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In a phase I safety and immunogenicity study, 112 healthy adult volunteers were randomly allocated to receive a new bivalent (A/Texas/36/91[H1N1-like], B/Harbin/7/94) split virion influenza vaccine propagated in Madin-Darby Canine Kidney cell culture or an identical vaccine manufactured using currently licensed egg propagated virus technology. Soreness at the injection site was common but generally mild (75% of the cell culture-derived vaccine group and 62.5% of the egg-derived vaccine group; p = not significant). General reactions were less common; headache was the most frequently reported adverse effect (26.8 and 30.4%, respectively; p = not significant). Geometric mean haemagglutination inhibition titres post-immunization against the A/Texas strain were 1012 reciprocal dilution in the cell culture-derived vaccine group and 790 in the egg-derived vaccine group; against the B/Harbin strain titres were 420 and 447, respectively (all comparisons, p = not significant). It is concluded that the cell culture-derived split virion influenza vaccine is safe and immunogenic in healthy adult volunteers.

An underlying cause of type III hyperlipoproteinemia is the presence of variant forms of apolipoprotein (apo) E that are defective in binding to apo B,E low density lipoprotein receptors. This disorder is associated almost exclusively with the apo E2/2 phenotype. However, structural and functional heterogeneity have been demonstrated within this phenotype. The apo E2(Arg158----Cys) variant, displaying 1% of normal apo E3 binding activity, is the most defective known form. In this study, we describe a method in which a pair of 19-mer synthetic oligonucleotide probes were used to distinguish between DNA coding for arginine or cysteine at position 158 in apo E. The specificity of the probes was demonstrated by using DNA from subjects whose apo E protein sequence or phenotype was known. The probes were used to screen a French-Canadian population of 34 apo E2/2 subjects to determine the frequency of the apo E2(Arg158----Cys) variant. All 34 subjects, most of whom displayed clinical or biochemical features of type III hyperlipoproteinemia, were found to be homozygous for apo E2(Arg158----Cys), strongly suggesting that this variant is the most common form of apo E2 within this ethnic and clinical population. In addition, the utility of this approach in detecting new apo E mutants was demonstrated when DNA from one of the apo E3/3 control subjects, whose family has a history of hyperlipidemia and coronary artery disease, reacted with both probes. This result suggests that this subject is heterozygous for normal apo E3 and a new apo E3 variant that is likely to be functionally equivalent to apo E2(Arg158----Cys).

A systematic study of plasma lipids and lipoproteins was carried out in 11 cases of Friedreich's ataxia and 6 cases of familial spastic ataxia (Charlevoix-Saguenay disease) using 11 healthy normolipidemic volunteers of comparable age and sex as controls. No differences were noted in the fatty acid profile of the total lipid fraction, in the total cholesterol and phospholipids or in the percentage distribution of the individual phospholipid classes. The triglycerides were significantly higher in Friedreich's ataxia, but remained within the normal range. Although no systematic abnormalities could be detected in the electrophoretic pattern of plasma lipoproteins or in the apolipoprotein profile on polyacrylamide gel electrophoresis, major differences were found in the high density lipoprotein (HDL) fraction. Their total amount was reduced and their composition was abnormal in both neurological diseases. In Friedreich patients, the relative proportion of cholesterol and triglycerides was increased while the relative protein content was greatly reduced. In Charlevoix disease, a similar abnormality was seen except for the excess of triglycerides. The proportion of phospholipids in HDL was the same in the three groups of patients. In addition, the low density lipoprotein (LDL) fraction was slightly reduced in both diseases. This anomaly of the HDL fraction could indicate that the HDL apolipoprotein moiety has a greater affinity for cholesterol and triglycerides in Friedreich's ataxia than its normal counterpart.

The predisposition for the development of hyperlipidemia rests almost equally on genetic and environmental factors and their interplay. Because one of the least understood factors is the duration of exposure to risk, the authors have chosen to review here some of the genetic factors and some of the relatively long-term environmental factors, such as diet and drug therapies, that are known to increase the risk of hyperlipidemia and likely the predisposition to cardiovascular disease.Some of the genetic factors and environmental factors such as diet and drug therapies that are known to increase the risk of hyperlipidemia and possibly the predisposition to cardiovascular disease are reviewed. The cholesterol associated with the low-density lipoproteins (LDL), accounting for 60-75% of the plasma levels, is responsible for the powerful and direct relationship which exists between plasma cholesterol and coronary heart disease. Also, the cholesterol that accumulates in atheromatous lesions is derived primarily from plasma LDL. Hyperlipidemia is defined by elevated levels of the plasma levels; the risk for atherosclerosis is associated with the classification types IIa, IIb, III, and possibly IV, a classification system based on phenotypic manifestations of increased lipoprotein fractions. The Lipid Research Clinics Program reports data on plasma lipid and lipoprotein cholesterol distributions of a large-scale screening of white men and women (both with and without sex hormone usage) aged 20-59 years in the US. They found age-related trends for rising triglycerides and cholesterol with differences between the sexes clearly demonstrated. It has been established that normolipemic individuals are not immune to the development of atherosclerosis. The recent focus on the apolipoprotein moieties has revealed a number of normolipemic dyslipoproteinemias associated with tissue lipid infiltration. Multifactorial population studies provide a strong case for the powerful role of the environment, i.e., predominantly dietary intake of total fat, saturated fat, saturated fats, and calories, in hyperlipidemia. According to the Seven Countries Study, populations with higher levels of cholesterol and LDL cholesterol (and increased atherosclerosis) have saturated fat intakes of 10% or more of calories. Migration studies of Japanese populations in Japan and in the US also show the influence of diet. As was shown early on, oral contraceptive (OC) use predisposes to the development of hyperlipidemia. OCs also predispose to other cardiovascular risk factors that, when combined with smoking, bring about a greatly magnified risk for myocardial infarction. Also reviewed in terms of their effect on the lipoprotein profile are antihypertensive therapies, retinoids, and hypolipidemic agents. Regarding genetic predisposition, single-gene mutations in apoproteins, lipoproteins, and some of the enzymes involved in lipoprotein may underlie disorders of hyperlipoproteinemia or hypolipoproteinemia.

Large Achilles tendon xanthomas of the type found in severe familial hypercholesterolemia were the first manifestation of cholestanolosis (cerebrotendinous xanthomatosis) in our patient, an otherwise asymptomatic normolipidemic 21-year-old woman. Extensive laboratory investigation disclosed the presence of hyperapobetalipoproteinemia which did not resolve with the administration of probucol. Immunofluorescent studies revealed marked accumulation of apolipoprotein B in a xanthoma excised from the tricipital area. This was in contrast to the spotty and weak fluorescence observed in a tuberous xanthoma, from the same anatomical area and histologically otherwise identical, obtained from a patient with heterozygous familial hypercholesterolemia. Hyperapobetalipoproteinemia has been reported before in association with sitosterolemia but not with cholestanolosis. We suggest that cholestanol, like sitosterol, may interfere with the normal uptake and degradation of low-density lipoproteins by peripheral cells.

We have found a novel apoE5 mutation, using isoelectric focusing (IEF), in two apparently unrelated French-Canadian subjects. Co-dominant inheritance was demonstrated in the family of the first proband, a healthy male subject. The presence of the apoE5 form was not associated with lipid abnormalities or cardiovascular disease in this family. The second proband was a hyperlipidemic female patient suffering from angina, with no informative relatives available for study. In both individuals, monoclonal antibody studies demonstrated that the mutation was associated with the loss of two overlapping epitopes at the amino terminus of the protein. Cysteamine treatment of the very low density lipoproteins indicated that the mutant apoE contained only one cysteine residue, suggesting that apoE3 was the parental form. Two-dimensional electrophoresis suggested that the mutated protein had a slightly lower molecular weight (by 1-2 kDa). However, DNA sequencing of the third exon of the apoE gene in both probands revealed a single G to A substitution at the 48th nucleotide, changing the amino acid at position 13 from glutamic acid to lysine. These results were confirmed by oligo melting experiments with allele-specific probes in relatives of the probands. The study of this apoE variant should provide additional insight into the structure-function relationship of apoE.