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Biomedical subjects

E Levy

Publications and source records attributed to E Levy.

At least 199 records · Page 11Linked to original sources
PubMed1990

Expression of a normal and variant Alzheimer's beta-protein gene in amyloid of hereditary cerebral hemorrhage, Dutch type: DNA and protein diagnostic assays.

Amyloid fibrils deposited in cerebral vessel walls in Dutch patients with hereditary cerebral hemorrhage with amyloidosis (HCHWA-D) are formed by polymerization of a 39-residue peptide similar to the beta-protein of Alzheimer's disease, Down syndrome, sporadic cerebral amyloid angiopathy and normal aging. Sequence analysis of genomic DNA in HCHWA-D patients demonstrated a point mutation, cytosine for guanine at position 1852 of the precursor beta-protein gene, which causes a single amino acid substitution (glutamine for glutamic acid) corresponding to position 22 of the amyloid protein. The normal allele was also present in these patients. To examine the expression of normal and variant beta-protein alleles in HCHWA-D we analyzed all the tryptic peptides obtained from several amyloid fractions from leptomeningeal vascular walls. Amino acid sequence of two peptides (T3a and T3b) with identical amino acid composition revealed that T3a had glutamine and T3b had glutamic acid at position 22. Thus both the normal and variant Alzheimer's beta-protein alleles are expressed in vascular amyloid in HCHWA-D and may be detected by tryptic peptide mapping. Moreover, we have developed a diagnostic assay for high risk populations and prenatal evaluation that is based on the existence of the mutation.

Alzheimer Disease↗
PubMed1990

Mutation of the Alzheimer's disease amyloid gene in hereditary cerebral hemorrhage, Dutch type.

An amyloid protein that precipitates in the cerebral vessel walls of Dutch patients with hereditary cerebral hemorrhage with amyloidosis is similar to the amyloid protein in vessel walls and senile plaques in brains of patients with Alzheimer's disease, Down syndrome, and sporadic cerebral amyloid angiopathy. Cloning and sequencing of the two exons that encode the amyloid protein from two patients with this amyloidosis revealed a cytosine-to-guanine transversion, a mutation that caused a single amino acid substitution (glutamine instead of glutamic acid) at position 22 of the amyloid protein. The mutation may account for the deposition of this amyloid protein in the cerebral vessel walls of these patients, leading to cerebral hemorrhages and premature death.

Aged↗
PubMed1990

Experimental nephrotic syndrome: removal and tissue distribution of chylomicrons and very-low-density lipoproteins of normal and nephrotic origin.

Lymph chylomicrons and plasma VLDL, 14C-labelled in vivo, were isolated from normal and nephrotic rats and injected into normal or nephrotic recipients. In normal recipients, the half-life of chylomicrons of nephrotic vs. normal origin was significantly longer (5.2 +/- 0.5 vs. 3.5 +/- 0.4 min-1). The nephrotic chylomicrons were larger in size, deficient in apo-E and apo A-I, rich in triacylglycerol and cholesterol, but poor in phospholipids, indicating that factors related to composition affected their removal. The half-life of nephrotic vs. normal VLDL, given to normal recipients, was unexpectedly shorter, (4.5 +/- 0.2 vs. 5.8 +/- 0.2 min-1). The nephrotic VLDL were also triacylglycerol- and cholesterol-rich and phospholipid-poor, but had a large diameter spread and contained a dense fraction according to the zonal ultracentrifugation pattern, suggesting the presence of faster removable IDL-like particles. When nephrotic rats received normal particles, a pronounced removal delay was seen, paralleling the extent of plasma triacylglycerol elevation. The half-life of chylomicrons was 8.3 +/- 1.4 and 15.2 +/- 2.5 min-1 in moderately and severely nephrotic rats, respectively, that of VLDL was 11.72 +/- 2.1 and 37.8 +/- 7.1 min-1 correspondingly. The chylomicron-triacylglycerol uptake was reduced both by adipose tissues and muscles of normal or nephrotic recipients, with some increase in entry into lungs, kidneys and spleen. Tissue distribution patterns of VLDL-triacylglycerol was similar to that of chylomicrons, except that the liver took up approx. 90% of the label. The low share of triacylglycerol uptake by tissues rich in lipoprotein lipase indicates that the activity of this enzyme was unlikely to limit the rate of removal. Lipoprotein lipase activity in adipose tissue and heart was slightly decreased in moderately nephrotic rats and declined only by approx. 35% in severely nephrotic ones. These results indicate that the removal defect in nephrosis seems to be due, in part, to changes in the composition of triacylglycerol-rich particles, compromising their accessibility to lipolysis and, in part, to their abundance, saturating the lipolytic capacity.

Animals↗
PubMed1990

[Noninvasive, local microwave hyperthermia for deep-seated tumors: III. Benign prostatic hyperplasia].

Poor operative risk patients with benign prostatic hyperplasia were treated as outpatients with local hyperthermia without sedation, for 1 hour, twice weekly. As a result of the treatment it was possible in 61% to remove indwelling catheters and voiding was resumed for up to 61 months after treatment. 70% of those without indwelling catheters improved clinically and remained so for 67 months after completion of treatment. There were no side-effects or sequellae of the treatment. Because of its safety, simplicity of application and good results, it is recommended as the treatment of choice for poor operative risks.

Catheters, Indwelling↗
PubMed1990

[Screening for colorectal neoplasms].

We screened groups at high risk for colorectal neoplasms, determining the efficacy of the leukocyte adherence inhibition test (LAI) for early detection, in comparison with that of the fecal occult blood (Hemoccult) test and sigmoidoscopy or colonoscopy. Those screened included 549 first-degree relatives of patients with colorectal cancer, 190 patients with a past history of colorectal adenoma or carcinoma and 67 with a past history of breast or gynecological cancer or inflammatory bowel disease. 146 normal volunteers served as controls. In 782 of those fully screened during a 3-year period, 121 had adenomas (15.5%) and 5 had invasive cancer (0.6%). The LAI test was positive in 21% of those at high risk and in 7.5% of the controls. The hemoccult test was positive in only 4.8%, but in 1/3 of them neoplasms were found. This predictive value of 33% compares with only 16% for the LAI test. That most of the neoplasms found were adenomas and not invasive cancer may be due to the relative youth of most of those screened. We conclude that the groups studied were indeed at high risk. The LAI test is not sensitive enough to identify benign adenomas but might serve as another risk-market for colorectal neoplasms. Long-term follow-up of those at high-risk with positive LAI tests may prove that we have identified a subgroup truly at risk.

Adenoma↗
PubMed1990

Surface immunoglobulin-positive T lymphocytes in HIV-1 infection: relationship to CD4+ lymphocyte depletion.

T lymphocytes bound to autologous immunoglobulin (surface Ig + T cells) and serum antibodies that bind to allogeneic lymphocytes have been detected in HIV-1-infected individuals, but their significance in the immunopathogenesis of HIV-1 infection is uncertain. We tested peripheral blood from HIV-1-infected individuals to determine if surface Ig+ T cells are specific for HIV-1 infection and are associated with CD4+ lymphocyte depletion. The majority of HIV-1-infected individuals contained substantial numbers of circulating surface Ig+ T cells. The presence of such cells was restricted to seropositive individuals and not related to risk factors associated with the acquisition of HIV-1 infection. Autologous immunoglobulin was detected on both CD4+ and CD8+ cells in all patients tested. Most individuals with surface Ig+ T lymphocytes also had serum anti-T-lymphocyte antibodies. The presence of surface Ig+ T lymphocytes correlated significantly with lower absolute CD4+ lymphocyte counts only in asymptomatic, HIV-1-infected individuals.

Antigens, CD↗
PubMed1990

Myocardial pathology in rats exposed to prolonged environmental heat.

STUDY OBJECTIVE: The aim was to assess the role of continuously high environmental temperature in the genesis of tropical cardiomyopathies. DESIGN: Rats were kept in a climatic chamber at a constant temperature of 34 degrees C (40% relative humidity) for 1 or 2 months. Controls were kept at 24 degrees C. The hearts, either taken directly from the animals or following Langendorff perfusion, were then examined by light and electron microscopy. EXPERIMENTAL MATERIAL: 69 rats of two different strains, aged about 1 month, were used as the study group. There were 32 suitable controls. MEASUREMENTS AND MAIN RESULTS: The weights of the heated rats and their hearts were lower than controls but the body to heart weight ratio was unchanged. The maximum pressure developed by the left ventricle was higher. With light microscopy, focal necrosis, lymphoid and mast cell infiltrations, fibrosis, and occasional calcifications were seen in most heat exposed rats. With electron microscopy most myocytes appeared normal when taken from whole animals. The additional trauma of heart suspension or hypo-osmolar perfusion caused severe membrane related pathology, while controls remained unaffected. CONCLUSIONS: Prolonged exposure to heat produces focal cellular reactions and disturbance of the myocyte membrane. The pathogenesis of the changes is as yet uncertain. It may be multifactorial and include calcium and/or oxygen derangements mediated by mast cells, catecholamines, hypothyroidism, and heat shock proteins.

Animals↗
PubMed1990

Mechanisms of hypercholesterolaemia in glycogen storage disease type I: defective metabolism of low density lipoprotein in cultured skin fibroblasts.

Hyperlipidaemia is a feature of glycogen storage disease type I (GSD-I) (Levy et al.). High levels of LDL cholesterol (200 +/- 25 mg dl-1) and apo B (387 +/- 44 mg dl-1) were found in association with hypercholesterolaemia in GSD-I. Related causative factors might be attributed to overproduction and/or delayed removal of LDL. In this study, a possible alteration in the clearance of LDL was examined. Using cultured fibroblasts for LDL receptor activity, the following observations were made: 1. GSD-I fibroblasts revealed only a slight decrease in LDL binding (65 +/- 7) when compared with controls (74 +/- 4 ng mg-1 protein), however, LDL internalization (382 +/- 24 vs. 570 +/- 52 ng mg-1 protein) and proteolytic degradation (2082 +/- 280 vs. 2916 +/- 12.5 ng mg-1 protein) were significantly affected (P less than 0.01). 2. Binding, internalization and proteolytic degradation of LDL from GSD-I were compared with that of controls, and were found to be significantly lower (P less than 0.01). 3. Substitution of control lipoprotein-deficient serum (LPDS) by GSD-I LPDS further diminished the above processes (P less than 0.05). Our results demonstrate that increased plasma cholesterol in GSD-I is due to a decreased catabolism of LDL. The data suggest that the problem may well be multifactorial, due to diminished receptor expression, abnormal LDL composition and impaired LDL receptor interaction due to a circulating inhibitory factor.

Adolescent↗
PubMed1990

In vitro remodelling of plasma lipoproteins in whole plasma by lipoprotein lipase in primary and secondary hypertriglyceridaemia.

In patients with familial lipoprotein lipase deficiency (FLPL-d) and glycogen storage disease type I (GSD-I), hypertriglyceridaemia (1445 +/- 247 and 1082 +/- 312 mg dl-1, n = 5 per group) was associated primarily with reduced extrahepatic lipoprotein lipase (LPL) activity (0.33 +/- 0.33 and 1.69 +/- 0.38 mumol FFA ml-1 h-1) when compared with controls (4.83 +/- 0.90). Hypercholesterolaemia was characterized by elevated LDL cholesterol (191 +/- 30 and 344 +/- 34 vs. 115 +/- 5 mg dl-1 in controls P less than 0.01) and low HDL cholesterol (12 +/- 2 and 22 +/- 2 vs. 56 +/- 3 in controls, P less than 0.001). In order to ascertain the role of LPL in the interconversion and remodelling of lipoproteins in these disorders, we analysed lipid and lipoprotein profiles before and following in vitro incubation of patient plasma with purified milk LPL (EC 3.1.1.34) for 6 h at 37 degrees C. The efficiency of exogenous LPL in vitro was demonstrated by the extent of hydrolysis of chylomicrons and of VLDL-TG in both groups. Concomitant with the disappearance of TG-rich lipoprotein particles, a consistent per cent increment of IDL (99.2 +/- 30.8 and 43.9 +/- 70.5), LDL (152.8 +/- 36.2 and 137.0 +/- 36.1) and of HDL2 (144.8 +/- 29.4 and 99.8 +/- 18.7) was observed in both groups of patients. The enhancement of the latter fractions contrasted with the decline of HDL3 mass concentration (25.4 +/- 7.7 and 51.4 +/- 5.8%), suggesting that a major shift of HDL3----HDL2 occurs following in vitro lipolysis by LDL. Simultaneous compositional and morphological changes of individual lipoprotein particles were noted, confirming the dynamic movement and exchange of neutral lipids and proteins. Specificity of LPL results was demonstrated by experiments in which incubation of the whole plasma at 37 degrees C without exogenous lipolytic enzyme did not cause any substantial changes. The present study, therefore, demonstrates a correction of the major lipoprotein abnormalities associated with FLPL-d and GSD-I by exogenous LPL. No substantial difference was noted between primary (FLPL-d) and secondary (GSD-I) hyperlipidaemias. These studies allow us to conclude that a simple in vitro system, utilizing an exogenous source of LPL and plasma from patients, may serve as a suitable model for the study of the metabolic relationships of lipoproteins. However, in view of the fact that the extent of lipolysis achieved in vitro did not differ between FLPL-d and GSD-I, it may not be able to separate primary from secondary hyperlipaemias.

Adolescent↗
PubMed1990

Efficiency of enteral nitrogen support in surgical patients: small peptides v non-degraded proteins.

In a prospective study, 12 intensive care patients, after abdominal surgery, received three alternate six-day courses of two enteral diets with identical nitrogen (0.3 g N/kg per day) and energy (60 kcal/kg per day) supply. The protein hydrolysate (PH) diet contained enzyme-hydrolysed casein and lactoserum (60% small peptides), while the non-degraded protein (NDP) diet contained a nitrogen source of similar amino acid composition, but in the form of non-degraded proteins. The patients were randomised to receive either PH-NDP-PH or NDP-PH-NDP. Parameters reflecting protein metabolism were assessed in the plasma, urine, and stomal effluent on days 1, 6, 12, and 18, three hours after stopping the nutrition (t0), and one hour after restarting it (t1). Comparisons of t1 and t0 values showed that 13 amino acids (including the eight essential amino acids) increased significantly with the protein hydrolysate diet, but only two increased with the non-degraded protein diet. Similarly, with protein hydrolysate, insulin-aemia at t1 was significantly higher than at t0 and correlated with plasma leucine, phenylalanine, alanine, and lysine concentrations. In addition, significant improvements in plasma albumin, transferrin, and retinol binding protein concentrations were seen with protein hydrolysate, together with a significant decrease in the plasma phenylalanine/tyrosine ratio and urinary 3-methylhistidine excretion. We conclude that in patients in intensive care after abdominal surgery enteral support containing small peptides is more effective than an equivalent diet containing whole proteins in restoring plasma amino acid and protein levels.

Adult↗
PubMed1990

Urinary excretion of apolipoproteins bound to HDL-like particles in rat nephrotic syndrome and their relation to plasma HDL.

Lipoprotein excretion was investigated in the urine of hyperlipidemic rats with nephrotic syndrome induced by aminonucleoside of puromycin. Incubation with phosphatidylcholine liposomes was employed to float apoproteins not bound to lipids, by ultracentrifugation at d = 1.21 g/ml. On ultracentrifugation of whole, untreated urine, the amount of protein floated was 6-fold greater in nephrotic vs. control rats and consisted mainly of HDL-like particles. Sodium dodecylsulfate-polyacrylamide gel electrophoresis showed that control urine contained apoproteins A-I, A-II, E and traces of C, whereas in the nephrotic urine apo-E and a large amount of apo-C was found. Addition of liposomes to the ultracentrifugal d = 1.21 g/ml infranate and reflotation at the same density resulted only in slight increment in the floated apoproteins, mainly C and A-I. Addition of liposomes to the whole urine and centrifugation at d = 1.21 g/ml also did not produce a greater yield in the floated apoproteins of control or nephrotic urine. These results indicated that the urine is virtually devoid of lipid-free apoproteins and those floated from both the nephrotic and control urine are complexed with lipids. The plasma VLDL + LDL fraction of nephrotic rats, though increased in quantity, did not differ markedly in composition from that of control rats. The HDL, approximately 3-fold elevated in nephrotic rats, were poorer in esterified cholesterol and richer in phospholipids. Relative to plasma HDL, the nephrotic urine HDL were protein-rich and phospholipid-poor and appeared to be larger in particle size as suggested by the lower estimated specific volume. The modified plasma HDL in nephrosis may have a pathophysiological implication.

Animals↗
PubMed1990

Apolipoprotein B-100: immunolocalization and synthesis in human intestinal mucosa.

Despite the evidence that the human small intestine produces two separate species of apoB mRNA encoding for B-100 and B-48, there is a paucity of data concerning the expression of the latter form in this organ. Using a high resolution immunogold approach, with specific polyclonal antibodies and a panel of monoclonal antibodies (2D8, 3A10, 4G3), both forms of apoB (B-48 and B-100) were revealed over enterocytes of pediatric intestinal samples. Intense labeling was observed over microvilli, apical smooth membrane vesicles, multivesicular bodies, the basolateral membrane, as well as the trans Golgi region. Only low labeling was found over the rough endoplasmic reticulum (rER). Similar patterns of apoB distribution characterized both duodenal and jejunal regions. The presence of labeling over the Golgi apparatus and rER suggests a synthetic activity of both forms of apoB by the epithelial cells. To test this hypothesis, human intestine was incubated with [3H]leucine, homogenized, and subjected to immunoprecipitation for apoB. Immunoprecipitates contained radioactivity mainly in apoB-48 with relatively small amounts in apoB-100 when examined by NaDodSO4-polyacrylamide gel electrophoresis. These findings were further supported by the biochemical determination of apoB-100 and apoB-48 in chylomicron particles isolated from thoracic duct lymph of a human donor. Taken together, our data suggest that the human intestine is able to synthesize and to express the apoB-100.

Apolipoprotein B-100↗
PubMed1990

Combined (n-3 and n-6) essential fatty deficiency is a potent modulator of plasma lipids, lipoprotein composition, and lipolytic enzymes.

Essential fatty acids (EFA) are important structural and functional components of cell membranes. Their deficiency has been associated with several clinical and biochemical abnormalities. In the present study, the lipid profile as well as the concentration, composition, and metabolism of lipoproteins were examined in rats rendered EFA-deficient over a period of 12 weeks. Changes in plasma fatty acids mainly induced an increase of palmitoleic (16:1 n-7) and eicosatrienoic (20:3 n-9) acids, while linoleic (18:2 n-6), arachidonic (20:4 n-6), linolenic (18:3 n-3), and docosahexaenoic (22:6 n-3) acids were decreased. The results show increased concentrations of free fatty acids (FFA) (P less than 0.001), triglycerides (P less than 0.001), total cholesterol (P less than 0.02), free cholesterol (P less than 0.005), and phospholipids (P less than 0.05) when compared to pair-fed controls. Similar levels of cholesteryl esters were found in the two groups, and lecithin: cholesterol acyltransferase activity (nmol/100 microliters plasma per h) (8.98 +/- 1.44 vs 8.72 +/- 0.50) did not differ. On the other hand, postheparin extrahepatic lipoprotein lipase (LPL) activity was significantly (P less than 0.002) decreased (5.96 +/- 0.29 vs 7.29 +/- 0.68 mumol FFA/ml per h) and could account for the hypertriglyceridemia as well for the relative triglyceride enrichment of very low density lipoprotein, intermediate density lipoprotein, and low density lipoprotein particles. This enzymatic depletion of LPL was mainly due to the adipose tissue, since a higher level (P less than 0.001) of hepatic lipase (325.8 +/- 16.0 vs 130.8 +/- 9.5 nmol FFA/mg protein per h) was found in liver acetone powder extracts.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Chylomicron synthesis in experimental nephrotic syndrome.

Mesenteric lymph was collected for 48 h from rats with aminonucleoside-induced nephrotic syndrome, receiving an intraduodenal infusion of a triacylglycerol emulsion. In nephrosis, the rates of lymph flow and triacylglycerol transport were approx. 2-fold higher, but the transport of total protein and of apoproteins A-I and E was 2- to 3-fold lower than that in control rats, resulting in chylomicrons with a 3-fold approx. elevated triacylglycerol/protein ratio. Supplementation of the triacylglycerol infusate with glucose and amino acids did not increase the protein or apoA-I and apoE transport. Production or transport of B and C apoproteins in nephrotic rats was also reduced, as indicated by tetramethylurea solubility, incorporation of intraduodenally infused [3H]leucine and staining of the chylomicron proteins on SDS-PAGE gels. Apoprotein A-IV was the only chylomicron component into which the leucine incorporation was elevated, but its relative content was not increased on SDS-PAGE gels. Lymph chylomicrons of nephrotic rats were larger in size (1498 +/- 37 vs. 1235 +/- 23 A), consistent with the higher triacylglycerol/protein ratio. The concentration of all lipoprotein classes was markedly elevated in the plasma of nephrotic rats, as was that of the total A-I and E apoproteins. Intravenous injection of 125I-labelled HDL, followed by tracing of the label in lymph chylomicrons, indicated a lower rate of transfer of HDL apoproteins from plasma to lymph in nephrotic rats. We conclude that the intestinal chylomicron formation in nephrosis is characterised by an enhanced triacylglycerol transport without the appropriate apoprotein complement. This is probably due to the limited capacity of enterocytes, in marked contrast to hepatocytes, to respond to the hypoproteinemia of nephrosis with increased production and/or transport of the apoproteins.

Animals↗
PubMed1989

Stroke in Icelandic patients with hereditary amyloid angiopathy is related to a mutation in the cystatin C gene, an inhibitor of cysteine proteases.

Cystatin C is an inhibitor of lysosomal cysteine proteases and consists of 120 amino acids. A variant of cystatin C lacking the first NH2-terminal residues and having one amino acid substitution at position 68 forms amyloid deposits mainly in the walls of brain arteries, causing fatal strokes in Icelandic patients with familial cerebral hemorrhage secondary to a form of an autosomal dominant amyloidosis. To understand the molecular basis of the genetic defect, the gene encoding cystatin C was isolated from genomic DNA libraries made from normal tissue and the brain of an Icelandic patient with hereditary cerebral hemorrhage with amyloidosis (HCHWA-I). The data indicate that the cystatin C gene encodes a polypeptide of 146 amino acids, of which the first 26 correspond to a secretory peptide signal sequence. The gene contains two intervening sequences that interrupt the coding region at amino acids 55 and 93. Comparison with genes encoding salivary cystatins and kininogen proteins show sequence homology and conservation of exon-intron structure. Except for a mutation in the second exon (CAG instead of CTG in the normal gene, resulting in the substitution of glutamine for a leucine residue), the gene cloned from the brain of the Icelandic patient is identical to the normal cystatin C gene. Thus, HCHWA-I is the first familial type of amyloidosis related to a point mutation in a gene encoding for an inhibitor. The mutation in the structural gene encoding cystatin C appears to be the primary defect in this inherited disorder causing amyloid fibril formation and accumulation followed by cerebral hemorrhage.

Amino Acid Sequence↗
PubMed1989

Cost analysis of osteoporosis related to untreated menopause.

Menopausal osteoporosis has many consequences for women over 50. Its complications incur high treatment costs both for society and the patients themselves. Collection of the epidemiological data required for a cost analysis of menopause-related osteoporosis is not easy, but we have calculated the direct (i.e. purely medical) costs as follows: hip fractures: approximate number per annum in women over 50: 55,000, minimum hospital costs (treatment and rehabilitation): 3.5 bn FF; forearm fractures: approximate number per annum: 35,000, cost of out-patient treatment: 200 m FF; vertebral fractures: common, but generally unrecorded: estimated number 40,000-65,000 cost: unevaluated. The relative benefit of hormone therapy versus nontreatment may be used to calculate the cost of osteoporosis due to non treated menopause. In France, where currently only 5% women over 50 are treated, this cost is 2.2 bn FF. If 50% of women were treated, the savings from hormone therapy (in terms of osteoporosis treatment costs) could be 1.2 bn FF, a figure which must be weighed against a cost analysis of oestrogen therapy.

Aged↗
PubMed1989

Direct transesterification of plasma fatty acids for the diagnosis of essential fatty acid deficiency in cystic fibrosis.

This study was aimed at redefining criteria for essential fatty acid (EFA) deficiency with the use of the direct transesterification procedure (1986. J. Lipid Res. 27: 114-120) and at determining whether a simple assay of total fatty acids (FA) is as predictive of EFA deficiency as the FA pattern from plasma, red cell, and platelet phospholipids. Fasting blood samples were taken from 163 cystic fibrosis (CF) patients who were encouraged to consume 35-40% of their calories as fat. Their mean (+/- SD) age was 9.6 +/- 4.8 yr. The control group consisted of 44 unaffected siblings aged 13.1 +/- 3.1 yr. The 20:3(n-9)/20:4(n-6) ratio in 77 (47%) CF children was more than 2 SD above the values (mean +/- SD) of 0.021 +/- 0.007 obtained in the 44 controls. Groups of EFA-sufficient (n = 10) and EFA-deficient (n = 7) subjects were selected for further studies. The plasma total FA 20:3(n-9)/20:4(n-6) ratios of 0.029 +/- 0.003 in EFA-sufficient and of 0.216 +/- 0.103 in EFA-deficient was as good a discriminant as FA in phospholipids from plasma, red cell PC, and platelets. Among the 21 individual fatty acids, 20:3(n-9), which was also found in controls, and 16:1(n-7) (palmitoleic) proved to be the most sensitive indices of EFA deficiency. They are equally reliable in plasma, red cells, and platelets, but the inverse linear relationship (r = -0.91) between the n-7 family and 18:2(n-6) proved to be more closely associated with EFA deficiency than the one (r = 0.66) between 20:3(n-9) and 20:4(n-6).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗