Anterior operculum syndrome localized by SPECT

The aim of this case report was to present a patient with complete anarthria and orofacial apraxia without other relevant neurological deficit. The clinical features are compatible with anterior operculum syndrome.

METHODS

A regional brain perfusion scan was done using 99mTc-HMPAO and a SPECT gamma camera. A brain CT scan and an MRI were also performed.

RESULTS

Brain CT and MRI were not diagnostic. On brain SPECT, hypoperfusion of the left inferior area of the frontal lobe was noted.

CONCLUSION

The patient studied showed an uncommon case of anterior operculum syndrome of focal degenerative origin localized by SPECT. SPECT may be a useful and effective method for diagnosis of this unusual neurological deficit.

Homozygous familial defective apolipoprotein B-100. Enhanced removal of apolipoprotein E-containing VLDLs and decreased production of LDLs

Familial defective apolipoprotein B-100 (FDB) is a frequently inherited disorder of lipoprotein metabolism. The glutamine-for-arginine substitution at position 3500 of apolipoprotein (apo) B-100 leads to defective binding of apo B-100 to the low density lipoprotein (LDL) receptor and accumulation of LDL in the plasma. We recently identified a patient homozygous for this mutation. His LDL cholesterol and apo B concentrations were approximately twice normal, whereas his apo E plasma level was low. Using a stable-isotope labeling technique ([2H3]leucine-primed constant infusion), we studied lipoprotein turnover in vivo in the fasting state in this patient and three clinically healthy, normolipidemic individuals not carrying the FDB mutation. The residence time of LDL apo B-100 was prolonged 3.6-fold in the FDB homozygote (8.3 vs 2.3 days). The production rate of LDL apo B-100 was decreased (7.4 vs 15 mg per kg per day). In FDB the residence time of very low density lipoprotein (VLDL) apo B-100 was longer (2.6 vs 1.3 hours), whereas the residence time of VLDL apo E was shorter (2.6 vs 4.5 hours) than normal. These data show that the in vivo metabolism of apo B-100-containing lipoproteins in FDB is different from that in familial hypercholesterolemia, in which LDL receptors are defective. In both conditions the residence times of LDL apo B-100 appear to be increased to approximately the same degree. This contrasts with the LDL apo B-100 synthetic rate, which is increased in familial hypercholesterolemia and decreased in FDB. The decreased production of LDL apo B-100 in FDB may originate from enhanced removal of apo E-containing LDL precursors by LDL receptors, which may be upregulated in response to the decreased flux of LDL-derived cholesterol into hepatocytes.

[Effects of lipid lowering measures on coronary perfusion]

Secondary intervention trials in coronary heart disease have unequivocally proven the effectiveness of lipid-lowering medication in addition to dietary means. Orderly application of available drugs leads to reductions in LDL cholesterol and triglycerides accompanied by increases in HDL cholesterol. Specifically, LDL cholesterol lowering is associated with clinical benefits in coronary heart disease, it reduces the necessity of hospitalization and interventions, and leads to significant reductions in coronary as well as in overall mortality. Besides morphological changes of coronary vessels like regression or retarded progression of plaques, lipid-lowering was shown to normalize endothelial dysfunction associated with hyperlipidemia. Restoring endothelial function and improving coronary perfusion may be one of the factors responsible for the huge clinical benefits in secondary intervention trials as compared to the modest morphological changes. As the fact of lipid-lowering rather than the means by which it is achieved is of specific importance, dietary means have to precede and then accompany an eventual additional drug treatment.

Polymorphisms of apolipoproteins A-IV and E in a Turkish population living in Germany

Human apolipoproteins (apo) E and apo A-IV are polymorphic with significantly different allele frequencies among different ethnic groups. Whereas the variation at the apo E gene locus affects plasma cholesterol levels in all populations studied so far and is associated with longevity in Caucasians, the influence of the common apo A-IV polymorphism on plasma lipoproteins has not been unanimously accepted. We have therefore determined the common apo E and apo A-IV polymorphisms by isoelectric focusing, calculated the respective allele frequencies and studied their effects on plasma lipoproteins in a random sample of 240 nonrelated Turkish subjects (141 males, 99 females) living in Germany and originating from central and eastern Anatolia. When compared with the German population and other Caucasians in Europe a prominence of the apo epsilon 3 allele frequency (0.885) was accompanied by a decrease in the frequencies of both the apo epsilon 2 allele (0.048) and the apo epsilon 4 allele (0.067). Thus, the Turkish population studied here clustered with populations mainly from southern Europe and Japan, which have low epsilon 2 and epsilon 4 allele frequencies. Also, the frequency of the A-IV-1 allele was higher (0.967) and that of the A-IV-2 allele lower (0.033) in the Turkish subjects studied than in other populations. At an average level of total cholesterol of 194.5 +/- 45 mg/dl, no significant influence of the A-IV alleles on plasma lipoproteins was seen. However, apo E and apo B differed significantly between apo E phenotypes, with high levels of apo E and low levels of cholesterol and apo B in carriers of the epsilon 2 allele, and vice versa for the epsilon 4 allele. The average cholesterol excess for the epsilon 2 allele was -7.95 mg/dl, for the epsilon 3 allele, -1.34, and for the epsilon 4 allele, + 14.15 mg/dl. Thus, despite the unusual frequency distribution of the apo E alleles, their effects on plasma lipoproteins are within the range reported for other populations in Europe.

Protection against atherogenesis in mice mediated by human apolipoprotein A-IV

Apolipoproteins are protein constituents of plasma lipid transport particles. Human apolipoprotein A-IV (apoA-IV) was expressed in the liver of C57BL/6 mice and mice deficient in apoE, both of which are prone to atherosclerosis, to investigate whether apoA-IV protects against this disease. In transgenic C57BL/6 mice on an atherogenic diet, the serum concentration of high density lipoprotein (HDL) cholesterol increased by 35 percent, whereas the concentration of endogenous apoA-I decreased by 29 percent, relative to those in transgenic mice on a normal diet. Expression of human apoA-IV in apoE-deficient mice on a normal diet resulted in an even more severe atherogenic lipoprotein profile, without affecting the concentration of HDL cholesterol, than that in nontransgenic apoE-deficient mice. However, transgenic mice of both backgrounds showed a substantial reduction in the size of atherosclerotic lesions. Thus, apoA-IV appears to protect against atherosclerosis by a mechanism that does not involve an increase in HDL cholesterol concentration.

[Alcohol, lipid metabolism and coronary heart disease]

Numerous epidemiological studies have unequivocally proven a protection from the development of coronary heart disease by moderate long-lasting alcohol consumption. During the past 20 years studies in different ethnic groups starting from an American cohort and spanning to the recently performed analysis in the MONICA-project gave evidence for a decreased morbidity and mortality from coronary heart disease at 1 to 3 drinks a day when compared to total abstainers. A part of the protection is thought to be mediated through alcohol effects on plasma lipoprotein metabolism. Substantial increases in high-density lipoprotein cholesterol and its subfractions occur and are believed to be responsible for as much as half of the alcohol-mediated benefits. In addition, moderate decreases in low-density lipoprotein cholesterol and probably also in lipoprotein(a), established cardiovascular risk factors, may contribute accordingly. Furthermore, antioxidants like flavonoids and polyphenols found in red wines by protecting low density lipoproteins from oxidative modification may explain the "French paradox", the decreased incidence of coronary heart disease in France despite a high consumption of saturated fats. Also, alcoholic vasodilation, decreases in platelet aggregability, changes in prostacyclin/thromboxane ratios and increased fibrinolytic activities are to be considered as additional benefits caused by moderate alcohol consumption.

Determination of isotopic ratios of L-leucine and L-phenylalanine and their stable isotope labeled analogues in biological samples by gas chromatography/triple-stage quadrupole mass spectrometry

A gas chromatographic/triple-stage quadrupole mass spectrometric (GC/MS/MS) method for measuring very low levels of enrichment of [5,5,5-2H3]-L-leucine and [ring-13C6]-L-phenylalanine in plasma and lipoprotein hydrolysates is described. The amino acids were derivatized to their N-heptafluorobutyryl isobutyl ester derivatives and the isotope ratio was determined by GC/MS/MS in the negative-ion chemical ionization mode. Parent ions were the [M-HF]- ions and fragment ions used for quantification were [P-2HF-C3H7]- (leucine) and [P-HF-OC4H9]- (phenylalanine), respectively. The limit of quantification was about 10 pg of the labeled compound co-eluting with 20 ng of the endogenous compound. The calibration curves were linear in the investigated range from 0.1% to 100% of the labeled compound. In biological samples, the higher selectivity of GC/MS/MS compared with GC/MS was demonstrated.

Multicenter comparison of micronized fenofibrate and simvastatin in patients with primary type IIA or IIB hyperlipoproteinemia

In 12 weeks of active treatment, we compared the efficacy and safety of a new (micronized) formulation of fenofibrate (F) (200 mg/day) with that of simvastatin (S) (20 mg/day), an inhibitor of hydroxy-methyl-glutaryl coenzyme A (HMG-CoA)-reductase. Men and women with primary hyperlipoproteinemia (HLP) with low-density lipoprotein (LDL) cholesterol level 180-300 mg/dl and triglyceride level < 500 mg/dl had dietary treatment for 8 weeks, and 133 (2 of 3 type IIa, 1 of 3 type IIb HLP) were randomized. The decrease in total cholesterol differed between type IIa patients (F - 17.9 vs. S - 25.8%), the decrease in triglyceride levels between the type II b groups (F - 52.8 vs. S - 14%), whereas the degree of decrease in LDL cholesterol (F - 20.9 vs. S - 34.9%) differed among all patients. Despite the difference in LDL cholesterol decrease, no difference was noted in total apolipoprotein (apo) B lowering (F - 20.8 and S - 26.5%). Increases in high-density lipoprotein (HDL) cholesterol (F + 18.5 vs. S + 15%) differed specifically in type IIb patients (F + 33.6 vs. S + 11.4%), accompanied by a more pronounced increase in apo AI with fenofibrate (F + 10.5% vs. S no change). Improvement in the ratios of total cholesterol/HDL cholesterol and apo AI/apo B occurred similarly with both drugs. Only fenofibrate, not simvastatin, decreased both fibrinogen (-10.3 vs. + 3.6%) and uric acid (-25% vs. no change) in type IIa and type IIb patients. Safety parameters reflected drug-specific known side effects, underscoring the safety of both drugs in addition to their efficacy in lipid lowering. Besides its advantages in type IIb hyperlipidemia, micronized fenofibrate proved a potent drug in decreasing total and LDL cholesterol and in very effectively decreasing apo B-containing lipoproteins, which is a recommendation for its use in primary hypercholesterolemia.

Lipoprotein(a) in health and disease

Lipoprotein(a) [Lp(a)] represents an LDL-like particle to which the Lp(a)-specific apolipoprotein(a) is linked via a disulfide bridge. It has gained considerable interest as a genetically determined risk factor for atherosclerotic vascular disease. Several studies have described a correlation between elevated Lp(a) plasma levels and coronary heart disease, stroke, and peripheral atherosclerosis. In healthy individuals, Lp(a) plasma concentrations are almost exclusively controlled by the apo(a) gene locus on chromosome 6q2.6-q2.7. More than 30 alleles at this highly polymorphic gene locus determine a size polymorphism of apo(a). There exists an inverse correlation between the size (molecular weight) of apo(a) isoforms and Lp(a) plasma concentrations. The standardization of Lp(a) quantification is still an unresolved task due to the large particle size of Lp(a), the presence of two different apoproteins [apoB and apo(a)], and the large size polymorphism of apo(a) and its homology with plasminogen. A working group sponsored by the IFCC is currently establishing a stable reference standard for Lp(a) as well as a reference method for quantitative analysis. Aside from genetic reasons, abnormal Lp(a) plasma concentrations are observed as secondary to various diseases. Lp(a) plasma levels are elevated over controls in patients with nephrotic syndrome and patients with end-stage renal disease. Following renal transplantation, Lp(a) concentrations decrease to values observed in controls matched for apo(a) type. Controversial data on Lp(a) in diabetes mellitus result mainly from insufficient sample sizes of numerous studies. Large studies and those including apo(a) phenotype analysis came to the conclusion that Lp(a) levels are not or only moderately elevated in insulin-dependent patients. In noninsulin-dependent diabetics, Lp(a) is not elevated. Conflicting data also exist from studies in patients with familial hypercholesterolemia. Several case-control studies reported elevated Lp(a) levels in those patients, suggesting a role of the LDL-receptor pathway for degradation of Lp(a). However, recent turnover studies rejected that concept. Moreover, family studies also revealed data arguing against an influence of the LDL receptor for Lp(a) concentrations. Several rare diseases or disorders, such as LCAT- and LPL-deficiency as well as liver diseases, are associated with low plasma levels or lack of Lp(a).

Lipoproteins containing apolipoprotein A-IV but not apolipoprotein A-I take up and esterify cell-derived cholesterol in plasma

Two-dimensional nondenaturing polyacrylamide gradient gel electrophoresis (2D-PAGGE) identifies distinct apoA-I-or apoE-containing subclasses of high-density lipoproteins (HDLs), each of which plays a different role in reverse cholesterol transport. In this study we used 2D-PAGGE to investigate the role of apoA-IV-containing lipoproteins in reverse cholesterol transport in native plasma. Incubation of 2D electrophoretograms with anti-apoA-IV antibodies identified up to three subclasses of particles. The smaller particle subclasses, LpA-IV-1 and LpA-IV-2, were found in every plasma sample. The largest particle subclass, LpA-IV-3, was observed in fewer than 10% of the plasmas analyzed. 2D-PAGGE of apoA-I-deficient plasma and apoA-I-depleted plasma and anti-apoA-I immunosubtracting 2D-PAGGE of normal plasma revealed that LpA-IV-1 and LpA-IV-2 do not contain apoA-I. The importance of LpA-IV-1 and LpA-IV-2 for uptake and esterification of cell-derived cholesterol was investigated using pulse-chase incubations of plasma with [3H]cholesterol-labeled fibroblasts followed by anti-apoA-I immunosubtracting 2D-PAGGE. During 1-minute pulse incubation with cells, [3H]cholesterol was taken up by gamma-LpE > LpA-IV-1 > pre-beta 1-LpA-I > LpA-IV-2 (">" denotes "more than"). During subsequent chase incubation without cells, proportionately less radioactivity disappeared from LpA-IV-1 and LpA-IV-2 than from pre-beta 1-LpA-I and gamma-LpE. During 5-minute pulse incubations, radioactive cholesteryl esters were formed in pre-beta 3-LpA-I > alpha-LpA-I > LpA-IV-1 > LpA-IV-2. The fractional estertification rate was highest in pre-beta 2-LpA-I and lowest in alpha-LpA-I.(ABSTRACT TRUNCATED AT 250 WORDS)

An angiotensin-converting enzyme gene variant is associated with acute myocardial infarction in women but not in men

We believe our data may speak to the issue of sexual dimorphism with respect to MI. Most studies have concentrated on men with this disease. In a recent study, Lindpaintner et al10 could find no relationship between the D/D genotype and AMI in subjects of the Physicians Health Study. However, this study consisted entirely of men. The D allele may provide an avenue to discern differences in the pathogenesis of MI in men and women.

Multicentre evaluation of a non-wipe system for the rapid determination of total cholesterol in capillary blood, Accutrend Cholesterol on Accutrend GC

Accutrend Cholesterol, a non-wipe test for the determination of total cholesterol in capillary blood, was evaluated at four clinical centres. Cholesterol determinations with the Accutrend system using capillary blood were compared with results obtained with the cholesterol oxidase/p-aminophenazone (CHOD-PAP) method using the respective capillary sera. Triacylglycerols, uric acid and haematocrit were determined to evaluate potential interference. Imprecision measurements were performed with venous blood. To examine the reproducibility of results from lot to lot, three different lots of test strips were included in these investigations. Results with Accutrend Cholesterol agree with those of the comparison method within systematic differences of +2.5% to -3.2%, depending on the lot. There was no interference by triacylglycerols up to 10.28 mmol/l (900 mg/dl), by uric acid 60 to 400 mumol/l (1 mg/dl to 7 mg/dl), or by haematocrits between 0.35 and 0.54. Impression data show coefficients of variation of generally less than 5%. Thus Accutrend Cholesterol proved to be a reliable system for the determination of total cholesterol.

Low molecular weight heparin does not necessarily reduce lipids and lipoproteins in hemodialysis patients

Recent studies have indicated a beneficial effect of one particular low molecular weight heparin preparation (Fragmin) on lipid metabolism in patients on chronic hemodialysis as compared to unfractionated heparin. We conducted a prospective crossover study with paired comparison of two different anticoagulant agents to examine the effects of a recently released new low molecular weight heparin (Sandoparin) on lipid and lipoprotein parameters in 24 patients starting hemodialysis. During the first six months of observation patients received Sandoparin. Then patients were switched to unfractionated heparin and observed for further six months. After switching from Sandoparin to unfractionated heparin we observed significant decreases in total cholesterol (from 168.6 +/- 42.2 to 154.4 +/- 41.9 mg/dl, p < 0.02), LDL cholesterol (from 106.4 +/- 35.2 to 89.9 +/- 32.3 mg/dl, p < 0.005), triglycerides (from 148.7 +/- 85.0 to 121.4 +/- 88.8 mg/dl, p < 0.05) and apolipoprotein B (from 100.0 +/- 35.3 to 89.9 +/- 30.4 mg/dl, p < 0.05) and a significant increase in HDL cholesterol (from 32.8 +/- 12.5 to 37.7 +/- 17.5 mg/dl, p < 0.02). This is in contrast to earlier results and can possibly be explained by a higher percentage of fractions with high M(r) in the investigated Sandoparin, which results in a more pronounced depletion of lipoprotein lipase. Together with the enhanced hepatic clearance of lipoprotein lipase induced by low molecular weight heparins, this may decrease lipoprotein lipase activity with a subsequent increase in plasma triglycerides, total and LDL cholesterol. We conclude from our data that a general recommendation for clinical use of low molecular weight heparin in hemodialysis patients cannot be given.

[Oral contraceptive-induced pancreatitis in the hyperchylomicronemia syndrome]

A now 24-year-old woman was found at the age of 2 years to have an hyperchylomicronaemia syndrome due to lipoprotein lipase deficiency: the triglyceride level was then 6000 mg/dl. But in subsequent years it had been reduced to between 550 and 2600 mg/dl by dieting. There were no xanthomas or abdominal symptoms during those years. When aged 20 years she was put on oral contraceptives (one-phase preparation: 0.03 mg ethinylestradiol and 0.075 gestodene). Six months later she had the first attack of severe necrotizing pancreatitis; three more attacks followed in the subsequent 6 months. All four attacks occurred during the drug-free period of the menstrual cycle. The relationship with contraceptive intake was not established until the fourth attack. The last acute pancreatitis (lipase 3283 U/l amylase 595 U/l, triglyceride 2400 mg/dl, WBC count 13,899/microliters; ultrasonography revealed fluid swelling and necrotic areas, especially around the splenic hilus) regressed within 5 days and has not recurred for 3 years after the patient stopped taking oral contraceptives. On a diet the triglyceride level has been around 880 mg/dl.

Increased number of high sensitive platelets in hypercholesterolemia, cardiovascular diseases, and after incubation with cholesterol

The number of low density platelets was found to be increased in patients with hypercholesterolemia, as compared with the number in controls. The percentage increase of the low density platelet subpopulation was even more pronounced in patients with hypercholesterolemia when compared with that in patients suffering from myocardial infarction or angina. In vitro studies with control platelets incubated with cholesterol rich liposomes showed also an increase in the subpopulation of low density platelets. After incubation of control platelets with cholesterol rich liposomes, a higher membrane anisotropy and a higher cholesterol to phospholipid (C/P) molar ratio of the plasma membrane were found. Furthermore, cholesterol-enriched platelets were more sensitive upon thrombin stimulation. The results suggest that a shift of platelet subpopulations to a higher number of low density platelets could be caused by either the level of plasma cholesterol or an in-vitro incubation with cholesterol rich liposomes.

Apolipoprotein AI, AII, and AIV isoforms in plasma determined by automated isoelectric focusing with PhastSystem and immunofixation

Distinct genetic variants of apolipoprotein (apo) AI have been shown to influence concentrations of high-density lipoprotein (HDL) cholesterol. The genetic polymorphism of apo AIV may modulate HDL-cholesterol, plasma triglycerides, and lipoprotein(a) concentrations. There is evidence for an antagonizing role of apo AII in reverse cholesterol transport. Since genetic polymorphisms and variants of these apolipoproteins are detectable by isoelectric focusing (IEF), we developed a rapid and easy automated method for IEF analysis of apos AI, AII, and AIV on self-made or commercially available gels, using the PhastSystem. Diluted plasma or serum samples (1 microL) are applied automatically onto the gel and IEF is carried out for 35-45 min. Afterwards, the apo A bands are precipitated by specific polyclonal antibodies and visualized by automated silver staining. This rapid procedure is suitable as a routine or screening method for IEF analysis of these major HDL apolipoproteins.

Apolipoprotein AI, AII, and AIV isoforms in plasma determined by automated isoelectric focusing with PhastSystem and immunofixation

Distinct genetic variants of apolipoprotein (apo) AI have been shown to influence concentrations of high-density lipoprotein (HDL) cholesterol. The genetic polymorphism of apo AIV may modulate HDL-cholesterol, plasma triglycerides, and lipoprotein(a) concentrations. There is evidence for an antagonizing role of apo AII in reverse cholesterol transport. Since genetic polymorphisms and variants of these apolipoproteins are detectable by isoelectric focusing (IEF), we developed a rapid and easy automated method for IEF analysis of apos AI, AII, and AIV on self-made or commercially available gels, using the PhastSystem. Diluted plasma or serum samples (1 microL) are applied automatically onto the gel and IEF is carried out for 35-45 min. Afterwards, the apo A bands are precipitated by specific polyclonal antibodies and visualized by automated silver staining. This rapid procedure is suitable as a routine or screening method for IEF analysis of these major HDL apolipoproteins.