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PubMed1983

Enhancement of natural cytotoxicity by beta-endorphin.

The role of enkephalins, beta-endorphin, or other neuropeptides produced by the nervous system in the alteration of immune responsiveness is generally unknown. The present studies were undertaken to investigate the role of these neuropeptides in the modulation of human spontaneous cytotoxicity induced by natural killer (NK) cells. Natural cytotoxicity was measured by using a standard 51Cr release assay with radiolabeled K562 cells. NK activity was significantly enhanced by both beta-endorphin (30.5 +/- 11.5%, M +/- SE, relative enhancement at 50:1, effector:target (E:T) ratio, 10(-14)M beta-endorphin) and methionine-enkephalin (met-enkephalin) (27.4 +/- 9.7% relative enhancement at 10(-9)M). The magnitude of relative enhancement significantly correlated with increasing concentrations of beta-endorphin. Leucine-enkephalin, alpha-endorphin, and morphine did not augment NK activity. The enhancement of NK activity with beta-endorphin increased at all E:T ratios tested. Naloxone inhibited the augmentation of NK activity produced by beta-endorphin and met-enkephalin. By using a combination of a standard 51Cr release and soft agarose single cell analysis assays, beta-endorphin increased both the number of E:T cell conjugates and the number of active killer cells among target-binding cells. The maximal effector cell recycling capacity was increased by 170%. These studies provide new insight into the mechanisms by which neuropeptides produced by the nervous system can alter immune responsiveness.

Binding, Competitive↗
PubMed1993

Biochemical and functional alterations induced by CD23 ligation in the human promonocytic cell line U937.

The early events triggered in interleukin-4 (IL-4)-stimulated U937 cells by ligation of CD23/Fc epsilon RII with specific monoclonal antibodies (mAb) were analysed, as a model of the action of this molecule on the differentiation of promonocytic cells. As well as IL-4-activated human monocytes, addition of anti-CD23 mAb to IL-4-treated U937 cells triggered cAMP accumulation but did not evoke significant polyphosphoinositide hydrolysis. However, by a microspectrofluorometric technique allowing single cell analysis, anti-CD23 mAb was found to elicit calcium mobilization in these cells. In addition, the treatment induced phenotypic alterations in these cells, as evidenced by the acquisition of the monocyte marker CD14 and the increase of the alpha-chain (CD11a) and of the common beta-chain (CD18) of the leucocyte function-associated antigen 1 (LFA-1) family antigens. Although weaker than in monocytes, CD23 ligation evoked a small secretion of the pro-inflammatory mediators IL-6 and thromboxane B2. These data suggest that a significant maturation of promonocytic cells towards a more mature monocytic phenotype can be achieved through successive exposure to IL-4 and CD23 ligation.

Antibodies, Monoclonal↗
PubMed1995

All-trans- and 9-cis-retinoic acid inhibit growth of normal human and murine B cell precursors.

In the present paper we demonstrate that physiologic levels (10 nM) of both all-trans- and 9-cis-retinoic acid (RA) are potent inhibitors of the growth of human as well as murine B cell precursors in vitro. Ten nanomolar concentrations of all-trans- and 9-cis-RA reduced the DNA synthesis ([3H]thymidine uptake) of human B cell precursors (CD19+ IgM-) stimulated with O-tetradecanoylphorbol-13-acetate and ionomycin by approximately 55% and 70%, respectively. Human B cell precursors stimulated with low m.w. B cell growth factor were also inhibited by RA. Ten nanomolar concentrations of either isoform of RA reduced DNA synthesis by approximately 50%. No effect of RA on differentiation to sIgM positive cells was noted. The potent growth-inhibiting effect of RA on human B cell precursors was confirmed in the murine cell system. B lymphopoiesis from murine hematopoietic precursors (Lin-B220(+)-containing cells) was induced by stimulation with IL-7. Concentrations of all-trans- and 9-cis-RA as low as 10 pM reduced the colony-forming ability of the IL-7-stimulated Lin-B220(+)-containing cells. Ten nanomolar concentrations of either isoform reduced colony formation by approximately 60%. RA was not toxic to the cells, as the inhibition of colony formation after 24 h was reversible at concentrations as high as 1 microM. The growth-inhibiting effect of RA was directly mediated, as revealed by single cell analysis of the Lin-B220(+)-containing cells. Thus, vitamin A appears to have an important role in regulation of B lymphopoiesis.

Animals↗
PubMed1995

Inhibition of human vascular smooth muscle cell migration and proliferation by beta-cyclodextrin tetradecasulfate.

Smooth muscle cell migration and proliferation are important regulatory processes in the development of intimal thickening after vascular injury. beta-cyclodextrin tetradecasulfate, an orally active synthetic heparin mimic, is effective in inhibiting rabbit aortic smooth muscle cell proliferation in vitro and in limiting restenosis in an experimental angioplasty restenosis model in rabbits (Hermann et al., 1993). However, its effects on migration are unknown, as are its effects on human vascular smooth muscle cell biology in general. Using a Transwell assay system, we demonstrated a dose dependent inhibition of human vascular smooth muscle cell random migration for beta-cyclodextrin tetradecasulfate with half maximal inhibition between 100-500 micrograms/ml and 85 +/- 1% inhibition at 10(3) micrograms/ml (P < .001, n = 4). At this latter concentration, inhibition of migration was also demonstrable using a linear under-agarose assay, where the mean velocity for beta-cyclodextrin tetradecasulfate-treated cells (8 +/- 2 microns/h, +/- S.E.) was significantly less than for control cells (21 +/- 4, P < .01), but equaled that of control cells 48 h after drug withdrawal (21 +/- 1, P = NS). Single cell analysis over 17 h using time lapse video microscopy revealed significant inhibition of total migration pathway distance for beta-cyclodextrin tetradecasulfate-treated smooth muscle cells compared with control smooth muscle cells (0.40 +/- 0.03 mm vs. 0.73 +/- 0.03, P < .01). We also demonstrated a dose-dependent inhibition of serum-induced proliferation by beta-cyclodextrin tetradecasulfate in both cultured human umbilical vein and coronary artery smooth muscle cells. To assess whether beta-cyclodextrin tetradecasulfate had any direct cellular toxicity, we measured the release of intracellular LDH at 6 or 24 h. At 10(3) micrograms/ml or less, there was no increase in LDH release compared with untreated cultures. Thus, beta-cyclodextrin tetradecasulfate may be an effective agent in inhibiting intimal thickening after vascular injury by limiting both smooth muscle cell migration and proliferation.

Cell Division↗
PubMed1994

[A study on subpopulation of helper T cells in chronic inflammatory demyelinating polyneuropathy].

Chronic inflammatory demyelinating polyneuropathy (CIDP) is thought to be an inflammatory autoimmune disease against peripheral myelin. Recently several animal models have suggested that preferential activation of Th1 cell response is central to the pathogenesis of this disease. We studied the function of CD4 positive T cell subsets, Th1 cells and Th2 cells by analyzing their representative secreting cytokines. Th1 cells secrete Interferon gamma (IFH gamma) and Th2 cells secrete Interleukin 4 (IL4). Using enzyme linked immunospot (ELISPOT) assay, a very sensitive single cell analysis system, we enumerated IFN gamma and IL4 secreting peripheral blood lymphocytes in patients with CIDP. Also we examined these cytokines in supernatants of cultured peripheral blood lymphocytes by a very sensitive enzyme linked immunosorbent assay (ELISA), Immunodot assay and westernblot assay. In culture supernatants of CIDP patients' peripheral blood lymphocytes, the levels of both IFN gamma and IL4 were higher during the exacerbation stage than the remission stage. In the remission period, though the levels of IFN gamma and IL4 were low in the supernatants, the ELISPOT assay revealed that the number of IL4 secreting cells was elevated compared with that of IFN gamma secreting cells. Our results suggest that the switch from Th1 to Th2 might play an important role in inducing the remission stage in patients with CIDP.

Adult↗
PubMed1977

Microchemical analytical techniques of potential clinical interest.

Microchemical techniques with the capability of single-cell analysis will become increasingly important in clinical laboratory practice. One of the current moves underway in this direction is determination of enzyme activities of cells by microscale spectrophotometry and spectrophotofluorometry for prenatal diagnosis of inherited enzyme deficiencies. Three less-common microanalytical techniques are considered here that are of potential interest in laboratory medicine. The first is dilatometry, which provides a means for enzyme or substrate assay involving measurement of the change in volume or density accompanying chemical reaction in solution. In this connection, the measurement of specific gravity itself to obtain certain chemical information is also of interest. The second of these techniques is the use of spectrophotometry to measure oxygen uptake for functional assays of cells. The third is the use of luminometry in a general system of analysis for determination of many important biochemical substances and activities. Each of these techniques can be used for microscale analysis without sacrifice of precision or accuracy; each is relatively simple, instrumentally ant technically, and could be automated.

Animals↗
PubMed1997

Multiple G-protein involvement in parathyroid hormone regulation of acid production by osteoclasts.

The involvement of multiple G-proteins in parathyroid hormone regulation of acid production was demonstrated in a highly enriched osteoclast population. Osteoclasts were isolated from the endosteum of 2.5 to 3-week-old chicken tibia using sequential enzymatic digestion. Single cell analysis of acid production was accomplished using microscope photometry and vital staining with acridine orange, a hydrogen ion concentration sensitive fluorescent dye. Lithium chloride, an uncoupler of G-proteins from their respective receptors, blocked parathyroid hormone stimulated production of acid. Cholera toxin, which permanently activates Gs-proteins, mimicked PTH stimulation. Pertussis toxin, which prevents receptor interaction with Gi- and Go-proteins, blocked both 10(-8) M and 10(-11) M PTH stimulated acid production, suggesting that the pertussis toxin-sensitive G-protein is utilized at both PTH concentrations. Immunoblots of osteoclast plasma membrane proteins, using a panel of antibodies generated against specific G-protein alpha subunits, revealed a 48 kDa Gs alpha, a 41 kDa Go alpha, a 34 kDa Gi alpha-3, and a unique 68 kDa G alpha subunit, with the 41 kDa and 34 kDa bands being the most intense. Immunoblots of osteoblast plasma membrane proteins had a substantially different profile with the most intense bands being a Gs alpha (48 kDa) and a Go alpha (36 and 38 kDa). The studies suggest the utilization of at least two different G-proteins in the parathyroid hormone regulation of acid formation by osteoclasts, a Gs and a pertussis toxin-sensitive G-protein (Go and/or Gi alpha-3).

Acids↗
PubMed1997

Evidence for a large compartment of IgM-expressing memory B cells in humans.

The recent finding of somatically mutated mu heavy chain transcripts in human peripheral blood (PB) B lymphocytes suggests that T-dependent B-cell memory might not be restricted to class-switched cells. We provide here evidence that IgM-only PB B cells are likely to be the IgM-expressing counterpart of classical (IgM- IgD-) memory B cells in humans. As shown by molecular single cell analysis, most IgM-only cells carry mutated V region genes, like class-switched cells. Although both subsets represent populations of nonactivated, resting cells, they express higher levels of Ig mRNA than naive (IgM+ IgD+) B cells. IgM-only and class-switched cells are CD38- CD77-, and mostly CD23-, thus neither resembling germinal center nor naive B cells. Because many IgM-expressing B cells located in secondary lymphoid tissues resemble IgM-only PB B cells in terms of cell phenotype, we propose that the human lymphoid system contains a large compartment of IgM-expressing memory cells. Moreover, these cells seem to represent the nonmalignant counterparts of IgM-expressing tumor cells in sporadic Burkitt's lymphoma, MALT lymphoma, monocytoid B-cell lymphoma, and diffuse large-cell lymphoma that were found to harbor somatically mutated V genes.

B-Lymphocyte Subsets↗
PubMed1997

Cell fate specification and symmetrical/asymmetrical divisions in the developing cerebral cortex.

Two different modes of cell division are adopted by progenitor cells to generate the neurons and glia of the cerebral cortex: they either divide symmetrically to generate other progenitors or a pair of postmitotic cells or divide asymmetrically to generate both a progenitor and a postmitotic cell. In this study we used a lineage marker, the BAG retrovirus, in embryonic day 16 rats in combination with bromodeoxyuridine (BrdU) to identify patterns of cell generation in the cerebral cortex, and investigated the relationship between the phenotype of cells and the history of their lineages. The location, phenotype and birth order of clonally related cells were studied in the subsequent 3 weeks. Only pyramidal neurons and/or astrocytes formed discrete clusters in which several generations of family members were present, whereas nonpyramidal neurons were found exclusively in pairs or as single cells. Analysis of BrdU levels in these cells showed that nonpyramidal neurons were originally part of larger clones and were found dispersed in the neocortex because of tangential migration of their progenitors, dispersion of postmitotic cells, or death of clonal relatives. These results suggest that both symmetrical and asymmetrical division can be adopted by progenitor cells to generate cortical neurons and glial cells and that cell extrinsic events contribute to the isolation of nonpyramidal neurons.

Animals↗
PubMed1997

Neuronal dopamine subpopulations maintained in hypothalamic slice explant cultures exhibit distinct tyrosine hydroxylase mRNA turnover rates.

Changes in mRNA stability have been shown to regulate critical intracellular processes. In this investigation, we studied tyrosine hydroxylase (TH) mRNA turnover in functionally and anatomically distinct dopaminergic (DA) populations of the rat hypothalamus. To this end, long-term slice explant cultures from postnatal, preoptic area/hypothalami, containing three anatomically discrete DA populations, were generated and maintained under defined conditions. The organotypic cultures were treated with the transcription inhibitors 5,6-dichloro-1-D-ribofuranosylbenzimidazole or actinomycin D and processed for in situ hybridization histochemistry. Relative TH mRNA content per cell was quantitated. Single-cell analysis showed marked differences in basal TH mRNA turnover rates between DA neuronal populations. Anterior and midhypothalamic DA neurons exhibited half-time turnovers of 9-12 and 11-23 hr, respectively. In contrast, in the caudal hypothalamus, DA neurons of the arcuate nucleus had a significantly lower baseline level and more rapid turnover (6-7 hr) of TH mRNA. This investigation shows that basal turnover of a phenotypic mRNA, TH mRNA in DA neurons, is not an intrinsic property of the phenotypic marker. Furthermore, we found that destabilization of TH mRNA in the caudal hypothalamus corresponds to the known rhythmic output displayed by arcuate DA cells and, as such, may be critical for normal function of this population. We propose that intrinsic differences in the post-transcriptional regulation of TH permits neuronal subpopulations, which subserve different physiological functions, an additional mechanism to control DA biosynthesis in response to their unique needs.

Animals↗
PubMed1997

V delta 1 T cells expanded in the blood throughout HIV infection display a cytotoxic activity and are primed for TNF-alpha and IFN-gamma production but are not selected in lymph nodes.

We have previously reported significant alterations of gamma delta subset distribution in the peripheral blood of HIV-infected donors. These modifications are characterized by the depletion of the V delta 2 subset associated with a strong increase in peripheral V delta 1 T cells. In addition, the latter exhibit ex vivo an activated phenotype and show a restricted complementarity-determining region 3 (CDR3) repertoire. In the present report we first address the question of the origin of these expanded cells. The lack of expansion and the Gaussian complementarity-determining region 3 size distribution of lymph node V delta 1 T cells suggest that lymph nodes do not represent the site of specific activation of this subset. The function of blood V delta 1 T cells was also explored. We report that patients' V delta 1 T cells express high levels of perforin and display an in vitro cytotoxic activity, whose characteristics are different from those of NK and LAK cells. In addition, single cell analysis of cytokine production revealed that, in contrast to V delta 1 T cells from control donors, patients' V delta 1 T cells are primed in vivo for IFN-gamma and TNF-alpha production. Together, these results indicate that in the course of HIV infection, expanded blood V delta 1 T cells are differentiated into a functional subset and raise the question of the contribution of this subset to AIDS pathogenesis.

Cell Differentiation↗
PubMed1997

Real-time monitoring of estrogen-regulated gene expression in single, living breast cancer cells: a new paradigm for the study of molecular dynamics.

Elucidation of the molecular mechanisms underlying the development and progression of breast cancer has been hindered by two considerations. First, mammary tumor cells exhibit a considerable degree of morphological and functional heterogeneity. Thus, the conventional strategy of measuring a population response may not provide an accurate reflection of the behavior of the functional unit: an individual cell. Second, important regulatory events are generally separated in time, yet the strategies we use to monitor them are usually static as opposed to dynamic. With these considerations in mind, it would appear that a system for studying this problem should ideally combine the resolving power of single-cell analysis with a dynamic paradigm for making multiple measurements of gene expression from the same, living cell. This report summarizes our efforts at developing, validating, and optimizing such a system for monitoring hormone-driven gene expression in T47-D human breast cancer cells.

Breast Neoplasms↗
PubMed1997

Luteinizing hormone-releasing hormone (LHRH) neurons maintained in hypothalamic slice explant cultures exhibit a rapid LHRH mRNA turnover rate.

Evidence indicates that neuropeptide gene expression is tightly coupled to biosynthesis and secretion. Moreover, rhythmic gene expression often accompanies rhythmic secretion. Luteinizing hormone-releasing hormone (LHRH) neurosecretion, which regulates gonadal function, is pulsatile, with interpulse intervals of approximately 1 hr and pulse decays of <30 min in rats. As a basis for a rapid fall in peptide secretion, we hypothesize that LHRH mRNA levels rapidly decay. To address this hypothesis, we examined LHRH mRNA turnover in primary postnatal LHRH neurons maintained in long-term hypothalamic/preoptic area slice explant cultures, using in situ hybridization histochemistry (ISHH). Relative LHRH mRNA content per cell was quantitated by single-cell analysis after transcription inhibition with 5, 6-dichloro-1-D-ribofuranosyl-benzimidazole (DRB) or actinomycin D. Cultures were maintained in serum-free medium with tetrodotoxin to suppress spontaneous electrical activity and hence assess only intrinsic cellular activity. A plot of LHRH mRNA level per cell versus DRB treatment time showed a rapid initial decay of LHRH mRNA (t1/2, 5-13 min), followed by a slower decay rate (t1/2, 329-344 hr). LHRH cell number after drug treatment as determined by immunocytochemistry did not change. Comparison of mammalian LHRH mRNA 3'-untranslated regions showed two conserved regions. These data indicate that, in primary LHRH neurons, LHRH mRNA has an intrinsically high rate of turnover and a mRNA stabilization component. Foremost, decay of LHRH mRNA, the fastest reported for a neuropeptide to date, corresponds to the decay of LHRH peptide pulses.

Animals↗
PubMed1998

Differential susceptibility to activation-induced apoptosis among peripheral Th1 subsets: correlation with Bcl-2 expression and consequences for AIDS pathogenesis.

It has been proposed that HIV infection is associated with an imbalance in Th1 and Th2 subsets. Recent reports indicate that Th1 and Th2 effectors differ in their susceptibility to activation-induced apoptosis. To determine whether increased T cell apoptosis in HIV-infected patients contributes to alterations in cytokine synthesis, we performed single-cell analysis of type 1 and type 2 cytokine production by CD4 and CD8 T cells, simultaneously with detection of apoptosis. We demonstrate that a differential alteration in representation of Th1 subsets, rather than commitment of T cells to secrete Th2 cytokines, occurs throughout HIV infection. A significant decrease in the number of IL-2- or TNF-alpha-producing T cells was observed, whereas those producing IFN-gamma remained preserved. Furthermore, there is a gradient of susceptibility to activation-induced apoptosis (IL-2 < IFN-gamma < TNF-alpha) among the different Th1 subsets. This gradient was detected in both CD4 and CD8 subsets, as well as in control donors and HIV-infected patients, in whom the susceptibility to apoptosis of IL-2 and IFN-gamma producers was increased compared with controls. This differential intrinsic apoptosis susceptibility of Th1 effectors was found to be tightly regulated by Bcl-2 expression. In HIV-infected persons, disappearance of IL-2-producing T cells was a good indicator of disease progression and was correlated with the progressive shrinkage of the CD4+ CD45RA+ T cell compartment and a gradual increased susceptibility to activation-induced apoptosis of the IL-2-producing subset. This close relationship between the CD45RA/CD45R0 ratio, the level of type 1 cytokine production, and susceptibility to apoptosis should be considered in HIV-infected patients under antiviral or immune-based therapies.

Acquired Immunodeficiency Syndrome↗
PubMed1998

Fluorescence in situ hybridization analysis of single-cell trisomies for determination of clonality.

Conflicting data currently exist pertaining to the significance of single-cell trisomies found in a 20-cell cytogenetic analysis of hematologic malignancies. In order to determine the clonality of the numerical abnormalities found in these cases, we performed a retrospective study on a cohort of patients previously analyzed by GTG-banding at Rhode Island Hospital, from July 1, 1990 to November 30, 1996. Fluorescence in situ hybridization (FISH) was performed using chromosome enumeration probes on previously fixed bone marrow and, in some cases, peripheral blood slides from patients identified to have single-cell trisomies of selected chromosomes in 20-cell routine GTG-banded analyses. We seek to determine whether the single cell trisomies represent random nonclonal events or "the tip of an iceberg." The results of the present study indicate that a single unifying answer to the above question does not exist. While some cases are apparently random events as predicted by chance, other cases appear to represent "the tip of an iceberg." It is therefore important for cancer cytogeneticists to interpret the results of each patient on a case-by-case basis and to formulate the most optimal strategy for follow-up in the particular case under study.

Adolescent↗
PubMed2026

Integrative evidence-knowledge marker selection enhances LLM-based cell type annotation in single-cell RNA-seq analysis.

BACKGROUND: Cell type annotation is essential for gaining biological insight from single-cell RNA sequencing data, yet manual labeling remains time-consuming and difficult to reproduce. Various computational approaches have been developed to automate this process, and recent studies suggest that large language models can infer cell types with promising accuracy in single-cell analysis. However, most workflows still rely on cluster-specific markers derived from gene expression alone or manual curation. As a result, marker selection can be sensitive to statistical criteria and dataset-dependent bias, which may lead to the selection of less informative genes or missing important markers, while providing limited biological context. RESULTS: To address this limitation, we introduce CELLIA, an LLM-based workflow for automated and robust cell type annotation. CELLIA employs an integrative evidence-knowledge marker selection strategy that combines statistical differential expression criteria with curated tissue-specific marker resources to identify informative marker genes. In benchmarking analyses of 102 cell types, this approach improved agreement with manual annotations. In addition, CELLIA achieved higher agreement in subtype-level analyses of closely related immune populations and was further evaluated in a non-immune stromal subtype setting, covering 25 cell types in total. CONCLUSION: By integrating evidence-knowledge from gene expression with curated biological prior knowledge, CELLIA provides a more stable marker selection and improves the reliability of LLM-cell type annotation.

Cell type annotation↗
PubMed1954

One-step growth curve of Western equine encephalomyelitis virus on chicken embryo cells grown in vitro and analysis of virus yields from single cells.

The rate of adsorption of WEE virus onto chicken embryo cells in vitro was determined both on a cell layer and on a cell suspension. One-step growth curves were determined in cell suspensions and on cell layers. The latent period varied between 2 and 3(1/2) hours; it was shorter on cell layers and decreased with higher multiplicity of infection. The shortest period is probably the real latent period. The growth curves of the virus showed an initial exponential rise and reached a maximal constant value after 6 to 8 hours. The maximum virus yield per cell varied between 200 and 1000 on the cell layer, and between 100 and 200 in suspended cells. The yield of single infected cells was determined. An analysis of the distributions of the individual yields obtained after various periods of virus growth led to two main conclusions: (1) that virus is released from the same cell over a long period of time; (2) that one phase of the intracellular virus growth is exponential.

Animals↗
PubMed1996

Tumor proliferative activity is predictive of pathological stage in clinical stage A nonseminomatous testicular germ cell tumors.

PURPOSE: Traditional histopathological features have failed to predict accurately the pathological stage of clinical stage A nonseminomatous germ cell tumors of the testis. Based on pilot studies in nonconsecutive patients at our university, we evaluated nontraditional risk factors (cell cycle analysis by flow cytometry, deoxyribonucleic acid analysis by single cell cytophotometry [image analysis] and assessment of proliferative activity by immunohistochemistry) combined with histopathological features in consecutive patients with clinical stage A nonseminomatous testis cancer. MATERIALS AND METHODS: Orchiectomy specimens from 105 consecutive patients with clinical stage A nonseminomatous germ cell tumors who underwent retroperitoneal lymph node dissection (76 with pathological stage A disease and 29 with proved metastasis) were recut, histopathologically reviewed, immunohistochemically stained with proliferation markers (for example Ki-67/MIB-1), and examined by flow cytometry and image analysis. RESULTS: After multiple logistic regression analysis, the G2M+S cell cycle fraction of the aneuploid tumor stemline was the most predictive parameter of pathological stage (p = 0.0004). Using a cutoff of 41%, patients with metastasis were predicted with a sensitivity of 71%. Of 61 patients with a G2M+S value of less than 41%, 53 had pathological stage A cancer (negative predictive value 87%). A low volume of embryonal carcinoma was predominant in patients at low risk for metastasis and MIB-1 immunohistochemical staining identified 23% of patients with pathological stage A tumor who were at extremely low risk for metastatic disease. CONCLUSIONS: Assessment of tumor cell proliferation cannot classify accurately high risk patients at a clinically applicable level. However, identification of patients at low risk for metastasis by flow cytometry, immunohistochemical proliferation markers and volume of embryonal carcinoma may be possible at the 90% level. MIB-1 staining is able to classify patients at extremely low risk for metastasis. These parameters deserve further study, since identification of patients at extremely low risk for metastasis could potentially decrease overall morbidity in the management of clinical stage A nonseminomatous testis cancer.

Cell Division↗