Simultaneous quantification of apolipoproteins B-100, B-48, and E separated by SDS-PAGE.
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Biomedical subjects
Publications and source records attributed to N Bergeron.
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The effects of diets rich in saturated fatty acids (SFA) (total polyunsaturated fatty acids [PUFA] [g]/total SFA [g][P/S ratio], 0.2) or omega-6 PUFA (P/S ratio, 1.3) on the postprandial response of triglyceride-rich lipoproteins (TRL) was determined in normolipidemic young men. After 15 and 29 days of diet intervention, the postabsorptive concentrations of apolipoprotein (apo) B-48 and apoB-100 were higher in the SFA group than in the PUFA group, but the absolute increase in apoB-48 was similar 3 hours after a challenge meal containing one third of daily energy and returned to postabsorptive values at 6 hours; this response was closely coupled to that of TRL triglycerides. In both groups, the percent increase in TRL apoB-48 and triglycerides was greater after the PUFA meal than after the SFA meal. The concentration of TRL apoB-100 also increased at 3 hours in both diet groups but returned to postabsorptive values at 6 hours only in those fed the PUFA diet; in the SFA group, apoB-100 remained high at 6 hours and fell below postabsorptive values only 9 hours after the meal. This apoB-100 response was affected primarily by the fatty acid composition of the diet and not by that of the challenge meal. The postprandial response of apoB-100 was closely coupled to that of cholesterol and apoE. These observations suggest that in healthy young men, neither the fatty acid composition of the diet nor that of the challenge meal affects the clearance of chylomicron remnants after a fat-containing meal. By contrast, the postprandial accumulation of hepatogenous TRL is prolonged in individuals fed a diet rich in SFA.
The following studies have been carried out to compare the effects of fish protein with other dietary proteins on plasma cholesterol and lipoproteins in animal models and in humans. In rabbits, fish protein has been shown to induce relatively variable effects compared to casein and soy protein on serum cholesterol depending in part on the origin of dietary lipids with which it is combined. In a protein-lipid interaction study, casein, soy or cod protein were combined with corn or coconut oil. Casein and soy protein in the presence of corn oil induced lower serum cholesterol levels despite its combination with either corn or coconut oil. This is in part due to serum high density lipoprotein (HDL) cholesterol concentrations, which were consistently higher with cod protein than with either casein or soy protein, regardless of the dietary lipid source. In rabbits, this rise in HDL cholesterol was associated with a decrease in very low density lipoprotein (VLDL) triglycerides and an increase in postheparin plasma lipoprotein lipase activity. The effects of lean white fish on plasma lipoproteins also have been investigated in post and premenopausal women fed a low-fat, high P/S (polyunsaturated/saturated fat) ratio diet. In postmenopausal women, lean white fish compared with other animal protein products induced higher concentrations of plasma cholesterol, LDL-apolipoprotein (apo) B and HDL cholesterol, mainly in the HDL3 fraction. In premenopausal women, lean white fish induced lower concentrations of VLDL triglycerides and higher concentrations of LDL-apoB in plasma.(ABSTRACT TRUNCATED AT 250 WORDS)
We have developed a procedure to quantify apolipoprotein (apo) B-100, apoB-48, and apoE in human triglyceride-rich lipoproteins. This procedure permits delipidation of small amounts of triglyceride-rich lipoproteins without appreciable losses, and quantification of these apolipoproteins in samples containing as little as 10 micrograms of protein. Delipidated triglyceride-rich lipoproteins are subjected to sodium dodecyl sulfate polyacrylamide slab gel electrophoresis, and the mass of apolipoproteins is estimated after densitometric scanning and volume integration of Coomassie blue-stained bands. The chromogenicities of apoB-100 and apoB-48 are virtually identical, and twofold lower than that of apoE. The standard curve for each apolipoprotein follows a power function over a wide protein range, permitting quantification of as little as 0.2 microgram of apoB-48 and as much as 30 micrograms of apoB-100 from a single application of triglyceride-rich lipoproteins to the gels. This method is suitable for routine use in studies of the intestinal and hepatic contributions to triglyceride-rich lipoproteins and their responses to postprandial lipemia.
The performance of the Roche Cobas Argos 5Diff (Argos) automated haematology analyser was evaluated by comparison to manual blood film examination and a Coulter STKS (STKS) analyser. The Argos demonstrated excellent between and inter-batch imprecision for all parameters, except the MCHC, and good linearity for Hb, WBC and platelet count (PLT). After an initial fall the PLT, results were stable for up to six h at 18 degrees C in EDTA(K3) after which an increasing proportion of cells were classified as lymphocytes. Results of 239 patient samples analysed on both instruments, compared by linear regression, gave excellent correlation (r2 > 0.90) for most parameters with the exceptions of the MCHC (0.317), eosinophils% (0.756), monocytes% (0.48) and basophils% (0.002). 'Flagging' of cellular abnormalities by the Argos resulted in excellent sensitivity (97.5%), specificity (93.2%) and efficiency/agreement (93.2%), with fewer false positive and negative results than the STKS, although these differences were not statistically significant. The performance characteristics of the Argos were comparable to those of the STKS with a possible improvement in its flagging abilities.
To explore the pathways by which fish protein feeding influences HDL metabolism, postheparin plasma lipoprotein lipase and hepatic triglyceride lipase activities were measured in rabbits fed fish protein or soybean protein combined with corn oil or coconut oil in a 2 x 2 factorial arrangement. In addition to greater serum total and LDL-cholesterol concentrations, the elevated HDL cholesterol concentration caused by feeding fish protein, compared with soybean protein, was accompanied by lower VLDL triglycerides and parallel higher lipoprotein lipase activity in fish protein-fed rabbits. These results suggest an enhanced assembly of circulating HDL through promoted lipoprotein lipase activity in rabbits fed fish protein. Moreover, dietary proteins and lipids interacted with one another to alter HDL triglycerides and liver cholesterol concentrations. Diet-induced changes in lipoprotein lipase activity were, however, not related to insulinemia, which was unaltered by purified diet feeding. The present results suggest that fish protein may affect HDL metabolism through the modulation of lipoprotein lipase activity in rabbits.
Purified diets varying in dietary protein, namely casein (CA), soy protein (SP), fish protein (FP), and lipid origin (corn oil (CN), coconut oil (CO)) were fed to rabbits to evaluate the effects of protein and fat source, as well as protein-lipid interactions, on serum total, lipoprotein and hepatic lipid levels. Dietary proteins and lipids exerted a separate effect on serum total cholesterol (C), very low-density lipoprotein cholesterol (VLDL-C), and low-density lipoprotein cholesterol to high density lipoprotein cholesterol (LDL-C/HDL-C) ratio. Hence, CA increased serum cholesterol compared to SP, while coconut oil enhanced serum and VLDL-C, and decreased LDL-C/HDL-C compared to corn oil. Dietary proteins interacted with dietary lipids to modulate HDL-C levels. Thus, FP maintained a high level of HDL-C regardless of lipid origin, compared to CA and SP whose HDL-C levels were decreased by corn oil, compared to coconut oil. A dietary protein-lipid interaction was also observed in the regulation of liver cholesterol levels. Coconut oil, compared to corn oil, decreased liver cholesterol in rabbits fed FP, whereas hepatic cholesterol concentration was unaltered by dietary lipid source in CA- and SP-fed rabbits. These results demonstrate that dietary proteins act synergistically with dietary lipids to regulate cholesterol metabolism in the rabbit.
Serum and hepatic cholesterol and triglyceride levels, and serum lipoprotein cholesterol were investigated in rabbits fed fish protein as compared to casein and soy protein as part of a 20% protein, low fat, cholesterol-free, semi-purified diet. A nonpurified diet was used as a control. After a 28-day experimental period, rabbits fed casein developed hypercholesterolemia compared to those fed the soy protein diet. Serum cholesterol levels of rabbits fed fish protein was intermediate and not different from that of the casein or the soy protein group. However, serum triglycerides were higher in the fish group than in the casein group. Feeding of fish protein resulted in a reduction of hepatic cholesterol compared to casein, indicating no direct relationship between serum and hepatic cholesterol. In addition, fish protein induced a decrease of cholesterol in the low density lipoproteins (LDL) compared to casein and an increase of cholesterol in the high density lipoproteins (HDL) compared to casein and soy protein. Reduction in LDL-cholesterol (LDL-C) and elevation in HDL-cholesterol (HDL-C) caused a 10-fold decrease in the LDL-C/HDL-C ratio of fish protein fed rabbits compared to those fed casein. This ratio was similar to that observed with soy protein which was also lower than the ratio of the casein group. Thus, since the LDL-C/HDL-C ratio has been shown to be a good indicator of the atherosclerosis risk, these results suggest that fish protein, as well as soy protein, may reduce the risk of atherosclerosis in rabbits, compared to casein.
In order to achieve a more complete blockade of androgens of both testicular and adrenal origins, 223 patients with advanced prostate cancer (stage D2 with bone metastases) received the combination therapy with the antiandrogen Flutamide and the LH-RH agonist [D-Trp6,des-Gly-HN10(2)] LH-RH ethylamide as first treatment. As assessed by the objective criteria of the US NPCP, a positive response was obtained in 94% of patients, thus leaving only 6% of patients with no response at the start of treatment while, following standard therapy, 20-40% of patients do not respond to treatment. The duration of response was increased while longer survival (an advantage of approximately 14 months compared to standard therapy, 38.5 vs approximately 24 months) was achieved with no or minimal side effects. Highly positive results were also obtained using the combination therapy in stage C prostate cancer patients while temporary treatment with the combination therapy in stages A and B prostate cancer facilitated radical prostatectomy. The present data supported by the results of independent studies indicate that combination therapy should be the treatment for all patients with advanced disease and possibly also at earlier stages of prostate cancer in combination with surgery.
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One hundred and ninety-nine patients with clinical stage D2 prostate cancer who had not received previous endocrine therapy or chemotherapy were treated with the combination therapy using the pure antiandrogen Flutamide and the LHRH agonist [D-Trp6]LHRH ethylamide for an average of 26 months (3-59 months). The objective response to the treatment was assessed according to the criteria of the U.S. NPCP. There was a 5.7-fold increase (26.3 vs 4.6%) in the percentage of patients who achieved a complete response compared with the results obtained in five recent studies limited to removal (orchiectomy) or blockade (DES or Leuprolide) of testicular androgens. Only 12 of the 186 evaluable patients (6.5%) did not show an objective positive response at the start of the combination therapy compared with an average of 18% in the same five studies using monotherapy. The duration of response was also significantly improved in the patients who received the combination therapy while the death rate was decreased by approximately two-fold during the first 4 yr of treatment. In fact, while an approximately 50% death rate is observed at 2 yr in all studies using monotherapy, the same 50% death rate is delayed by 2 yr in the present study. It should be mentioned that at the time of relapse under combination therapy, the treatment is continued and, in addition, further blockade of adrenal androgen secretion is achieved with aminoglutethimide. The marked (5.7-fold) improvement in the rate of complete objective responses coupled with the three-fold decrease in the number of non-responders, the increased duration of the positive responses and the two-fold decrease in the death rate during the first 4 yr of treatment are obtained with the combination therapy using Flutamide and castration, thus improving the quality and duration of life with no or minimal side-effects. By blocking the androgen receptors in the prostatic cancer tissue, the antiandrogen decreases the action of the androgens of adrenal origin and thus inhibits the growth of a large number of tumors which, otherwise, would continue to be stimulated by the adrenal androgens left after medical or surgical castration.
One hundred and eighty-six previously untreated patients with clinical stage D2 prostate cancer have been followed according to the criteria of objective response of the National Prostatic Cancer Project (NPCP). All patients received combination therapy with the antiandrogen Flutamide and the LHRH agonist (D-Trp6, des-Gly-NH2(10)]LHRH ethylamide (or surgical castration, 10 patients) as first treatment. Forty-nine patients (26.3%) achieved a complete response as best response while 56 (30.1%) and 69 (37.1%) patients had partial and stable responses, respectively, and only 12 patients (6.5%) did not respond to treatment. The median times required to achieve stable, partial and complete responses were 155, 183 and 401 days, respectively. The best response achieved has a major influence on the probability of continuing response and survival. While the 50% probability of continuing response is more than 3 years for the complete responders, it is reduced to 630 and 517 days for partial and stable responders, respectively. While the non-responders have a median life expectancy of 10.0 months, this value is increased to 30.3 and 37.8 months for the stable and partial responders, respectively. The best probability of survival is for the complete responders with a 95.9% probability of survival at 3 years. There is no significant correlation between the time required to achieve a best response (phase 1) and the duration of the response before progression occurs (phase 2) or the time between progression and death (phase 3) for any of the categories of responses. A longer period of time required to achieve a complete response is associated with a longer survival. When analysis is made, in an attempt to predict response, of the baseline characteristics of the patients before treatment, a low number of bone metastases and better performance status are associated with a greater chance of achieving a complete response while partial, stable and progression responses cannot be predicted from the baseline characteristics. The present data show the importance of standardization of the objective criteria of response to treatment in advanced prostate cancer. Thus, the patients who achieve a complete response have a much more favorable prognosis while partial and stable categories of response have a closely similar prognosis which is inferior to the complete responders. Moreover, the present data indicate that the stable category of response has an important prognostic value which is almost superimposable and not statistically different from the partial response in terms of duration of response and survival.(ABSTRACT TRUNCATED AT 400 WORDS)
Sixty-seven previously untreated patients presenting with clinical stage C prostatic carcinoma with no evidence of distant metastases received combination therapy using the antiandrogen Flutamide and the LHRH agonist [D-Trp6]LHRH ethylamide for an average duration of treatment of 23.5 months. Only five patients have so far shown treatment failure with 91.8% of the patients still in remission at 2 years. Three patients have died from prostate cancer while three have died from other causes, 93.5% of the patients being alive at 2 years. Local control was achieved rapidly in all except one patient. Urinary obstruction and hydronephrosis were corrected in all cases. When comparing to recent data obtained after single endocrine therapy (orchiectomy or estrogens), or radiotherapy, the rate of treatment failure at 2 years is 3.5-fold lower after combination therapy (8.2%) than monotherapy (28.4%). The death rate at 2 years following start of the combination therapy is 6.5% while it is on average 22.2% (3.4-fold higher) in the studies using monotherapy (orchiectomy or estrogens) or radiotherapy. The present data suggest that treatment of prostate cancer with combination therapy before clinical evidence of dissemination of the disease permits a better response which is possibly explained, at least in part, by the lower degree of dedifferentiation and heterogeneity of the tumors.
Two hundred and nine patients with biopsy-proven stage D2 prostatic carcinoma showing disease progression after orchiectomy or treatment with DES (stilboestrol) or an LHRH agonist alone received combination therapy with the pure antiandrogen flutamide. In patients treated with DES, the oestrogen was replaced by the LHRH agonist [D-Trp6]LHRH ethylamide. The objective response to therapy was assessed according to the criteria of the US NPCP. Thirteen patients had a complete response to treatment, while partial and stable responses were achieved in 20 and 39 patients respectively (total objective response rate of 34.5%). The mean duration of response was 24 months. In the non-responders the median survival was 8.1 months with a 17% probability of survival at 2 years; the probabilities of survival at 2 years of the patients who showed partial and stable responses were 87 and 67% respectively. All patients who achieved a complete response are still alive. Combination therapy with Flutamide and castration (surgical or LHRH agonist) appears to be the treatment of choice for prostate cancer patients in relapse after standard endocrine therapy.
Rabbits were fed purified diets consisting of casein (CA), fish protein (FP), and soy protein (SP) combined with MaxEpa oil (ME) or corn oil (CN) to determine the effects of dietary protein and lipid sources on serum total, lipoprotein, and hepatic lipid levels. Dietary proteins and lipids exerted significant (p < 0.05) separate effects on serum total cholesterol (TC) (p < 0.005), very-low-density lipoprotein cholesterol (VLDL-C) (p < 0.001), and high-density lipoprotein cholesterol (HDL-C) (p < 0.001), whereas only dietary proteins significantly affected low-density lipoprotein cholesterol (LDL-C) (p < 0.001) and the LDL-C/HDL-C ratio (p < 0.05). Hence, FP induced serum TC (233 mg/dl), VLDL-C (22 mg/dl), and LDL-C (151 mg/dl) intermediary to hypercholesterolemic CA (TC, 319 mg/dl; VLDL-C, 57 mg/dl; LDL-C, 204 mg/dl) and cholesterol-lowering SP (TC, 129 mg/dl; VLDL-C 19 mg/dl; LDL-C, 84 mg/dl). The twofold rise in HDL-C on feeding FP (35 mg/dl), compared with CA (20 mg/dl) and SP (16 mg/dl), resulted in a drop in LDL-C/HDL-C to a level similar to that of SP groups. The cholesterol-lowering action of ME (188 mg/dl), in contrast to CN (266 mg/dl), was reflected mainly in VLDL (ME, 15 mg/dl; CN, 50 mg/dl) but also in HDL (ME, 16 mg/dl; CN, 31 mg/dl) fractions. Compared with CN, the significant (p < 0.05) ME-induced rise in serum and VLDL triglycerides was accompanied by a significant (p < 0.001) drop in lipoprotein lipase activity.(ABSTRACT TRUNCATED AT 250 WORDS)
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