SarCNU, a nitrosourea analog on a day 1, 5, and 9 oral schedule: a phase I and pharmacokinetic study in patients with advanced solid tumors

PURPOSE

2-Chloroethyl-3-sarcosinamide-1-nitrosourea (SarCNU) is a novel chloroethylnitrosourea that demonstrates selective cytotoxicity in athymic mice bearing human glioma. SarCNU demonstrates selective cytotoxicity in vitro against human glioma at least in part because of the selective SarCNU uptake by the extraneuronal monoamine transporter. The purpose of this phase I study was to determine the maximum-tolerated dose (MTD), the toxicity profile, the pharmacokinetics profile, and recommended phase II dose.

PATIENTS AND METHODS

Forty-three eligible patients with advanced solid tumors were enrolled. SarCNU was administered orally on days 1,5, and 9 every 28 days. The dose ranged from 30 to 1,075 mg/m2. Pharmacokinetic evaluation was done on the first cycle (one dose was given intravenously on day 1 or 5 of the first cycle to determine bioavailability).

RESULTS

Delayed myelosuppression (thrombocytopenia and neutropenia occurring 4 to 6 weeks after administration) was the dose-limiting toxicity (DLT). Anemia occurred but was mild. Nonhematologic toxicity was generally mild, but one patient died with pulmonary toxicity that was probably secondary to SarCNU. There were no partial or complete responses, but eight patients had stable disease for 19 to 46 weeks. The oral bioavailability of SarCNU was 80% +/- 37%. The terminal phase half-life was similar after intravenous (58.4 +/- 23.5 minutes) or oral (64.0 +/- 34.8 minutes) administration. The total plasma clearance was 20.4 +/- 8.8 L/h/m2, and the apparent volume of distribution was 29.9 +/- 17.6 L/m2. The area under the plasma concentration-time profile increased proportionally with the dose, and the pharmacokinetics seemed to be independent of the route of administration and the number of doses.

CONCLUSION

SarCNU was well tolerated and the MTD was 1,075 mg/m2. The recommended starting dose for phase II trials is 860 mg/m2 orally on days 1, 5, and 9 every 6 weeks.

Plasma pharmacokinetics of a liver-selective nitric oxide-donating diazeniumdiolate in the male C57BL/6 mouse

1. The single-dose plasma pharmacokinetics of O(2)-vinyl 1-(pyrrolidin-1-yl)diazen-1-ium-1,2-diolate (V-PYRRO/NO) following intravenous (i.v.) and intraperitoneal (i.p.) bolus administration to the male C57BL/6 mouse was studied in an effort to characterize the disposition of the agent and to serve as a basis for the design of in vivo efficacy studies. 2. Plasma V-PYRRO/NO concentrations declined rapidly in a bi-exponential manner after i.v. administration of 5 mg kg(-1) body weight to mouse. The terminal half-life was 9.4 min and the mean residence time was 3.4 min. 3. V-PYRRO/NO was absorbed rapidly following i.p. administration, with peak plasma concentrations being observed 3 min after injection. Levels then declined with a terminal half-life of 11.7 min. The bioavailable fraction from the i.p. compartment was 19%, indicating a high first-pass effect. 4. The results provide additional evidence for a liver-selective metabolism of this nitric oxide-donating prodrug.

Role of Cyp1A1 in modulation of antitumor properties of the novel agent 2-(4-amino-3-methylphenyl)benzothiazole (DF 203, NSC 674495) in human breast cancer cells

2-(4-Amino-3-methylphenyl)benzothiazole (DF 203, NSC 674495) is a candidate antitumor agent with potent and selective activity against human-derived tumor cell lines in vitro and in vivo. Only sensitive cell lines (e.g., MCF-7) were able to accumulate and metabolize DF 203, forming the main inactive metabolite, 2-(4-amino-3-methylphenyl)-6-hydroxybenzothiazole (6-OH 203). Selective metabolism may therefore underlie its antitumor profile. DF 203 6-hydroxylase activity by MCF-7 cells was not constitutive but induced only after pretreatment of cells with DF 203, 3-methylcholanthrene, or beta-naphthoflavone. 6-Hydroxylation was strongly inhibited by either goat antirat cytochrome P450 1A1 (CYP1A1) serum or alpha-naphthoflavone. Both alpha-naphthoflavone and 6-OH 203 abrogated DF 203-induced growth inhibition. Microsomes from genetically engineered human B-lymphoblastoid cells expressing CYP1A1, CYP1B1, or CYP2D6 metabolized DF 203 to 6-OH 203. Immunoblot analysis detected significantly enhanced CYP1A1 protein in a panel of sensitive breast cancer cell lines after exposure to DF 203. Neither constitutive expression nor induction of CYP1A1 protein was detected in nonresponsive breast (HBL 100, MDA-MB-435, and MCF-7/ADR) and prostate (PC 3 and DU 145) cancer cell lines. The expression of CYP1B1 was also modulated by DF 203 in the same sensitive cell lines. However, of the two isoforms, only CYP1A1 activity was irreversibly inhibited by DF 203 and significantly inhibited by 6-OH 203. In sensitive cell lines only, [14C]DF 203-derived radioactivity bound covalently to a Mr 50,000, protein which was immunoprecipitated by CYP1A1 antiserum. The covalent binding of [14C]DF 203 to recombinant CYP1A1 enzyme was NADPH-dependent and reduced by 6-OH 203 and glutathione. CYP1A1 appears essential for the metabolism of DF 203 and may have a pivotal, yet undefined, role in its antitumor activity.

Identification of the principal circulating metabolite of a synthetic 5,4'-diaminoflavone (NSC 686288), an antitumor agent, in the rat

During the course of our study to develop analytical methodology for quantitating the investigative antitumor agent 5-amino-2-(4-amino-3-fluorophenyl)-6,8-difluoro-7-methyl-4H-1-benzopyran -4-one (DAF; NSC 686288) in plasma, a significant concentration of a metabolite was observed in a post-dosed rat. The results of electron-ionization (EI) mass spectrometric analysis of the metabolite suggested that N-acetylation had occurred, but, interestingly, that only one of the compound's two primary amino groups had been transformed. Comparing the mass spectra and gas chromatographic retention times of a mono-acetylated sample of DAF and that of the metabolite showed both to be the same. A retro-Diels-Alder (RDA) fragmentation of the B ring of DAF results in formation of two abundant product ions, each retaining one of the amino groups. The EI mass spectrum of mono-N-acetamido-d3 DAF shows loss of ketene-d2, leading to formation of an -NHD group. The ensuing RDA fragmentation easily identifies which of the two product ions contains the deuterium, thereby allowing us to assign the site of N-acetylation as the amino group on ring C (the 4' position) of DAF.

Antitumor benzothiazoles. 8. Synthesis, metabolic formation, and biological properties of the C- and N-oxidation products of antitumor 2-(4-aminophenyl)benzothiazoles

2-(4-Aminophenyl)benzothiazoles 1 and their N-acetylated forms have been converted to C- and N-hydroxylated derivatives to investigate the role of metabolic oxidation in the mode of action of this series of compounds. 2-(4-Amino-3-methylphenyl)benzothiazole (1a, DF 203, NSC 674495) is a novel and potent antitumor agent with selective growth inhibitory properties against human cancer cell lines. Very low IC(50) values (<0.1 microM) were encountered in the most sensitive breast cancer cell lines, MCF-7 and T-47D, whereas renal cell line TK-10 was weakly inhibited by 1a. Cell lines from the same tissue origin, MDA-MB-435 (breast), CAKI-1 (renal), and A498 (renal), were insensitive to 1a. Accumulation and metabolism of 1a were observed in sensitive cell lines only, with the highest rate of metabolism occurring in the most sensitive MCF-7 and T-47D cells. Thus, differential uptake and metabolism of 1a by cancer cell lines may underlie its selective profile of anticancer activity. A major metabolite in these sensitive cell lines has been identified as 2-(4-amino-3-methylphenyl)-6-hydroxybenzothiazole (6c). Hydroxylation of 1a was not detected in the homogenate of previously untreated MCF-7, T-47D, and TK-10 cells but was readily observed in homogenates of sensitive cells that were pretreated with 1a. Accumulation and covalent binding of [(14)C]1a derived radioactivity was observed in the sensitive MCF-7 cell line but not in the insensitive MDA-MB-435 cell line. The mechanism of growth inhibition by 1a, which is unknown, may be dependent on the differential metabolism of the drug to an activated form by sensitive cell lines only and its covalent binding to an intracellular protein. However, the 6-hydroxy derivative 6c is not the 'active' metabolite since, like all other C- and N-hydroxylated benzothiazoles examined in this study, it is devoid of antitumor properties in vitro.

Analysis of 2-(3-methyl-4-aminophenyl)-benzothiazole (NSC 674495) in plasma by gas chromatography with mass-selective detection

Certain naturally occurring isoflavonoids have been shown to inhibit protein-tyrosine kinases, and this has led to investigations of ring-modified structural analogs. Most recently, 2-(3-methyl-4-aminophenyl)-benzothiazole (MAB: NSC 674495) was shown to possess significant activity against certain breast cell cancer lines in vitro and in vivo. Our efforts thus focussed on developing a simple and sensitive method for quantitating MAB in plasma using GC-MS. The GC-MS assay was found to be linear over the range of 0.050 to 5.0 microg/ml, and was applied to monitor the plasma concentration of MAB in a rat dosed with 25 mg/kg as a 1 min intravenous infusion. Plasma was collected at intervals from 3 through 180 min, and concentrations of MAB were determined. Non-linear regression analysis of the plasma concentration-time data revealed that levels declined from a maximum at 3 min of 18 microg/ml to 1 microg/ml at 3 h in a biphasic manner. In another investigation, significant plasma concentrations of a major metabolite was detected and determined to be mono-N-acetylated MAB.

Identification of cytosolic aldehyde dehydrogenase 1 from non-small cell lung carcinomas as a flavopiridol-binding protein

The synthetic flavone flavopiridol can be cytostatic or cytotoxic to mammalian cells, depending on the concentration of the drug and the duration of exposure. It has been shown to inhibit the cyclin-dependent kinase (CDK) family of cell cycle regulatory enzymes. However, the existence of additional potential targets for drug action remains a matter of interest to define. To identify cellular targets, flavopiridol was immobilized. CDKs, particularly CDK 4, bound weakly to immobilized flavopiridol when ATP was absent but not in its presence. Two proteins with molecular weights of 40 kDa and 120 kDa had high affinities to the immobilized flavopiridol independent of the presence of ATP. They were present in all cell lines analyzed: cervical (HeLa), prostate and non-small cell lung carcinoma (NSCLC) cell lines. A 60-kDa protein, which was present only in NSCLC cells and bound similarly well to immobilized flavopiridol, was identified as cytosolic aldehyde dehydrogenase class 1 (ALDH-1). The level of this protein correlated with the resistance of NSCLC cell lines to cytotoxicity caused by 500 nM flavopiridol but not higher flavopiridol concentrations. Despite binding to ALDH-1, there was no inhibition of dehydrogenase activity by flavopiridol concentrations as high as 20 microM and flavopiridol was not metabolized by ALDH-1. The results suggest that high cellular levels of ALDH-1 may reduce cytotoxicity of flavopiridol and contribute to relative resistance to the drug. This is the first report that flavopiridol binds to proteins other than CDKs.

Selective toxicity of the tricyclic thiophene NSC 652287 in renal carcinoma cell lines: differential accumulation and metabolism

The tricyclic compound 2,5-bis(5-hydroxymethyl-2-thienyl)furan (NSC 652287) has shown a highly selective pattern of differential cytotoxic activity in the tumor cell lines comprising the National Cancer Institute (NCI) Anticancer Drug Screen. The mechanism underlying the selective cytotoxicity is unknown. We hypothesized that differential sensitivity to the compound observed in several renal tumor cell lines could be the result of selective accumulation or differential metabolism of this agent. We demonstrated here that the capacity of certain renal cell lines to accumulate and retain the compound, determined by accumulation of [14C]NSC 652287-derived radioactivity and by flow cytometric determination of unlabeled compound, paralleled the sensitivity of the renal cell lines to growth inhibition by NSC 652287: A-498 > TK-10 >> ACHN approximately/= to UO-31. The ability of the cell lines to metabolize [14C]NSC 652287 to a reactive species capable of binding covalently to cellular macromolecules also directly correlated with sensitivity to the compound. Different patterns of metabolites were generated by relatively more drug-sensitive cell lines in comparison with drug-resistant cell lines. The metabolizing capacity for NSC 652287 was localized primarily to the cytosolic (S100) fraction. The rate of metabolism in the cytosolic fraction from the most sensitive renal cell line, A-498, was faster than that observed in the cytosolic fractions from the other, less sensitive cell lines. The data support the hypothesis that both selective cellular accumulation and the capacity to metabolize NSC 652287 to a reactive species by certain renal carcinoma cell types are the basis for the differential cytotoxicity of this compound class.

Unsymmetric nonpeptidic HIV protease inhibitors containing anthranilamide as a P2' ligand

A series of novel unsymmetrical anthranilamide-containing HIV protease inhibitors was designed. The structure-activity studies revealed a series of potent P2-P3' inhibitors that incorporate an anthranilamide group at the P2' position. A reduction in molecular weight and lipophilicity is achieved by a judicious choice of P2 ligands (i.e., aromatic, heteroaromatic, carbamate, and peptidic). A systematic investigation led to the 5-thiazolyl carbamate analog 8 m, which exhibited a favorable Cmax/EC50 ratio (> 30), plasma half-life (> 8 h), and potent in vitro antiviral activity (EC50 = 0.2 microM).

Determination of flavopiridol (L86 8275; NSC 649890) in human plasma by reversed-phase liquid chromatography with electrochemical detection

PURPOSE

Flavopiridol is a flavone which inhibits several cyclin-dependent kinases, and exhibits potent growth-inhibitory activity against a number of human tumor cell lines both in vitro, and when grown as xenografts in mice. It is currently being evaluated in a phase I clinical trial at the National Cancer Institute. The objective of this project was to develop and validate an analytical method for the assay of flavopiridol in human plasma, with sufficient sensitivity to permit the plasma pharmacokinetics of flavopiridol to be studied during clinical trials.

METHODS

Flavopiridol was isolated from human plasma samples by extraction with t-butylmethyl ether following alkalinization with borate buffer (pH 8.0). The extract was evaporated, the residue was dissolved in mobile phase, and analyzed by reversed-phase high-pressure liquid chromatography. Chromatography was accomplished with a polymer-based C18 column eluted with a mobile phase consisting of methanol-phosphate buffer, pH 11.0 (53:47 v/v). Electrochemical detection (ECD) was employed.

RESULTS

Flavopiridol was recovered from human plasma with an efficiency of 85-87%. Calibration curves were linear over the concentration range 10-500 nM (4.4-219 ng/ml). Plasma standard concentrations were measured with an accuracy and precision ranging from 3.2% to 10%. Regression analysis of flavopiridol concentrations of 15 clinical trial plasma samples ranging in concentration from approximately 50 to 4000 microM quantitated by both ECD and mass spectrometry showed close agreement. The equation of the regression line was y = 1.02x + 8 with a correlation coefficient of 0.969. Continuous infusion of flavopiridol in four patients for 72 h at a rate of 50 mg/m2 per day, resulted in mean steady-state plasma concentrations of from 200 to 300 nM. Levels declined in a biexponential manner following termination of the infusion, falling to approximately 10 nM after 48 h.

CONCLUSIONS

An analytical method for the assay of flavopiridol in human plasma was developed with sensitivity to at least 10 nM. The assay is accurate, precise and specific, and is suitable for determination of plasma flavopiridol concentrations for pharmacokinetic studies during clinical trials.

Phase I trial of continuous infusion flavopiridol, a novel cyclin-dependent kinase inhibitor, in patients with refractory neoplasms

PURPOSE

We conducted a phase I trial of the cyclin-dependent kinase inhibitor, flavopiridol (National Service Center [NSC] 649890), to determine the maximum-tolerated dose (MTD), toxicity profile, and pharmacology of flavopiridol given as a 72-hour infusion every 2 weeks.

PATIENTS AND METHODS

Seventy-six patients with refractory malignancies with prior disease progression were treated with flavopiridol, with first-cycle pharmacokinetic sampling.

RESULTS

Forty-nine patients defined our first MTD, 50 mg/m2/d x 3 with dose-limiting toxicity (DLT) of secretory diarrhea at 62.5 mg/kg/d x 3. Subsequent patients received antidiarrheal prophylaxis (ADP) to define a second MTD, 78 mg/m2/d x 3 with DLT of hypotension at 98 mg/m2/d x 3. Other toxicities included a proinflammatory syndrome with alterations in acute-phase reactants, particularly at doses >50 mg/ m2/d x 3, which in some patients prevented chronic therapy every 2 weeks. In some patients, ADP was not successful, requiring dose-deescalation. Although approximately 70% of patients displayed predictable flavopiridol pharmacology, we observed unexpected interpatient variability and postinfusion peaks in approximately 30% of cases. At the two MTDs, we achieved a mean plasma flavopiridol concentration of 271 nM (50 mg/m2/d x 3) and 344 nM (78 mg/m2/d x 3), respectively. One partial response in a patient with renal cancer and minor responses (n=3) in patients with non-Hodgkin's lymphoma, colon, and renal cancer occurred.

CONCLUSION

The MTD of infusional flavopiridol is 50 mg/m2/d x 3 with dose-limiting secretory diarrhea at 62.5 mg/m2/d x 3. With ADP, 78 mg/m2/d x 3 was the MTD, with dose-limiting hypotension at 98 mg/m2/d x 3. Based on chronic tolerability, 50 mg/m2/d x 3 is the recommended phase II dose without ADP. Antitumor effect was observed in certain patients with renal, prostate, and colon cancer, and non-Hodgkin's lymphoma. Concentrations of flavopiridol (200 to 400 nM) needed for cyclin-dependent kinase inhibition in preclinical models were achieved safely.

Flavopiridol induces apoptosis of normal lymphoid cells, causes immunosuppression, and has potent antitumor activity In vivo against human leukemia and lymphoma xenografts

Flavopiridol is a novel semisynthetic flavone derivative of the alkaloid rohitukine. Flavopiridol is known to inhibit potently the activity of multiple cyclin-dependent kinases. We have assessed its effects on normal and malignant cells in preclinical animal models of localized and disseminated human hematopoietic neoplasms. Flavopiridol, when administered as daily bolus intravenous (IV) injections, produced selective apoptosis of cells in the thymus, spleen, and lymph nodes, resulting in atrophy of these organs. With the exception of the intestinal crypts, apoptosis or tissue damage was absent in all other organs investigated (kidneys, liver, lungs, bone/bone marrow, muscle, and heart). Flavopiridol had a marked apoptotic effect documented by DNA nick-end labeling, or DNA agarose gels in xenografts of human hematopoietic tumors HL-60, SUDHL-4, and Nalm/6. After treatment with 7.5 mg/kg flavopiridol bolus IV or intraperitoneal on each of 5 consecutive days, 11 out of 12 advanced stage subcutaneous (s.c.) human HL-60 xenografts underwent complete regressions, and animals remained disease-free several months after one course of flavopiridol treatment. SUDHL-4 s.c. lymphomas treated with flavopiridol at 7.5 mg/kg bolus IV for 5 days underwent either major (two out of eight mice) or complete (four out of eight mice) regression, with two animals remaining disease-free for more than 60 days. The overall growth delay was 73.2%. The acquired immunodeficiency syndrome-associated lymphoma AS283 showed no significant response when flavopiridol was used in advanced s.c. tumors, but when treatment was initiated in early stages, there was a complete regression of the early tumors, and a significant overall growth delay (>84%). When flavopiridol was used in severe combined immunodeficient mice bearing disseminated human acute lymphoblastic leukemia Nalm/6 cells, there was 15-day prolongation in survival (P = .0089). We conclude that flavopiridol greatly influences apoptosis in both normal and malignant hematopoietic tissues. This activity was manifested in our study as a potent antileukemia or antilymphoma effect in human tumor xenografts, which was dose and schedule dependent. These findings provide compelling evidence for the use of flavopiridol in human hematologic malignancies.

Preclinical evaluation of 9-chloro-2-methylellipticinium acetate alone and in combination with conventional anticancer drugs for the treatment of human brain tumor xenografts

Some ellipticine derivative salts, including 9-chloro-2-methylellipticinium (CME), have been found to have a marked selectivity against all eight brain tumor cell lines of the U.S. National Cancer Institute's disease-oriented in vitro screen. We initiated in vivo antitumor studies to explore the feasibility for further development of this class of compounds. We found that CME was extremely toxic to nude mice when given i.p. at a dose of 25 mg/kg for 3 consecutive days. Animals treated by this route experienced an increase in hepatic transaminases and histopathological changes in the liver, compatible with mitochondrial damage. In contrast, when the portal circulation was bypassed and the same dose of CME was given i.v., animals tolerated daily bolus injections for 5 consecutive days. This 5-day i.v. bolus schedule had consistent antitumor activity, with 28.1% growth delay on s.c. implanted human U251 gliomas. When the potentially high peaks of CME in the portal circulation were avoided by using a 3-day continuous infusion with osmotic minipumps implanted i.p. to release 3.4 mg kg(-1) h(-1) or 6.6 mg kg(-1) h(-1) CME, there were only modest increases in liver enzymes and leukopenia, but no meaningful antitumor activity was observed. In contrast, continuous infusion in the s.c. space was well tolerated and was accompanied by a demonstrable growth delay in s.c. U251 human gliomas of 37.8%. When CME was used in conjunction with carmustine, etoposide or cisplatin, no synergistic activities were observed, but additive effects were demonstrated. Our pharmacokinetic and disposition studies with CME argue against the notion that large and invasive tumors in the brain lack blood-brain barrier features. When CME was used in animals bearing orthotopically implanted U251 gliomas in the brain of nude mice, the survival of the treated animals was not better than vehicle controls, and the addition of CME to carmustine therapy did not improve the survival of those animals treated with carmustine alone. We conclude that, in spite of its marked cytotoxicity in vitro on a variety of human brain tumor cell lines, including U251 glioma cells, CME has a modest antitumor effect on extracranially implanted U251 glioma tumors, and no beneficial effect in animals bearing the same U251 tumor in the brain, owing to a poor penetration into the brain parenchyma.

Biological and biochemical anti-human immunodeficiency virus activity of UC 38, a new non-nucleoside reverse transcriptase inhibitor

UC 38, a simple analog of oxathiin carboxanilide, UC 84, lacking the oxathiin ring, was found to be a potent inhibitor of human immunodeficiency virus (HIV)-1-induced cell killing and HIV replication in a variety of human cell lines, as well as in human peripheral blood lymphocytes and macrophages. UC 38 was active against a wide range of biologically diverse laboratory and clinical strains of HIV-1. However, UC 38 was inactive against HIV-2 and both nevirapine- and pyridinone-resistant strains of HIV-1. UC 38 selectively inhibited HIV-1 reverse transcriptase (RT), but not HIV-2 RT. Combination of UC 38 with 3'-azido-3'-deoxythymidine synergistically inhibited HIV-induced cell killing. An HIV-1 isolate resistant to UC 38 was selected in cell culture, and the mutations in the RT nucleotide sequences were determined. Comparison with the wild-type RT sequence revealed an amino acid change at position 181 (Tyr to Cys). The UC 38-resistant virus was found to be cross-resistant to a variety of structurally diverse non-nucleoside RT inhibitors. UC 38 was susceptible to rapid degradation in vitro and in vivo; yet, nontoxic in vivo concentrations of UC 38 many-fold in excess of the in vitro effective concentrations could be achieved and maintained after s.c. or p.o. administration in hamsters. These results establish UC 38 as a new chemotype within the general class of HIV-1-specific RT inhibitors. The favorable physical characteristics, lack of toxicity, potency and bioavailability of UC 38 may make it a candidate for combination chemotherapy of acquired immune deficiency syndrome.

Morphological and immunocytochemical characteristics of human tumor cell lines for use in a disease-oriented anticancer drug screen

A panel of 60 human tumor cell lines is currently being used in the U.S. National Cancer Institute's in vitro anticancer drug screen. The panel is organized into 7 subpanels; 6 leukemia/lymphoma lines comprise one subpanel, and 54 other lines are organized into subpanels representing solid tumors of the central nervous system (CNS), colon, lung, ovaries, kidneys and melanomas. In the present study, the leukemia and lymphoma cell lines were analyzed by flow cytometry for appropriate CD antigens; all but 1 line showed patterns of expression consistent with their reported derivations. The solid tumor lines were characterized individually using morphological and immunocytochemical techniques to determine their relative degrees of representativity for the subpanels within which they are currently grouped. Histological, histochemical and ultrastructural examinations were performed on cell lines grown under identical conventional culture conditions and as xenografts in nude mice. Immunocytochemistry using panels of antibodies raised against 6 types of intermediate filaments, 7 adenocarcinoma-associated antigens, 7 melanoma/neuro-ectodermal-associated antigens, 3 neuroendocrine-associated antigens, 9 urinary tract associated antigens, and 4 markers of muscle differentiation was done on cells grown in monolayer culture. Central nervous system (CNS) cell lines lacked expression of glial fibrillary acidic protein, but all had other features consistent with derivation from glioblastoma. Lines derived from adenocarcinomas of the colon, lung and ovary, for the most part, expressed adenocarcinoma-associated antigens and showed histological and/or ultrastructural evidence of gland formation and other adenomatous features. Most of these lines were poorly differentiated. Lines derived from large-cell and squamous-cell cancers also showed some characteristics consistent with their reported origins, except for one line which showed immunocytochemical and morphologic characteristics consistent with rhabdomyosarcoma. The 2 lines derived from small cell lung cancer (SCLC) lacked neurosecretory granules and 3 other SCLC markers but showed morphologic features consistent with SCLC. Most melanoma cell lines strongly expressed melanoma-associated antigens and were morphologically similar to human melanoma. Five lines produced premelanosomes, melanosomes or melanin. Most of the renal cancer cell lines showed morphologic or immunocytochemical features consistent with renal clear cell carcinoma. Collectively, these morphological and immunocytochemical analyses provide information concerning tissue of origin, tumor type, degree of differentiation and other biologic features essential to the use of these lines in a disease-oriented in vitro antitumor drug screen and to the interpretation of data derived therefrom.

Multidrug-resistant phenotype of disease-oriented panels of human tumor cell lines used for anticancer drug screening

Disease-oriented panels of human tumor cell lines used by the National Cancer Institute for large-scale in vitro anticancer drug screening were evaluated for multidrug-resistant phenotype at the functional (in vitro drug sensitivity) and molecular levels. The cell line panels manifested a broad range of sensitivities to drugs typically associated with multidrug resistance (MDR) as well as to drugs not associated with MDR. Individual cell lines displayed unique and characteristic profiles of response. Patterns of correlated response were observed among, but not between, MDR and non-MDR drugs. Strong evidence of correlated response was limited to drugs sharing an intracellular mechanism of action. Several tumor cell lines exhibited a high degree of resistance to MDR drugs and relative sensitivity to non-MDR drugs, contained high levels of MDR-1 mRNA, and expressed cell surface P-glycoprotein detectable with one or more monoclonal antibodies. Parallel expression of all of these features representing the classic MDR phenotype was observed among members of the colon and renal tumor panels. Certain individual cell lines among other panels (lung, ovarian, melanoma, and central nervous system) also manifested some aspects of the MDR phenotype to various extents. Identification of MDR cell lines used for large-scale in vitro anticancer drug screening will facilitate interpretation of data in a way which may allow identification of new drug leads of potential value in treatment of MDR tumor cell populations.

Acute and long-term effects on limb function of combined modality limb sparing therapy for extremity soft tissue sarcoma

A retrospective review is presented on 145 patients who underwent limb-sparing surgery and radiation therapy (with or without adjuvant chemotherapy) for their primary soft tissue sarcomas of the extremities on protocol between 1975 and 1986. The focus on our analysis was the acute and long term toxicity of treatment on limb function. The most common acute complication was skin reaction, occurring in 52 patients (36%). Long term (occurring after more than 1 year following all treatment) treatment complications in the extremity were as follows: bone fracture = 6%; contracture = 20%; pain requiring narcotics = 7%; edema greater than 2+ = 19%; moderate to severe decrease in range of motion = 32%; moderate to severe decrease in manual muscle strength = 20%; orthotic device required = 9%; cane or crutch required = 7%; chronic infection = 9%; and tissue induration = 57%. Three amputations for treatment complications were required. Inclusion of more than 50% of the joint in the radiation portal was associated with a higher frequency of contracture. High nominal standard dose (greater than 1760 rets, greater than 63 Gy at 1.8 Gy per fraction) resulted in more painful limbs as well as limbs with increased edema, decreased manual muscle strength, decreased range of motion, and skin telangiectasias. Edema was more often noted in patients with a longer radiation portal (greater than 35 cm), as was tissue induration. Chronic ulcer or infection was more frequently seen in patients with lower extremity tumors and when more than 75% of the extremity diameter was irradiated. Although chemotherapy given concurrent with radiation therapy was associated with a higher number of acute skin reactions, this did not appear to translate into increased long term morbidity. The percentage of patients ambulating without assistive devices and with mild or no pain was 84%. Careful attention to the techniques of radiation therapy may have a significant impact on minimizing acute and long term complications of limb sparing treatment for extremity soft tissue sarcoma.

Oxathiin carboxanilide, a potent inhibitor of human immunodeficiency virus reproduction

Oxathiin carboxanilide (OC), NSC 615985, a compound originally synthesized as a potential fungicide, was demonstrated to be highly active in preventing human immunodeficiency virus (HIV)-induced cell killing and in inhibiting HIV reproduction. Virus-infected CD4+ lymphocytes were completely protected by 0.5 microM OC, whereas no toxicity was observed at concentrations below 50 microM OC. Production of infectious virus, viral p24 antigen, and virion reverse transcriptase were reduced by OC at concentrations that prevented viral cell killing. A variety of CD4+ T-cell lines were protected by OC from HIV cytopathicity, and OC inhibited two distinct strains of HIV-1. However, HIV-2 infections were unaffected by OC. OC had no direct effect on virions of HIV or on the enzymatic activities of HIV reverse transcriptase or HIV protease. Time-limited treatments of cells with OC before, during, or after exposure of cells to virus failed to protect cells from the eventual cytopathic effects of HIV, and OC failed to inhibit the production of virus from cells in which infection was established or from chronically infected cells. We conclude that the highly active OC has a reversible effect on some early stage of HIV-1 reproduction and cytopathicity. Pilot in vivo experiments showed that circulating concentrations of OC exceeding 1 microM could be achieved and sustained in hamsters for at least a week with no remarkable toxicological sequelae. OC represents a new class of anti-HIV agents that are promising candidates for drug development.

Morphological and cytokinetic responses of hamster airways to intralaryngeal or intratracheal cannulation with instillation of saline or ferric oxide particles in saline

The morphological and proliferative effects of intratracheal cannulation (ITC) or intralaryngeal cannulation (ILC), with or without the instillation of saline or Fe2O3 particles in saline, were studied in Syrian golden hamsters. Instillation of Fe2O3 in saline at either airway level resulted in a similar distribution of Fe2O3 particles in all lung lobes. ILC produced laryngeal mucosal wounds. ITC produced laryngeal and tracheal mucosal wounds. The cannula-induced wounds were associated with proliferative epithelial lesions. ITC, but not ILC, resulted in significant increases in the mitotic rates (MR, 6-h colchicine blockade) of tracheal epithelial cells at 24 and 32 h postcannulation. Instillation of saline by ITC produced slight increases in intrapulmonary bronchial and bronchiolar MR, but saline given by ILC did not increase MR at any airway level. Instillation of Fe2O3 particles in saline by ITC produced increases in tracheal, intrapulmonary bronchial, and bronchiolar MR. Instillation of Fe2O3 particles in saline by ILC had little effect on tracheal MR, but increased intrapulmonary bronchial and bronchiolar MR. Foci of Fe2O3 particle-laden macrophages were associated with mild bronchiolar-alveolar hyperplasia at the junctions of the terminal bronchioles and the alveolar ducts. The cytokinetic and morphological changes in the intrapulmonary airways were associated with the influx of inflammatory cells in response to Fe2O3 particle deposition. The marked increases in tracheal MR and the localized hyperplastic tracheal epithelial lesions were clearly associated with mechanical wounding from the cannula during ITC. Comparative studies using ILC or ITC instillation techniques allowed further investigations of the important role of tracheal mucosal wounding in the induction of respiratory carcinogenesis, as described in a companion paper (Keenan et al., Cancer Res., 49: 1528-1540, 1989).

Multifactorial hamster respiratory carcinogenesis with interdependent effects of cannula-induced mucosal wounding, saline, ferric oxide, benzo[a]pyrene and N-methyl-N-nitrosourea

The carcinogenic response induced in the respiratory tract of Syrian golden hamsters by repeated intratracheal instillations of benzo[a]pyrene (BP) adsorbed to ferric oxide (Fe2O3) particles suspended in saline, is shown to result from the interactions of these factors and cannula-induced tracheal wounding. Previous acute studies of intratracheal cannulation (ITC) versus intralaryngeal cannulation (ILC) showed that tracheal cell proliferation increased significantly in ITC-induced mucosal wounds. Only mild increases in intrapulmonary cell proliferation were produced by Fe2O3-saline given by ILC or ITC (Keenan et al., Cancer Res., 49: 1521-1527, 1989). The present chronic studies included the following variables: a single instillation by ILC of N-methyl-N-nitrosourea (MNU) at 5 weeks of age; 15 weekly treatments (beginning at 7 weeks of age) by ILC or ITC alone, or with instillations of saline, or Fe2O3-saline, or BP-Fe2O3-saline; and appropriate controls. Repeated ITC-induced tracheal wounds caused persistent tracheal epithelial hyperplasia, metaplasia and/or atrophy and submucosal fibroplasia during the observation period of 22 to 78 weeks of age (the time of terminal sacrifice). Tracheal cancers (in situ or invasive carcinomas) were seen only in those hamsters which had received repeated ITC and one or both carcinogens. The cancer latency was shortest and the incidence of tracheal (50%) and main-stem bronchial (21%) cancers highest in hamsters given MNU and repeated ITC with BP-Fe2O3-saline. Hamsters given carcinogens by ILC (which induced laryngeal but not tracheal wounds) developed proliferative lesions and cancers of the larynx but no tracheobronchial cancers. These data show the singular importance of repeated ITC-induced intratracheal wounding as an enhancing factor in this respiratory carcinogenesis model. The findings suggest that the mechanism of tumor enhancement involves not only changes in target epithelial cell proliferation, but also alterations in normal epithelial-mesenchymal interactions during tracheal regeneration from repeated chronic submucosal inflammation and mesenchymal repair. In the present experimental model, a single dose of MNU at 5 weeks of age, repeated instilled doses of BP, and tracheal mucosal wounding were each found to be important determinants of the carcinogenic response. Additional effects were observed for instilled Fe2O3 particles, and possibly saline. Interplay of all these factors, as well as of genetic, nutritional, and infectious factors, are considered in relation to risk assessment and prevention.

Spindle cell carcinoma of the hamster trachea induced by N-methyl-N-nitrosourea

The tracheas of 63 male Syrian golden hamsters were exposed once each week for 12 weeks to a flowing stream of 0.5% N-methyl-N-nitrosourea in phosphate-buffered saline (pH 4.5) with a specially designed intratracheal cannula. The animals were killed when moribund or 6 months after the final exposure, and the respiratory tracts were examined grossly, histologically, and ultrastructurally for tumor formation. A total of 13 neoplasms was found in the larynx or trachea. Six were papillomas, 3 were carcinomas, and 4 were diagnosed as spindle-cell carcinomas. The average time of observation of the various tumor types was 33, 31, and 21 weeks, respectively. The spindle cell carcinomas contained an exophytic portion protruding into the tracheal or laryngeal lumen and an infiltrating portion growing circumferentially between the intact mucosa and the cartilage rings or plates. They were composed of sheets of elongated and spindle-shaped cells. Ultrastructurally, the cells contained bundles of tonofilaments and keratohyalin, and were connected by numerous desmosomes. These findings are consistent with a squamous origin of the tumor cells and a diagnosis of spindle cell carcinoma.

Quantitation of differences between spontaneous and induced liver tumors in mice with an automated image analyzer

Spontaneous hepatocellular neoplasms of B6C3F1 mice (basophilic neoplasms) as well as those induced with the herbicide Nitrofen (eosinophilic neoplasms) were observed with an image analyzing computer to determine if quantifiable morphologic differences existed between them. Several morphologic parameters were measured on 5 liver sections from each of the following groups: (a) unexposed control liver; (b) non-trabecular basophilic neoplasms; (c) trabecular basophilic neoplasms; (d) small well circumscribed eosinophilic neoplasms; and large irregular eosinophilic neoplasms without (e) and with (f) pulmonary metastases. The total number of hepatocytes per unit area was significantly smaller in the eosinophilic neoplasms than in the basophilic neoplasms or the controls. This was the result of a greatly increased cell cross-sectional area in the eosinophilic neoplasms, caused predominantly by a larger cytoplasmic cross-sectional area. Nuclear cytoplasmic ratios of cells in eosinophilic neoplasms were lower than in the other groups for this reason. This demonstrates that quantitative morphologic differences exist between the spontaneous and induced neoplasms, which supports the conclusion that Nitrofen is a true carcinogen, and not a promoting agent.

Effect of three retinoids on tracheal carcinogenesis with N-methyl-N-nitrosourea in hamsters

Male Syrian golden hamsters received 12 weekly intratracheal exposures to 0.5% N-methyl-N-nitrosourea with a special catheter. Following exposures, animals were randomized into 4 groups of 63 hamsters and placed on diets of lab meal or meal with 120 mg 13-cis-retinoid acid (CRA)/kg, 327 mg ethyl retinamide (ER)/kg, or 343 mg N-(2-hydroxyethyl)retinamide (HR)/kg for 6 months at which time all hamsters were killed. The observed incidences of tracheal epithelial neoplasms (No. of animals with tumors/total No. of animals) were 10/63 (lab meal), 22/61 (CRA), 24/63 (ER), and 17/62 (HR). The incidence of carcinomas (No. of animals with tumors/total No. of animals) were 4/63 (lab meal), 12/61 (CRA), 12/63 (ER), and 11/62 (HR). The weight loss and mortality relative to those in the group fed the lab meal were significantly in the group fed HR but not in the other retinoid-treated groups.

Characteristics of proliferative lesions in the nasal cavities of mice following chronic inhalation of 1,2-dibromoethane

Groups of 50 male and 50 female B6C3F1 mice inhaled 10 or 40 ppm 1,2-dibromoethane 6 h/day, 5 days/week, for 103 (10 ppm) or 90 (40 ppm) weeks. Focal epithelial hyperplasia was found in 1 (low dose group) and 10 (high dose group) males and 3 (low dose group) and 11 (high dose group) females. Squamous papillomas or adenomas were seen in 3 males and 7 females in the high dose groups. Squamous, adeno-, or mixed carcinomas were present in 7 females in the high dose group. One poorly differentiated sarcoma and 2 hemangiosarcomas were observed in females in the low and high dose groups, respectively.

Prostatic hyperplasia and neoplasia in aging F344 rats

The prostates of 1775 (614 control and 1161 experimental) 2-year-old F344 rats from 12 different carcinogen bioassays conducted by the Bioassay Program of the NCI and the NTP were evaluated histologically. The incidence of prostatic lesions including (atypical) hyperplastic foci, adenomas, and carcinomas was 6.8%. There was no difference in the type or incidence of the lesions between treated and untreated animals. Adenomas or carcinomas were found in 71 (4.0%) of the rats, primarily as incidental findings. The number of tumors and hyperplastic foci varied from laboratory to laboratory depending on the anatomical localization of the plane of the section. Most of the neoplasms were found in the ventrolateral lobes of the prostate (ventral prostate). When adequate sections were prepared of the ventral lobe, 10-20% of the prostates had these proliferative lesions. The lesions were usually small and originated in the epithelium of the alveoli and small ducts and were usually small and originated in the epithelium of the alveoli and small ducts and were not associated with the common inflammatory lesions of the rat prostate. Thin fibrous capsules were formed in a few of the larger tumors. Metastases were not observed but there was local invasion into alveoli, ducts and interstitial connective tissue. Evidence is presented that the atypical hyperplasias progress to adenoma and carcinoma. The F344 rat offers a potential model for the study of latent prostatic preneoplastic and neoplastic lesions.

Histogenesis and morphology of naturally occurring prostatic carcinoma in the ACI/segHapBR rat

The prostates of 201 male virgin or breeder ACI (ACI/segHapBR) rats, 24 to 40 months of age were reviewed histologically, and the genesis of prostatic carcinoma was studied. At 24 months of age, 35 to 45 per cent of the rats had the earliest lesions, intraalveolar atypical hyperplasias. These lesions progressed to intraalveolar cribriform carcinomas which spread along alveoli and ducts. As the tumors enlarged, they became nodular and invaded the capsule or adjacent tissues. By 33 months, 95 to 100 per cent of the rats had intraalveolar prostatic atypical hyperplasias, and 35 to 40 per cent had invasive carcinomas. There was no difference between the incidence of these tumors in virgin or breeder rats. The ACI rat is unique model for studying the etiology and pathogenesis of naturally occurring prostatic cancer.

Respiratory pathology in rats and mice after inhalation of 1,2-dibromo-3-chloropropane or 1,2 dibromoethane for 13 weeks

Seventy F344 rats and 144 B6C3F1 mice were subdivided into seven groups. Three groups were each exposed via inhalation to 1, 5, or 25 ppm of 1,2-dibromo-3-chloropropane (DBCP) for 6 h per day, 5 days per week for 13 weeks. Three additional groups were each similarly exposed to 3, 15, or 75 ppm of 1,2-Dibromoethane (EDB). The remaining group was exposed to room air under the same conditions. At 13 weeks, rats and mice showed severe necrosis and atrophy of the olfactory epithelium in the nasal cavity after inhalation of 5 or 25 ppm DBCP and 75 ppm EDB. Lower concentrations induced squamous cell metaplasia, hyperplasia and cytomegaly of the epithelium of the respiratory nasal turbinals. Squamous metaplasia, hyperplasia and cytomegaly of the epithelium was also seen in larynx, trachea, bronchi and bronchioles. Other compound related toxic lesions in rats were seen in the liver, kidney and testes.

Histopathologic differences between liver tumors in untreated (C57BL/6 X C3H)F1 (B6C3F1) mice and Nitrofen-fed mice

A comparison was made of the histologic characteristics of naturally occurring and Nitrofen-induced liver tumors in (C57BL/6 X C3H)F1 (B6C3F1) mice. Whereas induced tumors generally consisted of solid sheets or nodules of frequently enlarged eosinophilic hepatocytes containing enlarged and/or hyperchromatic nuclei, the spontaneous neoplasms consisted predominantly of small basophilic cells containing oval or round nuclei and frequently arranged in trabeculae 1--2 cells wide. Within the livers of Nitrofen-treated animals, foci of hepatocytes resembling those within the tumor masses were also observed in the nonneoplastic areas. Metastases were not present in the lungs of any controls, whereas small emboli or large masses of neoplastic hepatocytes were present in incidences up to 29% in treated mice with tumors. This bioassay provides evidence that, in some cases, liver tumors in treated mice are morphologically different from those in controls and suggests that Nitrofen induces unique liver tumors rather than acts as a promoter of spontaneous neoplasms.

Morphology of nasal-cavity tumours in rats after chronic inhalation of 1,2-dibromo-3-chloropropane

Groups of 50 F344 rats of each sex sere exposed to 0.6 or 3.0 pts/10(6) of 1,2-dibromo-3-chloropropane (DBCP) by inhalation for 6 h/day, 5 days/week for 103 weeks. Fifty rats of each sex inhaling filtered air were used as unexposed controls. All survivors were killed at 104 weeks. Up to 93% of the male and female rats developed neoplasms of the nasal cavity. Most of the tumours were adenomas, squamous-cell papillomas, squamous-cell carcinomas, and adenocarcinomas. In the low-dose group 78% of the tumours in males and 66% in females were benign, whereas in the high-dose groups 89% in males and 76% in females were malignant. Invasion through the cribriform plate into the cerebrum or metastasis to the regional lymph nodes was found in 73% of the carcinomas in males and 51% in females. Electron-microscopic examination suggested that the basal cells of the olfactory epithelium were the site of origin of the poorly differentiated adenocarcinomas.

Morphology and sex-dependent manifestation of nasal tumors in B6C3F1 mice after chronic inhalation of 1,2-dibromo-3-chloropropane

Groups of 50 B6C3F1 mice of each sex were exposed to air containing of 1,2-dibromo-3-chloropropane at concentrations of 0.6 or 3.0 ppm for 6 hours per day, 5 days per week for 103 weeks. Untreated controls consisted of 50 mice of each sex. All surviving animals were killed at 104 weeks. Adenomas, squamous cell papillomas, adenocarcinomas, squamous cell carcinomas, carcinosarcomas, fibrosarcomas, and hemangiosarcomas of the nasal cavity occurred in male and female mice with dose related trends. Eighty-seven percent of the high dose female mice had nearly twice as many tumors as the high dose males (47%). Fourtynine percent of malignant neoplasms of the high dose female mice infiltrated the brain or metastasized to the lungs. Whereas two animals (4%) of the low dose female mice showed infiltrating carcinomas, no male mice exhibited this feature.

Lung tumors induced by chronic inhalation of 1,2-dibromo-3-chloropropane in B6C3F1 mice

1,2-Dibromo-3-chloropropane (DBCP) was inhaled by B6C3F1 mice of each sex at concentrations of 0.6 or 3.0 ppm for 6 h/day, 5 days/week, for 103 weeks. Untreated controls consisted of 50 mice of each sex. All surviving animals were killed at 104 weeks. Survival in the high-dose groups of female mice was significantly shorter than that in the corresponding controls. Alveolar-bronchiolar adenomas or carcinomas occurred in both male and female mice with dose-related trends (P < 0.007) in males and (P < 0.002) in females. Papillary carcinomas in the lung occurred in low-dose female mice at an increased incidence compared with controls (P < 0.006). Many induced tumors were morphologically different than those in controls.

Semiautomated autoradiographic measurement of DNA repair in normal and xeroderma pigmentosum cultured human fibroblasts

Assessment of DNA repair in cultured human fibroblasts by autoradiography may be facilitated by using semiautomated grain counting instruments. The instrument-determined number of autoradiographic grains per nucleus in cultured human skin fibroblasts was found to be linear in comparison to visual counts up to only 30 grains per nucleus. However, with two different instruments a greater range of linearity (to 100 to 120 grains per nucleus) was attained by measuring the grain surface area per nucleus. Semiautomated analysis of the grain surface area per nucleus yielded measurements of relative rates of unscheduled DNA synthesis after ultraviolet irradiation in xeroderma pigmentosum and normal human fibroblasts, which were reproducible and rapid.

Morphogenesis of neoplasms induced in the hamster trachea with N-methyl-N-nitrosourea

The tracheas of 95 male Syrian golden hamsters were locally exposed to a flowing stream of a 1% solution N-methyl-N-nitrosourea using a specially designed cannula at weekly intervals for 15 weeks. Animals were killed at specified times from 9 through 27 weeks following the first dose. Epithelial flattening was observed in over 90% of the tracheas throughout the study, but the proportion of the epithelium involved decreased from 100% at 9 and 16 weeks to 25 to 50% at 27 weeks. Hyperplastic foci of squamous metaplasia were found in 5% of the tracheas at 9 weeks, 90% of tracheas at 16 weeks, 83% of tracheas from 18 to 26 weeks, and 80% of tracheas at 27 weeks. Dysplastic foci of hyperplasia were observed in 5% of the tracheas at 9 weeks, 90% of the tracheas at 16 weeks, 17% of tracheas from 18 to 26 weeks, and 1% of tracheas at 27 weeks. Neoplasms were found in low incidences (2%) at 16 weeks. Papillomas and carcinomas were present in 13 and 42% of the tracheas from 18 to 26 weeks and 30 and 75% at 27 weeks, respectively. Dysplastic foci, as well as small focal carcinomas which had invaded the tracheal cartilages, were frequently found in close association with invaginations of the epithelium into the submucosa.

Atrophy induced in the tubules of the testes of Syrian hamsters by two retinoids

This paper describes toxic lesions induced in the hamster testes by 3 different retinoids. Groups of 13 Syrian Golden hamsters were fed diets containing 120 mg/kg 13-cis-retinoic acid (CRA), 327 mg/kg ethyl retinamide (ER), or 343 mg/kg 2-hydroxyethyl retinamide (HER) for 6 months. The germinal epithelium of the testicular tubules was completely atrophic in the groups fed ER and HER. Mean testicular weights were 0.8 g and 0.7 g respectively as compared to 3.3 g in the control group. No alterations in testicular weights or morphological characteristics, at the light microscopic level, were found in the group fed CRA. At the ultrastructural level, however, asymmetrical head caps and deformed acrosomes were observed in the spermatids.

Animal model of human disease: esophageal carcinoma

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Neoplasms and pigmentation of thyroid glands in F344 rats exposed to 2,4-diaminoanisole sulfate, a hair dye component

2,4-Diaminoanisole sulfate was fed at dietary levels of 0.12% (low dose) or 0.5% (high dose) to groups of 50 male and 50 female inbred F344 rats for 78 weeks. By 107 weeks after the initial exposure, 58% of the male rats and 42% of the female rats administered the high dose had thyroid neoplasms, whereas only 7--8% of the controls developed them. Follicular cell carcinomas were the primary type of neoplasm induced. None of the controls had these tumors. The carcinomas, which were papillary, cystic, or solid, were highly invasive but did not metastasize. A brown pigment was present as granules primarily in thyroid follicular cells in all exposed rats. The amount of pigment as determined by an image-analyzing computer revealed that the cross-sectional area occupied by the pigment granules and the optical density of the granules were dose related.

Pathology of esophageal neoplasms and associated proliferative lesions induced in rats by N-methyl-N-benzylnitrosamine

Multiple squamous cell neoplasms of the esophagus were induced in 24 inbred F344 rats by sc injection of N-methyl-N-benzylnitrosamine at a dose level of 2.5 mg/kg weekly for 20 weeks. All of these rats also developed papillomas, 67% developed pedunculated papillary carcinomas, and 63% developed carcinomas that invaded the wall. Of 191 total neoplasms, 66% were papillomas, 17% were papillary carcinomas, and 17% were carcinomas that invaded the wall. The neoplasms were well differentiated with various degrees of keratinization. Anaplastic areas were found in most lesions, but were more common in carcinomas. Neoplasms that invaded the wall were sessile, with prominent intraluminal growth, or infiltrating, with predominant intramural growth. Penetration through the wall was observed, but neither metastases nor invasion of adjacent tissues was found. In addition to neoplasms, atypical endophytic proliferation of basal and spinous cells was observed in some of these rats. Proliferative or neoplastic changes were not observed outside the upper gastrointestinal tract.

Ultrastructural evidence concerning the mode of secretion of electron-dense granules by Clara cells

An ultrastructural study of the secretory activity of non-ciliated bronchiolar epithelial (Clara) cells has been made. Membrane-bound, electron-dense granules were observed in the apical cytoplasm of Clara cells, immediately beneath the terminal web, and within terminal web regions, with their limiting membranes in close association with the plasma membrane of the cell. Granules were also observed in cytoplasmic pockets with varying amounts of their surfaces exposed to the bronchiolar, lumen, or within cytoplasmic projections into the lumen. Granules that were enveloped in a thin, uniform coat of cytoplasm and granules with no associated cytoplasm were both found free in the bronchiolar lumen. The study is consistent with the conclusion that the granules are secretory in nature, being extruded by a merocrine and possibly an apocrine mechanism.

13-cis-Retinoic acid: inhibition of bladder carcinogenesis induced in rats by N-butyl-N-(4-hydroxybutyl)nitrosamine

Transitional cell carcinoma was induced in the bladders of male Fischer rats by 12 oral doses of the carcinogen N-butyl-N-(4-hydroxybutyl)nitrosamine. Feeding of 13-cis-retinoic acid after completion of carcinogen treatment diminished the number and severity of cancers and other proliferative lesions of the bladder.

Quantitation with an automated image analyzer of nuclearcytoplasmic changes induced by hydrocortisone in bladder epithelium

Thirty-eight urinary bladders from Fischer rats were organ cultured for 7 days in Ham's Medium F12 with varying concentrations of hydrocortisone added. Measurements of cell numbers and relative areas of nuclei and cytoplasm (N/C ratios) were made with an automated image analyzer on 1.5-micronm-thick plastic sections of the tissues. Epithelia cultured in the absence of hydrocortisone became hyperplastic and dysplastic and contained approximately 2.5 times as many cells per unit length as uncultured controls. N/C ratios were increased by over 50%, caused mainly by a decrease in the cytoplasmic area. Concentrations of hydrocortisone below 10(-7) M had no significant effect on the hyperplasia or N/C ratios. Increasing concentrations above 10(-7) M resulted in progressive decreases of both the number of cells per unit length and the N/C ratios. Epithelia cultured in 2 X 10(-5) M hydrocortisone were not significantly different from uncultured controls. N/C ratios from 85 fields with a wide range of values were quanititated both with the image analyzer and a manual point-counting technique. Linear regression analysis revealed a close linear relationship and a correlation coefficient of 0.922. The analyzer provided an efficient, accurate tool for quantitating morphological observations.

Use of an automated image analyser to quantitate cellular hyperplasia in urinary bladder epithelium

The feasibility of using an automated image analyser to evaluate quantitatively hyperplasia caused by N-butyl-N-(4-hydroxybutyl) nitrosamine in bladder epithelium was studied. The number of cells per unit length of epithelium was counted manually, and compared with automated measurements of: (1) the number of nuclei, (2) the number of positive tangents to the lower edge of nuclei, (3) the nuclear cross-sectional area, and (4) the epithelial cross-sectional area per unit length respectively. Regression of each of the automated measurements on the manual counts all revealed close linear relationships with correlation coefficients in excess of 0-9. Coefficients of variation for repetitive automated measurements were less than or equal to 0-06 in each of the four modes. The automated system resulted in a great saving in time over manual counting. It is concluded that the automated image analyser provides an accurate, precise, and efficient tool for estimating epithelial cell numbers in normal and hyperplastic bladder epithelia.

Epithelial and surfactant changes in influenzal pulmonary lesions

Pulmonary epithelial cell destruction in mice infected with PR8-A influenza virus has been studied with light and electron microscopy and enzyme histochemistry, and correlated with pulmonary surfactant activity. All epithelial cell types were infected by the virus, resulting in destruction, pneumonitis, and atelectasis by seven to ten days. Pulmonary surfactant activity decreased progressively following onset of infection, and was minimal by seven to ten days. Before types 1 and 2 alveolar pneumocytes regenerated, the regenerating bronchial cells grew peripherally into some of the denuded alveolar ducts and alveoli to form epithelial nodules. Eventually the types 1 and 2 pneumocytes regenerated to cover the alveolar surfaces that were not invaded by bronchial epithelium. This regeneration was associated with increased surfactant activity in the postinfluenzal lesions, suggesting that the type 2 pneumocytes are a source of surfactant.

The destruction of type 2 pneumocytes by airborne influenza PR8-A virus; its effect on surfactant and lecithin content of the pneumonic lesions of mice

Influenzal pneumonia has been studied in mice subjected to sublethal doses of airborne PR8-A influenza virus. Electron microscopy revealed that the virus propagated in and at the same time destroyed the ciliated and nonciliated bronchial cells and the types 1 and 2 alveolar pneumocytes. The regenerating bronchial membranes were metaplastic and grew peripherally into the surrounding alveolar ducts and alveoli to form epithelial nodules which caused obstruction and collapse of the involved lobes. The development of the lung lesions was correlated with phospholipid (lecithin) levels in consolidated and unconsolidated infected and normal lungs. As the lungs became more and more consolidated, there was a corresponding and significant decrease in the amount of phospholipid (dipalmitoyl lecithin) compared to the amount of normal or unconsolidated infected tissue. The destruction of the type 2 pneumocytes by the influenza virus and their failure to regenerate is considered to be the reason for the low phospholipid levels in the involved lobes, and thus an important cause of post-influenzal collapse in mice. The above adds additional evidence to the view that the type 2 pneumocytes are a major source of surfactant in mammalian lungs.

Manual Procedure for Direct Microassay of Serum Glucose by Use of o-Toluidine, and Its Adaptation to the SMA 12/60 AutoAnalyzer

A direct o-toluidine method for serum glucose is described as an alternative to the usual Cu—neocuproine method used with the Technicon SMA 12/60 AutoAnalyzer. Routine operation of the machine is simplified: the number of reagents and manifold lines is decreased and the dialyzer and pre-heating bath are eliminated. Deterioration of manifold tubing is minimized, while maintaining optimal machine sensitivity by adding borate and water to the reagent. Serum glucose was measured by the automated o-toluidine and Cu—neocuproine methods with similar, highly correlated results. Thus, the "normal limits" are unchanged and the same recorder graph paper may be used. A direct manual micro-method is also described, in which an anhydrous o-toluidine reagent is used. Results of manual and automated methods agree satisfactorily.