Presence of α<sub>1</sub>-Lipoprotein in Patients with Familial Plasma Lecithin:Cholesterol Acyltransferase Deficiency

Torsvik, Harald

doi:10.3109/00365516909080151

Cited by 22 publications

(10 citation statements)

References 13 publications

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“…The two lipoprotein subfractions shown in Fig. 1 A (solid curve) emerge in the same positions as those obtained by Torsvik (19). They correspond approximately to the flanks of the single peak always obtained in comparable experiments with normal plasma (Fig.…”

Section: Methodssupporting

confidence: 62%

Plasma lipoproteins in familial lecithin:cholesterol acyltransferase deficiency: lipid composition and reactivity in vitro

Glomset¹,

Norum²,

King³

1970

J. Clin. Invest.

188

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A B S T R A C T Plasma lipoproteins from patients with familial lecithin: cholesterol acyltransferase (LCAT) deficiency have been fractionated by preparative ultracentrifugation and gel filtration and their lipid content and reactivity studied. All of the lipoproteins are abnormal with respect to lipid concentration or relative lipid content. The low density lipoproteins (LDL) and high density lipoproteins (HDL) appear to react normally with partially purified LCAT from normal plasma. Also, the lipids of the very low density lipoproteins (VLDL) and LDL, like those of the corresponding lipoproteins of normal plasma, are indirectly altered by the action of LCAT on normal HDL. Thus, during incubation in vitro VLDL cholesteryl ester is increased and VLDL triglyceride is decreased, as described by others for VLDL from hyperlipemic plasma, and both the unesterified cholesterol and lecithin of the VLDL and LDL are decreased. The patients' VLDL and LDL are abnormal, however, in that they lose unesterified cholesterol and lecithin to normal HDL in the absence of LCAT. Also, the patients' HDL lose these lipids to erythrocyte membranes in the absence of the enzyme.Our results provide further evidence that the abnormal cholesterol and phospholipid composition of the patients' lipoproteins is caused by the LCAT deficiency. They support the postulate that an excess of unesterified cholesterol and lecithin develops as VLDL are converted to LDL and HDL and suggest that in the absence of LCAT this excess lipid distributes among plasma lipoproteins and plasma membranes.

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Section: Methodssupporting

confidence: 62%

Plasma lipoproteins in familial lecithin:cholesterol acyltransferase deficiency: lipid composition and reactivity in vitro

Glomset¹,

Norum²,

King³

1970

J. Clin. Invest.

188

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“…As previously described, the HDL particles are eluted in the second protein peak by gel filtration on Sephadex G-200 of normal whole serum (Torsvik 1969). The H D L molecules from the patient with hyperlipoproteinemia of type IV emerged as those of normal serum.…”

Section: High Density Lipoprotein Fractions After G E L Filtration Onmentioning

confidence: 95%

“…Preparative ultracentrifugation was carried out at 8°C in a Spinco Model L2-65B ultracentrifuge using a Ti-50 rotor at 105,000 g. The different classes of lipoproteins were prepared as described elsewhere (Torsvik 1969), except that solid KBr was used to adjust the density of the serum. Three lipoprotein fractions were obtained: a fraction containing the lipoproteins of density < 1.006 g h l , designated very low density lipoprotein (VLDL); a fraction containing lipoproteins of density 1.019-1.063 g/ml, designated ,$lipoproteins or low density lipoproteins (LDL); and a fraction containing lipoproteins of density 1.063-1.195 g h l , designated al-lipoprotein or high density lipoproteins (HDL).…”

Section: Isolation Of Lipoprotein Fractionsmentioning

confidence: 99%

“…Gel filtrations of aliquotes from the HDL fractions were performed on Sephadex G-200 (Pharmacia Fine Chemicals, Uppsala) as previously described (Torsvik 1969).…”

Section: Isolation Of Lipoprotein Fractionsmentioning

confidence: 99%

“…In addition to the LCAT deficiency the preliminary studies of the disease indicated a deficiency of the serum al-lipoprotein or high density lipoprotein (HDL) (Norum & Gjone 1967). It has, however, been demonstrated that HDL is present in the serum of the patients, but that it behaves atypically in several ways (Torsvik 1969).…”

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confidence: 96%

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Serum lipoproteins in plasma lecithin:cholesterol acyltransferase deficiency, studied by electron microscopy

1970

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Serum lipoproteins from a patient with LCAT deficiency have been studied by electron microscopy and compared with lipoproteins from a normal individual and a patient with hyperlipo‐proteinemia of type IV. Particles of density < 1.006 g/ml from the LCAT deficiency patient were within a range of 230–3000 Å in diameter, whereas the diameters of the corresponding particles from the other two subjects fell within a range from 230 to 900 Å. A mean diameter of approximately 200 Å was found for the low density lipoproteins (l.019–1.063 g/ml) from the three subjects investigated. In LCAT deficiency the high density lipoprotein (1.063–1.195 g/ml) particles demonstrated a tendency to rouleau‐formation, giving the molecules a coinlike appearance with a mean diameter of 162 Å, and a mean thickness of 46 Å. In electron micrographs of HDL particles from the other two subjects studied, rouleau‐formation was not observed, and the mean diameters were of 82 and 85 Å, respectively. By gel filtration on Sephadex G‐200 of the HDL fraction from the patient with LCAT deficiency two populations of particles were found, one with a mean particle diameter of 163 Å and one with particle diameters of 35–56 Å.

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Lipoproteins in LCAT-deficiency

et al. 1972

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Presence of α₁-Lipoprotein in Patients with Familial Plasma Lecithin:Cholesterol Acyltransferase Deficiency

Cited by 22 publications

References 13 publications

Plasma lipoproteins in familial lecithin:cholesterol acyltransferase deficiency: lipid composition and reactivity in vitro

Plasma lipoproteins in familial lecithin:cholesterol acyltransferase deficiency: lipid composition and reactivity in vitro

Serum lipoproteins in plasma lecithin:cholesterol acyltransferase deficiency, studied by electron microscopy

Lipoproteins in LCAT-deficiency

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Presence of α1-Lipoprotein in Patients with Familial Plasma Lecithin:Cholesterol Acyltransferase Deficiency

Cited by 22 publications

References 13 publications

Plasma lipoproteins in familial lecithin:cholesterol acyltransferase deficiency: lipid composition and reactivity in vitro

Plasma lipoproteins in familial lecithin:cholesterol acyltransferase deficiency: lipid composition and reactivity in vitro

Serum lipoproteins in plasma lecithin:cholesterol acyltransferase deficiency, studied by electron microscopy

Lipoproteins in LCAT-deficiency

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Presence of α₁-Lipoprotein in Patients with Familial Plasma Lecithin:Cholesterol Acyltransferase Deficiency