Insulin resistance and membrane abnormalities.
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Diabetes Mellitus, Type 2↗
Biomedical subjects
P Drouin
Publications and source records attributed to P Drouin.
Laparoscopic staging of early ovarian cancer.
The relevance of staging in early ovarian carcinoma is reviewed in light of the advances in surgical laparoscopy. Data from the literature suggest that a lymphadenectomy should be performed instead of a sampling. We have realized the former through laparoscopy. In this paper we propose a detailed surgical technique, similar to the laparotomy approach, that ensures an adequate nodal evaluation. Ten patients underwent a completion of staging by laparoscopy, including peritoneal washings for cytology, peritoneal and ovarian biopsies, an infracolic omentectomy, and a lymph node dissection. The use of laparoscopy for staging of early ovarian carcinoma appears to be a valuable alternative to traditional surgical staging.
Adult↗
Decreased erythrocyte membrane fluidity in poorly controlled IDDM. Influence of ketone bodies.
OBJECTIVE: To examine the factors that might alter the fluidity of erythrocyte membrane in insulin-dependent diabetes mellitus (IDDM) patients. RESEARCH DESIGN AND METHODS: The subjects were 10 health men and 30 IDDM mem: 10 with good blood glucose (BG) control (HbA1c 5.88 +/- 0.60% [mean +/- SD]), 10 with poor BG control (HbA1C 9.48 +/- 1.05%), and 10 with poor BG control and mild to moderate diabetic ketoacidosis (DKA) (HbA1C 9.12 +/-2.25%, strongly positive ketonuria 3+ and elevated plasma beta-hydroxybutyrate). Erythrocyte membrane fluidity was determined by fluorescence polarization using 6-(9-anthroyloxy stearic acid as fluorescent probe. RESULTS: Membrane fluidity was normal in the diabetic patients with good BG control but significantly lower in the two groups of patients with poor BG control than in the healthy subjects (P < 0.01). The membrane fluidity in the poor BG control groups was also lower in the patients with DKA than in those without DKA (P < 0.01). CONCLUSIONS: The factors that most influence membrane fluidity in IDDM patients appear to be hyperglycemia and ketone bodies.
Adult↗
[Lipoprotein (a) and diabetes mellitus].
Lp(a) has atherogenic and thrombotic properties and is considered to be a major risk factor for the development of atherosclerotic disease. The risk of cardiovascular disease is increased in both insulin-dependent (IDDM) and non-insulin-dependent diabetes mellitus (NIDDM), and Lp(a) has attracted attention as a potential risk factor in diabetic patients. Lp(a) levels are "probably" elevated in IDDM patients and related to altered metabolic control and increased urinary albumin excretion rate or renal insufficiency, although results are controversial. There appears to be a real difference between the Lp(a) of patients with proliferative diabetic retinopathy and those with or without background retinopathy. The plasma Lp(a) level may therefore be associated with microangiopathy in some IDDM patients. However, data relating Lp(a) to complications of diabetes are limited, and the literature is conflicting. The few available data suggest that Lp(a) is not elevated in NIDDM patients and that there is no strong link between blood glucose control and plasma Lp(a). There is no clear evidence as to whether Lp(a) is related to microalbuminuria in NIDDM patients. There is little evidence for a correlation between increased risk of cardiovascular disease and plasma Lp(a) among diabetic patients. However, some diabetic patients with coronary heart disease have elevated plasma Lp(a), which seems to be correlated with genetic factors (especially the isoforms of apolipoprotein a) rather than to diabetes per se. Lp(a) synthesis and catabolism could be influenced by insulin or by diabetes and its metabolic concomitants. The atherogenic and thrombogenic potential of Lp(a) could also be increased in diabetic patients. Plasma Lp(a) should be measured for both IDDM and NIDDM patients. If the Lp(a) level is elevated, it seems reasonable to check the other major vascular risk factors.
Cardiovascular Diseases↗
Non-enzymatic glycosylation of apolipoprotein A-I and its functional consequences.
High-density lipoproteins (HDL) are believed to protect against atherosclerosis by promoting the process of reverse cholesterol transport. This process involves different steps including efflux of cellular cholesterol, cholesterol esterification and lipid transport and exchange. Apolipoprotein (apo) A-I, the major HDL apolipoprotein, and the HDL-associated enzyme lecithin-cholesterol acyltransferase (LCAT), which uses apo A-I as a cofactor, play a crucial role in reverse cholesterol transport. HDL may be classified into species according to their apolipoprotein content. Recent data concerning HDL particles indicate that lipoproteins containing apo A-I but not apo A-II (LpA-I) are more effective carriers of free cholesterol and are associated with a protective effect against coronary heart disease. In vitro studies have shown that glycosylated HDL are functionally abnormal and may be considered atherogenic. Our study considers the different impacts of non-enzymatic glycosylation of apo A-I or protein-HDL on the reverse cholesterol transport process.
Apolipoprotein A-I↗
[Dyslipidemia in the diabetic patient. Recommendations of ALFEDIAM (French Language Association for the Study of Diabetes and Metabolic Diseases)].
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Cardiovascular Diseases↗
Minimal model for determination of insulin sensitivity: repeatability in control and obese subjects.
A mathematical model was recently developed (minimal model) to estimate insulin sensitivity from the analysis of blood glucose and insulin concentration after a modified intravenous glucose tolerance test. This approach was successfully compared with the euglycemic glucose clamp in humans. In this study, we have analysed the distribution and reproducibility of this method in 10 healthy subjects and seven obese patients. We have observed a lower insulin sensitivity (SI) in obese patients (1.96 +/- 0.38 x 10(-4)/min/microU/ml) than in healthy subjects (8.19 +/- 1.16 x 10(-4)/min/microU/ml) with a small overlap between the two groups. The test was repeated twice and good repeatability was found with the method of Blank and Altman when a log transformation was applied to the data.
Adult↗
Improved visual evoked potential latencies in poorly controlled diabetic patients after short-term strict metabolic control.
OBJECTIVE: To determine whether short-term strict control of blood glucose can improve abnormal visual evoked potentials (VEPs) in poorly controlled diabetic patients with no overt diabetic complications. RESEARCH DESIGN AND METHODS: VEPs (P100 wave latencies) were recorded in 12 poorly controlled diabetic patients (7 with insulin-dependent diabetes mellitus and 5 with non-insulin-dependent diabetes mellitus) before and after at least 3 days of near normoglycemia obtained by continuous subcutaneous insulin infusion (CSII). Exclusion criteria were overt diabetic neuropathy or retinopathy. The control subjects were 12 healthy subjects matched for age and sex. Fifty-two other subjects formed a reference control population. The intra-individual coefficient of variation for P100 latency was < 3%. RESULTS: The P100 latencies were longer in diabetic patients than in control subjects (means of both eyes +/- SD: 116.8 +/- 10.1 vs. 106.2 +/- 4.5 ms, P < 0.01), and 4 of the 12 diabetic patients had abnormal VEPs. After 3 days of close blood glucose control (mean blood glucose profile fell from 13.7 +/- 2.2 mmol/l to 6.8 +/- 1.2 mmol/l, P < 0.01), the mean P100 latencies were significantly shorter (112.5 +/- 7.6 ms, P < 0.01) but were still significantly longer than control values. The longer the initial P100 latency, the greater the decrease after CSII. There was no correlation between the fall in blood glucose and improvement in VEPs. CONCLUSIONS: Short-term blood glucose normalization is associated with improved P100 wave latency in uncomplicated diabetic patients. These data suggest that abnormal VEPs are partly reversible and include functional disturbances related to glucose metabolism.
Adult↗
[Insulin in type 2 diabetes. Why, when, how?].
Non insulin-dependent diabetes is often associated with obesity and always with some degree of insulin resistance. First choice treatment consists of appropriate and sometimes hypocaloric diet and oral hypoglycemic agents. Using insulin becomes mandatory in patients with associated pathology or at risk of metabolic imbalance. Insulin administration must be discussed in each individual case when it aims at a long-term improvement of blood glucose control, taking into account the lack of consensus on this point and the potential drawbacks of insulin therapy, notably weight increase and risk of hypoglycaemia.
Diabetes Mellitus, Type 2↗
A multicenter comparison of the effects of simvastatin and fenofibrate therapy in severe primary hypercholesterolemia, with particular emphasis on lipoproteins defined by their apolipoprotein composition.
This multicenter, double-blind, randomized study was designed to compare the effects of simvastatin (20 mg/d and 40 mg/d) and fenofibrate (400 mg/d) on plasma lipids, lipoproteins, apolipoproteins (apo), and lipoprotein particles defined by their apo composition (Lp A-I, Lp A-II:A-I, Lp E:B, Lp C-III:B) in primary hypercholesterolemia. After 6 and 10 weeks of therapy, both drugs lowered plasma cholesterol, low-density lipoprotein (LDL) cholesterol, and apo B. The effect on LDL and apo B was significantly more pronounced for simvastatin (P = .01). Simvastatin increased Lp A-I, but did not change Lp A-II:A-I, while fenofibrate decreased Lp A-I and increased Lp A-II:A-I. Lp E:B and Lp C-III:B were decreased with both drugs, but fenofibrate was significantly more effective in reducing these particles than simvastatin. This study demonstrates that both drugs have beneficial effects on the parameters positively or negatively correlated with the atherosclerotic risk, with simvastatin being more effective in reducing some of them. These results suggest that the drugs led to different structural modifications of the lipoproteins, which would not be revealed by examination of lipoprotein density classes. These differences are probably related to the different mechanisms of action of the agents.
Adolescent↗
Pathogenicity and preliminary antigenic characterization of six infectious bursal disease virus strains isolated in France from acute outbreaks.
Six isolates originating from acute outbreaks of infectious bursal disease recently reported in broiler and pullet flocks in France were studied with respect to their pathogenicity and their antigenic relatedness to the Faragher 52/70 reference strain. Although the mortality experimentally induced in susceptible chickens by the field strains was sometimes four times higher than that which followed the inoculation of the reference strain (16 to 48% versus 12%), neither mortality nor morbidity were observed in chickens previously vaccinated with a commercial live vaccine and then challenged under the same conditions. Agar gel precipitation tests demonstrated the existence of common antigens in the different strains, and high cross-neutralization indices measured in embryonated specific pathogen free eggs showed them all to belong to serotype I. These data are discussed with reference to previous European and North-American studies on the antigenic status of infectious bursal disease virus.
Acute Disease↗
Cisplatin-cyclophosphamide versus carboplatin-cyclophosphamide in advanced ovarian cancer: a randomized phase III study of the National Cancer Institute of Canada Clinical Trials Group.
PURPOSE: Given the potential for improved tolerance, a trial was initiated to compare the toxicity and efficacy of a standard regimen of cisplatin-cyclophosphamide (75 mg/m2 and 600 mg/m2, respectively) with an experimental regimen of carboplatin-cyclophosphamide (300 mg/m2 and 600 mg/m2, respectively) in women with postoperative macroscopic residual ovarian cancer. PATIENTS AND METHODS: Between 1985 and 1989, 447 (417 eligible) patients were randomized. Treatment arms were well balanced; most patients had stage III (82%), grade 3 (54%) tumors with bulky residual (greater than 2 cm in 59%), and good performance status (Eastern Cooperative Oncology Group [ECOG] 0 or 1, 77%). Response was assessed after six 4-week cycles. RESULTS: The treatments were equally deliverable, with 76% of patients completing their allocated regimen. The reported reasons for failure to complete treatment differed; toxicity/refusal predominated on the cisplatin arm, and progressive disease predominated on the carboplatin arm (P = .0092). Cisplatin-treated patients were more likely to develop neuropathy and nephropathy, and carboplatin patients experienced myelosuppression, particularly thrombocytopenia. Efficacy was similar, with no significant differences for the cisplatin and carboplatin arms in clinical response rate (57% v 59% in those with measurable disease), pathologic response rate (52% v 54% in those suitable for relaparotomy), time to progression (median, 56 v 58 weeks), or overall survival (median, 100 weeks v 110 weeks). Time to progression and survival were predicted by residual disease size, performance status, and treatment center (with those treated at centers that accrued more patients doing better). CONCLUSION: Neither regimen is optimal in that relapse remains the norm. It may be inappropriate to expect that any single regimen can be an effective therapy for all patients with advanced ovarian cancer. Both cisplatin and carboplatin are likely to have a role in future treatment strategies.
Adult↗
Apolipoprotein A-I-containing particles and reverse cholesterol transport in IDDM.
Lipoprotein particles containing apoA-I but not apoA-II are, among high-density lipoproteins, effective protectors against atherosclerosis that act by promoting the efflux of cellular cholesterol and the reverse cholesterol transport process. Because previous studies showed that in vitro nonenzymatic glycosylation of HDL impairs HDL receptor-mediated cholesterol efflux, we isolated Lp A-I from two poorly controlled insulin-dependent diabetic patients and compared the chemical composition and ability to promote cholesterol efflux with the same particles purified from two matched nondiabetic control subjects. No differences in lipid composition or in the ability to promote cholesterol efflux from cultured adipose cells were noted between the two types of Lp A-I preparations. However, when we separated Lp A-I from diabetic subjects by degree of glycosylation, the specifically glycosylated subfractions were about 50% less effective in producing cholesterol efflux than the nonglycosylated particles.
Adult↗
Lipoprotein particle analysis comparing simvastatin and fenofibrate.
This study compares the effects of fenofibrate and simvastatin in primary hypercholesterolemia, with particular regard to lipoprotein particles, as defined by their apolipoprotein composition: LpAI, LpAII: AI, LpE:B, LpCIII:B. This was a double-blind study in which patients were randomized to 2 groups, one receiving simvastatin 20 mg once daily and the other receiving fenofibrate 200 mg b.i.d., if their total cholesterol and their LDL cholesterol remained above 7.60 mmol/l (300 mg/dl) and 4.95 mmol/l (195 mg/dl) after a 4-week placebo period. Simvastatin dosage was doubled at the end of 6 weeks of therapy if the LDL-cholesterol level remained above 3.55 mmol/l (140 mg/dl). Analyses were done after 6 and 10 weeks of therapy. Apolipoprotein AI was increased significantly only at week 10 with fenofibrate (+7.4%). Simvastatin had a more pronounced effect than fenofibrate on apolipoprotein B. There was a significant difference between drugs at weeks 6 and 10. No change was observed in the LpAII:AI level with simvastatin, whereas fenofibrate increased these particles quite significantly (+13.9 and +22.3%). The drugs had opposite effects on LpAI (+2.5 and +5.6% with simvastatin; -12.8 and -15.1% with fenofibrate). LP E:B (-33.0 and -40.8% with simvastatin; -53.8 and -52.2% with fenofibrate) and LpCIII:B (-23.8 and -31.8% with simvastatin; -35.1 and -43.5% with fenofibrate) were decreased by both drugs, but fenofibrate was significantly more effective in reducing these particles than simvastatin at week 6. This study suggests that both drugs led to different structural modifications of the lipoproteins, which would not be revealed by total apolipoprotein analysis. These differences are probably related to the mechanisms of action of these drugs.
Adolescent↗
Hemobiological activity of gliclazide in diabetes mellitus.
The hemovascular abnormalities encountered in diabetes include platelet alterations, shifts in prostaglandin metabolism and disorders of fibrinolysis. Diabetes is thus associated with increased platelet adhesiveness, increased platelet aggregation with hypersensitivity to proaggregants, increased plasma levels of beta-thromboglobulin and platelet factor 4 as an expression of platelet hyperactivity, increased levels of thromboxane A2 (TXA2) and prostacyclin (PGI2), and reduced levels of tissue plasminogen activator (t-PA). It is not clear which, if any, of these abnormalities are generated by chronic hyperglycemia and can be corrected by adequate glycemic control. Studies with gliclazide have demonstrated that it exerts hemovascular effects which can be valuable to patients. Thus, treatment with gliclazide leads to a decrease in platelet adhesiveness and aggregability. This treatment also reduces thromboxane levels and increases TPA levels. The mechanisms of action of gliclazide are not fully known but it has been demonstrated that its antiplatelet action is independent of its hypoglycemic activity and is not accompanied by clinical abnormalities of blood clotting. The mechanism of direct action on platelet activity may be mediated by inhibition of activated glycogen synthetase, activation of adenylate cyclase, modulation of arachidonic acid release from platelet membranes, stimulation of PGI2 production, and inhibition of the proaggregant action of TXA2. Thus, gliclazide not only has a hypoglycemic action but also improves hemovascular parameters in type 2 diabetes when used at normal therapeutic doses.
Blood Platelets↗
[The efficacy and tolerance of simvastatin and fenofibrate in primary hypercholesterolemia].
The effects of simvastatin and fenofibrate on blood lipids and the side-effects of these two drugs were compared in a double-blind trial involving 184 adults with primary hypercholesterolemia (total cholesterol levels: 3.87 +/- 1.02 g/l in the simvastatin group, 3.78 +/- 0.79 g/l in the fenofibrate group; N.S.). During a 10-week period, the patients received either fenofibrate 200 mg twice daily or simvastatin 20 mg once daily with doubling of the dosage at week 6 if the LDL-cholesterol level remained above 1.40 g/l. Simvastatin significantly (P less than 0.01) reduced total cholesterol by -29.9 percent, LDL-cholesterol by -35.4 percent, apoprotein B by -27.3 percent and triglycerides by -16.7 percent. Fenofibrate significantly (P less than 0.01) reduced total cholesterol by -19.2 percent, LDL-cholesterol by -22.3 percent apoprotein B by 13.9 percent and triglycerides by 28.9 percent. Reduction of the first 3 parameters was significantly (P less than 0.01) greater with simvastatin and reduction of triglycerides significantly greater with fenofibrate. Apoprotein A1 levels were increased by fenofibrate (+ 7.4 percent) but not by simvastatin. Side-effects occurred with a frequency of 6 percent under simvastatin and 9 percent under fenofibrate.
Adolescent↗
An insertion deletion polymorphism in the signal peptide of the human apolipoprotein B gene.
In this communication we report the genetic properties of an insertion/deletion polymorphism in the signal peptide of the human apolipoprotein B (apo b) gene. There are two alleles of the apo B signal peptide; one codes for a peptide 27 amino acids in length and the other a peptide only 24 amino acids in length. Using the polymerase chain reaction the difference of nine nucleotides between the two alleles is readily detectable after electrophoresis of the amplification products. The relative frequencies of the Ins and Del alleles are 0.655 and 0.345, respectively. The apo B signal peptide genotypes are transmitted in a manner consistent with an autosomal codominant mode of inheritance with two alleles.
Alleles↗
Rheological properties and membrane fluidity of red blood cells and platelets in primary hyperlipoproteinemia.
Lipid fluidity of the erythrocyte membrane and intact platelets was examined in 32 male patients affected by types IIA, IIB and IV primary hyperlipoproteinemia and 15 control subjects. Lipid fluidity was determined by fluorescence polarization using two probes: DPH and TMA-DPH which are localized in different lipid areas of the cell membrane. Classical haemorheological tests were also performed including plasma viscosity, whole blood viscosity and erythrocyte aggregation. As compared to a control group, plasma viscosity and whole blood viscosity at low shear rate was significantly increased in types IIB and IV, but not in type IIA patients. In contrast, the increase in erythrocyte aggregation was significant in all HLP types. Concerning lipid fluidity, the results recorded with red cells and platelets were not significantly different for type IIA HLP compared to the control group. In contrast, erythrocyte membranes from patients with types IIB and IV HLP had a significantly higher level of fluidity in lipid regions characterized by TMA-DPH. Using DPH as a fluorescent probe, identical results were only noted in type IIB patients. Regarding intact platelets of IIB and IV patients, an increase in lipid fluidity was noted for two fluorescent probes. These findings suggest that HLP associated erythrocyte and platelet fluidity alterations are not related to hypercholesterolemia but to the triglyceride level.
Adult↗