The inability of phosphatidylinositol 3-kinase activation to stimulate GLUT4 translocation indicates additional signaling pathways are required for insulin-stimulated glucose uptake

Recent experimental evidence has focused attention to the role of two molecules, insulin receptor substrate 1 (IRS-1) and phosphatidylinositol 3-kinase (PI3-kinase), in linking the insulin receptor to glucose uptake; IRS-1 knockout mice are insulin resistant, and pharmacological inhibitors of PI3-kinase block insulin-stimulated glucose uptake. To investigate the role of PI3-kinase and IRS-1 in insulin-stimulated glucose uptake we examined whether stimulation of insulin-sensitive cells with platelet-derived growth factor (PDGF) or with interleukin 4 (IL-4) stimulates glucose uptake; the activated PDGF receptor (PDGFR) directly binds and activates PI3-kinase, whereas the IL-4 receptor (IL-4R) activates PI3-kinase via IRS-1 or the IRS-1-related molecule 4PS. We found that stimulation of 3T3-L1 adipocytes with PDGF resulted in tyrosine phosphorylation of the PDGFR and activation of PI3-kinase in these cells. To examine whether IL-4 stimulates glucose uptake, L6 myoblasts were engineered to overexpress GLUT4 as well as both chains of the IL-4R (L6/IL-4R/GLUT4); when these L6/IL-4R/GLUT4 myoblasts were stimulated with IL-4, IRS-1 became tyrosine phosphorylated and associated with PI3-kinase. Although PDGF and IL-4 can activate PI3-kinase in the respective cell lines, they do not possess insulin's ability to stimulate glucose uptake and GLUT4 translocation to the plasma membrane. These findings indicate that activation of PI3-kinase is not sufficient to stimulate GLUT4 translocation to the plasma membrane. We postulate that activation of a second signaling pathway by insulin, distinct from PI3-kinase, is necessary for the stimulation of glucose uptake in insulin-sensitive cells.

Epiglottitis and Haemophilus influenzae immunization: the Pittsburgh experience--a five-year review

OBJECTIVE

Current trends in the clinical presentation and management of children with epiglottitis at Children's Hospital of Pittsburgh were reviewed for the years 1988 to 1993.

METHODOLOGY

The medical records of all patients diagnosed as having epiglottitis between July 1988 and June 1993 at the Children's Hospital of Pittsburgh were reviewed. An additional telephone survey was conducted among the primary care physicians of those patients to collect information regarding administration of Haemophilus influenzae type b (HIB) vaccines.

RESULTS

During the study period 28 children (age range, 11 months to 11 years, 10 months) were admitted with the diagnosis of epiglottitis. Cases declined remarkably in 1991. Fever, sore throat, and stridor were the usual symptoms. HIB was the most common cause of epiglottitis accounting for 21 cases. Candida albicans was recovered from the surface culture of the epiglottis in two patients. At least 11 children experienced vaccine failure: nine with polysaccharide vaccine and two with the conjugate vaccine for HIB.

CONCLUSION

Cases of epiglottitis have declined dramatically since licensure of HIB conjugate vaccines for use in early infancy. At least 52% of the reported cases represent vaccine failures with the purified polysaccharide vaccine.

Evidence for involvement of opioid receptors in ischemic preconditioning in rat hearts

The purpose of the present study was to investigate a possible role of opioid receptors in ischemic preconditioning (PC). To test this hypothesis, anesthetized, open-chest, male Wistar rats were subjected to five different protocols. In group I, the control group was subjected to 30 min of left coronary artery occlusion and 2 h of reperfusion. In group II, ischemic PC was elicited by three 5-min occlusion periods interspersed with 5 min of reperfusion. In group III, naloxone (NL, 3 mg/kg iv), a nonselective opioid antagonist, was given to nonpreconditioned rats 10 min before the 30-min occlusion period. Finally, NL was administered 10 min before preconditioning (NL + PC, group IV) or immediately after the last 5-min preconditioning period (PC + NL, group V). Infarct size (IS) as a percentage of the area at risk (AAR) (IS/AAR) was determined by 2,3,5-triphenyltetrazolium chloride staining. PC resulted in a marked reduction in myocardial IS from 45 +/- 5 to 8 +/- 1 (P < 0.05). NL treatment before or immediately after PC abolished this protective effect; however, NL had no effect on IS in non-PC rats. These results are the first to support the hypothesis that activation of opioid receptors may play an important role in ischemic PC in the rat myocardium.

Evidence for involvement of opioid receptors in ischemic preconditioning in rat hearts

The purpose of the present study was to investigate a possible role of opioid receptors in ischemic preconditioning (PC). To test this hypothesis, anesthetized, open-chest, male Wistar rats were subjected to five different protocols. In group I, the control group was subjected to 30 min of left coronary artery occlusion and 2 h of reperfusion. In group II, ischemic PC was elicited by three 5-min occlusion periods interspersed with 5 min of reperfusion. In group III, naloxone (NL, 3 mg/kg iv), a nonselective opioid antagonist, was given to nonpreconditioned rats 10 min before the 30-min occlusion period. Finally, NL was administered 10 min before preconditioning (NL + PC, group IV) or immediately after the last 5-min preconditioning period (PC + NL, group V). Infarct size (IS) as a percentage of the area at risk (AAR) (IS/AAR) was determined by 2,3,5-triphenyltetrazolium chloride staining. PC resulted in a marked reduction in myocardial IS from 45 +/- 5 to 8 +/- 1 (P < 0.05). NL treatment before or immediately after PC abolished this protective effect; however, NL had no effect on IS in non-PC rats. These results are the first to support the hypothesis that activation of opioid receptors may play an important role in ischemic PC in the rat myocardium.

Cladribine in the treatment of relapsed or refractory chronic lymphocytic leukemia

PURPOSE

Cladribine (2-CdA), a purine analog resistant to adenosine deaminase, has significant activity in a variety of lymphoproliferative diseases. This study was designed to determine the efficacy of 2-CdA in patients with relapsed or refractory chronic lymphocytic leukemia (CLL).

PATIENTS AND METHODS

Twenty-six patients aged 40 to 88 years (median, 64) who either had relapsed after an initial response or were refractory to conventional chemotherapy with at least an alkylating agent were treated with 2-CdA 0.1 mg/kg/d by continuous intravenous infusion for either 5 or 7 days every 28 days for a maximum of six cycles.

RESULTS

No complete remissions (CRs) occurred. Eight of 26 patients (31%) achieved a partial remission (PR). The actuarial median time to progression (TTF) in responding patients is 16 months (range, 6 to 22). The actuarial median survival duration of the responding patients is 12 months (range, 8 to 28). Eight of 26 patients (31%) sustained early toxicity. Seven of these eight patients died before the first reevaluation of infection (n = 3), pericardial tamponade (n = 1), Stevens-Johnson syndrome (n = 1), and stroke (n = 2). No nausea, emesis, alopecia, or renal, hepatic, or cardiac toxicity was observed.

CONCLUSION

2-CdA has activity in patients with relapsed or refractory CLL. However, patients who have received multiple prior regimens that included fludarabine are less likely to respond, and there can be significant morbidity. Treatment of patients with less prior therapy earlier in the natural history of the disease may lead to improved and more durable responses.

Association between GRB2/Sos and insulin receptor substrate 1 is not sufficient for activation of extracellular signal-regulated kinases by interleukin-4: implications for Ras activation by insulin

Insulin receptor substrate 1 (IRS-1) mediates the activation of a variety of signaling pathways by the insulin and insulin-like growth factor 1 receptors by serving as a docking protein for signaling molecules with SH2 domains. We and others have shown that in response to insulin stimulation IRS-1 binds GRB2/Sos and have proposed that this interaction is important in mediating Ras activation by the insulin receptor. Recently, it has been shown that the interleukin (IL)-4 receptor also phosphorylates IRS-1 and an IRS-1-related molecule, 4PS. Unlike insulin, however, IL-4 fails to activate Ras, extracellular signal-regulated kinases (ERKs), or mitogen-activated protein kinases. We have reconstituted the IL-4 receptor into an insulin-responsive L6 myoblast cell line and have shown that IRS-1 is tyrosine phosphorylated to similar degrees in response to insulin and IL-4 stimulation in this cell line. In agreement with previous findings, IL-4 failed to activate the ERKs in this cell line or to stimulate DNA synthesis, whereas the same responses were activated by insulin. Surprisingly, IL-4's failure to activate ERKs was not due to a failure to stimulate the association of tyrosine-phosphorylated IRS-1 with GRB2/Sos; the amounts of GRB2/Sos associated with IRS-1 were similar in insulin- and IL-4-stimulated cells. Moreover, the amounts of phosphatidylinositol 3-kinase activity associated with IRS-1 were similar in insulin- and IL-4-stimulated cells. In contrast to insulin, however, IL-4 failed to induce tyrosine phosphorylation of Shc or association of Shc with GRB2. Thus, ERK activation correlates with Shc tyrosine phosphorylation and formation of an Shc/GRB2 complex. Thus, ERK activation correlates with Shc tyrosine phosphorylation and formation of an Shc/GRB2 complex. Previous studies have indicated that activation of ERks in this cell line is dependent upon Ras since a dominant-negative Ras (Asn-17) blocks ERK activation by insulin. Our findings, taken in the context of previous work, suggest that binding of GRB2/Sos to Shc may be the predominant mechanism whereby insulin as well as cytokine receptors activate Ras.

Primary therapy of Waldenström's macroglobulinemia with 2-chlorodeoxyadenosine

PURPOSE

To assess the activity of 2-chlorodeoxyadenosine (2CdA) as primary therapy for patients with Waldenström's macroglobulinemia.

PATIENTS AND METHODS

2CdA was given to 26 consecutive, previously untreated and symptomatic patients with Waldenström's macroglobulinemia. Two courses were administered to outpatients at a dose of 0.1 mg/kg body weight per day for a 7-day continuous infusion using a portable pump through a central venous catheter. Responding patients were followed up without further therapy and were scheduled to receive two additional treatments with 2CdA on disease relapse.

RESULTS

Twenty-two of 26 patients responded to the 2CdA therapy (85%; 95% confidence interval [CI], 65% to 96%), including three patients who achieved a complete response and 19 patients who had a partial response. Treatment was well tolerated, with no acute hematologic toxicity. A marked and sustained reduction of CD4+ lymphocytes occurred in all patients and may have contributed to a fatal infection with disseminated herpes simplex in one patient. With a median follow-up of 13 months, five patients have relapsed and all re-treated patients have responded again to 2CdA.

CONCLUSION

2CdA is highly active in previously untreated patients with Waldenström's macroglobulinemia. A limited program of treatment induced responses of good quality and long duration in more than 80% of patients.

Prospective evaluation of internal adenopathy in a cohort of 43 patients with hairy cell leukemia

PURPOSE

To determine the role of computed tomography (CT) in patients with hairy cell leukemia (HCL), we report a series of 43 patients prospectively evaluated for internal adenopathy by CT before and after treatment with 2-chlorodeoxyadenosine (2-CdA).

PATIENTS AND METHODS

CT was performed on 43 consecutive patients with HCL before and 3 months after a single cycle of 2-CdA. Twenty-four patients were previously diagnosed and 19 were newly diagnosed. Adenopathy was considered bulky if the greatest dimension of any confluent mass was between 5 and 10 cm and massive if greater than 10 cm.

RESULTS

Internal adenopathy was present in six of 43 patients (14%). Three of the six patients had massive abdominal adenopathy and one had bulky abdominal adenopathy. All six patients with adenopathy were previously diagnosed, while none of the 19 newly diagnosed patients had internal adenopathy. In those patients previously diagnosed, the six with adenopathy had a median disease duration of 68 months, while the 18 patients without adenopathy had a median disease duration of 24 months (P = .01). Adenopathy was more common in splenectomized patients. In previously diagnosed patients, adenopathy occurred in five of 10 (50%) splenectomized patients and one of 14 (7%) nonsplenectomized patients (P = .05). However, the 10 splenectomized patients had a median disease duration of 56 months, while the 14 nonsplenectomized patients had a median disease duration of 16 months (P = .004). All six patients had significant reduction in adenopathy 3 months after 2-CdA and were without residual HCL in the bone marrow.

CONCLUSION

Significant internal adenopathy in patients with HCL is more frequent than previously recognized. Adenopathy is rare at diagnosis and appears to be related to disease duration. As patients treated with 2-CdA have long disease-free survival durations, detection of significant adenopathy by CT scan may be important; however, routine CT scans are not recommended at the time of diagnosis.

Sensorineural hearing loss from quinolinic acid: a neurotoxin in middle ear effusions

Quinolinic acid (QUIN) is an endogenous metabolite that exerts a neurotoxic effect by binding to specific neuronal receptors. Studies involving a broad spectrum of infectious and inflammatory central nervous system diseases have suggested a role for QUIN in causing neuronal injury. Since there is evidence for presence of the QUIN receptor in mammalian cochleas, QUIN was measured in middle ear effusions (MEEs). Gas chromatography/mass spectrometry detected QUIN in each of 65 diluted human MEEs, with a mean of 482 +/- 75 (SEM) nmol/L and a range from 15 to 2667 nmol/L. QUIN was also detected in each of 197 chinchilla MEEs from five different models of otitis media, with a mean of 10.6 +/- 1.3 (SEM) mumol/L and a range from 0.23 to 146.0 mumol/L (corrected for dilution). To determine whether QUIN causes sensorineural hearing loss (SNHL), QUIN solutions were placed on round window membranes (RWM) for 20 to 240 minutes, in 20 chinchillas. SNHL was detected by electrocochleography in QUIN-exposed animals, but not in saline controls. We conclude that QUIN is present in MEEs and that QUIN in the middle ear has the potential to cross the RWM and cause sensorineural hearing loss, possibly by binding to specific neuronal receptors in mammalian cochleas.

Very low maternal serum chorionic gonadotropin levels in association with fetal triploidy

OBJECTIVE

The objective of this study was to identify the parental origin of the extra haploid set of chromosomes in triploid pregnancies and to correlate the parental origin to very low levels of human chorionic gonadotropin and unconjugated estriol levels (multiple of the median < or = 0.20) and normal alpha-fetoprotein levels.

STUDY DESIGN

Three triploid pregnancies were ascertained retrospectively, and three pregnancies were identified prospectively. Maternal sera samples were analyzed for levels of alpha-fetoprotein, human chorionic gonadotropin, and unconjugated estriol. Deoxyribonucleic acid analysis was performed on parental bloods and fetal fibroblasts in two prospectively identified pregnancies to establish the parental origin of the extra set of chromosomes.

RESULTS

Levels of alpha-fetoprotein were normal in all pregnancies. Levels of human chorionic gonadotropin were very low in five of six of pregnancies, and unconjugated estriol levels were low in three of six pregnancies. Deoxyribonucleic acid analysis indicated maternal origin of the extra haploid set of chromosomes in two triploids.

CONCLUSION

When the extra haploid set of chromosomes are maternally derived, some triploid pregnancies exhibit very low levels of maternal serum human chorionic gonadotropin and unconjugated estriol with normal levels of alpha-fetoprotein.

Preparing high school students with learning disabilities for the transition to postsecondary education: teaching the skills of self-determination

Increasing numbers of students with learning disabilities (LD) are looking to postsecondary education and training to help them achieve success in career development and eventual job placement. Unfortunately, research suggests that many of these students are having difficulty staying in and completing postsecondary programs. A number of self-determination skills have been identified that are related to students' making a successful transition to postsecondary education. These include stating one's disability and its impact on school performance, and identifying instructional accommodations and strategies for arranging those accommodations with their regular classroom teachers. The purpose of this study was to examine whether these self-determination skills could be acquired through direct instruction, and subsequently generalized to general education classrooms. The results of the effectiveness of this self-determination training are reported and their implications for teachers, parents, and students discussed.

Clinical evaluation of M43: a novel cancer-associated mucin epitope

A monoclonal antibody to colon carcinoma mucin was found to react with a colon carcinoma-associated carbohydrate epitope. This antibody was used to develop a quantitative solid phase immunoassay, M43. We prospectively and retrospectively evaluated the assay in patients with and without gastrointestinal carcinoma and compared the sensitivity and specificity with that of carcinoembryonic antigen (CEA) and CA 19-9. One hundred ninety-two patients (181 with no evidence of malignancy) referred for upper or lower gastrointestinal endoscopy were prospectively studied. Sera from 172 patients with histologically confirmed gastrointestinal adenocarcinoma were retrospectively studied. Optimal discrimination cutoffs for M43 (5 units/ml), CEA (5 ng/ml), and CA 19-9 (30 units/ml) were determined by receiver operating characteristic curves analysis. M43 was positive in 112 of 151 patients with colorectal carcinoma (sensitivity 74%) and was negative in 167 of 181 patients without carcinoma (specificity 92%). Sensitivity and specificity were 77% and 93% for CEA and 60% and 83% for CA 19-9. Sixty-four % of 73 patients with colorectal carcinoma limited to the bowel wall had a positive M43 with a mean value of 178 units/ml. Eighty-one % of 27 patients with nonhepatic metastasis had a positive M43 with a mean value of 223 units/ml. Eighty-four % of 51 patients with hepatic metastasis had a positive M43 assay with a mean value of 2532 units/ml. Sensitivity in these three groups was 67%, 82%, and 82%, respectively, for CEA and 43%, 68%, and 79%, respectively, for CA 19-9. Of 38 carcinoma patients with a negative CEA, 45% had a positive M43. No correlation between the levels of M43 and CEA in patients with colorectal carcinoma was found. We conclude that M43 is positive in most patients with colorectal carcinoma, even in early stages. As a diagnostic test, its sensitivity and specificity are equivalent to those of CEA. However, the M43 assay is measuring a tumor antigen which is fundamentally different from CEA and which is present in a high percentage of CEA-negative patients.

A multicentre, double-blind, placebo-controlled trial of quinapril in mild, chronic heart failure

Angiotensin converting enzyme (ACE) inhibitors are of proven value in patients with severe chronic heart failure (CHF). Studies of the effects of ACE inhibitors on exercise capacity and quality of life in mild CHF have produced conflicting results. We have studied the effects of quinapril, a new ACE inhibitor with a relatively short plasma half-life, in mild CHF. Once daily (o.d.) dosing was compared with twice daily (b.i.d.) dosing in a three-way cross-over, double-blind, placebo-controlled trial. Thirty-two patients (two female), mean age 59 (range 32-76) years were enrolled in three cardiology centres in the U.K. in 29 patients, and non-ischaemic in three. The mean (range) radionuclide ejection fraction was 20.4% (8%-47%). Following full familiarization with the protocol, the treadmill exercise time (modified Bruce protocol) was determined for each patient during a placebo run-in phase, and at the end of each of three 8-week double-blind treatment phases with quinapril o.d., quinapril b.i.d. (maximal total daily dose 20 mg) and placebo. Three patients were withdrawn due to adverse events while receiving quinapril (unstable angina, exacerbation of CHF and arrhythmia); there were no deaths and no patient was withdrawn due to hypotension. Mean exercise time (the primary end-point) was 65 s and 53 s longer in patients receiving quinapril o.d. and b.i.d. respectively compared to placebo (both P < 0.01, ANOVA). There was no significant period effect during the trial and no significant difference between the two quinapril dosing regimens. Quinapril had no significant effect on secondary end-points including ejection fraction, functional class and quality of life.(ABSTRACT TRUNCATED AT 250 WORDS)

An association between fetal abdominal wall defects and elevated levels of human chorionic gonadotropin in mid-trimester

We analysed maternal serum human chorionic gonadotropin (hCG) in 16 pregnancies with fetal abdominal wall defects previously identified prenatally by elevated maternal serum alpha-fetoprotein (AFP) or at birth. The AFP levels had a mean of 6.38 MOM (range 0.34-15.65), as expected with these defects. The hCG levels had a mean of 1.82 MOM (range 0.23-4.11). The hCG levels in five pregnancies (31.25 per cent) were above 2.30 MOM. Elevated levels of hCG may be associated with fetal abdominal wall defects.

A single cycle of 2-chlorodeoxyadenosine results in complete remission in the majority of patients with hairy cell leukemia

Twenty-six patients with hairy cell leukemia (HCL) were treated with 2-chlorodeoxyadenosine (2-CdA), a purine analogue resistant to adenosine deaminase, at 0.1 mg/kg/d for 7 days by continuous intravenous infusion. Fifteen patients were previously untreated, while 11 patients had received prior treatment with splenectomy alone (three patients), interferon alpha alone (four), splenectomy, then interferon alpha (two), or splenectomy, interferon alpha, then 2-deoxycoformycin (2-DCF) (two). Sixteen (80%) of 20 patients evaluable at 3 months achieved complete remission (CR), and four (20%) achieved partial remission (PR) following a single cycle of therapy. All four patients in PR had complete recovery of their peripheral blood counts (except one patient whose platelet count remained 84,000/microL), but had residual HCL in the bone marrow (three patients) or residual splenomegaly (one). Patients with bulky adenopathy, massive splenomegaly, and severe pancytopenia responded as well as those with only modest marrow involvement. The three patients with residual marrow disease received a second cycle of 2-CdA, and two have attained CR. Therefore, 18 of 20 (90%) achieved CR with either one or two cycles of therapy. No patient achieving CR has relapsed at a median follow-up of 12 (+/- 2.1) months. Toxicities included myelosuppression and culture-negative fever. A community-acquired pneumonia was the only infectious complication. Since a single cycle of 2-CdA induces sustained CR in the vast majority of patients with minimal toxicity, this agent is emerging as the treatment of choice for all patients with HCL.

Congenital deficiency of alpha-fetoprotein

Although alpha-fetoprotein may play a role in fetal immune function or in maintenance of osmotic pressure, its exact function is unknown. We report two infants documented to have congenital deficiency of alpha-fetoprotein. One infant had cord blood levels less than 0.5 ng/ml. The second infant had a neonatal level of 120 ng/ml, which is about 2% of the usual concentration for a term newborn. These infants document the existence of congenital deficiency of serum alpha-fetoprotein. Because it is homologous to albumin, congenital deficiency of alpha-fetoprotein may be analogous to analbuminemia, a benign genetic trait.

Follow-up evaluation of cervicovaginal human papillomavirus infection in adolescents

We performed a second examination for human papillomavirus (HPV) DNA on 51 sexually experienced 13- to 21-year-old (mean = 17.8 years) female patients seen at an urban teaching hospital. Cervicovaginal lavages were performed 6 to 36 months apart (median = 13.3 months) to collect cells for HPV DNA detection and typing by Southern blot hybridization. At the first and second visits, 39.2% (20/51) and 25.5% (13/51) of patients, respectively, were infected with HPV. Collectively, 56.9% (29/51) of patients had at least one positive HPV test result. Although 7.8% (4/51) were infected with HPV at both visits, only one patient had infection with the same HPV type. These findings suggest that although HPV infection is a common sexually transmitted disease, genotype-specific HPV infection detected by Southern blot at two visits was rare.

Maternal serum alpha-fetoprotein, beta-human chorionic gonadotropin, and unconjugated estriol levels in midtrimester trisomy 18 pregnancies

OBJECTIVE

The purpose was to evaluate the levels of maternal serum human chorionic gonadotropin, alpha-fetoprotein, and unconjugated estriol in trisomy 18 pregnancies compared with normal singleton pregnancies.

STUDY DESIGN

Sera from 14 trisomy 18 pregnancies (13 retrospectively and one prospectively ascertained) were analyzed for human chorionic gonadotropin, alpha-fetoprotein, and unconjugated estriol.

RESULTS

The alpha-fetoprotein levels in the 10 trisomy 18 pregnancies without open neural tube or ventral wall defect had a median of 0.65 multiple of the median, although two had alpha-fetoprotein levels above 2.5 multiples of the median. The human chorionic gonadotropin levels had a median of 0.32 multiple of the median and the unconjugated estriol levels had a median of 0.56 multiple of the median. Although most women with trisomy 18 pregnancies had serum human chorionic gonadotropin levels that were less than 1.0 multiple of the median, three had markedly elevated human chorionic gonadotropin levels (greater than 5.0 multiples of the median).

CONCLUSION

Our data are partially consistent with those previously published but suggest the possibility of a bimodal distribution of alpha-fetoprotein and human chorionic gonadotropin levels in trisomy 18-affected pregnancies, unrelated to a neural tube or abdominal wall defect. The efficiency of screening for trisomy 18 prospectively, using the three serum markers, requires further evaluation.

Alpha-fetoprotein levels in normal adults

Alpha-fetoprotein (AFP) is a fetal specific glycoprotein normally produced primarily by the fetal liver. Normally, AFP levels decline rapidly after birth, reaching undetectable levels (less than 10 ng/ml) within several months after birth. The authors have developed a more sensitive radioimmunoassay, which has allowed them to study low levels of AFP in normal adults and to determine factors which may affect its normal level. Two hundred and seventy normal Houston blood donors were screened for the absence of hepatitis B and normal ALT levels. The mean AFP level was 3.04 ng/ml +/- 1.9 SD. There was a statistically significant higher level in men compared to women (p less than .004). Regression analysis demonstrated a statistically significant increase of AFP levels with age both in men (p less than .05) and in women (p less than .01). These data delineate the normal level of serum AFP in normal adults in the United States. With the normal level now defined, it becomes possible to compare levels in different populations including those exposed to hepatotoxins or hepatocarcinogens in the environment.