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Biomedical subjects

E Köhler

Publications and source records attributed to E Köhler.

At least 19 recordsLinked to original sources

Association of the GPIa C807T and GPIIIa PlA1/A2 polymorphisms with premature myocardial infarction in men.

Aims Recent studies have reported an association between the platelet glycoprotein (GP) Ia C807T polymorphism and myocardial infarction, whereas other studies have reported contradictory results concerning the platelet GPIIIa PlA1/A2 polymorphism. In most of these studies the patients were older than 45 years. Thus we decided to examine both genotypes in 287 men who had their first myocardial infarction before age 45, and a group of 138 healthy controls. Methods and Results The frequency of T807 allele carriers was similar among myocardial infarction patients and among controls (54.6% vs 62.3%; odds ratio (OR) 0.73; 95% confidence interval (CI), 0.47-1.12). The frequency of PlA2 carriers was higher in cases than in controls (26.5% vs 15.2%; OR 1.65; CI, 1.09-2.54). After performing a logistic regression analysis, taking into account other cardiovascular risk factors, this difference did not remain significant. The combination of the risk alleles of both genotypes had no major effect on the myocardial infarction risk. Conclusions The GPIIIa PlA2 allele is not independently associated with the risk of premature myocardial infarction. The T807 allele of the GPIa gene alone or in combination with the PlA2 allele had no major effect on premature myocardial infarction risk.

Adult↗

Association of serum apolipoprotein A-I (but not high-density lipoprotein cholesterol) with healed myocardial infarction in men independent of serum insulin and C-peptide.

Low serum levels of high-density lipoprotein (HDL) cholesterol or apolipoprotein A-I and high serum levels of insulin increase the risk of coronary heart disease (CHD) and can indicate insulin resistance. We tested the strength, independence, and interactions of associations between HDL cholesterol (or apolipoprotein A-I), insulin (or C-peptide), glucose, and CHD in 95 male nondiabetic patients with CHD who were <60 years old, in 92 probands from the PROCAM study, and in 61 non-cardiologic patients; all subjects were matched by age, body mass index, and smoking habits. Systemic hypertension (odds radio [OR] 2.8, 95% confidence intervals [CI] 1.6 to 4.8), high serum levels of glucose (OR 2.3, 95% CI 1.6 to 4.8), insulin (OR 2.1, 95% CI 1.3 to 3.6), and C-peptide (OR 4.1, 95% CI 2.2 to 7.5) as well as low serum levels of HDL cholesterol (OR 2.0, 95% CI 1.1 to 3.5) or apolipoprotein A-I (OR 3.9, 95% CI 2.1 to 7.1) had significant associations with CHD. At multivariate analysis, systolic blood pressure, glucose, apolipoprotein A-I, and C-peptide, but not HDL cholesterol and insulin, had consistent independent associations with CHD. Thus, the combined measurement of apolipoprotein A-I and C-peptide may improve the identification of nondiabetic patients at increased risk for CHD.

Adult↗

Assessment of prenatal smoke exposure by determining nicotine and its metabolites in maternal and neonatal urine.

Urine specimens were collected from 75 pregnant women before childbirth and from their newborns within 48 postnatal hours. A high-performance liquid chromatography (HPLC) method was used to determine urinary nicotine and its metabolites, cotinine and trans-3'-hydroxycotinine (OH-cotinine) to objectivise prenatal smoke exposure. Using the sum of nicotine metabolites as a marker, 34 women were classed as not exposed to smoke ( < 15 nmol/l), 18 as passive smokers (15-400 nmol/l), and 23 as active smokers ( > 400 nmol/1). The newborns of active smokers exhibited significantly (P < 0.001) higher nicotine metabolite concentrations than did those of either non-exposed women or passive smokers. A close correlation was found to exist between maternal and neonatal nicotine and cotinine concentrations (r=0.8968 and r=0.9205, respectively). For OH-cotinine, this correlation was particularly close when maternal, but not neonatal, OH - cotinine was adjusted to creatinine (r=0.9792). The neonatal/maternal urine concentration ratios for cotinine and OH-cotinine were noted to not significantly depend on the time of postpartal urine collection. Within the first two postnatal days, the extent of current prenatal smoke exposure attributable to active smoking of the mother was best reflected by the urinary concentrations of cotinine plus OH-cotinine without adjustment to creatinine.

Adult↗

Urokinase plasminogen activator induces human smooth muscle cell migration and proliferation via distinct receptor-dependent and proteolysis-dependent mechanisms.

In order to define the relative contribution of the proteolytic domain and the receptor-binding domain of urokinase plasminogen activator (uPA) toward its mitogenic properties we studied the effects of different uPA isoforms on migration and proliferation of human aortic smooth muscle cells (hSMC). The isoforms tested included native human glycosylated uPA, and two recombinant uPA forms, namely a recombinant uPA with wild type structure (r-uPA), and a uPA-mutant in which the first 24 N-terminal amino acid residues of the receptor binding domain were replaced by 13 foreign amino acid residues (r-uPAmut). Cell migration was evaluated using a micro-Boyden chamber assay, and cell proliferation assessed by measurement of [3H]-thymidine incorporation into DNA. Competition binding studies on hSMC using 125I-r-uPA as ligand demonstrated that r-uPA and r-uPAmut exhibited equivalent displacement profiles. However, migration of hSMC was promoted by r-uPA and not by r-uPAmut. r-uPA-induced migration occurred at concentrations (half-maximally effective concentration of 2 nM) approximating the Kd for uPA-uPAR binding (1 nM). r-uPA-induced migration was not affected by the plasmin inhibitor aprotinin. In contrast to their differential chemotactic properties, uPA, r-uPA and r-uPAmut, which possess similar proteolytic activities, all stimulated [3H]-thymidine incorporation in hSMC. Since the [3H]-thymidine incorporation response to each isoform occurred at concentrations (> 50 nM) much higher than necessary for uPAR saturation by ligand (1 nM), this mitogenic response may be independent of binding to uPAR. [3H]-thymidine incorporation responses to r-uPA and -uPAmut were sensitive to the plasmin inhibitor aprotinin, and uPA stimulated DNA synthesis was inhibited by plasminogen activator inhibitor. We conclude that hSMC migration in response to uPA depends upon on its binding to uPAR, whereas uPA-stimulated DNA synthesis in these cells requires proteolysis and plasmin generation.

Amino Acid Sequence↗

Extracellular matrix deposition by primary human lung fibroblasts in response to TGF-beta1 and TGF-beta3.

Increased collagen and extracellular matrix (ECM) deposition within the lung is a characteristic feature of lung fibrosis. Transforming growth factor (TGF)-beta isoforms play a pivotal role in the production of collagen and ECM. In this study, we investigated the effects of TGF-beta1 and TGF-beta3 on the main processes controlling ECM deposition using primary human lung fibroblasts. We analyzed 1) collagen metabolism by [3H]proline incorporation, 2) matrix metalloproteinase (MMP) expression by substrate gel zymography, and 3) tissue inhibitor of metalloproteinases (TIMP) expression by Western blot analysis. TGF-beta1 and TGF-beta3 increased the percentage of secreted collagens in supernatants of primary fibroblasts from 8.0 +/- 1.2 (control) to 23.6 +/- 4.6 and 22.3 +/- 1.3%, respectively. The collagen percentage in deposited ECM was increased from 5.8 +/- 0.3 (control) to 9.0 +/- 0.5 and 8.8 +/- 0.5% by TGF-beta1 and TGF-beta3, respectively. Secretion of MMP-1 (interstitial collagenase) by fibroblasts was reduced by both TGF-beta isoforms, whereas secretion of MMP-2 (gelatinase A) was unaffected by either of the two isoforms. Both TGF-beta isoforms increased TIMP-1 protein expression, whereas TIMP-2 protein was decreased. We thus conclude that TGF-beta1 and TGF-beta3 are equally potent in increasing ECM deposition. Their fibrotic effect in lung fibroblasts results from 1) an increase in the secretion and deposition of total ECM and collagens, 2) a decrease in MMP-1 secretion, and 3) an increase of TIMP-1 expression.

Blotting, Western↗

Passive smoke exposure in infants and children with respiratory tract diseases.

1. The adverse effect of passive smoke exposure on the respiratory tract, particularly in infants and children, is not an issue of dispute. It was the objective of this study to analyse the extent and the intensity of passive smoke exposure in infants and children with respiratory tract diseases, and compare the information obtained with parents' subjective assessment. At the time of admission to the hospital, the parents of 295 infants and children (aged 1 month to 11 years) were questioned by the physician as to the smoking habits in the families' homes. An HPLC method was employed to determine simultaneously nicotine, cotinine and trans-3'-hydroxycotinine in the children's urine. 2. The sum of the nicotine metabolites turned out to be a sensitive marker in determining passive smoke exposure. Measurements revealed passive smoke exposure in 66% of the children, the frequency in younger children being significantly (P < 0.001) higher than in children over 5 years (84% vs 52%). The average concentration of nicotine metabolites in younger passive smokers was significantly (P < 0.001) higher when compared to the older ones (193 nmol/l vs 86 nmol/l). Forty-nine per cent of the parents assessed that their children had experienced passive smoke exposure, and another 10% emphasised that they only smoked in the absence of their child. In children with cystic fibrosis and bronchial asthma, the number of passive smokers as assessed by their parents were lower by 65% and 29% respectively when compared to the findings obtained from measurements. In children without respiratory diseases, the difference was as little as 18%. 3. Parents when questioned in conjunction with an illness of their children, tended to understate, or even withhold the truth about, passive smoke exposure. Therefore, reliable information on passive smoke exposure of patients can only be obtained through objective measurements.

Adult↗

Plasminogen activator inhibitor-1 4G/5G-polymorphism and factor V Q506 mutation are not associated with myocardial infarction in young men.

Several recent studies have reported contradicting results concerning the relevance of the plasminogen activator inhibitor-1 (PAI-1) 4G/5G-polymorphism for myocardial infarction. In addition, the common factor V Q506 (FV:Q506) mutation is frequently discussed as a risk factor for arterial thrombosis, but evidence is rare. In order to further highlight the role of both polymorphisms in myocardial infarction, we investigated 241 young male myocardial infarction patients (< or = 45 years-of-age) aged 38.6+/-4.4 years (mean+/-SD) for the presence of both genotypes. The control group consisted of 179 healthy men aged 47.1+/-6.4 years (mean+/-SD) of the same ethnic background as the patients. Neither the distribution of the PAI-1 4G/5G-polymorphism nor the prevalence of the FV: Q506 mutation was significantly different between young patients and controls (4G/4G-genotype: chi2=2.08, NS; odds ratio 1.36, 95% confidence interval 0.89-2.06; FV:Q506 mutation: chi2=0.33, NS; odds ratio 1.33, 95% confidence interval 0.64-2.78). Moreover, the PAI-1 4G/5G-distribution did not differ significantly between patients and controls in subgroups by tertiles of triglyceride levels. In conclusion, in the present study neither homozygosity for the 4G allele of the PAI-1 4G/5G-polymorphism nor the FV:Q506 mutation led to an increased risk of myocardial infarction in young men.

Adult↗

Relationship between plasma viscosity and the severity of coronary heart disease.

Several studies have indicated that plasma viscosity contributes to cardiovascular risk in men. So far, a significant relationship between plasma viscosity and the severity of coronary heart disease has not been found. Thus, the present study is the first to report on the relationship of plasma viscosity and the severity of coronary heart disease. In a collective of 1142 male myocardial infarction patients, plasma viscosity and additional laboratory parameters were determined. Atherosclerotic changes were quantified by coronary angiography. Patients were divided into groups without any, and with one to three stenosed vessels. We found a positive relationship between plasma viscosity and the severity of coronary heart disease, even after adjusting groups for age, fibrinogen, and use of diuretics. Mean plasma viscosity ranged from 1.141+/-0.035 mPa s in patients without stenosed vessels to 1.162+/-0.044 mPa s in patients who had three coronary vessels with stenoses >50%. Differences between the groups were significant (P<0.001 to 0.05), with two exceptions: differences between patients without any and with one stenosed vessel, as well as between patients with one and two stenosed vessels, did not reach the significance level. On the whole, we can give further support to the hypothesis that cardiovascular risk factors and coronary heart disease may be linked by plasma viscosity.

Blood Viscosity↗

Involvement of protein kinase C in hypoxia-induced desensitization of the beta-adrenergic system in human endothelial cells.

In order to better understand the mechanisms whereby oxygen deficiency promotes blunting of the endothelial beta-adrenergic receptor (beta-AR) system we examined the effects of hypoxia on beta-AR, adenylate cyclase (AC) activity and phosphoinositide turnover in cultures of human pulmonary artery and umbilical vein endothelial cells. 1 hr of hypobaric hypoxia (290 mm Hg) increased basal levels of inositol mono-, bis-, and tris-phosphate to those following histamine stimulation under normoxia. Basal and isoproterenol-stimulated AC activities were lowered after 1 hr of hypoxia. beta-AR density was decreased after 2-3 hrs of hypoxia and after treatment of EC with histamine, platelet activating factor or phorbol myristate acetate (PMA). In protein-kinase C (PK-C)-downregulated EC, neither hypoxia nor PMA influenced beta-AR density or AC activity. Hypoxia-induced desensitization of beta-AR signal transduction in EC may involve hypoxia-stimulated phosphoinositide turnover and subsequent PK-C activation.

Adrenergic beta-Agonists↗

DNA binding specificity of the EcoRV restriction endonuclease is increased by Mg2+ binding to a metal ion binding site distinct from the catalytic center of the enzyme.

In contrast to many other type II restriction endonucleases, EcoRV binds specifically to DNA only in the presence Mg2+. According to the co-crystal structure of an EcoRV-DNA complex, Mg2+ ion(s) bind to the active site of EcoRV liganded by Glu45, Asp74, and Asp90. Here we present experimental evidence suggesting that the EcoRV-DNA complex also interacts with Mg2+ ions at other sites: (i) We have prepared an EcoRV triple mutant, in which all acidic amino acids in the catalytic center are replaced by alanine. This mutant is catalytically inactive. It binds nonspecifically to DNA in the absence of Mg2+, whereas it binds specifically to DNA in the presence of Mg2+. This means that Mg2+ induces specific DNA binding in this mutant, although all Mg2+ ligands in the catalytic center are removed. Therefore, additional interactions between Mg2+ and the EcoRV-DNA complex probably occur at sites distinct from the catalytic center. (ii) We have measured the specific and nonspecific DNA binding constants of EcoRV and of the triple mutant in the presence and absence of Mg2+. Mg2+ reduces nonspecific binding by 3-4 orders of magnitude, presumably because Mg2+ ions bound to the DNA have to be released upon complex formation. In contrast, the specific binding of the wild-type enzyme and the triple mutant is increased in the presence of Mg2+. This result can only be explained if a Mg2+ ion binds to the specific EcoRV-DNA complex probably at a site distinct from the catalytic center.(ABSTRACT TRUNCATED AT 250 WORDS)

Base Sequence↗

Impact of polymorphisms in the alpha- and beta-fibrinogen gene on plasma fibrinogen concentrations of coronary heart disease patients.

Despite many investigations in a variety of experimental settings, uncertainty remains concerning the size of the genetic contribution to plasma fibrinogen levels. We used the polymerase chain reaction to amplify the polymorphic sites for the restriction enzymes TaqI in the alpha-fibrinogen gene and HaeIII, HindIII and BclI in the beta-fibrinogen gene. Three hundred and eighty-four male coronary heart disease patients were investigated. Two alleles for each enzyme (+ or - designating, respectively, the presence or absence of the cutting site) were detected. The HaeIII and HindIII cutting sites were in complete linkage disequilibrium. A small but significant increase in fibrinogen level was associated with the rare cutting sites of HaeIII/HindIII, BclI and TaqI. At all polymorphic sites homozygosity for the frequent alleles was associated with about 0.20 g/l lower plasma fibrinogen concentrations than heterozygosity at the respective sites (p < 0.05). The frequencies and natures of the rare alleles were as follows: TaqI (+) 0.28, HaeIII/HindIII (-) 0.22 and BclI (+) 0.17. Mean fibrinogen levels in patients heterozygous for each of the four polymorphisms were 0.47 g/l greater than in subjects homozygous for the frequent allele at each cutting site (HaeIII/HindIII + -, TaqI + -, BclI + -: fibrinogen level 3.58 g/l (n = 32); HaeIII/HindIII + +, TaqI - -, BclI - -: fibrinogen level 3.11 g/l (n = 99), p = 0.003). Each polymorphism accounted for between 0.5 and 1.4% of the overall variance in fibrinogen concentration. Together, the polymorphisms in HaeIII, HindIII and TaqI explained 5.8% of overall variance, a proportion equivalent to that explained by age, smoking and body mass index (5.5%).(ABSTRACT TRUNCATED AT 250 WORDS)

Alleles↗

Electrophoretic screening for human apolipoprotein C-II variants: repeated identification of apolipoprotein C-II(K19T).

Screening for apolipoprotein (apo) C-II variants in the plasma of 400 students, 600 patients of a cardiological rehabilitation center, and 1200 patients of an outpatient lipid clinic by isoelectric focusing and subsequent anti-apo C-II immunoblotting led to the identification of four individuals whose plasma samples contained an apo C-II isoform with an abnormal isoelectric point. In all cases direct sequencing of PCR-amplified DNA assessed a heterozygous A to C transversion in codon 19 of the apo C-II gene which leads to the replacement of lysine with threonine. Two of the four index patients presented with moderate hypertriglyceridemia; one suffered from severe hyperlipidemia, with triglyceride levels ranging between 180 and 1900 mg/dl, depending on dietary changes. Sequencing of this proband's lipoprotein lipase gene showed no alteration compared to the wild-type sequence. A study in his family revealed that heterozygosity for apo C-II(K19T) is not associated with differences in mean lipid and lipoprotein concentrations. In conclusion, apo C-II(K19T) occurs in Germany at a frequency of approximately 1 in 550. Although this variant is not sufficient to cause hypertriglyceridemia, it may be possible that apo C-II(K19T) cause hypertriglyceridemia in the presence of additional as yet unidentified environmental and/or genetic factors.

Adult↗

Screening for naturally occurring apolipoprotein A-I variants: apo A-I(delta K107) is associated with low HDL-cholesterol levels in men but not in women.

Isoelectric focussing (IEF) in carrier ampholyte-generated pH gradients and hybrid isoelectric focussing (HIEF) in immobilized pH gradients under nondenaturing conditions were used in parallel to screen 5,500 plasma samples for naturally occurring variants of apolipoprotein A-I (apo A-I). The following defects were identified in four unrelated subjects heterozygous for apo A-I variants: apo A-I(delta K107)(2 x), apo A-I(K107M)(1 x), and apo A-I(E41R)(1 x). The later variant is a novel finding. Family studies did not reveal any association of apo A-I(K107M) and apo A-I(E41R) with dyslipidemia, but identified several heterozygotes for apo A-I(delta K107) who had low levels of high density lipoprotein (HDL)-cholesterol. Therefore, and since the apo A-I(delta K107) is the most frequent apo A-I variant in Germany (1: 5,000) we evaluated our data and that reported from 11 families with 32 heterozygous carriers and 30 unaffected controls. This analysis revealed that apo A-I(delta K107) is associated with lower HDL-cholesterol (-30%) and higher triglycerides (+48%) in men but not in women as compared with unaffected family members as well as with controls from the Prospective Cardiovascular Münster (PROCAM) study. Moreover, 11 of 15 male apo A-I(delta K107) heterozygotes but only 2 of 17 female apo A-I(delta K107) heterozygotes had HDL-cholesterol levels below the 20th percentile of sex-matched controls from the PROCAM study. We conclude that heterozygosity for apo A-I(delta K107) decreases HDL-cholesterol and increases triglycerides in men but not in women.

Apolipoprotein A-I↗

Association of variables of coagulation, fibrinolysis and acute-phase with atherosclerosis in coronary and peripheral arteries and those arteries supplying the brain.

We investigated the vessel status of coronary and peripheral arteries and those arteries supplying the brain in 929 consecutive male patients admitted to a coronary rehabilitation unit. The severity of coronary atherosclerosis was scored using coronary angiography. Changes in extracranial brain vessels and manifest cerebrovascular disease (CVD) were determined by B-mode ultrasound and Doppler examination. Peripheral arterial disease (PAD) was diagnosed using base-line and stress oscillography. We assessed variables of coagulation, fibrinolysis, and the acute phase response. There was a significant increase in plasma fibrinogen, plasminogen, d-dimer and C-reactive protein (CRP) with increasing severity of coronary heart disease. Compared to men with unaffected arteries, men with 3 diseased coronary arteries had 58% greater d-dimer concentrations. Patients with CVD and PAD, respectively, also had significantly higher fibrinogen, d-dimer and CRP concentrations. We did not find an association between plasminogen activator inhibitor activity and the severity of coronary atherosclerosis. In conclusion, plasma fibrinogen, d-dimer and CRP concentrations were significantly related to atherosclerosis in the coronary, peripheral and extracranial brain arteries.

Acute-Phase Reaction↗

[Inpatient length of stay and physical capacity after aortocoronary bypass operation, after heart valve replacement and myocardial infarct].

The present investigation was performed to determine the dependence of the length of stay in community hospitals and rehabilitation clinics from patient characteristics and physical activity at the end of treatment. Comparing age, end-diastolic volume index, left ventricular ejection fraction, number of stenosed coronary arteries, number of bypass grafts, levels of physical exercise, body mass index and the ratio total cholesterol/HDL-cholesterol, no significant differences were found in patients, who reached the rehabilitation clinic in the early postoperative period (7.4 +/- 2.0 days, n = 98), after 15-28 days (n = 74) or later than 28 days (n = 156) after bypass-surgery. Similar results were observed in 103 patients after heart-valve replacement, who arrived at the rehabilitation clinic after a corresponding length of hospital care like the bypass patients. Also, no significant differences in the clinical characteristics and physical activity appeared in patients who were admitted in the early phase (9.2 +/- 4.5 days) after transmural myocardial infarction (n = 37) and those entering the rehabilitation clinic after 26.7 +/- 9.4 days of hospital stay (n = 32). The absence of any relationship between the length of stay in hospitals on the one hand and severity of the heart disease on the other hand points out that the whole duration of stay in community hospitals and rehabilitation clinics after surgical intervention and also after transmural myocardial infarction could be drastically shortened by an optimal cooperation of both, hospitals and rehabilitation clinics, without any impairment of clinical results.

Activities of Daily Living↗

Significant improvement to the catalytic properties of aspartate aminotransferase: role of hydrophobic and charged residues in the substrate binding pocket.

The substrate specificity of tyrosine aminotransferase (eTAT) from Escherichia coli has been tested by transferring the critically different residues Leu39, Glu141, and Arg293 into equivalent positions of aspartate aminotransferase (eAAT). These residues are not directly involved in the catalytic process. The single mutant eAAT V39L possesses greater values of kcat/KM not only for tyrosine but also for aspartate and glutamate. In contrast, the double mutant eAAT P141E,A293R and also the triple mutant eAAT V39L,P141E,A293R exhibit smaller changes of kcat/KM. The converse mutants of tyrosine aminotransferase, in which critical residues of eAAT (Val39) and of mitochondrial AAT (Ala39, Val37) were transferred into equivalent positions of eTAT, exhibited generally decreased values of kcat/KM for both dicarboxylic and aromatic substrates. On the basis of the known structures of eAAT and eAAT V39L as well as of a refined model of eTAT, these results indicate that the different substrate specificities of eAAT and eTAT are due to multiple side chain differences and minor rearrangements of the backbone. The generally improved catalytic efficiency of the mutant eAAT V39L appears to be due to an indirect effect, namely, the facilitated closure of the active site upon substrate binding.

Amino Acid Sequence↗

Effects of age, lipoproteins, and hemostatic parameters on the role of homocyst(e)inemia as a cardiovascular risk factor in men.

Previous studies have identified moderately elevated plasma concentrations of homocyst(e)ine as an independent risk factor for coronary heart disease (CHD). The atherogenicity of homocyst(e)ine has mostly been attributed to its effects on endothelial cells, platelets, and the hemostatic system. In this case-control study of 199 male CHD patients and 156 age-matched control subjects, we analyzed the role of homocyst(e)ine as a cardiovascular risk marker in the context of traditional risk factors as well as of plasma fibrinogen, plasminogen, and viscosity. Both univariate and multivariate regression analyses revealed that homocyst(e)ine levels were significantly correlated with age, fibrinogen, and plasma viscosity in both study groups. Geometric mean homocyst(e)ine levels by univariate analysis were significantly higher in patients than in control subjects (8.9 versus 7.8 mumol/L, P < .001). This difference remained significant on multiple logistic function analysis after being adjusted for body mass index, systolic blood pressure, serum cholesterol, and high-density lipoprotein cholesterol but not after additional adjustment for fibrinogen. By contrast, geometric mean fibrinogen levels after adjustment for homocyst(e)ine levels were significantly different between patients and control subjects (296.4 versus 230.8 mg/dL, P < .001). Within the group of CHD patients, both fibrinogen and homocyst(e)ine significantly increased in parallel with the number of stenosed coronary vessels. We conclude that hyperhomocyst(e)inemia is an independent coronary risk factor and that its interrelation with fibrinogen levels merits further study.

Adult↗

Sex-specific effects of the glutamine/histidine polymorphism in apo A-IV on HDL metabolism.

In Caucasians, a histidine for glutamine substitution (Gln-->His) at residue 360 in apolipoprotein (apo) A-IV leads to an electrophoretically detectable polymorphism whose contribution to lipid metabolism regulation is controversial. In this study of 426 male and 188 female coronary heart disease patients, we analyzed the impact of this polymorphism on lipid metabolism, particularly high-density lipoprotein (HDL). The frequency of the rarer apo A-IV (360:His) allele was .069. This polymorphism exerted opposite effects in men and women in terms of serum concentrations of total cholesterol; triglycerides; HDL cholesterol; LDL cholesterol; lipoprotein (Lp) A-I; and apo A-I, A-II, and B. Only the difference in Lp A-I levels between male apo A-IV (360:Gln/Gln) homozygotes and apo A-IV (360:Gln/His) heterozygotes was significant (P < .05). In randomly selected subgroups of 38 male and 15 female apo A-IV (360:Gln/His) heterozygotes and 104 male and 15 female apo A-IV (360:Gln) homozygotes, heterozygosity for apo A-IV (360:Gln/His) in both sexes was associated with lower plasma cholesteryl ester transfer protein (CETP) activity (P < .05) and higher serum apo A-IV concentrations (P < .01 in men). Moreover, only men had significantly higher mean plasma activity levels of lecithin:cholesterol acyltransferase (LCAT) (P < .01).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗