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Biomedical subjects

J B Ragland

Publications and source records attributed to J B Ragland.

At least 19 recordsLinked to original sources
PubMed1983

Isolation and characterization of lipoprotein of density less than 1.006 g/ml from rat hepatic lymph.

The lipoprotein composition of rat hepatic lymph was studied using an animal model. The hepatic lymph duct of the adult male rat was cannulated and the hepatic lymph was collected. Hepatic lymph contains less than 1% of the total triglyceride output from the liver. Agarose gel electrophoresis of hepatic lymph showed the presence of two major lipoproteins bands, the alpha-migrating HDL and a band moving between plasma beta and pre-beta bands. Lipoprotein of density p less than 1.006 g/ml was then isolated by ultracentrifugation and it was found to correspond to the slow-moving pre-beta band. There was no difference in the mean diameter of hepatic lymph VLDL (64.4 nm) and that of plasma VLDL (64.6 nm). Compared with plasma VLDL, hepatic lymph VLDL has significantly more phospholipid (40% by weight), a higher cholesterol/cholesteryl ester ratio, and a marked reduction in triglyceride content (40% by weight). Although both plasma VLDL and hepatic lymph VLDL have apoE and apoB as the major apolipoproteins, there are other marked differences in apolipoprotein composition. Hepatic lymph VLDL has significantly less apoC and the apoB of hepatic lymph VLDL is predominantly the apoB240k (mol wt 240,000), with a small amount of the apoB330k (mol wt 335,000). On the other hand, plasma VLDL has an equal proportion of both apoB240k and apoB330k. This study presents for the first time the lipid and protein composition of rat hepatic lymph VLDL. Furthermore it has provided evidence that the hepatic lymph duct-cannulated rat can be used as an in vivo model for studying the secretion of nascent hepatic lymph VLDL.

Animals↗
PubMed1982

Effects of insulin on plasma lipoproteins in diabetic ketoacidosis: evidence for a change in high density lipoprotein composition during treatment.

To determine the acute effects of insulin on lipoprotein metabolism, we have followed the plasma lipoprotein lipid and apolipoprotein levels during insulin therapy for the first 24 hr in 13 patients with diabetic ketoacidosis. Corrections were made for plasma volume changes during treatment. Before insulin treatment, mean plasma triglyceride and cholesterol levels were 574 mg/dl (range 53-2355) and 212 mg/dl (range 118-416), respectively. Insulin therapy resulted in rapid decreases in triglyceride-rich lipoproteins, chylomicrons, and very low density lipoproteins (VLDL), with most patients achieving plasma triglyceride levels below 150 mg/dl at 24 hr. Mean basal levels of intermediate density lipoproteins (IDL) and low density lipoproteins (LDL)-cholesterol were low (9.9 and 72 mg/dl, respectively) and were statistically invariant with therapy. Mean basal levels of high density lipoprotein (HDL) cholesterol were also low (26 mg/dl, range 5-48) and were invariant during the first 12 hr and increased significantly to 29 mg/dl by the 24th hr. Plasma apoprotein (apo) B levels were in the upper normal range (101 mg/dl) before treatment and decreased with therapy due to significant decreases in VLDL, but not IDL or LDL apoB. VLDL appeared to have a normal apoprotein composition which did not change with treatment. Mean apoA-I levels which were near normal in plasma and HDL before therapy, decreased significantly (16%) by 12 hr and subsequently increased towards basal levels between 12 and 24 hr. The ratio of apoA-I to cholesterol in HDL also fell significantly during the entire 24 hr. Density gradient ultracentrifugal analysis of the d > 1.006 g/ml fractions indicated a selective decrease in "lighter" density fractions of HDL-apoA-I during treatment. These results provide evidence that insulin may decrease the secretion of apoA-I into plasma or increase catabolism.-Weidman, S. W., J. B. Ragland, J. N. Fisher, Jr., A. E. Kitabchi, and S. M. Sabesin. Effects of insulin on plasma lipoproteins in diabetic ketoacidosis: evidence for a change in high density lipoprotein composition composition during treatment.

Adolescent↗
PubMed1982

Plasma lipoprotein composition in alcoholic hepatitis: accumulation of apolipoprotein E-rich high density lipoprotein and preferential reappearance of "light'-HDL during partial recovery.

Abnormal lipoproteins accumulate in the plasma of alcoholic hepatitis patients in association with a deficiency of the cholesterol esterifying enzyme, lecithin:cholesterol acyl-transferase. Most of these abnormal lipoproteins are found in the d > 1.006 g/ml density fraction. To investigate the composition and morphology of the lipoproteins at various times during the illness in four patients, we have employed density gradient ultracentrifugation combined with analyses of gradient fractions by polyacrylamide gel electrophoresis, electroimmunoassay, and electron microscopy. At the onset of the illness, plasma cholesteryl esters ranged from 19-34% of total cholesterol; high density lipoprotein (HDL) cholesterol and apoA-I, the major HDL apoprotein, were <10% of normal; and most of the d > 1.006 g/ml triglycerides and phospholipids were found in the LDL density region. A linear correlation (r = 0.964, P < 0.001) was found between the d > 1.006 g/ml apoB concentration and the summation of the triglyceride and esterified cholesterol for that fraction, indicating a constant ratio of apoB to the summation of these two "core lipids". ApoA-I was primarily found in the fraction d > 1.18 g/ml (HDL(3) and VHDL) but not at all in the HDL(2) density range of the gradient. No cholesteryl esters were present in the apoA-I containing fractions. In contrast to normal, large amounts of apoE accumulated in lipoproteins isolated at d 1.055-1.114 g/ml. The apoE-rich fractions contained primarily phospholipids and unesterified cholesterol; they appeared by electron microscopy to be mixtures of spherical particles, vesicular particles, and chains of bilamellar discs. Analyses of the density gradient fractions by SDS polyacrylamide gel electrophoresis under reducing conditions indicated that apoA-II levels and distribution paralleled apoA-I, not apoE, providing evidence against appreciable concentrations of apoE-apoA-II complexes. During partial recovery from alcoholic hepatitis in three patients, the d > 1.006 g/ml unesterified cholesterol and triglyceride levels decreased, while esterified cholesterol, HDL-cholesterol, and apoA-I levels increased. The first HDL fractions to reappear were lipoproteins with HDL(2) density characteristics, as evidenced by simultaneous increases of apoA-I, apoA-II, cholesteryl esters and phospholipids. Lipoproteins with HDL(3) density characteristics appeared later. Long-term (6-10 months) follow-up studies indicated a substantial elevation of HDL cholesterol and apoA-I in three of the four patients that appeared to have resulted from further increases in their HDL(2)-like subspecies. The above results illustrate the diversity of abnormal lipoproteins in alcoholic hepatitis and the ability of density gradient ultra-centrifugation combined with lipid and apolipoprotein quantitation, electron microscopy, and polyacrylamide gel electrophoresis to partially resolve those lipoproteins in the d > 1.006 g/ml plasma fraction.-Weidman, S. W., J. B. Ragland, and S. M. Sabesin. Plasma lipoprotein composition in alcoholic hepatitis: accumulation of apolipoprotein E-rich high density lipoprotein and preferential reappearance of "light"-HDL during partial recovery.

Apolipoproteins↗
PubMed1982

Alterations in lipoprotein composition associated with galactosamine-induced rat liver injury.

The apoprotein and lipid composition and the morphology of lipoproteins was determined in rats with D-(+)-galactosamine (GalN) hepatitis. Single intraperitoneal injections of GalN at several dose levels and postinjection exsanguination times resulted in depressed levels of cholesteryl esters, an index of plasma lecithin:cholesterol acyltransferase (LCAT) activity, and increased levels of phospholipids, unesterified cholesterol, and triglycerides. Plasma withdrawn from rats 24 hr after injection of 1000 mg/kg GalN was most deficient in cholesteryl ester and was studied further by sequential isolation of VLDL, LDL, HDL1, HDL2, and HDL3. The increased plasma triglyceride (TG) after GalN treatment accumulated in TG-rich VLDL which contained two types of particles: a large (mean diameter 193.6 +/- 48.3 nm) and rough-edged particle, and a smooth one with a mean diameter (63.4 +/- 13.2 nm) similar to control VLDL (69.4 +/- 20.2 nm). The increased phospholiThe increased plasma triglyceride (TG) after GalN treatment accumulated in TG-rich VLDL which contained two types of particles: a large (mean diameter 193.6 +/- 48.3 nm) and rough-edged particle, and a smooth one with a mean diameter (63.4 +/- 13.2 nm) similar to control VLDL (69.4 +/- 20.2 nm). The increased phospholiThe increased plasma triglyceride (TG) after GalN treatment accumulated in TG-rich VLDL which contained two types of particles: a large (mean diameter 193.6 +/- 48.3 nm) and rough-edged particle, and a smooth one with a mean diameter (63.4 +/- 13.2 nm) similar to control VLDL (69.4 +/- 20.2 nm). The increased phospholipids and unesterified cholesterol were predominantly in LDL, HDL1, and HDL2 which were largely rouleaux of flattened vesicles. Density gradient ultracentrifugation of d greater than 1.006 g/ml lipoproteins confirmed these results. GalN hepatitis appeared to decrease the larger apoB335K subspecies and the apoC-III0 and apoC-III2 content of VLDL. However, total apoB concentration as GalN VLDL was increased 2.6-fold over control. LDL and HDL were markedly enriched in apoE. LDL apoB concentration was decreased by 41% while HDL was deficient in apoA-I, A-II and A-IV, and C. These results demonstrate association of increased plasma triglycerides with particles of grossly abnormal apoprotein composition, and the association of increased plasma phospholipids and unesterified cholesterol with apoE-rich lipoproteins during the LCAT defect produced by GalN hepatitis. These abnormal lipoproteins may represent an abnormal level of normal LCAT substrates important in the transport and esterification of plasma cholesterol.

Animals↗
PubMed1982

Computerized rapid high resolution quantitative analysis of plasma lipoproteins based upon single vertical spin centrifugation.

A method has been developed for rapidly quantitating the cholesterol concentration of normal and certain variant lipoproteins in a large number of patients (over 240 in one week). The method employs a microcomputer interfaced to the vertical autoprofiler (VAP) described earlier (Chung et al. 1981. J. Lipid Res. 22: 1003-1014). Software developed to accomplish rapid on-line analysis of the VAP signal uses peak shapes and positions derived from prior VAP analysis of isolated authentic lipoproteins HDL, LDL, and VLDL to quantitate these species in a VAP profile. Variant lipoproteins VHDL (a species with density greater than that of HDL(3)), MDL (a species, most likely Lp(a), with density intermediate between that of HDL and LDL), and IDL are subsequently quantitated by a method combining difference calculations with curve shapes. The procedure has been validated qualitatively by negative stain electron microscopy, gradient gel electrophoresis, strip electrophoresis, chemical analysis of the lipids, radioimmunoassay of the apolipoproteins, and measurement of the density of the peak centers. It has been validated quantitatively by comparison with Lipid Research Clinic methodology for HDL-, LDL-, and VLDL-cholesterol, and for MDL- and IDL-cholesterol by comparison of the amounts of MDL or IDL predicted to be present by the method with that known to be present following standard addition to whole plasma. These validations show that the method is a rapid and accurate technique of lipoprotein analysis suitable for the routine screening of patients for abnormal amounts of normal or variant lipoproteins, as well as for use as a research tool for quantitation of changes in cholesterol content of six or seven different plasma lipoprotein fractions.-Cone, J. T., J. P. Segrest, B. H. Chung, J. B. Ragland, S. M. Sabesin, and A. Glasscock. Computerized rapid high resolution quantitative analysis of plasma lipoproteins based upon single vertical spin centrifugation.

Apolipoproteins↗
PubMed1977

Hepatic triglyceride lipase deficiency in liver disease.

The activity of post-heparin lipases in patients with alcoholic hepatitis and viral hepatitis was evaluated. Lipoprotein lipase and hepatic triglyceride lipase were differentiated by assay under high and low salt conditions and also by separation on heparin-agarose affinity chromatography columns. The mean activity of hepatic triglyceride lipase in the sera of liver disease patients was only 21-24% of the mean of controls, but lipoprotein lipase in patients' sera was not different from normal levels. Hepatic triglyceride lipase deficiency may partially account for the accumulation of a triglyceride-rich low density lipoprotein in liver disease.

Alcoholism↗
PubMed1977

Abnormal plasma lipoproteins and lecithin-cholesterol acyltransferase deficiency in alcoholic liver disease.

Serial studies of plasma lipids and lipoproteins were performed in 4 patients with acute alcoholic liver disease characterized by a massive fatty liver and laboratory evidence of intrahepatic cholestasis. There were striking alterations in the plasma lipoprotein electrophoretic patterns characterized by the absence of alpha- and pre-beta-lipoprotein bands and the presence of a single band of abnormal mobility. These changes were associated with an extreme decrease in plasma lecithin-cholesterol acyltransferase activity, resulting in greatly reduced levels of plasma cholesteryl esters and increased levels of unesterified cholesterol. In 2 patients hypertriglyceridemia and hypercholesterolemia were present, the latter because of an increase in unesterified cholesterol. Lipoproteins were isolated from the plasma by sequential ultracentrifugation at the densities used for separation of normal very low density, low density, and high density lipoproteins; however, the patients' lipoproteins were different from normal in lipid composition and ultrastructure. All of the lipoprotein fractions were decreased in cholesteryl esters and the major lipoprotein was a triglyceride-rich low density lipoprotein. Electron microscopic studies of the low and high density lipoprotein fractions revealed the presence of bilamellar vesicles and stacked discs. All of the changes in lipoprotein composition and ultrastructure gradually returned to normal with clinical improvement. These observations indicate that alcoholic liver injury is associated with profound alterations in lipoprotein composition and metabolism which may be related in part to lecithin-cholesterol acyltransferase deficiency.

Acyltransferases↗
PubMed1976

Effects of norgestrel and metyrapone on pituitary-adrenal-ovarian function.

To assess the effects of d-norgestrel on pituitary-adrenal-ovarian function, basal levels and responses to metyrapone of urinary 17-ketogenic steroids (17-KGS) and 17-ketosteroids (17-KS), plasma cortisol (F), plasma delta4-androstenedione (A), plasma testosterone (T), plasma estrone (E1) and estradiol (E2), plasma and urinary LH and FSH were determined in 10 normal women before and while taking d-norgestrel 1 mg/day. Cortisol secretion rate (CSR) and binding capacities of cortisol binding globulin (CBG) and testosterone-estradiol binding globulin (TeBG) were also measured. Norgestrel did not significantly alter 17-KGS, 17-KS, F, LH, FSH, CSR, or the 17-KGS and 17-KS responses to metyrapone. Norgestrel reduced TeBG binding capacity but not CBG binding capacity. Norgestrel competitively inhibited the binding of dihydrotestosterone to TeBG under in vitro conditions. Levels of T, E2, and E1 were reduced by norgestrel. All measured hormone levels except FSH were increased following metyrapone prior to norgestrel administration. Norgestrel completely blocked the metyrapone-induced increases in LH and E2 and markedly reduced the E1 increase. Metyrapone reduced E2 during norgestrel treatment.

17-Hydroxycorticosteroids↗
PubMed1975

Lipoprotein and lecithin: cholesterol acyltransferase changes in galactosamine-induced rat liver injury.

Abnormal lipoproteins and drcreased lecithin: cholesterol acyltransferase activity are found in rat plasma following intraperitoneal injection of D-galactosamine. The changes observed, including absence of alpha-lipoprotein and the presence of lipoproteins rich in phospholipid and unesterified cholesterol but deficient in cholesteryl esters, are remarkably similar to changes found in human pathologic states of lecithin: cholesterol acyltransferase deficiency. When examined by electron microscopy, all of the major lipoprotein classes isolated by ultracentrifugation showed morphological abnormalities including the formation of rouleaus consisting of disk-shaped particles.

Acyltransferases↗
PubMed1975

Quantitative, multicomponent analysis of fatty acids from cholesteryl esters by chemical ionization reconstructed mass chromatography.

Reconstructed mass chromatography using methane as a carrier and reagent gas for chemical ionization gas chromatography-mass spectrometry of the derived methyl esters allows rapid, quantitative microdeterminations of complete cholesteryl ester fatty acid profiles. The sensitivity of this method is consistent with completely specific, multicomponent assay at the picomole level. Introduction of two homologues as internal standards, one into the intact biological specimen and the other after derivatization, provides a measure of the net efficiency of the processes of extraction and derivatization. This procedure may be extended readily to the determination of fatty acid profiles in most biological fluids.

Body Fluids↗
PubMed1975

Adrenal function in hirsutism I. Diurnal change and response of plasma androstenedione, testosterone, 17-hydroxyprogesterone, cortisol, LH and FSH to dexamethasone and 1/2 unit of ACTH.

ACTH dependency of plasma androstenedione (A) and testosterone (T) was determined in normal and hirsute women by measuring the magnitude of change of A and T between the time of the cortisol (F) peak and F nadir in a diurnal study. There was a significant diurnal rhythm of A synchronous with F in both normal and hirsute women (P less than 0.01). Five of 12 hirsute women had a greater than normal diurnal swing of A (P less than 0.05), but only 2 of the 12 had a greater than normal diurnal swing of T. Responsiveness of A and T to 1/2 unit of intravenous ACTH was determined after dexamethasone 1 mg was given the night before. Plasma A and T were elevated in most of the hirsute women during acute ACTH suppression by dexamethasone, indicating ACTH-independent hypersecretion of androgens. Nine of 17 hirsute women had a greater than normal A response to ACTH (P less than 0.05). Those who had an exaggerated diurnal swing of A also had hyper-responsiveness of A secretion to ACTH. Only 2 hirsute women had an exaggerated T response to ACTH. Some T levels were decreased by ACTH. Seven of the 9 hiruste women who had an exaggerated A response to ACTH had a normal maximum F response, but a greater than normal 17-hydroxy-progesterone (17-OHP) response to ACTH with a high 17-OHP to F ratio, suggesting they have a mild but compensated reduction in 21-hydroxylase or 11beta-hydroxylase activity. Two women with hyper-responsiveness of A secretion had low F and 17-OHP responses to ACTH suggesting reduced C21 but intact C19 3beta-hydroxysteroid dehydrogenase-delta-5,-4 isomerase activity. These apparent reduced enzyme activity may not be congenital, but induced by an altered hormonal milieu such as an abnormal androgen-estrogen ratio. It is concluded that ACTH uniformly stimulated A secretion but not T secretion and that approximately 50% of the hirsute women had ACTH-dependent hypersecretion of A, but most of these also had concurrent ACTH-independent hypersecretion of androgens.

Adrenal Glands↗