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PubMed1969

Triglyceride synthesis by the small-intestinal epithelium of the pig, sheep and chicken.

1. A comparative study was made of triglyceride synthesis by the intestinal epithelium of pigs, sheep and chickens. In pig and chicken tissue both the glycerol 3-phosphate and the monoglyceride pathway of triglyceride synthesis were operative, but the former pathway predominated in sheep tissue. 2. The fatty acid specificity of the glycerol 3-phosphate pathway was studied in pig and sheep total-homogenate preparations. Maximum incorporation was obtained with myristic acid and palmitic acid under optimum conditions for each fatty acid. Lauric acid, myristic acid, oleic acid, linoleic acid and linolenic acid were inhibitory at concentrations above their optimum, but octanoic acid, decanoic acid, palmitic acid and stearic acid did not show this effect. 3. Subcellular fractionation located the glycerol 3-phosphate and monoglyceride pathways of triglyceride synthesis in the microsomes in all instances. Phosphatidate phosphohydrolase was associated with both the microsomes and the particle-free supernatant. 4. Glycerol 1-mono-oleate was incorporated into triglycerides to a greater extent than glycerol 1-mono-palmitate or glycerol 1-monostearate by microsomal preparations from pig and chicken. 5. A lipase specific for monoglycerides was detected in the particle-free supernatant of all the species examined.

Animals↗

PubMed1981

Characterization of a radiation-resistant Acinetobacter.

For characterizing the radiation-resistant Acinetobacter strain FO-1 reported in the previous paper (1980), we investigated the structure of cell wall, the cellular fatty acid composition, and the detailed taxonomic characteristics. The results denoted that the cell division occurred by simple constriction with the formation of a slight septum and the intermediate dense layer between the outer membrane and the plasma membrane was seen, the main components of the cellular fatty acids were oleic acid, palmitic acid, and palmitoleic acid, and that the strain was tolerant to salt and could not produce acids from cellobiose, melibiose, lactose, and ribose.

Acinetobacter↗

PubMed1978

Comparison of stationary phases in reversed-phase TLC for correlation between structure and biological response of probiotics.

A series of C16,C18 and C20 fatty acids and their ethyl esters and alcohols were investigated as possible stationary phases in reversed-phase TLC for the correlation between structure and biological response (antistaphylococcal activity). Ten probiotics (omego-amino acids and their L-histidine dipeptides) were used as the biologically active compounds. The mobile phase was 70% acetone in water. The best correlations were obtained with hexadecanoic acid (palmitic acid) or cis9,cis-12,cis-15-octadecatrienoic acid, 1-hexadecanol or cis-9-octadeconol, and ethyl hexadecanoate for the fatty acids, their alcohols, and their ethyl esters, respectively. Among all compounds, the following relation was obtained: fatty acids = alcohols greater than ethyl esters greater than white paraffin oil.

Anti-Bacterial Agents↗

PubMedDate not supplied

Characterisation of castor oil by on-line and off-line non-aqueous reverse-phase high-performance liquid chromatography-mass spectrometry (APCI and UV/MALDI).

A non-aqueous reverse-phase HPLC method, based on two columns in series, has been used to separate the major triacylglycerols (TAGs) from commercial castor oil and to perform either on-line negative ion atmospheric pressure chemical ionisation (APCI), or off-line positive ion matrix-assisted laser desorption ionisation (MALDI)/MS. The resulting Mass Spectra showed chloride-attached TAG molecules [M + CI]- in the case of negative-ion APCI, and sodium-attached TAG molecules [M + Na]+ in the case of positive-ion MALDI. For MALDI time-of-flight (TOF)/MS, a liquid binary matrix system consisting of sodium ferrocyanide and glycerol was applied, resulting in excellent TAG sensitivity, which was necessary for the determination of trace amounts of TAGs in castor oil. Both techniques allowed unambiguous molecular mass determination of the intact TAG molecules with no thermal degradation. Furthermore, seamless post source decay (PSD) fragment ion analysis by means of a curved field reflector TOF mass spectrometer allowed the determination of the fatty acid composition of each individual TAG. Castor oil contained eight different TAGs which were successfully determined by both APCI and MALDI techniques. In each TAG, at least two units of 12-hydroxy-9-octadecenoic acid (ricinoleic acid) were present. The following fatty acids were determined by seamless PSD fragment ion analysis and APCI/MALDI molecular mass determination as TAG substructures: ricinoleic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, dihydroxy stearic acid and eicosenoic acid. Triricinolein was the dominating TAG.

Castor Oil↗

PubMed1998

Role of human CYP4F2 in hepatic catabolism of the proinflammatory agent leukotriene B4.

Leukotriene B4 (LTB4), an arachidonic acid derivative, is a potent proinflammatory agent whose actions are terminated by catabolism via a microsomal omega-hydroxylation pathway. Although the liver serves as the principal site for LTB4 clearance from the systemic circulation, the attributes of hepatic LTB4 metabolism are ill defined in humans. Thus, we examined metabolism of LTB4 to its omega-hydroxylated metabolite 20-hydroxyleukotriene B4 (20-OH LTB4) by human liver microsomes and also purified the hepatic P450 enzyme underlying this reaction. Liver microsomes from 10 different subjects converted LTB4 to 20-OH LTB4 at similar rates (1.06 +/- 0.3 nmol/min/nmol P450; 0.25 +/- 0.1 nmol/min/mg protein). Analysis of the microsomal LTB4 20-hydroxylation reaction revealed kinetic parameters (apparent Km of 74.8 microM with a VMAX of 2.42 nmol/min/nmol P450) consistent with catalysis by a single P450 enzyme. Conventional chromatography combined with immunochemical screening with rat CYP4A1 antibodies was then used to isolate a P450 enzyme from human liver microsomes with a molecular weight of 57,000 and an NH2-terminal amino acid sequence 94% homologous (12Trp --> 12Gly) over the first 17 residues with the human CYP4F2 cDNA-derived sequence. Upon reconstitution with P450 reductase and phospholipid, CYP4F2 converted LTB4 to 20-OH LTB4 at a turnover rate of 392 pmol/min/nmol P450, whereas the other human liver P450s tested, including CYP4A11, exhibited neglible LTB4 omega-hydroxylase activity. Polyclonal antibodies to CYP4F2 were found to markedly inhibit (91.9 +/- 5%; n = 5) LTB4 20-hydroxylation by human liver microsomes. Microsomal 20-OH LTB4 formation was also inhibited 30% by arachidonic acid, a known CYP4F2 substrate, and 50% by prostaglandin A1 but was unaffected by lauric acid, palmitic acid, and PGF2alpha. Finally, a strong correlation (r = 0.86; P < 0.002; n = 10) was observed between CYP4F2 content and LTB4 20-hydroxylase activity in the human liver samples. Our results indicate that CYP4F2 is the principle LTB4 omega-hydroxylating enzyme expressed in human liver and, as such, may play an important role in regulating circulating as well as hepatic levels of this powerful proinflammatory eicosanoid.

Amino Acid Sequence↗

PubMed1993

[The effect of zinc depletion on the fat content and fatty acid composition of the liver and brain in forcibly fed rats].

In the present work the influence of zinc deficiency on fat content and fatty acid composition of liver and fatty acid composition of brain of rats with a high food intake was investigated. Using the force-feeding technique the rats were fed 14.5 g food daily at days 1 to 4, and then 11.6 g food for later days. After 7 days the zinc-deficient animals had a fatty liver which was characterized by an increase in fat content (68%) and dry matter (23%). The amounts of lauric acid, myristic acid, myristoleic acid, palmitic acid, palmitoleic acid, and oleic acid were also increased by 100 to 200% in the liver of zinc-deficient animals, whereas the amount of arachidonic acid was decreased by 29%. The amounts of phosphatidylcholine and phosphatidylethanolamine in the liver were not changed by zinc deficiency, but the fatty acid composition of these phospholipids was changed. The liver phospholipids of zinc-deficient animals had a decreased proportion of arachidonic acid, but an increased proportion of docosahexaenoic acid. In the zinc-deficient animals there also existed a positive correlation between the fat content in the liver and the ratio between linoleic and arachidonic acid in the liver and a negative correlation between the fat content in the liver and the amount of arachidonic acid in the liver. These correlations as well as the changes in liver fatty acid composition of zinc-deficient animals suggest that the fatty liver might be the result of a disturbed metabolism of linoleic acid. In contrast, zinc deficiency did not influence the fatty acid composition of brain. This means that brain is protected against the effects of short-term zinc deficiency.

Alkaline Phosphatase↗

PubMed1986

Potential therapeutic efficacy of inhibitors of human phospholipase A2 in septic shock.

Soluble phospholipase A2 has been implicated in the pathogenesis of local and systemic inflammatory reactions. Elevated levels of circulating phospholipase A2 (PLA2) correlate with the severity of circulatory collapse and pulmonary dysfunction in gram-negative septic shock. Characterization of septic shock serum PLA2 revealed a calcium-dependent enzyme with absolute 2-acyl specificity with a pH optimum of 7.5. We tested a number of therapeutic agents for their ability to inhibit PLA2 from human septic shock serum. Chloroquine, chlorpromazine, dexamethasone base, dexamethasone sodium phosphate, indomethacin, lidocaine, oleic acid, palmitic acid, promethazine, trans-retinoic acid, rutin and dl-alpha-tocopherol were all studied over the range of 10(-2) to 10(-7) M. All agents, with the sole exception of dexamethasone base, inhibited PLA2 activity at concentrations greater than 10(-3) M. PLA2 inhibition by dexamethasone sodium phosphate was factitious, due to the formation of calcium-phosphate complexes. Of the 11 agents studied, chlorpromazine was the most effective, with an IC50 of 7.5 X 10(-5) M, a membrane concentration achievable within its therapeutic range. Inhibition was non-competitive with an apparent Ki of 5 nM. Since serum PLA2 levels correlate with mortality in both experimental endotoxemia and clinical gram-negative septic shock, and chlorpromazine was previously shown to improve survival in these conditions, we postulate that its therapeutic efficacy resides at least in part in its PLA2-inhibitory activity.

Dexamethasone↗

PubMed1977

[Thermal inactivation and storage behavior of technologically important enzymes. III. Effect of reagents added to peroxidase and lipoxygenase].

The influence of milieu factors on the thermal inactivation of peroxidase and lipoxigenase was investigated. Cationogenic, anionogenic, non-ionogenic and amphoteric tensides were more or less effective in inactivating horseradish peroxidase. Most effective in this respect were lecithine and monoglyceride, both capable of swelling in water. In presence of lecithine, peroxidase was inactivated already at 0 degrees C and pH 4.0. Linoleic acid was more efficient in an oxygen stream than in presence of nitrogen, in a stream of nitrogen its influence was comparable to oleic acid. This suggests an additional effect by lipid peroxides which are formed of linoleic acid under the heating process. Tensides prevented the regeneration of the heated peroxidase. In the case of lipoxigenase, the authors investigated the influence of lecithine and various fatty acids on the thermal inactivation at 60 degrees and pH 7.0. Lecithine accelerated the inactivation less distinctly than with peroxidase. The accelerated the inactivation less distinctly than with peroxidase. The accelerating effect of the fatty acids decreased in the order oleic acid, linoleic acid, palmitic acid, myristic acid and stearic acid.

Drug Stability↗

PubMed2004

Hydrolysis of carbaryl by human serum albumin.

Human serum (HS) and human serum albumin (HSA) were able to hydrolyse the carbamate carbaryl. Carbarylase activity found in HSA was slightly activated by 1 mM Zn2+, Mn2+, Cd2+, Ni2+ and Na+ and by 0.01 mM Pb2+. The organophosphorus compounds paraoxon and O-hexyl O-2,5-dichlorophenyl phosphoramidate, caprylic acid, palmitic acid and the carboxyl ester p-nitrophenyl butyrate inhibited the hydrolysis of carbaryl by HSA, being in the last case a competitive inhibition. Using selective amino acid reagents, we concluded that Cys, Trp, Arg and Tyr seem to play important roles in the carbarylase activity of HSA. In addition, Tyr and Arg seem to be located in the active centre of the enzyme since carbaryl protected the activity from the inhibition. It was concluded that HSA hydrolyses carbaryl by a mechanism similar to that described for rabbit serum albumin based in transient carbamylation of a Tyr residue. The extrapolation of the hydrolysis rate to physiological albumin concentrations suggests that albumin might be playing a critical role in the detoxication of carbaryl.

Carbaryl↗

PubMed1999

Lymphatic fatty acid absorption profile during 24 hours after administration of triglycerides to rats.

In this study we determined in rats the complete 24-h lymphatic fatty acid profile after administration of either rapeseed oil (RO) or rapeseed oil interesterified with 10:0 (RO/C10) with special emphasis on the transition from absorptive to postabsorptive phase. Rats were subjected to cannulation of the main mesenteric lymph duct and the next day oils were administered through a gastric feeding tube. Lymph was collected in 1-h fractions for the following 24 h. The time for maximum lymphatic transport of fatty acids was at 4 h with fast changes in fatty acid composition from the fatty acids of endogenous origin to those of the administered oils. Seven to eight hours after administration the transport was significantly lower than maximum, indicating the change from absorptive to postabsorptive phase. At 24 h after administration of either oil the transport of total fatty acids, palmitic acid (16:0), and linoleic acid (18:2n-6) together with oleic acid (18:1 n-9) after RO had not returned to the transport at baseline. In contrast, the transport of decanoic acid (10:0) and alpha-linolenic acid (18:3n-3) returned to baseline values between 12 and 15 h. This indicated that the absorption of purely exogenous fatty acids (illustrated by 10:0 and 18:3n-3) was complete at 15 h and that the fatty acids transported between 15 and 24 h were derived mostly from endogenous stores.

Animals↗

PubMed1993

Abnormal fatty acid composition in sarcolemma and sarcoplasmic reticulum from myotonic ADR mouse muscle.

The fatty acid composition of membrane lipids from sarcolemma and sarcoplasmic reticulum isolated from biceps and gastrocnemius muscle has been compared in normal (wildtype, +/adrmto or +/+) and affected (adrmto/adrmto) myotonic mice. The adrmto mouse exhibits an arrested development of the righting response, and arose spontaneously from the SWR/J strain. These mice exhibit classical myotonia similar to the human disease, Becker's myotonia [1]. Significant alterations, characterized by a decrease in the saturated fatty acid, palmitic acid (16:0), and the polyunsaturated fatty acid, arachidonic acid (20:4), and an increase in stearic (18:0) and linoleic (18:2) acids, were observed between sarcolemma and sarcoplasmic reticulum from normal and affected mice. These changes in fatty acid composition of muscle membrane from ADR mice may be adequate to cause an alteration in membrane fluidity and affect the function of ion channels. The fatty acid composition of erythrocytes ghosts was also examined, as a potential marker for alterations in muscle membranes. In erythrocyte ghosts isolated from affected mice, the only alteration observed was a decrease in the proportion of oleic acid (18:1), an effect completely different from those observed in muscle membranes. Therefore, erythrocyte ghosts do not serve as an adequate indicator of changes in fatty acid composition of muscle membranes in this model of myotonia.

Animals↗

PubMed1981

Comparative study on ganglioside compositions of various rabbit tissues. Tissue-specificity in ganglioside molecular species of rabbit thymus.

Ganglioside compositions of various organs of rabbit (NIBS strain, male, 10 months old) were studied. Organs examined contained lipid-bound sialic acid at various concentrations but the amounts in extraneural tissues were less than one-fifth of that in brain. The gangliosides of various tissues were analyzed by ganglioside-mapping and by isolating individual components and determining their structures chemically or enzymatically. According to their backbone asialocarbohydrate chain, the major gangliosides of various tissues were classified into three groups: (1) lactose and ganglio-N-triose (lung, stomach, liver, intestine, kidney, testis and muscle); (2) ganglio-N-tetraose (brain); (3) lacto-N-neotetraose (thymus). 70% of all thymus gangliosides had a lacto-N-neotetraose backbone, which was tissue-specific. In marked contrast to the case in other tissues, in thymus N-glycoloylneuraminic acid constituted 90% of the total lipid-bound sialic acid, and all molecular species of thymus gangliosides contained N-glycoloylneuraminic acid. Palmitic acid was a major fatty acid of thymus gangliosides. Distinct differences were found in the fatty acid compositions of gangliosides with longer carbohydrate chains in various tissues.

Animals↗

PubMed1986

Selective inhibition of long-chain fatty acid uptake in short-term cultured rat hepatocytes by an antibody to the rat liver plasma membrane fatty acid-binding protein.

Uptake of long-chain fatty acids by short-term cultured hepatocytes was studied. Rat hepatocytes, which were cultured for 16 h on plastic dishes (3.6 X 10(6) cells/dish), were incubated with [3H]oleate in the presence of various concentrations of bovine serum albumin as a function of the concentration of unbound [3H]oleate in the medium. At 37 degrees C initial uptake velocity (V0) was saturable (Km = 9 X 10(-8) M; Vmax = 835 pmol/min per mg protein). V0 was temperature dependent with an optimum at 37 degrees C and markedly reduced at 4 degrees C and 70 degrees C. To evaluate the biologic significance of a previously isolated rat liver plasma membrane fatty acid-binding protein as putative carrier protein in the hepatocellular uptake of fatty acids, cultured hepatocytes were treated with a monospecific rabbit antibody (IgG-fraction) to this membrane protein or the IgG-fraction of the pre-immune serum as controls. Uptake kinetics of [3H]oleate in antibody pretreated short-term cultured hepatocytes revealed a depression of Vmax by 70%, while Km was only reduced by 16% compared to controls, indicating a predominant non-competitive type of inhibition. V0 of a variety of long-chain fatty acids (oleic acid, arachidonic acid, palmitic acid, stearic acid) was reduced by 56-69%, while V0 of [35S]sulfobromophthalein, [3H]cholic acid and [14C]taurocholic acid remained unaltered. These data support the concept that in the system of cultured hepatocytes, uptake of long-chain fatty acids is mediated by the rat liver plasma membrane fatty acid-binding protein.

Animals↗

PubMed1988

Purification and chemical characterisation of the inhibitor of lipid peroxidation from intestinal mucosa.

The antioxidant previously isolated from intestinal mucosa has been subjected to further purification and identification. Although this inhibitor moved as a single spot on thin-layer chromatography in a number of different solvent systems, it proved to be a mixture of free carboxylic acids whose relative composition was similar in different batches. Detailed studies involving the use of high-pressure liquid chromatography, combined gas chromatography-mass spectrometry, high-field 360 MHz proton nuclear magnetic resonance spectroscopy, fast atom bombardment mass spectrometry and other techniques established that the inhibitor was a mixture of carboxylic acids of the following identity and relative composition (the major components comprising 92% of the total fatty acids): palmitic acid, 14.8%; palmitoleic acid, 3.6%; stearic acid, 7.0%; oleic acid, 21.0%; linoleic acid, 27.6% arachidonic acid, 18.0%. Mixtures of authentic fatty acids of the same relative concentration showed inhibition of peroxidation, comparable with the purified inhibitor from intestinal mucosa. A study of the inhibitory activity of the components of the mixture using malonaldehyde estimation, diene conjugation and arachidonic acid estimation showed that the inhibitory activity was due to palmitoleic and oleic acids only, the latter being the major component.

Animals↗

PubMed1989

Arachidonic acid metabolism in isolated gastric mucous and parietal cells.

Arachidonic acid metabolism was studied in isolated gastric mucous and parietal cells. During a 90 min incubation, mucous cells incorporated [1-14C]arachidonic acid (4.5 mumol/l) into triacylglycerols (500 pmol/mg protein), phosphatidylcholine (520), phosphatidylethanolamine (290) and phosphatidylinositol (100). 230 pmol/mg protein was recovered as 14CO2 and 130 pmol/mg protein in the form of unidentified water-soluble metabolites. The incorporation rates were linearly related with arachidonic acid concentration up to 10 mumol/l. Neither equimolar concentrations of oleic acid, palmitic acid and linoleic acid nor prostaglandin E2 (1 mumol/l) or indomethacin (10 mumol/l) affected incorporation. During prolonged incubation incorporated arachidonic acid was transferred from triacylglycerols and phosphatidylcholine to phosphatidylethanolamine. Upon subcellular fractionation most of the incorporated arachidonic acid was found in the microsomal fraction. Compared with mucous cells, parietal cells incorporated arachidonic acid less quickly into phospholipids, but utilized it more efficiently for energy metabolism. In conclusion gastric cells show a highly dynamic metabolism of arachidonic acid which is qualitatively similar but quantitatively different between cell types.

Animals↗

PubMed1985

Effects of diabetes mellitus on renal fatty acid activation and desaturation.

We report the first direct measurement of delta-6 desaturase and delta-9 desaturase (EC 1.3.99.3, acyl-CoA dehydrogenase) activities in the rat kidney. Crude renal cortical homogenates from alloxan-diabetic and from normal rats were assayed for delta-6 and delta-9 desaturase activities. The delta-6 desaturation pathway activity measured with 9,12-octadecadienoic acid (linoleic acid) as substrate was increased, while the delta-9 desaturation pathway measured with hexadecanoic acid (palmitic acid) as substrate was unchanged in diabetic renal cortex, suggesting that the two enzymes are regulated independently in this tissue. In contrast to the kidney, delta-6 desaturase pathway activity was unchanged and the delta-9 desaturase pathway activity was greatly depressed in diabetic liver. When exogenous long-chain acyl-CoA synthetase (EC 6.2.1.3; acid: CoA ligase, AMP-forming) was added to the delta-6 desaturase assay system, the rate of delta-6 desaturation in normal kidney increased to a rate similar to that found in diabetic kidney; rates in diabetic extracts were unchanged. These results suggest that the rate of fatty acid substrate activation to the coenzyme A ester limits the rate of delta-6 desaturation in normal renal cortex. These results also suggest that the rate of fatty acid activation by long-chain acyl-CoA synthetase activity is increased in diabetic renal cortex. Direct measurement of the activity of long-chain acyl-CoA synthetase demonstrated that its activity was indeed increased significantly in the renal cortex of diabetic rats.

Acyl-CoA Dehydrogenase, Long-Chain↗

PubMed1994

Biochemical epidemiology of colon cancer: effect of types of dietary fiber on colonic diacylglycerols in women.

BACKGROUND/AIMS: In view of the potential significance of dietary fat and fiber in colon cancer and the possible indirect involvement of diacylglycerols (DAGs) in the pathogenesis of colon cancer, the effect of types of dietary fiber on fecal DAG in premenopausal women was investigated. METHODS: Forty-eight women consuming a typical western diet provided two 24-hour stool specimens and two sets of preintervention 4-day food records. They were randomly assigned to one of the fiber groups, namely, a wheat, oat, or corn bran supplement. They consumed their control diet plus 13-15 g of dietary fiber from each source for 8 weeks. At the end of the fiber period, each subject provided two 24-hour stool specimens and 4-day food records. Stool samples collected during the two periods were analyzed for total fat and DAG fatty acids. RESULTS: All sources of dietary fiber increased the amount of fecal fat excreted. Dietary wheat bran decreased the concentrations of total DAG and DAG containing lauric acid, myristic acid, palmitic acid, stearic acid, and linoleic acid, whereas oat bran increased the DAG composed of oleic acid and linoleic acid compared with the control diet. Corn bran decreased the DAG containing stearic acid. CONCLUSIONS: These results show that the modifying effect of dietary fiber on DAG depends on the type of fiber consumed.

Adult↗

PubMed1990

A cell culture system that enhances mononuclear cell IgE synthesis induced by recombinant human interleukin-4.

A new culture system is described in which recombinant human interleukin-4 (rhIL-4) consistently induces the synthesis of large quantities of IgE by human blood mononuclear cells (MNC). Unfractionated MNC were cultured in complete Iscove's modified Dulbecco's medium (C-IMDM), composed of IMDM enriched with human transferrin, bovine insulin, bovine serum albumin, oleic acid, palmitic acid, linoleic acid, and fetal calf serum (FCS). Under these culture conditions, MNC from four donors synthesized mean quantities of IgE of 76 ng/ml at plateau after stimulation with rhIL-4 in concentrations ranging from 0.04 to 80 ng/ml (plateau rhIL-4 concentrations were 5 ng/ml or greater). In contrast, rhIL-4 failed to induce significant IgE synthesis at any of those doses of rhIL-4 in parallel MNC cultures performed in RPMI 1640 supplemented with FCS (RPMI 1640). Additional optimal conditions for the induction of IgE synthesis in this system were a MNC concentration of 1-2 X 10(6)/ml and a culture time of 18 days. Variability was noted in the amount of IgE produced by different donors (CV 0.22) and by the same donor when tested on different occasions (mean CV 0.21), but no donor's MNC failed to produce significant IgE in response to rhIL-4 when cultured in C-IMDM. The geometric mean IgE production induced by optimal IL-4 concentrations for the entire group of 16 subjects was 36.8 ng/ml IgE, with the lowest day 18 mean IgE concentration for any donor being 10.6 ng/ml and the highest 372.2 ng/ml. The enhanced rhIL-4-induced IgE synthesis supported by C-IMDM was due to the combined effects of the added enrichment factors and not to differences in the viabilities of MNC cultured in C-IMDM and RPMI 1640. This culture system will alleviate the problems of inconsistent and low quantities of IgE induced by IL-4 that confound most current culture systems used to examine rhIL-4-induced IgE synthesis. It will, thereby, facilitate further investigation of the regulation of human IgE synthesis.

Analysis of Variance↗