gravis. However, such auto-antibodies also occur in disease states not accompanied by neuromuscular symptoms. Patients with primary biliary cirrhosis have a high prevalence of different auto-antibodies, including antibodies against the acetylcholine receptor. In primary biliary cirrhosis, these anti-receptor antibodies are predominantly of IgM isotype. The IgM antibodies show a broader reactivity with receptors from other species than antibodies from myasthenic patients. Immunoglobulins from patients with primary biliary cirrhosis bear the same receptor antibody-associated idiotypes, but the repertoire is quantitatively different from that found in myasthenia gravis patients. The IgM receptor antibody activity in a serum from a patient with primary biliary cirrhosis could be inhibited by cardiolipin, poly[dT], poly[I], and ssDNA, whereas this antibody activity in serum from a patient with myasthenia gravis was slightly reduced only by cardiolipin. Generally, IgM antibodies from patients with primary biliary cirrhosis had a broader reactivity with polynucleotides and phospholipids than IgG antibodies and antibodies from patients with myasthenia gravis. These results indicate a difference in the fine specificity between acetylcholine receptor antibodies in primary biliary cirrhosis and in myasthenia gravis.

Animals↗
PubMed1985

Purification and analysis of phospholipids in the inner mitochondrial membrane fraction of bovine corpus luteum, and properties of cytochrome P-450scc incorporated into vesicles prepared from these phospholipids.

Cytochrome P-450scc, which catalyses the conversion of cholesterol to pregnenolone in steroidogenic tissues, can be incorporated into artificial phospholipid vesicles and cholesterol binding to the cytochrome is affected by the composition of the vesicles. We have purified the phospholipids from the inner mitochondrial membrane fraction of the bovine corpus luteum where the cytochrome is located. The composition in mol % was 49% phosphatidylcholine, 34% phosphatidylethanolamine, 8.7% cardiolipin, 6.4% lysophosphatidylethanolamine and 1.5% phosphatidylinositol. The ratio of cholesterol to phospholipid (mol/mol) in the inner membrane fraction was 0.14 to 1. The Km for cholesterol of purified luteal cytochrome P-450scc incorporated into vesicles prepared from the total inner mitochondrial membrane phospholipids was 0.063 mol of cholesterol per mol of phospholipid. Removal of the cardiolipin component of the inner mitochondrial membrane phospholipids prior to preparation of vesicles caused a four fold increase in the Kd of cytochrome P-450 for cholesterol and a two fold increase in Km. The data suggests that in the inner mitochondrial membrane of the bovine corpus luteum the cholesterol concentration is less than saturating for cytochrome P-450scc.

Animals↗