| For medical practitioners and the general public - Cholesterol Journal Article Catalog. |
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| Isolation of a human biliary glycoprotein inhibitor of cholesterol crystallization Ohya, T., J. Schwarzendrube, et al. (1993), Gastroenterology 104(2): 527-38. Abstract: BACKGROUND: About 50% of populations in developed countries have bile supersaturated with cholesterol, which is a major risk factor for cholesterol gallstone formation. Despite the prevalence of supersaturated bile, only about 10% of these populations develop gallstones. The existence of a biliary protein that inhibits cholesterol crystallization was hypothesized to explain this discrepancy. This report outlines the purification and characterization of such a human biliary glycoprotein. METHODS: Chromatographic methods were used for separation and characterization. Additional steps included activity analysis by crystal growth assay, electrophoresis, and deglycosylation. RESULTS: The glycoprotein consists of a heterodimer, M(r) of 120 kilodalton, with subunits of M(r) of 63 kilodalton and 58 kilodalton. Each of the subunits is characterized by an isoelectric point of 6.6 and shows comparable inhibitory activity. Deglycosylation of the subunits show that they share a similar polypeptide backbone (M(r) of 35 kilodalton) based upon a highly similar amino acid profile. This suggests that differential subunit glycosylation alone may account for the apparent heterodimeric structure. CONCLUSIONS: No other human biliary glycoprotein has been found thus far that shows cholesterol crystal growth-inhibiting activity. Thus, it may be of importance in preventing gallstone formation in healthy populations. |
| Isolation of a potent cholesterol nucleation-promoting activity from human gallbladder bile: role in the pathogenesis of gallstone disease Groen, A. K., C. Noordam, et al. (1990), Hepatology 11(4): 525-33. Abstract: Gallbladder bile contains nucleation-promoting activity that binds to concanavalin A. The activity was found in gallbladder bile from cholesterol gallstone patients but also in gallbladder bile from patients without stones and patients with pigment stones. Bile from patients with multiple cholesterol gallstones contained high concanavalin A-binding nucleation-promoting activity. The activity was much lower in bile samples from pigment stone patients, patients without stones and patients with a solitary cholesterol stone. Serum contained very little activity and no concanavalin A-binding nucleation-promoting activity could be demonstrated in gallbladder mucosa. This suggests that concanavalin A-binding nucleation promoter is produced in the liver or bile duct epithelium. The activity was fully resistant to digestion with pronase but was heat labile and could be destroyed by prolonged incubation with a mixed glycosidase preparation indicating that sugar residues are important for this activity. On a Superose 12 gel permeation column, promoting activity eluted in two major peaks at apparent molecular weights of 150 +/- 30 kD (n = 5) and less than 5 kD respectively. The mobility on the column was not influenced by pronase digestion. The factor with the higher molecular weight could be isolated further by polyacrylamide gel electrophoresis under nondenaturing conditions. On sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the apparent molecular weight of the glycoprotein was 130 kD. In conclusion, gallbladder bile contains nucleation-promoting activity that binds to concanavalin A. The activity is increased in bile from patients with multiple cholesterol gallstones and could therefore play an important role in the pathogenesis of gallstone disease. |
| Isolation of an organic-solvent-tolerant cholesterol-transforming Bacillus species, BC1, from coastal sediment Sardessai, Y. and S. Bhosle (2003), Mar Biotechnol (NY) 5(2): 116-8. Abstract: Steroid transformation is of great importance in the pharmaceutical industry. The major limiting factor in this process is the extremely poor solubility of steroids in aqueous media, which lowers their transformation rate and increases costs. This problem can be overcome by using organic-solvent-tolerant bacteria (OSTB), which can carry out the desired bioconversions in an organic-solvent-saturated system. OSTB are a relatively novel group of extremophilic microbes that have developed various adaptations to withstand solvent toxicity. The aim of this study was to isolate marine bacteria producing organic-solvent-stable cholesterol-transforming enzymes. A Bacillus species, BC1, isolated from Arabian Sea sediment was found to degrade cholesterol and exhibit excellent solvent tolerance particularly to chloroform. OSTB have tremendous potential in industrial processes involving nonaqueous biocatalysis and transformation in the presence of an organic phase. |
| Isolation of calcifiable vesicles from aortas of rabbits fed with high cholesterol diets Hsu, H. H., N. P. Camacho, et al. (2000), Atherosclerosis 153(2): 337-48. Abstract: Advanced arterial wall calcification in atherosclerosis imposes a serious rupturing effect on the aorta. However, the mechanism of dystrophic calcification linked to hyperlipidemia, that causes atherosclerosis remains unknown. Emerging morphological and biochemical evidence reveals that calcifiable vesicles may have a role in plaque calcification. To determine whether a high cholesterol diet can induce arterial calcification and produce or activate calcifiable vesicles in aortas, a rabbit model was used. After 2 months of daily high lipid feeding (supplemented with 2% cholesterol and 6% peanut oil), typical atherosclerotic lesions developed. However, the mineral, if present in aortas, was insufficient to be detected by Fourier transform-infrared spectroscopy (FT-IR) or alizarin red staining, indicative of a non-calcifying stage of atherosclerosis. Small segments of thoracic aortas were digested in a crude collagenase solution to release calcifiable vesicles. Vesicles were also isolated from normal aortas as control to consider the possibility that membrane vesicles may be produced by crude collagenase digestion, which could cause the degradation of some cells. Calcifiable vesicles were precipitated at 300,000 x g after subcellular particles were removed by centrifugation at 30,000 x g. Calcifiability of isolated vesicles was then tested using calcifying media containing physiological levels of Ca2+ and Pi and 1 mM ATP. Electron microscopic observations showed that the isolated vesicles were heterogeneous in size and shape and capable of depositing electron dense particles. Fourier transform infrared spectroscopic analysis of the deposited particles revealed the presence of an amorphous mineral phase. The spectroscopic mineral to matrix ratios, related to the amount of mineralization, indicated that vesicles from cholesterol-fed rabbits produced more minerals than control vesicles obtained from the normal aortas. Alizarin red staining for mineral further demonstrated substantially higher calcifiability of the experimental vesicles. A 3-5 h exposure of the vesicles to calcifying media caused significant deposition of 45Ca and 32Pi in a vesicle protein-concentration dependent manner. Similar to previously reported observations with human atherosclerotic aorta vesicles, rabbit vesicles were enriched in ATP-hydrolyzing enzymes including Mg2+- or Ca2+-ATPase and NTP pyrophosphohydrolase that are implicated in normal and pathological calcification. Altogether, these observations suggest that accumulation of the released calcifiable vesicles, as a result of high cholesterol diets, may have a role in dystrophic calcification in hyperlipidemia-related atherosclerosis. |
| Isolation of cholesterol oxidation products from animal fat using aminopropyl solid-phase extraction Johnson, C. B. (1996), J Chromatogr A 736(1-2): 205-10. Abstract: Cholesterol oxidation products were separated from triglycerides and cholesterol in a single step on an aminopropyl solid-phase extraction column. The products were purified by subsequent transesterification and saponification, derivatized to trimethylsilyl ethers and analyzed by gas chromatography. Heated cholesterol-containing fat samples were autoxidized by bubbling air through them. When the flow-rate of air was set at 100 ml/min, the concentration of cholesterol oxidation products in the fat increased to a maximum after 1-2 h and then decreased to almost a zero level after 8 h. The concentration of cholesterol oxidation products in the fat increased over a similar time period, without reaching a maximum, when the flow-rate of air was decreased to 5 ml/min. |
| Isolation of cholesterol-dependent Candida glabrata from clinical specimens Hazen, K. C., J. Stei, et al. (2005), Diagn Microbiol Infect Dis 52(1): 35-7. Abstract: In the past few years, we have detected in the United Kingdom and in the United States several isolates of Candida glabrata that grew poorly unless bile was available. Cholesterol, a component of bile, stimulated equivalent growth of the bile-dependent isolates. The bile-dependent C. glabrata isolates appeared resistant to amphotericin B, but their resistance to fluconazole was unclear. These results demonstrate that occasional isolates of C. glabrata require cholesterol to grow, they may not be detected in specimens set up on standard primary plating media, and they may be difficult to eradicate in patients with antifungal agents directed against ergosterol and its synthetic pathway. |
| Isolation of cholesterol-lowering lactic acid bacteria from human intestine for probiotic use Lim, H. J., S. Y. Kim, et al. (2004), J Vet Sci 5(4): 391-5. Abstract: Cholesterol-lowering effect of lactic acid bacteria (LAB: Streptococcus, Lactobacillus and Bifidobacterium) is well-known. Thus, we investigated LAB isolated from human intestine on the cholesterol-lowering effect in vitro. Seven Streptococcus (61.1%), 11 Lactobacillus (71.8%) and 7 Bifidobacterium (27.9%) were isolated as acid (pH 2.5 and 3.0) and bile (0.3% oxgall) tolerant strains. Streptococcus HJS-1, Lactobacillus HJL-37 and Bifidobacterium HJB-4 were finally selected as probiotic strains to use through the bile salt hydrolase (BSH) activity assay by using MRS media added taurodeoxycholic acid (TDCA) and the cholesterol-lowering test by using soluble cholesterol containing MRS broth. These studies suggested that the isolated LAB had an excellent hypocholesterolemic effect. |
| Isolation of cholesterol-requiring mutant Chinese hamster ovary cells with defects in cleavage of sterol regulatory element-binding proteins at site 1 Rawson, R. B., D. Cheng, et al. (1998), J Biol Chem 273(43): 28261-9. Abstract: The synthesis and uptake of cholesterol requires transcription factors designated sterol regulatory element-binding proteins (SREBPs). SREBPs are bound to membranes in a hairpin orientation with their transcriptionally active NH2-terminal segments facing the cytosol. The NH2-terminal segments are released from membranes by two-step proteolysis initiated by site 1 protease (S1P), which cleaves in the luminal loop between two membrane-spanning segments. Next, site 2 protease (S2P) releases the NH2-terminal fragment of SREBP. The S2P gene was recently isolated by complementation cloning using Chinese hamster ovary cells that require cholesterol for growth, due to a mutation in the S2P gene. A similar approach cannot be used for S1P because all previous cholesterol auxotrophs manifest defects in S2P, which is encoded by a single copy gene. To circumvent this problem, in the current studies we transfected Chinese hamster ovary cells with the S2P cDNA, assuring multiple copies. We mutagenized the cells, selected for cholesterol auxotrophy, and identified two mutant cell lines (SRD-12A and -12B) that fail to cleave SREBPs at site 1. Complementation analysis demonstrated that the defects in both cell lines are recessive and noncomplementing, indicating a mutation in the same gene. These cells should now be useful for expression cloning of the sterol-regulated S1P gene. |
| Isolation of mucin from human hepatic bile and its induced effects on precipitation of cholesterol and calcium carbonate in vitro Yamasaki, T., K. Chijiiwa, et al. (1993), Dig Dis Sci 38(5): 909-15. Abstract: Biliary mucin was isolated from human hepatic bile, and its induced effects on the appearance time of cholesterol monohydrate crystals (nucleation time) and on the precipitation of calcium carbonate were studied in vitro to examine the possible significance of mucin for ductular gallstone formation. Mucin was isolated by gel filtration on Sepharose CL-4B and a subsequent CsCl density gradient ultracentrifugation. Mucin thus obtained had a high purity as shown by a high-molecular-weight band on SDS-polyacrylamide gel electrophoresis and by the compatible amino acid composition with mucin purified from the gallbladder. The mucin at as low a concentration as 100 micrograms/ml significantly shortened the cholesterol nucleation time in the supersaturated model bile, mimicking human hepatic bile. On the other hand, the addition of mucin inhibited calcium carbonate precipitation in vitro. Taking account of that both cholesterol and calcium salts are major constituents of ductular gallstones, we conclude that biliary mucin is likely to play an important regulating role in the formation of ductular stones. |
| Isolation of plasma cholesterol-lowering components from ningyotake (Polyporus confluens) mushroom Sugiyama, K., H. Kawagishi, et al. (1992), J Nutr Sci Vitaminol (Tokyo) 38(4): 335-42. Abstract: The present study was undertaken to isolate component(s) which contributes to the hypocholesterolemic action of Ningyotake (Polyporus confluens) mushroom. The mushroom powder was extracted with 80% ethanol, and the extract and residue were fractionated into five fractions according to the solubility to solvents. When each fraction was added to a diet containing 1% cholesterol and 0.25% sodium cholate and fed to rats, the plasma cholesterol level was significantly decreased only by ethyl acetate-soluble fraction. Therefore, ethyl acetate-soluble fraction was further fractionated by silica gel column chromatography. Two major compounds, which comprised 45.0% and 28.5% of the ethyl acetate-soluble fraction, were obtained in a pure form by the chromatography, and the compounds were identified as grifolin (2-trans, trans-farnesyl-5-methylresorcinol) and neogrifolin (4-trans, trans-farnesyl-5-methylresorcinol), respectively. The addition of grifolin and neogrifolin to the high cholesterol diet was found to lower plasma cholesterol level significantly. |
| Isolation, characterization and biological activities of novel triprenyl phenols as pancreatic cholesterol esterase inhibitors produced by Stachybotrys sp. F-1839 Sakai, K., K. Watanabe, et al. (1995), J Antibiot (Tokyo) 48(6): 447-56. Abstract: Ten triprenyl phenol metabolites were isolated as inhibitors of pancreatic cholesterol esterase from cultures of Stachybotrys sp. F-1839 by solvent extraction and column chromatographies. Combination of spectroscopic analyses revealed that two of these compounds are K-76 (1) and stachybotrydial (2), and that the remaining eight are new congeners (designated F1839-A (3), -B (4), -C (5), -D (6), -E (7), -F (8), -I (9) and -J (10). These compounds inhibited pancreatic cholesterol esterase by 50% at 6 x 10(-5) to 1.1 x 10(-1) M. Inhibition of the enzyme by compound 2, the most potent one among these compounds, was time-dependent and irreversible. When administered to normal rats, 2, at a single oral dose of 100 mg/kg, reduced 14Ccholesterol absorption by 50-60%. In cholesterol-fed mice, dietary supplementation of 2 (0.1%) for 14 days resulted in a 20% reduction in serum total cholesterol level without causing significant change in the high density lipoprotein cholesterol level. |
| Isoprenoid lipid metabolism in the retina: dynamics of squalene and cholesterol incorporation and turnover in frog rod outer segment membranes Fliesler, S. J., R. Florman, et al. (1995), Exp Eye Res 60(1): 57-69. Abstract: Frogs were injected intravitreally with 3Hacetate, and the formation of 3H-labeled squalene and cholesterol in the retina and their incorporation into rod outer segment (ROS) membranes were evaluated biochemically over a 60-day time course. ROS 3Hsqualene specific activity was maximal by 1-3 days, then declined with a half-time of approximately 20-30 days. In contrast, the specific activity of ROS 3Hcholesterol initially increased to a level substantially less than that of 3Hsqualene, and then remained constant. Thus, ROS squalene appears to turn over without obligatory conversion to, or coturnover with, ROS cholesterol. When 3Hacetate was injected into one eye, radiolabel in non-saponifiable lipids of the contralateral retina represented < 1% of those recovered from the ipsilateral retina; hence, systemic contributions to de novo synthesis were obviated. Long-term (> or = 8 hr) in vitro incubations of isolated retinas with 3Hacetate resulted in incorporation of 3H-labeled sterols and squalene into ROS, at levels comparable to those observed in ROS from companion incubated eyecup preparations and from retinas 8 hr after intravitreal injection of 3Hacetate. These results demonstrate that the in vitro system faithfully reflects the in vivo biosynthetic capacity with respect to isoprenoid lipid metabolism, and suggest that de novo synthesis within the neural retina is responsible for generating most, if not all, of the 3Hsqualene and 3Hcholesterol formed under the given conditions. Treatment of retinas in vitro with brefeldin A or energy poisons blocked transport of newly synthesized opsin, but not squalene, to the ROS. Furthermore, frogs maintained at 8 degrees C exhibited marked suppression of incorporation of newly synthesized protein into the ROS, while 3Hsqualene incorporation was only minimally reduced, compared with frogs maintained at 22 degrees C. These results are consistent with prior findings that suggest that lipids are transported to the ROS by a mechanism distinct and independent from that employed for intracellular trafficking of opsin and other ROS-destined membrane proteins. |
| Isotopomer spectral analysis of cholesterol synthesis: applications in human hepatoma cells Kelleher, J. K., A. T. Kharroubi, et al. (1994), Am J Physiol 266(3 Pt 1): E384-95. Abstract: Cholesterol synthesis from 13C-labeled precursors produces a discrete spectrum of mass isotopomers detectable using gas chromatography-mass spectrometry. The isotopomer spectral analysis (ISA) method matches the observed spectrum of cholesterol isotopomers with a mathematical model to obtain the best fit of model spectrum to data spectrum. The model was based on multinomial probability expressions that simulate cholesterol synthesis as a condensation of mevalonate fragments. As many as four unknown parameters, representing fluxes between compartments, were included in the model. Models were developed to assess cholesterol synthesis from 13C-enriched precursors including mevalonate, acetate, acetoacetate or octanoate. Models were tested in the human hepatoma cell line, Hep G2, which readily incorporated the 13C substrates into cholesterol. The ISA approach was used to estimate the fractional amount of the cholesterol precursors derived from the 13C substrate and the fraction of total cellular cholesterol synthesized in the presence of the 13C substrate. The study demonstrated the feasibility of the ISA approach for a condensation biosynthesis that is not a simple polymerization and for models with more than two unknown parameters. |
| Isotopomer spectral analysis of intermediates of cholesterol synthesis in human subjects and hepatic cells Lindenthal, B., T. A. Aldaghlas, et al. (2002), Am J Physiol Endocrinol Metab 282(6): E1222-30. Abstract: Steroid intermediates of the cholesterol synthesis pathway are characterized by rapid turnover rates relative to cholesterol due to their small pool size. Because the small pools will label rapidly, these intermediates may provide valuable information about the incorporation of isotopes in de novo synthesis of cholesterol and related compounds. The labeling of cholesterol synthesis intermediates from 1-(13)Cacetate was investigated in human subjects and in liver cell models by means of isotopomer spectral analysis (ISA). In human subjects, infusing 1-(13)Cacetate into the duodenum for 12 h demonstrated that approximately 50% of the plasma lathosterol pool was derived from de novo synthesis during this interval. The lipogenic acetyl-CoA precursor pool enrichment reached a constant value within 3 h of the start of the infusion. In vitro studies indicated that liver cell models decrease de novo lathosterol synthesis when cholesterol synthesis is inhibited by statins or cholesterol-containing serum. We propose a new calculation to increase the accuracy and precision of cholesterol synthesis estimates in vivo combining the ISA of lathosterol and cholesterol. |
| Isotopomer spectral analysis of intermediates of cholesterol synthesis in patients with cerebrotendinous xanthomatosis Clarenbach, J. J., B. Lindenthal, et al. (2005), Metabolism 54(3): 335-44. Abstract: Four patients with cerebrotendinous xanthomatosis (CTX) and 2 healthy controls received a constant proximal intraduodenal infusion of 1- 13 C-acetate as a stable-isotope-labeled marker of sterol synthesis. One patient was treated with pravastatin (20 mg twice daily) and another patient with chenodeoxycholic acid (250 mg tid). Every hour, venous blood and duodenal samples were obtained. Stable-isotope enrichment of neutral and polar sterols in serum and bile was assessed by gas chromatography/mass spectrometry. Isotopomer spectral analysis was performed on cholesterol, lathosterol, Delta-8-cholesterol, methylsterol, and lanosterol. Stable-isotope labeling of cholestanol, bile acids, and bile alcohols was analyzed by assessing the change over time of the ratio of M + 3 to M + 0. Eleven hours after marker infusion, we found up to 50% newly synthesized lathosterol in serum and up to 80% in bile, with similar results for other cholesterol precursors. In cholesterol, stable-isotope labeling could be demonstrated in all study subjects with a more prominent labeling in bile than in serum. No stable-isotope labeling was detected in cholestanol. Only minor stable-isotope incorporation was detectable in polar sterols in some subjects. Therapy with pravastatin did not have any effect on fractional or absolute synthesis rates or on the concentrations of cholestanol or cholesterol precursors compared to untreated patients with CTX. In contrast, therapy with chenodeoxycholic acid markedly lowered the concentrations of cholestanol and cholesterol precursors, led to a disappearance of bile alcohols, and reduced absolute synthesis rates of lathosterol. Isotopomer spectral analysis proved to be a powerful method to assess the endogenous synthesis of cholesterol precursors in patients with CTX. Higher fractional synthesis in bile than in serum may be due to the size of the pools in bile vs serum. Cholestanol exhibits no marker uptake and is therefore probably synthesized from preformed cholesterol. Biliary cholesterol secretion in patients with CTX is decreased compared to healthy controls. |
| Issue of lower limit for LDL cholesterol unresolved Wunsch, H. (1998), Lancet 351(9111): 1257. |
| It takes more than patient education to reach low-density lipoprotein cholesterol goals Kline-Rogers, E. M. and K. A. Eagle (2004), Am Heart J 147(3): 381-2. |
| Italian style brewed coffee: effect on serum cholesterol in young men D'Amicis, A., C. Scaccini, et al. (1996), Int J Epidemiol 25(3): 513-20. Abstract: BACKGROUND. Increases in blood lipids have been observed in humans when coffee is brewed by the boiling method. The purpose of this study was to evaluate if giving up Italian coffee might reduce blood cholesterol levels. METHODS. Eighty-four normolipidaemic young adult males, after a 3-week baseline (BL), were randomly assigned to three different regimens of coffee consumption: espresso (E), mocha (M), and no coffee, but tea (T). The average coffee consumption during intervention (I) was 3.1 +/- 1.2 and 2.8 +/- 1.1 cups per day for espresso and mocha group respectively (espresso: 25-35 ml/cup; mocha: 40-50 ml/cup). Total cholesterol, HDL-cholesterol, LDL-cholesterol and triglycerides were measured eight times during the study. Dietary pattern, alcohol consumption, smoking habits, drug use, and anthropometric data were also recorded. RESULTS. The changes observed in serum cholesterol concentration between baseline and intervention were not statistically different in all groups. The changes were 0.0 mmol/l (T), +0.01 mmol/l (E) and +0.05 mmol/l (M) for total serum cholesterol; 0 mmol/l (T), -0.02 mmol/l (E) and -0. 03 mmol/l (M) for HDL-C; -0.13 mmol/l (T), +0.02 mmol/l (E) and -0. 05 mmol/l (M) for LDL-C. Serum triglycerides showed a significant increase during intervention (P < 0.01 by ANOVA) in all groups with a change of 0.18 mmol/l, 0.18 mmol/l and 0.22 mmol/l, for tea, espresso and mocha group respectively. CONCLUSIONS. The results indicate that coffee brewed in the Italian way does not alter blood levels of total cholesterol, HDL-cholesterol and LDL-cholesterol, since no significant differences were observed in these blood parameters after a 6-week break from coffee consumption. |
| Janus kinase 2 modulates the apolipoprotein interactions with ABCA1 required for removing cellular cholesterol Tang, C., A. M. Vaughan, et al. (2004), J Biol Chem 279(9): 7622-8. Abstract: ATP-binding cassette transporter A1 (ABCA1) mediates transport of cellular cholesterol and phospholipids to high density lipoprotein (HDL) apolipoproteins, such as apoA-I. ABCA1 mutations can cause a severe HDL deficiency and atherosclerosis. Here we show that the protein-tyrosine kinase (TK) Janus kinase 2 (JAK2) modulates the apolipoprotein interactions with ABCA1 required for removing cellular lipids. The protein kinase A (PKA) inhibitor H89, the TK inhibitor genistein, and the JAK2 inhibitor AG490 suppressed apoA-I-mediated cholesterol and phospholipid efflux from ABCA1-expressing cells without altering the membrane ABCA1 content. Whereas PKA inhibition had no effect on apoA-I binding to cells or to ABCA1, TK and JAK2 inhibition greatly reduced these activities. Conversely, PKA but not JAK2 inhibition significantly reduced the intrinsic cholesterol translocase activity of ABCA1. Mutant cells lacking JAK2 had a severely impaired apoA-I-mediated cholesterol and phospholipid efflux and apoA-I binding despite normal ABCA1 protein levels and near normal cholesterol translocase activity. Thus, although PKA modulates ABCA1 lipid transport activity, JAK2 appears to selectively modulate apolipoprotein interactions with ABCA1. TK-mediated phosphorylation of ABCA1 was undetectable, implicating the involvement of another JAK2-targeted protein. Acute incubation of ABCA1-expressing cells with apoA-I had no effect on ABCA1 phosphorylation but stimulated JAK2 autophosphorylation. These results suggest that the interaction of apolipoproteins with ABCA1-expressing cells activates JAK2, which in turn activates a process that enhances apolipoprotein interactions with ABCA1 and lipid removal from cells. |
| Japanese family with a deficiency of lecithin:cholesterol acyltransferase (LCAT) Naito, M., E. Maeda, et al. (1994), Intern Med 33(11): 677-82. Abstract: We present findings in the ninth known Japanese family with lecithin:cholesterol acyltransferase (LCAT) deficiency. A 54-year-old man (proband) and his 58-year-old brother presented with corneal opacity. Both subjects showed a marked decrease in serum high density lipoprotein (HDL)-cholesterol and in the cholesteryl ester ratio. Although apo A-I and A-II were low, apo E tended to be high. Serum LCAT activity and mass were not detectable. Urinary examination showed microhematuria or proteinuria. Renal function was normal and no anemia was demonstrated, but blood smears showed poikilocytosis with target cells. The serum LCAT activity of the proband's three sons, obligate heterozygotes of LCAT deficiency, was about one-half the normal level, and HDL-cholesterol and apo A-I levels were low normal. |