Detection of numerical chromosomal aberrations by flow cytometry: a novel process for identifying aneugenic agents.

Aneuploidy plays a significant role in adverse human health conditions including birth defects, pregnancy wastage, and cancer. Currently, there is no screening method sufficiently validated that can be used routinely to identify aneugenic agents in vitro because most conventional test systems rely on the labor-intensive microscopic assessment of the aneuploid cell population. Our laboratory has recently developed a flow cytometry-based procedure for assessing numerical chromosomal aberrations in mitotic populations of lymphocytes on the basis of DNA content. Studies were conducted in 24 h treated human lymphocyte cultures to determine the sensitivity of this flow cytometry-based procedure to detect aneugenic agents. A comparison between the microscopic and the flow cytometry-based procedures for scoring polyploidy shows a strong agreement exists between the two methods. Treatments with two known aneugenic agents, griseofulvin, and paclitaxel (taxol), resulted in a dose-related increase in the mitotic index, aneuploidy, and polyploidy. In contrast, results from the treatments with two known clastogenic agents, mitomycin-C, and etoposide, show a dose-related decrease in the mitotic index with a slight increase in the frequency of hypodiploidy at concentrations that produce severe chromosomal breakage. There were no increases in hyperdiploidy and polyploidy observed. In conclusion, the reproducibility of the results obtained in this study indicates that this flow cytometry-based procedure for assessing numerical chromosomal effects in mitotic populations on the basis of DNA content is promising for the routine detection and characterization of aneugenic agents.

Measuring the mitotic index in chemically-treated human lymphocyte cultures by flow cytometry.

In the human lymphocyte chromosome aberration assay, the mitotic index (MI) is the standard cytotoxic parameter for determining which test concentrations will be evaluated for chromosome aberrations. Assessment of the MI is performed microscopically by determining the frequency of mitotic cells in a population of 1000 cells. With the commercial availability of antibodies to the mitosis-specific marker, phosphorylated-histone H3 at serine 10, automating the assessment of the MI using flow cytometry is now possible [Cytometry 32 (1998) 71]. Our laboratory has utilized and validated this technology to measure the mitotic index of chemically-treated human lymphocyte cultures. Comparisons between the microscopic and flow MI frequencies from 24h treatments with mitomycin-C, aphidicolin, eugenol, etoposide, hydroxyrurea, potassium cyanide, staurosporine, ethyl alcohol, noscapine and colcemid((R)) are presented. Our results show that the mitosis specific H3-P marker is excellent for measuring the MI frequency in human lymphocyte cultures treated up to toxic concentrations. In addition, this study demonstrates that automation of analysis by flow cytometry is an excellent alternative to the microscopic method of analysis producing less variability than the microscopic scoring and a more complete dose response curve.

Noscapine hydrochloride-induced numerical aberrations in cultured human lymphocytes: a comparison of FISH detection methods and multiple end-points.

The cytokinesis block in vitro micronucleus (MN) assay in combination with CREST staining and fluorescence in situ hybridization (FISH) with chromosome-specific DNA probes allows mechanistic information on the induction of numerical chromosomal aberrations to be obtained through a rapid and simple microscopic analysis. These techniques can now be used to investigate relationships between the induction of chromosomal loss, non-disjunction and polyploidy by aneuploidy-inducing agents. In the present study, we treated 72 h cultured lymphocytes for the last 24 h of culture with various concentrations of the cough medicine noscapine hydrochloride (NOS) (3.9-120 micro g/ml) in the presence of either cytochalasin B (CYB) (3 micro g/ml) or 5-bromo-2'-deoxyuridine (BrdU) (1 micro M). Using the CREST staining modified MN assay in the CYB-treated cultures, we detected significant increases in CREST-positive but not CREST-negative MN in both binucleated and, to a lesser extent, mononucleated cells, demonstrating the ability of this compound to induce chromosomal loss. In addition, using FISH with chromosome 1- and 9-specific classical satellite probes, a significant induction of chromosomal non-disjunction in the binucleated lymphocytes and polyploidy in the mononucleated lymphocytes was seen, indicating that polyploidy induced by NOS may occur without progression through a normal anaphase and/or telophase. In the BrdU-treated cultures, a dose-dependent induction of hypodiploidy, hyperdiploidy and polyploidy was observed using FISH with a chromosome 9-specific alpha-satellite probe in the labeled cells. By comparison, in the unlabeled non-cycling cells, only a slight increase in hyperdiploidy/polyploidy but not hypodiploidy was seen. A comparison of the effects seen at different concentrations shows that at the lower effective concentrations, all three types of numerical aberrations, chromosomal loss, non-disjunction and polyploidy, contributed to the numerical aberrations seen, whereas at the highest concentration tested, polyploidy was the predominant alteration. These studies indicate that FISH in combination with CYB or BrdU immunfluorescent staining can be sensitive tools for the identification of aneuploidy-inducing agents.

A prospective, randomized, double-blind, placebo-controlled trial evaluating the effect of nystatin on the development of oral irritation in patients receiving high-dose intravenous interleukin-2.

Interleukin-2 (IL-2) has been used to treat patients with metastatic melanoma and renal cell cancer for nearly two decades, and much progress has been made in ameliorating its adverse effects. One bothersome adverse effect, oral pain or oral irritation, is usually treated with an oral antifungal antibiotic, nystatin. The authors performed a prospective, randomized, double-blind, placebo-controlled trial involving 64 patients to evaluate the effect of prophylactic administration of nystatin or placebo on the development of oral irritation in patients receiving high-dose intravenous IL-2. No difference was found between patients randomized to receive nystatin or placebo in their rates of development of oral irritation, the severity of IL-2 adverse effects, the duration of their treatment, the rate of development of positive studies for oral yeast, or their pattern of experiencing other adverse effects. Thus, patients who receive high-dose intravenous IL-2 should not be treated prophylactically with nystatin to prevent oral irritation, and clinicians should seek evidence of the presence of oral thrush before using antifungal agents to treat oral pain in these patients.

Clinical pathways for managing patients receiving interleukin 2.

As biologic therapies enter the mainstream for cancer and HIV treatments, clinicians need the knowledge and expertise to safely and competently care for their patients who are undergoing these therapies. This article provides an overview of the immune system, emphasizing the elements that are affected by the biologic agent interleukin 2 (lL-2), lL-2 has been approved for use in the treatment of metastatic renal cell carcinoma and metastatic melanoma. Clinical trials currently are being conducted to determine its use in treating other cancers. The severity of side effects of lL-2 varies with the dose, route, and schedule of administration. The most common effects with all methods of administration are flu-like symptoms. Because the side effects of lL-2 are relatively predictable, clinical pathways offer practical tools for anticipating and managing the toxicities associated with lL-2 administration.

Surgery for cancer patients. Critical care needs.

Patients with cancer provide a unique challenge for critical care nurses. Outcomes of clinical trials, new surgical modalities, and pioneering cancer treatments have helped prolong lives. The patient with cancer can require surgical and critical care intervention at the time of diagnosis, at the point of definitive therapy, or in the later stages of disease. Treatment is individual and sometimes aggressive. Surgical intervention is undertaken with a view toward the patient's ultimate outcome, quality of life, and potential cure. Multimodality cancer therapy will continue to flourish, demanding astute assessment skills by the critical care nurse. The critical care nurse must be able to integrate knowledge of the patient's type of cancer, treatment history, comorbid conditions, and surgical interventions into routine postoperative critical care.

Noscapine hydrochloride disrupts the mitotic spindle in mammalian cells and induces aneuploidy as well as polyploidy in cultured human lymphocytes.

Noscapine hydrochloride is a centrally acting antitussive opium derivative widely used in cough suppressants. Recent studies have reported that noscapine is a potent inducer of polyploidy but not of aneuploidy in vitro. To obtain more comprehensive information about the cytogenetic effects of this compound, we treated cultured human lymphocytes (HPL) and Chinese hamster ovary (CHO) cells with various concentrations of noscapine hydrochloride. Using a differential staining technique noscapine was shown to disrupt the mitotic spindle at concentrations < 5 micrograms/ml in both cell types. The use of multicolor fluorescence in situ hybridization (FISH) on noscapine-treated human lymphocytes showed a dose-dependent induction of hyperdiploidy of chromosome 1 but not of chromosomal breakage in the 1cen-q12 region under in vitro conditions, indicating that noscapine is specifically inducing numerical chromosomal aberrations. FISH with probes targeting different chromosomes revealed that noscapine is capable of inducing both polyploidy and true hyperdiploidy. Our results show that noscapine, by disrupting the function of the mitotic spindle, has the ability to induce aneuploidy and not uniquely polyploidy as previously reported. By using these types of molecular cytogenetic techniques, it should be possible to evaluate the ability of noscapine to induce aneuploidy in the upper intestinal tract in vivo.

Preclinical toxicology studies with azithromycin: genetic toxicology evaluation.

Azithromycin was subjected to a series of three in vitro and one in vivo genetic toxicology assays for the detection of drug-associated gene or chromosomal effects. In the Ames Salmonella typhimurium tester strains TA1535, TA1537, TA98 and TA100, the presence of azithromycin was not associated with any increase in the number of his- revertants. Urine from mice dosed with up to 200 mg/kg of azithromycin also had no effect on the number of revertants in these same strains suggesting the absence of mutagenic excretory products following oral exposure. When tested up to the cytotoxic level of 240 micrograms/ml, azithromycin caused no increase in the mutant frequency at the thymidine kinase locus of L5178Y/TK cells. Both the mammalian and microbial gene mutation assays included the presence of rat-liver postmitochondrial (S9) fraction for the detection of mutagenic biotransformation products. Mitogen-stimulated human lymphocytes cultured in the presence of 2.5-7.5 micrograms/ml azithromycin for 24 h or 30.0-40.0 micrograms/ml azithromycin for 3 h in the presence of rat S9 had chromosomal aberration frequencies that were no different than negative control cells even though slight to moderate mitotic suppression was associated with these concentrations. In vivo assessment of this compound was completed in male and female mice with a single oral dose of 200 mg/kg followed by sacrifice at 6, 24 or 48 h later and metaphase analysis of bone marrow for chromosomal aberrations. No statistically significant elevations of chromosomally aberrant cells were found. We conclude that azithromycin does not cause gene mutations in microbial or mammalian cells, or chromosomal aberrations in cultured human lymphocytes or in mouse bone marrow in vivo.

Genetic profile of a nalidixic acid analog: a model for the mechanism of sister chromatid exchange induction.

In recent years, evidence has accumulated that suggests that mammalian topoisomerase may play a role in the formation of spontaneous or chemically induced sister chromatid exchange (SCE). In microbial systems, nalidixic acid is known to disrupt the function of a topoisomerase-like enzyme, DNA gyrase. To explore the possible relationship to topoisomerase function and SCE formation in mammalian cells, an analog of nalidixic acid with potent topoisomerase II inhibitory activity was selected for examination in a variety of genetic toxicology assays. This analog, CP-67,015, proved to be a positive direct-acting mutagen in the L5178Y/TK+/-, CHO/HGPRT, and V79/HGPRT systems. However, no gene mutational activity was observed using the Ames test in direct plate, mouse and rat metabolic activation, and mouse urine tests. In vitro cytogenetic studies showed strong clastogenic activity in human lymphocytes and in CHO cells. Compound-induced chromosome damage was also observed in vivo in mouse bone marrow cells. Surprisingly, SCE studies in vitro in human lymphocytes or CHO cells showed only slight increases, even at levels producing severe chromosome breakage. Mouse bone marrow showed no significant elevation of SCE following parenteral treatment with CP-67,015. These results, taken together, demonstrate that CP-67,015 is a direct-acting mutagen in mammalian cells with both gene and chromosomal level effects. The relative ineffectiveness in producing SCEs suggests that CP-67,015 may interfere with a DNA replicative/repair process, perhaps by alteration of one or more DNA polymerase activities. This suggestion is based in part on the known effect of the analog nalidixic acid on DNA gyrase in microbial cells and on topoisomerase in mammalian cells. The profile of genetic activity of CP-67,015, coupled with its inhibitory effect on topoisomerase function, gives rise to a model for SCE formation that is based on anomalies of topoisomerase activity during DNA synthesis.