Search PubMed⌕ Search

Biomedical subjects

M L Kashyap

Publications and source records attributed to M L Kashyap.

At least 73 records · Page 4Linked to original sources
PubMed1982

Effects of dietary carbohydrate and fat on plasma lipoproteins and apolipoproteins C-II and C-III in healthy men.

Effects of isocaloric changes in dietary fat and carbohydrate on plasma apolipoproteins (apo) C-II, C-III, and lipoproteins were assessed in nine healthy men. Carbohydrate and fat comprised 80% of total calories. After a 1-week basal diet (40% of calories from carbohydrate), the subjects received either a high (65% of calories) or low (15% of calories) carbohydrate diet for 3 weeks; subsequently the diets were switched, those initially on high carbohydrate going on to low carbohydrate, and vice versa, and the new diets were maintained for 3 weeks. ApoC-II, C-III, and triglycerides initially rose and then declined during the high carbohydrate diet period; high density lipoprotein cholesterol (HDL-C) decreased. Comparing results after 3 weeks of high carbohydrate diet to those after 3 weeks on low carbohydrate, we observed the following significant differences: 1) total plasma apoC-II and C-III were higher; the apoC-III/C-II ratio in very low density lipoproteins (VLDL) and in the lighter HDL subfraction (HDL2) was lower indicating net lipoprotein enrichment with apoC-II than with apoC-III; 2) unsialylated apoC-III0 comprised a higher percent of total VLDL apoC-III mass; 3) HDL2 and HDL2/HDL3 ratio were lower. Isocaloric changes in dietary carbohydrate and fat cause significant alterations in plasma levels of VLDL and HDL 2, the two major lipoproteins that transport apoC-III and apoC-II. Diet-induced changes in circulating apoC-III and C-II may, in part, play a role in regulation of plasma triglycerides in man.

Adult↗
PubMed1981

Catabolism of human very low density lipoproteins in vitro: a fluorescent phospholipid method for monitoring lipolysis.

The catabolism of human plasma very low density lipoproteins (VLDL) by purified bovine milk lipoprotein lipase has been measured in vitro using a fluorescent phospholipid as a method to monitor lipolysis. Dansyl phosphatidylethanolamine (DPE) was incorporated into VLDL to form DPE-VLDL, and the rate of catabolism was followed by measuring the increase in fluorescence at 490 nm after the addition of the enzyme. The studies were performed with VLDL isolated from 20 normal individuals. In addition, the VLDL from 8 mildly obese subjects with primary hypertriglyceridemia (Type IV phenotype) was studied. With this in vitro system and with a constant amount of lipoprotein lipase, the rate of lipolysis did not differ in normal and in these hypertriglyceridemic subjects. Furthermore, there was no correlation between the rates of hydrolysis and the plasma levels of triglyceride or high density lipoprotein cholesterol.

Adult↗
PubMed1981

The 16-hour-standing test and lipoprotein electrophoresis compared for detection of chylomicrons in plasma.

We compared the 16-hour-standing plasma test to lipoprotein electrophoresis on agarose gel for detection of chylomicrons in 129 patients' samples with triglyceride values greater than or equal to 4.00 g/L. Chylomicrons were observed in 12 samples (9.3%) by use of the standing-plasma test and in 58 samples (45.0%) by use of agarose-gel electrophoresis. Thus the standing-plasma test did not detect chylomicrons in 46 samples where they were observed by electrophoresis, or 79.3% of all cases where chylomicrons were present. Chylomicronemia was missed in the presence of lower triglyceride concentrations as well as at very high ones. We recommend that lipoprotein electrophoresis be routinely performed on plasma of patients with triglycerides concentrations greater than 4.00 g/L to distinguish between types IV and V hyperlipoproteinemia, as well as to detect failure of a patient to fast before sample collection.

Chylomicrons↗
PubMed1981

Hydrolysis of guinea pig nascent very low density lipoproteins catalyzed by lipoprotein lipase: activation by hjman apolipoprotein C-II.

Very low density lipoproteins isolated from guinea pig liver perfusate (VLDLp) lack the equivalent of human apolipoprotein C-II (apoC-II), the activator of lipoprotein lipase (LpL). These lipoproteins are therefore ideal substrates with which to investigate the mechanism by which apoC-II activates the enzyme. VLDLp binds apoC-II, and apoC-II associated with VLDLp markedly increases the rate of lipoprotein lipase-catalyzed hydrolysis of VLDLp-triglycerides. The activator potency of apoC-II is independent of the method of enrichment of VLDLp with apoC-II: delipidated human apoC-II and apoC-II transferred from human high density lipoproteins activate lipoprotein lipase to equal extents. ApoC-II causes pH-dependent changes in both apparent Km and VmaX of LpL-catalyzed hydrolysis of VLDLp-triglycerides. At pH l7.4--7.5, the major effects of apoC-II is to decrease the apparent Km by 3.3--4.0 fold. The apparent Vmax is increased 1.3-fold. At pH 6.5 and 8.5, the decrease of apparent Km is less marked, 1.6-fold and 1.4-fold, respectively. At pH 6.5, apoC-II increases the apparent Vmax ty 1.3-fold, while at pH 8.5 the primary effect of apoC-II is a 1.6-fold increase of apparent Vmax. Based on a simple kinetic model, the data suggest that apoC-II favors direct interaction between enzyme and triglyceride within the lipoprotein particle, as well as subsequent catalytic turnover.

Animals↗
PubMed1981

Quantitation of human apolipoprotein C-III and its subspecie by radioimmunoassay and analytical isoelectric focusing: abnormal plasma triglyceride-rich lipoprotein apolipoprotein C-III subspecie concentrations in hypertriglyceridemia.

A specific, accurate, and sensitive double antibody radioimmunoassay for measuring human apolipoprotein (apo) C-III has been developed. Anti-apoC-III(1) developed in rabbits cross-reacted completely with apoC-III subspecies. Analytical isoelectric focusing of delipidated triglyceride-rich lipoproteins (TRL) was done to assess the percentage of total apoC-III mass comprised by apoC-III(0), C-III(1), and C-III(2), and the data were used to compute the absolute plasma TRL apoC-III subspecie concentration. Total plasma apoC-III was 11.1 +/- 0.9 mg/dl (mean +/- SEM) in 29 normolipidemic healthy subjects; 21.3 +/- 4.9, 27.5 +/- 2.2, and 53.6 +/- 7 mg/dl in 3, 16, and 13 patients with primary types III, IV, and V hyperlipoproteinemia, respectively, and significantly (P < 0.01) higher than normal. Total plasma triglycerides (TG) correlated positively with total plasma apoC-III (r = 0.88; P = 0.0001) and TRL apoc-III (r = 0.88; P = 0.0001). Progressive hypertriglyceridemia was associated with a rise in the percent of total apoC-III in TRL isolated at d < 1.006 g/ml (r = 0.78; P < 0.0001; n = 43) and a reciprocal decline in the TRL-free plasma fraction (d > 1.006 g/ml). ApoC-III comprised significantly more of HDL(2) than HDL(3) protein (7.3 +/- 0.2 versus 1.6 +/- 0.2%, respectively, P < 0.01). HDL(2) and HDL(3) isolated from patients with type IV hyperlipoproteinemia had subnormal apoC-III as percent of total protein (2.4 +/- 0.5 and 0.6 +/- 0.1, respectively). Total plasma TG correlated negatively with i) apoC-III as percent of total HDL protein (r = -0.67; P = 0.002, n = 20); ii) apoC-III as percent of total HDL(2) protein (r = -0.52; P = 0.019); and iii) apoC-III as percent of total HDL(3) protein (r = -0.72; P = 0.0004). Plasma TRL apoC-III subspecie concentrations were significantly higher in the three hypertriglyceridemic groups (primary types III, IV, and V) compared to normals. TRL apoC-III(0) levels in patients with type IV and V were comparable (2.4 +/- 0.3 and 2.2 +/- 0.6 mg/dl, respectively). However, TRL apoC-III(1) and C-III(2) in patients with type V hyperlipoproteinemia were significantly higher (P < 0.01) than in patients with types IV or III hyperlipoproteinemia. Total plasma TG correlated positively with TRL apoC-III(0) (r = 0.56; P = 0.0004), TRL apoC-III(1) (r = 0.82; P = 0.0001) and TRL apoC-III(2) (r = 0.76; P = 0.0001). The slope of regression line relating total plasma TG with TRL apoC-III(1) was significantly steeper (P < 0.0001) than that for apoC-III(0). Thus, for a given interval of plasma TG, the change in concentration of TRL apoC-III(1) was much greater than that in TRL apoC-III(0). The development of the RIA and its combined use with analytical isoelectric focusing thus allows quantitation of this important glycopeptide and its subspecies in human plasma and its subfractions. Because apoC-III inhibits not only tissue lipoprotein lipase but also the hepatic uptake of triglyceride-rich lipoproteins and remnants, the data support the possibility that an abnormal metabolism of apoC-III subspecies may be linked pathogenetically to elevated plasma TG levels.-Kashyap, M. L., L. S. Srivastava, B. A. Hynd, P. S. Gartside, and G. Perisutti. Quantitation of human apolipoprotein C-III and its subspecies by radioimmunoassay and analytical isoelectric focusing: abnormal plasma triglyceride-rich lipoprotein apolipoprotein C-III subspecie concentrations in hypertriglyceridemia.

Apolipoprotein C-III↗
PubMed1980

Post-heparin plasma lipoprotein and hepatic lipases. Relationships to high density lipoprotein cholesterol and to apolipoprotein CII in familial hyperalphalipoproteinemic and in normal subjects.

Post-heparin lipoprotein lipase (PH-LPL)-high density lipoprotein cholesterol (HDL-C) interrrelationships were assessed in 9 subjects with documented familial hyperalphalipoproteinemia (FHA) and in 8 controls to focus on potential biochemical etiologies of FHA and relationships of HDL-C to triglyceride hydrolysis and PH-LPL. FHA subjects had mean HDL-C and HDL2-C levels > twice controls; their PH-LPL levels (mean +/- SEM) (3.14 +/- 2.3 mumol FFA/h/ml) were also > twice that of controls (15.0 +/- 1.6) (P < 0.01), but post-heparin hepatic lipase levels (PH-HL) in the FHA and control subjects did not differ (18.1 +/- 1.6 vs 26.6 +/- 4.3, P > 0.1). For all subjects (FHA and controls) PH-LPL was positively correlated with HDL-C (r = 0.79, P < 0.01) and with HDL2-C (r = 0.90, P < 0.01), but not with HDL3-C (r = --0.02). There were no significant PH-HL and HDL-C interrelationships, P > 0.1. The amount of apo CII (the primary activator of PH-LPL) in HDL2 was greater in the FHA (mean +/- SEM) (16.1 +/- 2.5 microgram/ml plasma) than in control subjects (4.7 +/- 0.9, P < 0.01). There were strong positive correlations between HDL2 apo CII and both PH-LPL (r = 0.79, P < 0.01) and HDL2-C (r = 0.80, P < 0.01). Apo CII as a percentage of HDL2 protein was higher in FHA than control subjects (mean +/- SEM) (1.2 +/- 0.3% vs 0.5 +/- 0.2%, P < 0.01). Apo CII as a percentage of HDL3 protein was similar in FHA and control subjects. We postulate that increased turnover rate of triglyceride-rich lipoproteins due to high LPL activity may be an important factor leading to the elevation of HDL-C in FHA. The highly significant positive correlation between HDL2-C and PH-LPL provides strong clinical evidence for the theory that HDL2 is formed during the hydrolysis of triglycceride-rich lipoproteins. The high concentration of HDL2 apo CII in FHA subjects may be caused by increased catabolism of triglyceride-rich lipoproteins in the presence of high endothelial LPL, with transfer of apo CII from very low to high density lipoproteins.

Adolescent↗
PubMed1980

Glucose infusions increase plasma levels of amyloid proteins in high density lipoproteins.

Malmendier et al. (4) have described six apoproteins from human plasma high density lipoproteins (HDL) which were isolated from patients given an intravenous infusion of 10% glucose. Inspection of their amino-terminal sequences indicate that Malmendier et al. have isolated various forms of serum amyloid AA. Since amyloid is present in patients with various chronic diseases which are associated with decreased HDL levels, we suggest that there is a relationship between amyloid and HDL.

Amino Acid Sequence↗
PubMed1980

A rapid and simple method for measurement of total protein in very low density lipoproteins by the Lowry assay.

When total protein in very low density lipoprotein samples is measured by the method of Lowry et al. (1951. J. Biol. Chem 193:265-275), turbidity remains in the final color reaction. Addition of 0.1 ml of 2.5% (v/v) solution of Triton X-100 removes this turbidity immediately and effectively. This simple modification is faster, less cumbersome, and more economical than removing turbidity with ethyl ether or chloroform. Addition of 0.1 ml of 2.5% (w/v) sodium dodecyl sulfate to the final reaction mixture is also effective in removing turbidity and can be used as an alternative method.

Chloroform↗