The level and species of plasma non-esterified fatty acids are not related to elevated plasma apolipoprotein B levels in familial combined hyperlipidemia.

Familial combined hyperlipidemia (FCHL), the leading cause of familial hyperlipidemia with premature coronary artery disease, has been associated with insulin resistance and elevated plasma levels of apolipoproten B (apoB) and non-esterified fatty acids (NEFA). Becaus dietary fats affect plasma cholesterol levels, and specific saturated fatty acids (FA) are particularly potent stimulators in vitro of apoB secretio from hepatocytes, we hypothesized that FCHL patients would exhibit elevations in plasma levels of total FA or specific saturated species. Five families containing 12 FCHL subjects (5 adults, 7 children and 8 normals (5 adults, 3 children) were assessed by dietary, anthropometric, and plasma measurements (glucose, insulin, lipoproteins, total NEFA, and specific FA types). After adjustment of the data for age, gender, and family affiliation, multivariate ANOVA indicated that FCHL was significantly associated with elevated plasma levels of apoB (p = 0.001) and insulin (p< 0.001) and increased body weight (p=0.043). Nevertheless, dietary intakes of total and saturated fat were comparable in the two groups, as were plasma levels of total NEFA and the major saturated species. In a study population possessing the salient features of FCHL, circulating total NEFA were not elevated, nor were specific saturated NEFA that had been associated with apoB oversecretion in vitro. Despite the speculated link between plasma FA and apoB overproduction in FCHL, our data suggest that other metabolic factors underlie this disease.

Age-related changes in cardiovascular disease risk factors of hypercholesterolemic children.

OBJECTIVE: To describe the age-related changes in cardiovascular disease risk factors in young, hypercholesterolemic (HC) children. METHODS: Hypercholesterolemic (n = 227) and nonhypercholesterolemic (NHC) (n = 80) children between the ages of 4 and 10 years were identified. Height, weight, skin-fold and blood pressure measurements, and total cholesterol levels were measured. The HC group also had insulin levels evaluated. The groups were compared by analysis of variance. Simple Spearman correlations evaluated the associations between factors within each group. RESULTS: The HC and NHC groups had similar mean ages, heights, and weights, both contained 51% girls, and all were white subjects. Percent weight-for-height median, and biceps, triceps, suprailiac and subscapular skin-fold measurements were all larger for the HC group. A significant age interaction demonstrated that the HC group's larger suprailiac and sum of skin-fold measures were expressed in the 8.0- to 9.9-year-old children, but not the 4.0- to 5.9-year-olds. For both groups, systolic blood pressure was associated with the measures of adiposity. For the HC group, insulin levels were also associated with adiposity. CONCLUSIONS: These results suggest that: (1) children with HC have greater body fat, (2) the expression of the hypercholesterolemia precedes the expression of increased body fat, (3) body fat increases with age, and (4) altered insulin and blood pressure levels are expressed in association with the increased body fat in children with HC. Confirmation with longitudinal data is necessary.

One-year follow-up of nutrition education for hypercholesterolemic children.

OBJECTIVES: This study evaluated retention of the effect of a home-based, practitioner-initiated nutrition education model. METHODS: Children with elevated low-density lipoprotein (LDL) cholesterol levels were randomly assigned to one of two nutrition interventions or to an at-risk control group. Intervention effects were evaluated 3, 6, and 12 months postbaseline. RESULTS: The parent-child autotutorial group demonstrated significant increases in knowledge and, along with the counseling group, decreases in total and saturated fat intake. Also, the autotutorial and counseling groups retained a majority of their initial LDL cholesterol decrease. CONCLUSIONS: Knowledge of heart-healthful eating and dietary fat intake as well as dietary change can be affected and retained via home-based, practitioner-initiated nutrition interventions with hypercholesterolemic children, although some form of ongoing intervention may be necessary to produce lasting decreases in LDL cholesterol levels.

Effects of family history of heart disease, apolipoprotein E phenotype, and lipoprotein(a) on the response of children's plasma lipids to change in dietary lipids.

We examined the effects of family history of coronary artery disease (CAD), apolipoprotein E (apo E) phenotype, and lipoprotein(a) [Lp(a)] on the response of plasma lipids to change in dietary lipid intake after 3 mo of nutrition education in 125 children aged 4-10 y. The subjects were healthy children with elevated low-density-lipoprotein (LDL)-cholesterol concentrations who participated in the Children's Health Project, a nutrition-education program designed to lower plasma cholesterol by means of dietary modifications in accordance with recommendations of the National Cholesterol Education Program. Dietary and plasma lipids were measured by three 24-h recalls and assessments of two fasting plasma samples collected before and 3 mo after the start of intervention. Family history of CAD was determined by questionnaires administered to parents at baseline. Apo E phenotyping was done with isoelectric focusing followed by immunostaining; Lp(a) was measured with two-site immunoradiometric assays of frozen aliquots of plasma samples collected at baseline and 3 mo. After adjustment for intervention group, age, sex, and body mass index, analysis of covariance showed that baseline plasma lipid concentrations were the strongest independent predictors of change in plasma lipids after 3 mo. Plasma total and LDL-cholesterol concentrations in children with less family history of CAD were significantly more responsive to change in dietary cholesterol than concentrations in children with a stronger family history of CAD. Neither apo E phenotype nor Lp(a) significantly influenced change in plasma lipids independently or interactively with change in dietary lipids.

Kinetics of retinyl esters during postprandial lipemia in man: a compartmental model.

Orally ingested vitamin A (retinol) is incorporated into intestinal chylomicrons (CHYLO) in the form of retinyl esters (RE) along with newly absorbed dietary triglycerides (TG). As the intestinal lipoproteins undergo hydrolysis in the circulation, the majority of the RE remain with the secreted intestinal particles and have been used as a marker for intestinally derived lipoproteins during the early phase of the postprandial state. A multicompartmental model was developed for the kinetics of RE during postprandial lipemia in individuals with normal lipid levels (n = 16) and in patients with hyperlipidemia (n = 44). The assumptions used in the development of the model are presented in this report. Some of the key findings include (1) as much as 50% of the newly synthesized RE may be secreted by the intestine as very-low-density lipoprotein (VLDL)-sized particles of S(f) 20 to 400 following consumption of a test meal containing a moderate amount of fat (20 to 30 g); (2) in most individuals, approximately 50% of the RE secreted in S(f) greater than 400 are converted to smaller, less buoyant fractions, and 50% are irreversibly removed directly from the plasma; (3) as much as 5% to 20% of the ingested retinol may be secreted as small intestinal lipoproteins with the buoyance of low-density lipoprotein (LDL) in some individuals; and (4) less than 5% of RE flux through S(f) 20 to 400 is converted to S(f) less than 20, and the primary catabolic pathway for RE in this fraction is direct uptake. Comparable estimates can be obtained for the kinetic parameters when repeat studies are made in the same subjects under comparable conditions.

Met-HGF/SF: tumorigenesis, invasion and metastasis.

Hepatocyte growth factor/scatter factor (HGF/SF) is synthesized by mesenchymal cells and is a paracrine effector of cells, predominantly epithelial, that express the Met tyrosine kinase receptor. We have demonstrated that autocrine Met-HGF/SF expression in mouse fibroblasts results in transformation and tumorigenesis. HGF/SF-treated cells expressing Met can respond in a variety of ways: mitogenically, by scattering (motility), and by forming branching tubules in gel matrices (branching morphogenesis). HGF/SF also induces in vitro invasiveness and is angiogenic in in vivo assays. A human cell line and several mouse cell lines that we have constructed to express Met-HGF/SF in an autocrine fashion are tumorigenic, invasive and metastatic in athymic nude mice. Thus, the very complex process of invasion and metastasis can be mediated by a ligand-receptor signalling pathway, and the cell lines we have developed provide important model systems for identifying the signalling molecules that mediate these phenotypes: For example Met-HGF/SF signalling activates the urokinase plasminogen proteolysis network, thus coupling this signal transduction pathway to the proteases that mediate dissolution of the extracellular matrix. Branching morphogenesis, mediated by Met-HGF/SF signalling, is dependent on this process, as well as the formation of cell-cell junctions and interaction with the extracellular matrix. We have proposed a hypothesis for the role of Met and downstream signalling molecules in generating normal ducts and lumenal structures, as well as a model for how interruption of this signalling leads to abnormal malignant progression. Is Met involved in human cancer? Human sarcomas often inappropriately express Met, suggesting that it is an important oncogene in these cancers, and an increasing number of reports have implicated Met-HGF/SF signalling in a variety of human cancers.

The influence of age and relative weight on the presentation of familial combined hyperlipidemia in childhood.

BACKGROUND: Familial combined hyperlipidemia (FCHL) has been described as the leading cause of familial hyperlipidemia. FCHL is dominantly inherited, occurs in at least 1% of the population, and is responsible for about 10% of premature coronary artery disease (CAD). OBJECTIVE: Because FCHL in childhood is not well characterized, we evaluated the interrelationships among age, percentage of ideal body weight (%IBW) and plasma lipoprotein levels in FCHL children (age 2-18 years), exploring the possibility that obesity and age may influence the presentation of FCHL in childhood. METHODS: One hundred and eighty-nine children with FCHL were studied. Significant correlations within this group were further evaluated by examining a subset of 36 FCHL children, each of whom had an unaffected sibling who could serve as a control for comparison. RESULTS: When the full group was divided into those with TG levels > 90% and those with TG levels < 90%, the correlation with %IBW was stronger in the former (r = 0.45, P < 0.005) as compared with the latter (r = 0.25, P = 0.05). Within the subset of 36 FCHL children and their 36 unaffected siblings (controls), age and sex distributions were similar. Percentage IBW (mean +/- S.D.) (117.3 +/- 29.1 for FCHL and 111.2 +/- 19.4 for controls) was similar and in the overweight range. FCHL children had significantly higher levels of total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), apolipoprotein B (apo B) and triglyceride (TG) levels compared with controls (P < 0.0005 for all comparisons). Of several significant correlations observed in the full group (n = 189), only the correlations of %IBW with plasma TG levels (r = 0.45, P = 0.006), and of age with plasma TG levels (r = 0.48, P = 0.003) persisted with a similar degree of magnitude in the subset of 36 FCHL children. No correlation was significant in the controls. By Fisher's Z-test, the correlation between %IBW and TG in the FCHL children was significantly different from controls. CONCLUSIONS: These results suggest that TG levels in FCHL children, but not in their unaffected siblings, and sensitive to the presence of obesity, implying an interaction between obesity and the underlying condition, in addition, the association between age and TG level in FCHL children suggests a gradual expression of the hyperlipidermia (i.e. TG) during childhood.

A 5' splice-region mutation and a dinucleotide deletion in the lysosomal acid lipase gene in two patients with cholesteryl ester storage disease.

Cholesteryl ester storage disease (CESD) results from inherited deficiencies of the lysosomal hydrolase, acid lipase (LAL; E.C. 3.1.1.13). To establish the molecular defects in LAL deficiency, two unrelated probands with severely reduced LAL activity were examined. DNA amplification by reverse-transcription polymerase chain reaction and subsequent sequence analysis of LAL cDNA identified two mutant alleles. Patient 1, presenting with hepatosplenomegaly, mildly elevated liver function tests, and hyperlipidemia, was homozygous for a deletion of nucleotides 823 to 894 of the LAL cDNA. This 72-bp deletion maintained the reading frame and resulted in a loss of 24 amino acids from the LAL protein. Analysis of genomic DNA revealed that the 72 bp corresponded to an exon of the LAL gene. A single G to A point mutation at the last exon position was observed in the genomic DNA of patient 1, indicating a splicing defect with consecutive exon skipping underlying the 72-bp deletion. Patient 2 was a compound heterozygote for the 72-bp deletion and a dinucleotide deletion at positions 967 and 968. This deletion resulted in a shifted reading frame carboxyterminal of codon 296, and 43 random amino acids followed the frame shift. A premature stop at codon 339 truncated the mutant LAL protein by 34 amino acids. Allele-specific hybridization confirmed that patient 1 was homozygous for the 72-bp deletion mutation, and that patient 2 was a compound heterozygote for the 72-bp deletion and the 2-bp deletion.

The Met-HGF/SF autocrine signaling mechanism is involved in sarcomagenesis.

Hepatocyte growth factor/scatter factor (HGF/SF) can elicit a wide variety of effects upon cells expressing its receptor, the tyrosine kinase proto-oncogene product Met, including mitogenicity, motility, and morphogenesis. Normally, met expression is restricted to epithelial cells and is activated in a paracrine fashion by HGF/SF secreted from cells of mesenchymal origin. In this chapter, we review data showing that: (i) met over-expression in HGF/SF-expressing NIH/3T3 fibroblasts leads to sarcomagenesis and metastasis via an autocrine mechanism; (ii) Met-HGF/SF autocrine signalling occurs to a low level in normal fibroblasts and to a much greater extent in human sarcomas and sarcoma cell lines; (iii) met expression is enhanced as p53-deficient fibroblasts are passaged in vitro and (iv) met and HGF/SF over-expression are selected for during tumorigenesis of p53-deficient late-passage fibroblasts. Thus, loss of p53 predisposes a mesenchymal cell to over-express met and high level Met-HGF/SF autocrine signaling in mesenchymal cells promotes both sarcomagenesis and metastasis through inappropriate induction of the pleiotropic responses to Met-HGF/SF stimulation.

Reduction of elevated LDL-cholesterol levels of 4- to 10-year-old children through home-based dietary education.

OBJECTIVE: To assess the effects of a home-based, parent-child autotutorial (PCAT) dietary education program on the dietary knowledge, lipid consumption, and plasma low density lipoprotein-cholesterol (LDL-C) of 4- to 10-year-old children with elevated plasma LDL-C. METHODS: "At-risk" children (screening total cholesterol, (TC), exceeded 4.55 mmol/L and average LDL-C from two fasting samples was between 2.77 and 4.24 mmol/L for boys or 2.90 and 4.24 mmol/L for girls) were randomized to the PCAT program (N = 88), for dietary counseling with a registered dietitian (N = 86), or to an at-risk control group (N = 87). Dietary knowledge, diet, and LDL-C of these groups were assessed at baseline and after the educational period (3-month follow-up). The knowledge and diet of a not-at-risk (TC below 4.22 and 4.34 mmol/L for boys and girls, respectively) control group (N = 81) was also assessed and compared with that of the at-risk control group. RESULTS: At the 3-month follow-up, the PCAT children's knowledge scores had increased three times more than those of the counseling and at-risk control groups (P < .001). Mean grams of total and saturated fat consumed by PCAT and counseling groups declined while that of the at-risk control group increased slightly; these differences were significant (P < .05). The mean LDL-C decline of the PCAT group was significantly different (P < .05) from the decline of the at-risk control group (0.26 vs 0.09 mmol/L), and approached significance (P = .07) when compared with that of the counseling group (0.26 vs 0.11 mmol/L). The at-risk control group's knowledge and diet did not differ from that of the not-at-risk group. CONCLUSION: The PCAT program offers a mechanism for providing effective dietary education to children with elevated cholesterol and to their families.

Familial combined hyperlipidemia in children: clinical expression, metabolic defects, and management.

The first evidence that elevation of plasma levels of cholesterol is a risk factor for the development of atherosclerosis in children came from the Bogalusa Heart Study in 1986, which reported an association between aortic fatty streaks in 3- to 26-year-old subjects and increased plasma levels of low-density lipoprotein cholesterol (LDL-C). The most compelling evidence of a cause-and-effect relationship has come from the multicenter cooperative study called the Pathobiological Determinants of Atherosclerosis in Youth. When the investigators examined the abdominal aorta and the right coronary artery of adolescents and young adults who had died of trauma, they found a significant relationship between the sum of the very low density lipoprotein (VLDL) plus LDL-C level and both fatty streaks and raised atherosclerotic lesions. They also found an inverse relationship between those lesions and increased high-density lipoprotein cholesterol (HDL-C) levels. In addition, their studies showed that smoking (as assessed by the serum thiocyanate level) promotes atherogenesis in children as young as age 15 years. Thus many pediatricians have now accepted the importance of identifying children with significant hypercholesterolemia so that appropriate dietary and life-style modifications can be recommended. This is especially important because there is often a major genetic component to the hyperlipidemia seen in children.

Familial combined hyperlipidemia in children: clinical expression, metabolic defects, and management.

Familial combined hyperlipidemia (FCHL) is a dominantly inherited hyperlipidemia that occurs in at least 1% of the adult population and is responsible for 10% of premature coronary artery disease. In families referred for evaluation because of primary hyperlipidemia in a child, FCHL is expressed three times more commonly than familial hypercholesterolemia and half of the siblings are affected. Several metabolic defects apparently are associated with the FCHL phenotype. Most commonly, excess production of very low density lipoprotein apolipoprotein B can be demonstrated. In other families, reduced lipoprotein lipase activity is associated. One allele at a locus influencing apolipoprotein B levels predicts FCHL in a large proportion of families ascertained through affected children. Whether this allele is responsible for the excess of very low density lipoprotein apolipoprotein B detected in metabolic studies has not been elucidated. Management of FCHL in children begins with dietary modification. A bile acid sequestrant may be considered as well if diet cannot reduce the plasma low-density lipoprotein cholesterol level to less than 4.13 mmol/L (160 mg/dl) after the age of 10 years. Although the hydroxymethylglutaryl-coenzyme A reductase inhibitors are not currently recommended for children younger than 19 years of age, we speculate that they will be increasingly utilized for the management of FCHL in teenage boys who continue to have low density lipoprotein cholesterol levels greater than 4.13 mmol/L (160 mg/dl) after dietary modification.

An inhibitory Raf-1 mutant suppresses expression of a subset of v-raf-activated genes.

The proto-oncogene Raf-1 is a cytoplasmic serine/threonine kinase implicated in the signaling process in cell proliferation. To determine if Raf-1 is sufficient and necessary to transmit mitogenic signals to growth-responsive genes, we examined the effect of constitutively activated (v-raf) or inhibitory (Raf-C4) Raf-1 proteins on reporter gene activation in transient expression assays of NIH 3T3 cells. In serum-starved cells, v-raf strongly activated transcription from the promoters of the immediate-early genes c-fos and egr-2, as well as the proximal or B promoter of the late growth response gene rep-3 (rep-3b). Two other late response gene promoters, cad and dhfr, were only modestly activated by v-raf, however. An individual serum response element from the c-fos or egr-2 promoter conferred both serum-inducibility and v-raf-responsiveness to a heterologous promoter. Consistent with the degree to which antisense c-raf-1 RNA and dominant-negative Raf-1 proteins interfere with NIH 3T3 cell proliferation, Raf-C4 reduced serum-induced transcription from the egr-2 and rep-3b promoters in a dose-dependent manner by 50%. In contrast, Raf-C4 did not significantly reduce transcription from the c-fos or cad promoters or the serum response element-driven heterologous promoters. We conclude that Raf-1 is both sufficient and necessary to activate a subset of early and late growth response genes.

A quality assurance program for the measurement of capillary blood cholesterol levels in private pediatric practices. The Children's Health Project.

OBJECTIVE: To develop an easy to use quality assurance program for the measurement of capillary blood cholesterol levels in private pediatric practices. The program needed to comply with the guidelines laid down by the National Cholesterol Education Program. DESIGN: Intervention study. SETTING: Nine private pediatric practices in and around northern Philadelphia, Pa. PARTICIPANTS: The analysts included clinic staff members with laboratory expertise ranging from none to some previous experience. None of the participants had previous experience with a quality assurance program. INTERVENTIONS: Progress was reported monthly to the Lipid Research Laboratory, Philadelphia, and action was taken to correct inaccuracies in bias or variance. MAIN OUTCOME MEASURE: Compliance with the analytical guidelines laid down by the National Cholesterol Education Program in that the coefficient of variation was no greater than 5% and the bias was no greater than +/- 5% in the first year of the study. RESULTS: Within the first year of the study, there were 152 monthly quality assurance returns for each of two lyophilized control materials. On four occasions the coefficient of variation was greater than 5% while the overall bias was within the desired +/- 5% on 143 (94%) of 152 occasions. After the first 3 months of the study, as user confidence increased, intervention by the Lipid Research Laboratory became minimal. The internal quality assurance was further evaluated by a successful performance in a quarterly external quality assurance program. CONCLUSIONS: It is possible to devise an easy to use quality assurance program for extra laboratory measurement of cholesterol levels in children, and, with minimal assistance, maintain acceptable standards of cholesterol analysis. The quality assurance improved following the first 3 months of training and education. Subsequent continuous quality improvement was maintained with minimal involvement of the specialist center. Should the controversial issue of private office measurement of blood cholesterol levels become universally acceptable, the implication from our study is that standards acceptable to the National Cholesterol Education Program and the Clinical Laboratory Improvement Amendments of 1988 are possible using a suitable quality assurance program.

Use of cholestyramine in the treatment of children with familial combined hyperlipidemia.

We studied the effectiveness of and compliance with the use of cholestyramine in children with heterozygous familial hypercholesterolemia (FH) and familial combined hyperlipidemia (FCHL). During a 10-year period, 673 children (aged 10.5 +/- 4.0 years) were referred for evaluation of hyperlipidemia, of whom 87 (36 with FH; 51 with FCHL) were treated with cholestyramine (8 to 24 gm/day). In both groups, total cholesterol, low-density lipoprotein (LDL)-cholesterol, and apolipoprotein B levels were significantly reduced after cholestyramine use. In those with FH, plasma LDL-cholesterol levels decreased from 258 +/- 35 mg/dl (6.67 +/- 0.90 mmol/L) to 190 +/- 31 mg/dl (4.91 +/- 0.80 mmol/L); in those with FCHL, LDL-cholesterol levels dropped from 207 +/- 40 mg/dl (5.35 +/- 1.03 mmol/L) to 141 +/- 35 mg/dl (3.64 +/- 0.90 mmol/L). High-density lipoprotein-cholesterol levels were not significantly changed after cholestyramine use in either group. In the FCHL group, plasma triglyceride levels increased significantly from 81 +/- 35 mg/dl (0.92 +/- 0.40 mmol/L) to 134 +/- 42 mg/dl (1.52 +/- 0.48 mmol/L). Seven patients were lost to follow-up; 18 discontinued the medication within 1 month. Of the remaining 62 children, 59 had a good response to the drug. Of the 62 patients, 52 discontinued the medication after 21.9 +/- 10 months. Adverse effects included foul taste (73%), nausea with bloating (18%), and constipation. Cholestyramine is effective in reducing LDL-cholesterol levels in children with inherited hyperlipidemia, but the majority of children will not comply with its long-term use.

Genotype at a major locus with large effects on apolipoprotein B levels predicts familial combined hyperlipidemia.

A sample enriched for familial combined hyperlipidemia (FCHL) was examined for evidence of an association between genotype at an apolipoprotein B (apoB) elevating locus defined by complex segregation analysis and FCHL. Complex segregation analysis detected a locus with a large effect on plasma apoB levels and was used to compute the most probable genotype of family members. None of the 35 normolipidemic adults carried a copy of the allele associated with elevated apoB levels, yet 58% of the 109 adults with FCHL carried 1 (29%) or 2 (28%) copies. Two of 28 (7%) normal children had 1 copy of this allele and none had 2 copies, while 88 of 182 (48%) children with FCHL had 1 (26%) or 2 (22%) copies. Further, 41 of 48 (85%) individuals classified as having hyperapobetalipoproteinemia did not carry a copy of this "elevated apoB" allele. Therefore, the presence of the allele associated with elevation of apoB level is highly predictive of FCHL and this association cannot be explained solely by the presence of elevated apoB levels in FCHL, suggesting that the locus controlling apoB levels may play an etiologic role in FCHL.

The effect of lovastatin on very low-density lipoprotein apolipoprotein B production by the liver in familial combined hyperlipidaemia.

Overproduction of very low-density lipoprotein apolipoprotein B by the liver is a metabolic marker for familial combined hyperlipidaemia, a common inherited disorder of lipoprotein metabolism. Four subjects with familial combined hyperlipidaemia had rates of apolipoprotein B production which were 2-7 times normal, using a protocol in which [15N]glycine was used to label newly synthesized hepatic proteins. Following 4-6 months of therapy with lovastatin, very low-density lipoprotein apolipoprotein B production in all four subjects had returned to the normal range. This demonstrates that lovastatin, an inhibitor of cholesterol biosynthesis, acts also to reduce the apparent production rate of apolipoprotein B by the liver.

krox 20 messenger RNA and protein expression in the adult central nervous system.

krox 20 is an inducible immediate early response gene. To determine if krox 20 has a physiological role in the adult central nervous system (CNS), this study sought to demonstrate the presence of krox 20 in adult rat brain. RNA analysis showed the presence of krox 20 transcripts in the CNS, including the cortex. Polyclonal antibodies to a Krox 20 fusion protein demonstrated 79 and 55 kDa antigens in nuclear CNS homogenates. Neither RNA nor protein analysis was able to demonstrate an induction of krox 20 by a seizure at times when other immediate early response genes are known to be induced. Immunohistochemical analysis revealed staining at several levels throughout the nervous system. This staining was predominantly nuclear, consistent with the role of krox 20 as a transcription factor. These data show that krox 20 is present in the adult CNS, yet differs in response to stimuli as compared to other related transcription factors with a zinc finger motif, such as NGFI-A and NGFI-C.