Route-specific cellular expression of cytochrome P4501A (CYP1A) in fish (Fundulus heteroclitus) following exposure to aqueous and dietary benzo[a]pyrene.

Mummichog (Fundulus heteroclitus), an estuarine, teleost fish, were exposed for 456 hr to environmentally relevant concentrations of aqueous (10 micrograms/liter) and dietary (10 micrograms/g) benzo[a]pyrene (BP) in static renewal aquaria. Cellular expression of BP-inducible cytochrome P4501A (CYP1A) was evaluated several times during exposure by immunohistochemistry in longitudinal histologic sections of whole fish. CYP1A-associated staining intensities in tissues were scored by a subjective rating system similar to that used previously for qualitative information. Exposure to aqueous BP resulted in high levels of CYP1A-associated immunohistochemical staining in gill pillar cells, heart endothelium, and vascular endothelium. Exposure to dietary BP resulted in only mild to moderate staining in these tissues but high-intensity staining in gut mucosal epithelium. CYP1A induction in hepatocytes appeared most sensitive to aqueous exposure. Route-specific patterns of CYP1A expression were also observed in other cells including gill epithelia, pseudobranch, and skin. Expression of CYP1A in renal tubules and interrenal tissues was not affected by either treatment. Coexposure to both aqueous and dietary BP resulted in a pattern of induction reflecting both routes of exposure. In addition to the subjective rating system for scoring CYP1A expression, we developed a photometric approach that was used to obtain quantitative data on CYP1A-associated staining intensity. Photometric values of CYP1A staining intensity revealed patterns essentially the same as those observed during subjective ranking but were amenable to statistical analysis. The results of this study support the use of tissue-specific patterns of CYP1A expression in identification of target sites and exposure routes for polycyclic aromatic hydrocarbons and other compounds.

Role of interleukin 6 in the growth of myeloma-derived cell lines.

The role of interleukin 6 (IL-6) in the growth of five multiple myeloma-derived cell lines was characterized. The U266 and RPMI 8226 cell lines demonstrated increased DNA synthesis when cultured with exogenous IL-6, expressed IL-6 cell surface receptors (IL-6Rs) and expressed mRNA for IL-6R. However, these cells did not secrete detectable IL-6 protein, and a neutralizing antibody to IL-6 did not inhibit their growth. Three other myeloma-derived cell lines ARH-77, IM-9 and HS-Sultan did not respond to exogenous IL-6, secrete IL-6 or express cell surface IL-6Rs. The IL-6 responsive cell lines bore late B-cell surface antigens (Ags), CD38 and PCA-1, whereas those lines which were non-IL-6 responsive strongly expressed B1 (CD20) and B4 (CD19) Ags, representing earlier stages in B-cell differentiation. Finally, the two IL-6 responsive cell lines did not express Epstein-Barr virus (EBV) proteins; in contrast, EBV encoded proteins typically expressed during latency could be detected in the three non-IL-6 responsive lines, confirming infection with virus. These studies clarify the heterogeneity observed in the myeloma cell line phenotype and biology and suggest that the U266 and RPMI 8226 cell lines, which express IL-6 cell surface receptors and are IL-6 responsive, may be useful for further study of IL-6 signal transduction in and related IL-6 mediated growth of myeloma in vivo. In contrast, those cell lines which are IL-6-independent provide a model for further study of EBV transformation and IL-6-dependent growth mechanisms in malignancy.

Emergence of motor and vocal tics during imipramine administration in two children.

ABSTRACT Two children with major depression experienced the emergence of motor and vocal tics after 2-3 weeks on imipramine at doses of 75-100 mg daily. The tics did not show any sign of subsiding for 9-10 days following the discontinuation of imipramine, but subsequently responded to treatment with haloperidol. Case 1 involved an 8-year-old child with depression, attention-deficit hyperactivity disorder (ADHD), other behavioral problems, and a history of a single febrile seizure. His family history was positive for tics, depression, anxiety, and seizures. He was found to have a toxic plasma level of the tricyclic antidepressant. Case 2 involved a 13-year-old child with depression, ADHD, behavioral problems, obsessive compulsive symptoms, intellectual deficit, developmental delays, grand mal seizures, and concomitant use of phenytoin. The child had previously developed tics while receiving methylphenidate. The family history was positive for tics, depression, obsessive compulsive symptoms, suicide, and alcohol abuse. The child had a subtherapeutic plasma level of the antidepressant. It is suggested that tricyclic antidepressants may precipitate tics consistent with the symptoms of Tourette's syndrome in genetically vulnerable children. Although this possibility has been suggested in the literature, these are the first two documented cases of this phenomenon. Speculating from these two cases, ADHD may be a risk factor for the appearance of imipramine-induced tic symptoms in depressed children.

Response patterns of hairy cell leukemia to B-cell mitogens and growth factors.

The effect of mitogens and/or recombinant B-cell growth factors (M/GFs) on the in vitro growth of hairy cells was examined. Tumor cells were isolated from the spleens of four patients with hairy cell leukemia (HCL) by Ficoll-Hypaque sedimentation and E-rosetting. Enrichment for tumor cells was confirmed with intracytoplasmic immunoglobulin (Ig) staining, tartrate resistant acid phosphatase (TRAP) staining, and staining using monoclonal antibodies (MoAbs) directed at B, T, myeloid, and monocytoid antigens (Ags) in indirect immunofluorescence assays. Tumor cells were B1(CD20)+ B2(CD21)- B4(CD19)+ IL-2R(CD25)+ PCA-1 +/- TRAP+. HCLs neither synthesized DNA nor secreted Ig in response to culture with granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-1 alpha (IL-1 alpha), IL-1 beta, IL-2, IL-3, IL-4, IL-5, or IL-6. However, a proliferative response (stimulation index greater than or equal to 3.0) without Ig secretion was triggered in HCLs by mitogens or combinations of GFs. Specifically, DNA synthesis was induced at 3 days in three of four HCL samples cultured with Staphylococcus aureus Cowan A (SAC) or the combination of phorbol ester (TPA) and the calcium ionophore A 23187 (Ca2+); DNA synthesis was triggered later (day 7) by tumor necrosis factor (TNF) or by IL-4 and IL-5. In contrast, the fourth patient, a nonresponder to SAC or TPA/Ca2+, demonstrated increased DNA synthesis at day 3 when cocultured with IL-4 and IL-5. Both autoradiography and staining with antibromodeoxyuridine (BrdU) MoAb conjugated to fluorescein confirmed DNA synthesis by only a minority (5% to 23%) of tumor cells within each patient. Dual staining confirmed that responsive cells were both BrdU+ and TRAP+. DNA synthesis induced by TPA/Ca2+ was blocked specifically by anti-IL-6 Ab; in contrast, the HCL proliferative response to SAC, TNF, or IL-4 and IL-5 was not inhibited by anti-IL-6 Ab. alpha-Interferon inhibited the response to TPA/Ca2+, TNF, or IL-4 and IL-5 without any effect on response to SAC. Finally, peroxidase-antiperoxidase staining demonstrated that HCLs are induced by TPA/Ca2+, but not by SAC, to produce intracytoplasmic IL-6. These data demonstrate IL-4, IL-5, and IL-6 mediated DNA synthesis by HCLs in vitro and suggest a possible in vivo role for these growth factors in the pathophysiology of HCL.

Steady-state nonlinear pharmacokinetics of 5-fluorouracil during hepatic arterial and intravenous infusions in cancer patients.

Hepatic arterial catheters were placed for therapy in 8 patients with primary or metastatic liver cancer. Temporary hepatic venous catheters allowed direct sampling of blood for hepatic venous drug concentrations. Patients were administered from three to six infusions at rates of 10, 30, 90, 135, 180, 210, and 270 mg/kg/day (0.053 to 1.43 microM/kg/min), given over 2 h, of 5-fluorouracil (FUra). In Method 1, FUra was infused i.v., and FUra was measured in plasma from hepatic arterial and hepatic venous blood. In Method 2, FUra was given i.v. at one time and infused into hepatic arterial blood at another time, and FUra was measured in plasma from peripheral blood at the same site in both cases. Steady-state FUra plasma concentrations were measured by a sensitive and specific high-performance liquid chromatography method. Data were computer fitted to the equations appropriate for a physiological two-compartment flow model with Michaelis-Menten elimination from the peripheral compartment and blood flow rate, Q, between the central and peripheral compartment. Methods 1 and 2 gave mean Vmax and Km values which did not differ significantly; the overall mean Vmax was 2.02 microM/kg/min, and the overall mean Km was 10.9 microM. For Method 1 the mean Q1 value was 0.0803 liters/(kg X min) or 5.26 liters/min, which is the same as cardiac output, but for Method 2 the mean Q2 value was higher, namely 0.189 liters/(kg X min) or 13.0 liters/min. Steady-state systemic and intrinsic clearances and extraction ratios decreased progressively as the dose rate increased. Intra- and inter-subject variation of both Vmax and Km were of the same order of magnitude. As a result, dose rate escalation should be conservative for dose rates above 135 mg/kg/day. The results support hepatic arterial infusion as a means of improving the therapeutic index of FUra in the treatment of cancer of the liver.