Time course of opsin expression in developing rod photoreceptors

We have investigated the time course of rod photoreceptor determination in the goldfish retina. Rod precursor cells located in the outer nuclear layer of the mature retina continuously generate rod photoreceptors. In this study, we asked when rod precursor cells begin to express opsin, which would signal their commitment to the rod pathway of differentiation. There are three possibilities: a rod precursor could express opsin while still mitotic, at or shortly after the terminal mitosis but before differentiation, or during differentiation. We used immunocytochemistry with antibodies against bromodeoxyuridine, BrdU (a thymidine analogue) and against opsin to determine when during the mitotic history of a cell the expression of opsin first occurred, taking a double labelled cell to be evidence of commitment to the rod cell fate. We found that the first double labelled cells appeared at 4 days after BrdU injection. The number of double labelled cells increased to peak at 10 days, and then fell. These results support the hypothesis that dividing rod precursor cells are probably multipotent stem cells not committed to the rod cell fate.

DNA synthesis in radiation-induced micronuclei studied by bromodeoxyuridine (BrdUrd) labelling and anti-BrdUrd antibodies

DNA synthesis in radiation-induced micronuclei of Chinese hamster cells was studied as a function of time after irradiation using pulse labelling of cells with bromodeoxyuridine (BrdUrd) and an immunofluorescence technique with anti-BrdUrd antibodies. It was shown with this technique that DNA synthesis in micronuclei corresponds with DNA synthesis in nuclei during S phase in approximately 98% of the micronuclei. The presence of radiation-induced micronuclei that are too large to be produced by acentric fragments alone was therefore attributed at least in part to DNA synthesis in micronuclei. A partially synchronized progression of micronuclei from G1 phase into S phase could be observed allowing the measurement of the duration of G1 phase in cells containing micronuclei. The duration of G1 phase in these cells agreed with the duration of G1 phase in unirradiated cells.

Cell kinetic study on experimental tongue carcinoma in rats

Tongue carcinomas were produced in rats by oral administration of 0.001% 4-nitroquinoline 1-oxide (4NQO) in drinking water, and the biological characteristics and tumor kinetics were correlated. Bromodeoxyuridine (BrdU) was used to investigate cell kinetics of rat tongue tumors in vivo. BrdU-labeled S-phase cells were demonstrated by an indirect peroxidase method using anti-BrdU monoclonal antibody, and their percentage, the labeling index (L.I.), was determined. The average BrdU L.I. in normal tongue epithelium, well differentiated and moderately differentiated squamous cell carcinoma was 5.7 +/- 1.1, 8.8 +/- 3.7 and 14.9 +/- 5.4, respectively. The differences among the three groups are significant. These results indicate that the BrdU L.I. correlates well with the degree of differentiation of tongue epithelium. Furthermore, the distribution patterns of BrdU-labeled cells in the tissue sections of each group were different. If these cell kinetics studies using BrdU are applied to human tongue carcinomas, the data may provide information on the biological characteristics and help in establishing the diagnosis and in choosing treatment regimens.

Cell kinetic study of human and mouse hair tissues using anti-bromodeoxyuridine monoclonal antibody

To determine sites of cell proliferation in hair tissues, in vitro and in vivo labeling with bromodeoxyuridine (BrdU) and immunohistochemical demonstration of BrdU incorporation sites by anti-BrdU monoclonal antibody were performed on human and mouse hairs and hair follicles. The germinative area of the hair bulb of human anagen hair was divided into three portions: (A) the upper and inner portion, (B) the middle portion and (C) the lowest outer portion. A-cells intermingled with melanocytes, were regarded as germinative cells of the hair cortex. B-cells appeared to develop into Huxley's layer, cuticle of inner root sheath (IRS), and hair cuticle. C-cells seemed to develop into bulbar outer root sheath (ORS), the innermost cell (IMC) layer of the ORS and Henle's layer. The suprabulbar portion, where the ORS abruptly increased in thickness, was found to be the fourth main germinative portion (D). The ORS cells, except for the IMCs, seemed to originate mostly from the D-cells. In the late anagen phase, first, C-cells became BrdU negative, then, A- and B-cells gradually turned negative, and finally, D-cells lost their germinative activity. In catagen and telogen hair tissues, BrdU-positive cells were found in the two outer cell layers in the ORS. The structure of anagen hair tissues seems to be maintained by the coordinated mitotic activities of characteristically distributed germinative cells of various hair cell layers. The sequential cessation of mitotic activity of these cells is associated with the morphological changes from anagen through catagen to telogen. These findings were common to both human and mouse hair tissues.

Frequency and distribution of chiasmata in Syrian hamster spermatocytes studied by the BrdU antibody technique

The frequency and distribution of chiasmata and the nature of terminal "associations" was re-examined in Syrian hamster spermatocytes using the 5-bromo-2'-deoxyuridine (BrdU) antibody technique (BAT) for differential chromatid labelling. Differential chromatid substitution was achieved by BrdU incorporation at the penultimate pre-meiotic S-phase followed by one of three different staining protocols: (i) fluorescence plus Giemsa (FPG), (ii) acridine orange staining or (iii) BAT. For analysis of chiasmata frequency and localization in the diplotene/diakinesis stages the resolution of FPG and acridine orange staining was comparable to that of BAT. In metaphase II chromosomes BAT was more informative than FPG and acridine orange staining and revealed small, terminal crossover exchanges. This finding proves that many terminal associations of meiotic chromosomes actually represent chiasmata at the end of the first meiotic division. Some crossover exchanges were localized in the constitutive heterochromatin of autosomes. Using BAT we also detected crossover exchanges in close vicinity to each other. This observation is reminiscent of the fact that crossing over interference means a reduction in frequency and does not imply total inhibition.

[An experimental study of anticancer agent sensitivity test in human gastric cancer cell lines by flow cytometry]

The purpose of this study is to assess the lethal and kinetic effects of CDDP, ADM, MMC and 5FU on human gastric cancer cell lines, MKN28, MKN45 and KATO III. The lethal effect was examined by growth inhibition test and colony forming test. The DNA content and DNA synthesis rate of individual cells were simultaneously measured by DNA/BrdU double staining method. In growth inhibition test, MKN45 was sensitive to CDDP, and all cell lines were sensitive to ADM, MMC and 5FU. On the other hand, in colony forming test, these cell lines were sensitive to all drugs. In the cell kinetics, CDDP, ADM and MMC yielded a significant increase of G2 phase fraction at 24, 48 and 72 hours, and caused a significant decrease of BrdU labeling index at 48 hours. The changes of G2 phase fraction and BrdU labeling index were correlated well to the lethal effect of CDDP, ADM and MMC. However, 5FU did not cause these changes to the cell lines employed in the cell kinetic study. Therefore, it was suggested that these results of the cell kinetics might be applied to anticancer agent sensitivity test by selecting adequate anticancer drugs.

Cytokinetic investigation of lung tumors using the anti-bromodeoxyuridine (BUdR) monoclonal antibody method: comparison with DNA flow cytometric data

In order to investigate the cytokinetics of malignant tumors and non-malignant lesions of the lung, tissue samples from 57 patients affected by non-small-cell carcinoma (NSCLC), small-cell carcinoma (SCLC), and benign and inflammatory lesions have been analyzed using the BUdR monoclonal antibody (MAb) method. This method is based on the preparation, at the time of surgery, of viable monocellular suspensions (using collagenase and DNase treatment) and the concomitant administration of BudR. The percentage of BudR-labelled cells was monitored by fluorescent microscopy using an FITC-labelled second antibody. In NSCLC, each histological group showed a wide range of labelling index (LI) values. On the contrary, SCLC exhibited a more homogeneous kinetic behaviour as evidenced by a narrowly distributed, higher LI. Tumors shown to be diploid by flow cytometry did not show a lower LI than aneuploid tumors. Furthermore, differences were constantly observed between the S-phase percent calculated using BUdR and that calculated using the DNA flow cytometric (FC) histogram, the latter always showing higher S-phase values. In an attempt to study the intra-tumor proliferative heterogeneity, multiple-site sampling was performed. Proliferative heterogeneity seemed to be higher inter-tumor than intra-tumor. Finally, a positive correlation (p less than 0.05) was found between LI and the actual doubling time (DT) of the primary tumor mass, evaluated using sequential radiographs. In conclusion, the present BUdR method can be considered a useful source of relevant information on in vivo cell growth, in parallel to other clinical (DT) and biological (DNA content) approaches.

Rapid estimation of the proliferating index of brain tumours

A rapid and versatile method has been developed for estimating proliferating/labelling indices (enumerated S-phase cells) of brain tumours. Fragments of fresh, surgically excised tumour specimens are labelled in vitro with 10 microM bromodeoxyuridine (BrdU) at 37 degrees for 1 hour in MEM + 10% FCS, washed in PBS, blotted dry and then imprinted on glass slides leaving a mirror image monolayer of cells of the impressed surface. The incorporated BrdU is then detected indirectly by immunoperoxidase staining after fixation. No fewer than 1000 cells are counted under high power and the PI is expressed as the % of BrdU positive cells to the total number counted. The PI of the various tumours analysed ranged 2.54-13.08% for gliomas, 5.29-7.60% for metastases, 0-0.83% for benign meningiomas. Thirty one cases have been studied. Results, obtainable within a few hours of tumour biopsy/resection, correlate favourably with published flow-cytometry proliferating indices for the tumours analysed and thus validate the method as a comparable alternative to in vivo BrdU labelling.

A rapid immunogold-silver staining for detection of bromodeoxyuridine in large numbers of plastic sections, using microwave irradiation

A rapid and convenient method for the large scale, immunogold-silver staining (IGSS) of bromodeoxyuridine (BrdU) incorporated by S phase cells, by means of a monoclonal antibody (anti-BrdU) is described. Nineteen slides at a time can be incubated with the antibodies and the protein A-gold (PAG) in staining jars. The antibody and protein A-gold solutions could be used at least five times to incubate new batches of slides. The incubation times with these solutions were shortened by means of microwave irradiation. In this way 200 slides carrying at least 800 sections could be easily processed under the same conditions in one day, using 1.25 ml neat antibody solutions of anti-BrdU and rabbit anti-mouse. For light microscopy both plastic embedding systems: methylmethacrylate (MMA) and glycolmethacrylate (GMA) can be stained with this technique. The MMA sections, of which the plastic has to be removed before the IGSS, has the advantage of a stronger labelling intensity. The GMA plastic, which contains a cross-linking agent cannot be removed and consequently for GMA sections it is necessary to incubate the sections with a proteolytic enzyme (trypsin) before the IGSS, to reexpose the antigenic binding sides. However, the GMA sections can be allowed to air dry during the IGSS without negative effects on the morphology. This makes it possible to perform the antibody and the PAG-incubating steps on one day and to finish the IGSS the next day. In this way twice as many GMA slides can be incubated with the same antibody and PAG solutions than with MMA slides.(ABSTRACT TRUNCATED AT 250 WORDS)

Late cytokinetic abnormalities in irradiated rectal mucosa

Late cytokinetic changes of the colonic crypt epithelium after radiation therapy were investigated. A monoclonal antibody to bromodeoxyuridine (anti-BrdU MAb) was used in tissue specimens previously incubated with BrdU to show S-phase cells by immunohistochemical technique. Endoscopic rectal biopsies were taken from 30 patients previously treated with radiotherapy for gynaecological cancer and from 50 patients with comparable but untreated neoplasms, as controls. Number and height distribution of S-phase cells were evaluated by dividing each crypt column into 5 equal longitudinal compartments. No statistically significant differences were found in total Labelling Index (LI) between controls and irradiated mucosa, whereas LI per crypt compartment, percentage of labelled compartments and percentage of BrdU-positive cells in the middle and superficial portions of the crypt were significantly higher in patients submitted to radiation therapy. This kinetic abnormality corresponds to a progressive shift of the major zone of DNA synthesis to the upper third of the crypt as a late reaction to radiation and represents an early step in the histogenesis of colorectal cancer. These results lend support to the view that there is a higher risk of colorectal carcinoma after pelvic irradiation.

In vivo bromodeoxyuridine incorporation in normal mouse kidney: immunohistochemical detection and measurement of labelling indices

A method is reported for in vivo bromodeoxyuridine incorporation in mice and its subsequent visualization in kidney by immunohistochemistry. Following formal-sublimate fixation of the kidney, bromodeoxyuridine labelled nuclei were detected in paraffin sections with a monoclonal antibody and visualized by an immunoperoxidase technique. This rapid and unequivocal method was used to measure labelling indices in tubules, glomerular tuft and Bowman's capsule in normal male T70 (Beige) mice, at intervals up to 72h after labelling. Significant differences were found between the labelling indices of these three populations of cells, which appeared to show different cell kinetic behaviour.

An enzyme-linked immunosorbent assay for bromodeoxyuridine incorporation using fixed microcultures

We report a quantitative method by which a single microculture can be examined for (i) cell morphology; (ii) cell number; (iii) DNA synthesis; and (iv) expression of cell antigens. This method first involves measuring by enzyme-linked immunosorbent assay (ELISA) the total bromodeoxyuridine (BrdU) incorporation into DNA by monolayer microcultures. The BrdU-ELISA measurement was followed by simultaneous immunostaining for BrdU-positive nuclei and for a cytoplasmic antigen. The method was applied to the measurement of mitogen-induced proliferation of rat sciatic nerve Schwann cell and cerebral astroglia microcultures. The ELISA measurement of BrdU incorporation compares favorably with measurements of tritiated thymidine incorporation and offers the additional advantages that the same microculture can subsequently be examined for cell number, for cell morphology, and for the percentage of cells having BrdU-labeled nuclei and other antigens.

[Evaluation of turnover of olfactory epithelium in mice by using anti-BrdU monoclonal antibody]

Among nerve cells of vertebrates, the olfactory elements are uncommon in their capacity to turnover and to be replaced after injury. An autoradiographical and morphological observation has shown that degenerated olfactory nerve cells are reconstituted by a new population of neurons which originate from basal cells. However, an autoradiographic method requires a special isotope institute and it takes a long time for the final specimen to observe. Recently, a rapid technique without the radioisotope has been alternatively developed in which a thymidine analogue, 5-bromo-2'-deoxyuridine (BrdU), is incorporated into replicating DNA and subsequently localized using a specific monoclonal antibody. In the present study, cell dynamics of olfactory mucosa in mice were investigated by means of immunohistological technique. The results were as follows. 1. The labelled elements were concentrated at the basal layer of the epithelium, which were observed 5 hrs after the first injection of BrdU. 2. At 15 days after administration of BrdU, the labelled elements were located in the mid-layer of the epithelium, where can be recognized as the compartment of nerve cells. 3. After 30 days, the labelled cells disappeared from the epithelium. It indicates that the period of turnover in the olfactory epithelium of mice is within 30 days. 4. Fifteen days after axotomy of the olfactory nerves, two stained patterns which were numerously or sparsely labelled regions were observed. The former is considered that immature neurons predominantly exist, and the latter is the area which mature neurons abundantly locate. It is considered that this immunohistological approach is useful for the observation of the turnover of the olfactory epithelium.

Immunohistochemical demonstration of DNA polymerase alpha in human brain-tumor cells

The proliferative capacity of brain-tumor cells was analyzed in vitro and in situ using monoclonal antibody (MAb) against deoxyribonucleic acid (DNA) polymerase alpha. For the in vitro studies, two cultured human glioma cell lines were investigated using MAb against DNA polymerase alpha, the MAb Ki-67, a serum against proliferating cell nuclear antigen (PCNA/cyclin), bromodeoxyuridine (BUdR), and an anti-BUdR MAb. During exponential growth of the cells, the percentage of polymerase alpha-positive cells (the "polymerase alpha score") ranged from 72.0% to 77.1%, the Ki-67-positive cells (the "Ki-67 score") ranged from 43.4% to 59.4%, the PCNA/cyclin-positive cells from 30.9% to 41.4%, and the BUdR labeling index from 28.6% to 39.3%. For the in situ studies, tissue from 60 human brain tumors and from two normal human brains was investigated and the polymerase alpha scores and Ki-67 scores were compared. In normal brain tissue, no immunostaining was found by either method. In brain tumors, both the polymerase alpha scores and the Ki-67 scores correlated with the histological grade of malignancy. Polymerase alpha scores were generally higher than Ki-67 scores in the same specimen, especially in malignant brain tumors. These findings suggest that immunostaining of DNA polymerase alpha is a convenient and important new method by which to estimate the cellular proliferation rate of brain tumors. Polymerase alpha scores may be closer to the growth fraction of the individual tumor than the MAb Ki-67 or other scores.

Relation of proliferative activity to survival in patients with gastric carcinoma

The prognostic significance of proliferative activity in 167 gastric carcinomas was studied by means of an in vitro labeling method with bromodeoxyuridine (BrdU), using specimens obtained by endoscopic biopsy, and the results were correlated with conventional prognostic factors. The BrdU labeling indicates (BrdU LI) varied from 2.1 to 45%. When the in vitro BrdU LI were plotted against in vivo BrdU LI, a significant correlation was found between in vitro and in vivo BrdU LI (P less than .01). These results show that the in vitro BrdU LI of specimens obtained by endoscopic biopsy indicate accurate proliferative activities of gastric cancers. The BrdU LI were closely correlated with nodal status, vessel invasion, and tumor size. With regard to the correlation of BrdU LI and prognosis, patients whose tumors had a high BrdU LI (BrdU greater than LI less than 10%). When the BrdU LI and all the pathologic findings were entered simultaneously into the regression model, nodal status, tumor size, serosal involvement, and BrdU LI emerged as independent prognostic parameters. The present studies demonstrated the usefulness of the in vitro BrdU-labeling method to estimate the malignancy of gastric cancer preoperatively, and this method may be useful in designing the operative procedure and multimodal therapy for individual patients.

Visualization of DNA in pachytene by monoclonal antibodies against BrdU reveals synaptonemal complex-like structures

Most of the techniques used to visualize structures of the synaptonemal complex (SC) are based on specific staining properties or immunocytochemical detection of proteinaceous SC components. The SC is therefore considered to be mostly protein. We have now accomplished visualization of the DNA within the SC by use of the BrdU antibody technique, following BrdU substitution during the last premeiotic S phase. Preparations of mouse meiotic chromosomes were obtained by spreading on a water surface. The DNA content in the SCs, which appeared as light threads, was clearly lower than the DNA content in the surrounding chromatin. At higher magnification, dark, longitudinal structures appeared in these threads. These structures are made up of DNA, which forms the inner part of the lateral elements of the SCs. Within the SCs, DNA is confined mostly to these threads. Thus, DNA staining reveals the same structures already known from protein staining of SCs. The DNA mass surrounding the SCs is often nonhomogeneously distributed along the chromosome axis. The more dense parts appear to be chromomeres. The DNA staining technique described in this paper may therefore be a useful complement to standard protein staining techniques for pachytene chromosomes.

In vitro immunohistochemical localization of S-phase cells by a monoclonal antibody to bromodeoxyuridine

Bromodeoxyuridine, an analogue of thymidine, can be detected by means of monoclonal antibodies and utilized as a marker of the S-phase of the cell cycle. In vitro immunohistochemical application of the BrdU/anti-BrdU-MAb method permits a quantitative assessment of the proliferative activity of a tissue as well as the direct location of the actively replicating cells in histological sections. In this paper, a method for the detection of the labeling index of S-phase cells in normal and neoplastic tissues with in vitro BrdU labeling and standard immunohistochemical techniques using anti-BrdU-MAb and avidin-biotin peroxidase complex is described. We have employed this method in 47 human solid tumor samples, including squamous cell carcinomas of head and neck and cervix uteri, adenocarcinomas and malignant lymphomas, and also evaluated the possible application of the BrdU labeling index to estimate the cycling S-phase cells in neoplastic cell populations. In our data, the in vitro labeling index varied greatly in an individual case (3.56-29.2%) and from an area to an area within the same case. Squamous cell carcinomas of the head and neck showed higher LI than those of the cervix uteri. A case of metastatic carcinoma to the lung from ductal carcinoma of the breast had the highest LI (29.2%), in contrast to the low LI (3.6%) in the primary ductal carcinoma of breast.

Rapid in situ cellular kinetics of intracerebral tumor angiogenesis using a monoclonal antibody to bromodeoxyuridine

The application of a monoclonal antibody to bromodeoxyuridine (BUdR) provides a rapid, reproducible, nontoxic, immunohistochemical method to measure cellular kinetics of intracerebral tumor angiogenesis. The rabbit brain tumor model of angiogenesis consists of tumor and endothelial cell populations with high proliferative rates that demonstrate the close interdependence between microvascular and neoplastic growths as well as topographic gradients, heterogeneity, and regional microdomains of cell proliferation. The labeling index (LI) of endothelial cells was 25.8% at the tumor periphery, compared to 1.7% in the tumor center (P less than 0.001). Concomitant with an increased turnover of neoplastic cells at the tumor periphery. LI was 26.6% with a LI of 7.7% in the center (P less than 0.01). Furthermore, labeled tumor cells tended to be organized around proliferating capillaries, with less DNA synthesis farther from the nearest blood vessel. The established normal microvessels of the brain, e.g., in the opposite tumor-free hemisphere, were mitotically inactive with a LI of less than 0.001%. Quantitation of vascular cytokinetics should be useful in further studies of the pathophysiology of brain tumor angiogenesis and the development of pharmacological approaches directed toward the microvasculature.

[Flow cytometric cell cycle analysis using a monoclonal antibody to bromodeoxyuridine on gastric cancers]

Flow cytometric cell cycle analysis using a monoclonal antibody to Bromodeoxyuridine was performed on 117 gastric cancers. Dissociated cells were stained with indirect immunostaining for BrdU (FITC-BrdU) and propidium iodide. Bivariate BrdU/DNA distribution were obtained using EPICS-C flow cytometry. Tumor ploidy was classified as follows, D1: diploidy, D2: diploidy + aneuploidy, A1: single aneuploidy, A2: multiple aneuploidies. The ploidies of noncancerous gastric mucosa were all diploidy and that of S-phase fraction(SPF) were ranged from 0.0% to 1.2%. In 117 gastric cancers, aneuploidy was observed in 80 cases, D2: 38, A1: 15, A2: 27. SPF was higher in aneuploidy (14.5 +/- 5.1%) than diploidy (6.1 +/- 5.1%). Significant differences were observed between that of D1 (6.1 +/- 2.5) and D2 (13.6 +/- 6.2), A1 (12.5 +/- 4.5), A2 (16.0 +/- 3.2), and A1 and A2 (p less than 0.01). The patients with aneuploid tumors had poor prognosis than diploid tumors (p less than 0.05). In concerned with DNA ploidy pattern, the patients with A2 had most poor prognosis than the other (p less than 0.05). Furthermore, the patients with SPF over 10% had poor prognosis than that of SPF below 10%. These results indicated that DNA ploidy pattern and SPF may possibly be useful prognostic markers for gastric cancers.

Improved bromodeoxyuridine/DNA analysis by anti-BudR monoclonal antibody versus right angle light scatter

Dynamic cell cycle analysis is based on the incorporation of labelled precursors into DNA. Although antibodies to BrdU are very useful for analysing in flow cells which synthesize DNA, this approach has two main limitations. First, the detection of low incorporating cells is often difficult; second, four parameter flow cytometry is not able to correlate cell cycle to any other cellular marker. We have developed a methodology that, employing an IgGH + L as a second antibody and side scatter instead of propidium iodide fluorescence, allows a better discrimination of BudR+ cells. This approach allows the collection of an extra-fluorescent signal, and the analysis of specific cellular markers within the cell cycle.

Double immunocytochemical labeling of cell and tissue samples with monoclonal anti-bromodeoxyuridine

We describe a new monoclonal antibody (designated Bu20a) against bromodeoxyuridine (BrdU). This antibody was selected by screening against human tissues using the APAAP technique, and shows no crossreactivity with normal nuclei. It stains BrdU incorporated into the nuclei of a wide range of cell types, including human tonsil lymphoid cells, normal mouse tissues, and human tumors growing in nude mice. A double-labeling technique is described using this antibody in which cell smears or tissue sections are first labeled by an immunoperoxidase procedure for a cellular antigen (e.g., mouse or human histocompatibility class II antigen, T-lymphocyte antigen, keratin) and BrdU is then detected by indirect immunofluorescence. This procedure, which was applied to a variety of human and animal cells and tissues, is of wide potential value in analyzing the phenotype of S-phase cells and in co-localizing antigen expression and BrdU incorporation in tissue sections.

Immunocytochemical detection of 5'-bromodeoxyuridine incorporation in the central nervous system of the mouse

In order to label postmitotic neuroblasts, pregnant mice received a single pulse of 5'-bromodeoxyuridine (BrdU) between embryonic days E11 and E17. Young adult offspring were stained for BrdU using a monoclonal antibody and the peroxidase-antiperoxidase method. The distribution of immunoreactive nuclei was very similar to the [3H]thymidine data reported in the literature. The pattern of labelled nuclei after injection at different embryonic ages followed the spatiotemporal gradients described for cortical and hippocampal neurogenesis. Lightly and heavily labelled nuclei, probably representing subsequent postmitotic generations, were distinguished in BrdU-immunoreacted preparations. These data indicate that BrdU can be used to map neuronal birthdates.

Evaluation of antisera to 5-(2-bromo-E-ethenyl)-2'-deoxyuridine for the radioimmunoassay of a potent antiviral agent

The production and evaluation of antibodies specific for 5-(2-bromo-E-ethenyl)-2'-deoxyuridine (BVDU) is described. Antibodies were raised against 5-(2-carboxy-E-ethenyl)-2'-deoxyuridine bovine albumin conjugates (CVDU20-BA and CVDU54-BA) and 5'-carboxy-propionyl-BVDU7-BA. The molar substitution ratio of the conjugates was determined by differential ultraviolet absorption or isotope dilution and compared to a newer method based upon the determination of unsubstituted protein residues. Usable antibody titers were obtained from all the New Zealand White rabbits immunized, but only one-third of the half-lop rabbits responded. The antisera were highly specific for BVDU and did not significantly cross-react with naturally occurring nucleosides, pyrimidines, or sugars. However, the lowest cross-reaction observed (0.21%) for the major metabolite bromovinyl uracil using antisera raised to CVDU-BA could not ensure adequate assay specificity under all conditions of use. An alternative approach using 5'-carboxy-propionyl-BVDU7-BA proved unsuccessful because the antisera could not discriminate between BVDU and bromovinyl uracil.

[Experimental studies on drug uptake by metastatic liver tumor after intra-arterial, intraportal and intravenous administration of BrdU]

To compare the pharmacological advantage of intra-arterial, intraportal and intravenous administration of anticancer drug for metastatic liver tumor, BrdU was administered to rabbits with metastatic liver tumor of VX2 from various routes and taken up into the nuclei of tumor cells. Both one-shot injection and continuous infusion (30 min) of BrdU was performed from celiac artery, portal vein or peripheral vein. In some rabbits, the portal vein or the celiac artery was ligated to form one blood supply to the liver. After the administration of BrdU, the liver was removed. The samples were stained by the immunohistochemical procedure using monoclonal antibody to BrdU. The result was that the drug uptake of small metastatic liver tumor by both arterial and portal one-shot injection was good, and the uptake following intra-arterial injection of BrdU was superior to its intraportal injection in large metastatic tumor. However, only peripheral cells of large tumor took up BrdU after intra-arterial injection and inner cells of large tumor did not take up BrdU after any continuous infusions. The intraportal and intravenous administration of BrdU without ligation of celiac artery had the same effect as its intra-arterial administration.

In situ demonstration of tissue proliferative activity using anti-bromo-deoxyuridine monoclonal antibody

Immunohistochemical staining with anti-bromo-deoxyuridine (BrdU) monoclonal antibody was performed on a variety of human tissues following in vitro incubation with BrdU. The effect of different fixatives and DNA denaturation techniques on the reactivity with anti-BrdU was investigated. Optimal preservation of the antigenicity of BrdU incorporated into the DNA of proliferating cells was seen in tissues fixed in Bouin's fluid, while samples which had been fixed with cross-linking reagents, such as formalin, were usually unreactive. Positivity for BrdU was restored in formalin fixed tissues after digestion with pepsin, but this was usually associated with loss of morphological details. Acid and thermal DNA denaturation techniques gave similar results. It is concluded that Bouin fixation followed by acid or thermal denaturation of DNA is the method of choice for the in situ detection of cells in S-phase using anti-BrdU monoclonal antibody.

[Cell kinetic study of urogenital tumors utilizing in vitro BrdU-labelling method and anti-BrdU monoclonal antibody]

With the aim to apply a rapid analytic method of cell kinetics using in vitro BrdU labelling and anti-BrdU monoclonal antibody to the clinical fields, we investigated the cell kinetics of 20 urogenital malignant tumors. The DNA synthesizing cells which take up BrdU in its nuclei can be detected so clearly, since the labelling index (LI) is easily identified. The correlations between LI and age and with histological grade and stage of 14 transitional cell cancers of urinary tract were investigated. There was no correlation between LI and age. The LI of high grade groups (G2 & G3) were significantly higher than that of the low grade group (G1) (p less than 0.05). Also between LI of pT1 group and pT3 group, there was a statistical significance (p less than 0.05) and generally LI tended to increase according to stage progression. Therefore, the cytokinetic data obtained from the before mentioned method can be utilized as a useful marker for measuring malignant potentials of each tumor.

[Flow cytometric analysis of cell proliferation kinetics using the anti-BrdUrd antibody]

There is a growing interest in analysis of cell kinetics in a field of clinical oncology. The development of a monoclonal antibody to bromodeoxyuridine (BrdUrd), a thymidine analogue, is epoch making in the research of cell kinetics, and flow cytometry (FCM) combined with the antibody facilitates clinical use of information concerning cell kinetics of tumor cells. In this review article, we show flow cytometric analysis of cell kinetics using the antibody. Two color analysis of DNA-BrdUrd makes it easy and rapid to obtain cell kinetic data of both tumor and non-tumor cells, without the use of DNA precursors labeled with isotopes. A fraction of labeled cells in the mid S phase (FLSm) method provides more detail analysis of the cell cycle, although it needs multiple samplings after pulse labeling with BrdUrd. Alternatively, a short term continuous labeling method can roughly estimate cell kinetic parameters but this method very simple. Furthermore, effects of anticancer drugs and radiation to human malignant tumors can be rapidly evaluated with the above methods. The protocol of cancer treatment will be determined based on cell kinetic data from an individual patient.

Determination of proliferative fractions detected by immunohistochemistry with the monoclonal antibodies to bromodeoxyuridine and Ki-67 in malignant lymphomas

The stainability of proliferating cells with monoclonal antibodies to both bromodeoxyuridine (BrdU) and Ki-67 were compared in 22 malignant lymphomas and six related conditions. A significant correlation was observed (r = 0.78) between the positivities of proliferating cells determined using these two monoclonal antibodies. The growth fractions determined with the antibodies were usually related to the histologic classification, but labelling index was more varied in diffuse large cell type lymphoma. BrdU labelling was well correlated with the Working Formulation, and more useful as a prognostic indicator. On the other hand, Ki-67 was useful for broad recognition of cell proliferative ability.

A sequential double immunoenzymic staining procedure to obtain cell kinetic information in normal and hyperproliferative epidermis

A sequential double immunoenzymic staining procedure was developed using the monoclonal antibody anti-BrdUrd and Ki67 in order to determine whether hyperproliferative skin disorders, such as psoriasis, are characterized by an increased growth fraction rather than a much shorter cell cycle time of all germinative cells. Ki67 binds to a proliferation-associated nuclear antigen in a variety of human cell types, and anti-BrdUrd can be used to identify DNA-synthesizing cells. Although in hyperproliferative epidermis the absolute numbers of BrdUrd-positive cells as well as Ki67-positive cells were grossly increased, the ratio of these values was not changed compared to the ratio found in the epidermis of the clinically uninvolved skin of psoriatic patients and in normal epidermis. This suggests an increased growth fraction in hyperproliferative epidermis. Our data show that immunohistochemical double-staining techniques can be a valuable tool in the study of cell cycle kinetics in epithelial tissues.

[Analysis of cell kinetics after gamma ray irradiation using anti-BrdU monoclonal antibody]

The cell cycle was analyzed using anti-BrdU monoclonal antibody, and changes in cell kinetics after gamma ray irradiation as evaluated by this BrdU-PI double staining were compared with those evaluated by the DNA histogram method based on PI staining. The effect of irradiation on the cell kinetics has been studied according primarily to the number of G2 blocked cells. By the present BrdU method, rapid transition of the G1-S phase was observed within 2 hours of irradiation, and then G1 block was observed. Cells in the S phase progressed to the G2 + M phase, in which they were arrested, resulting in a decrease in the percentage of S cells to 5% or less. After 8 hours, release of G1 block was observed, and G2 + M cells returned to the G1 phase after 18 or more hours. These initial G1 blocked cells induced by irradiation were confirmed for the first time by the present BrdU-PI double staining. By the conventional method based on the DNA histogram, accurate determination of S cell fraction was difficult due to overlapping of the DNA contents of G1 cells and early S cells and those of late S cells and G2 cells. On the other hand, BrdU-PI double staining allowed direct differentiation of G1, S, and G2 + M cells, especially between G1-S and S-G2 + M cells. The analysis of cell kinetics using BrdU is advantageous over the conventional autoradiographic methods in that it allowed more rapid assay with very high sensitivity.(ABSTRACT TRUNCATED AT 250 WORDS)

[Cell kinetic effects of cis-platinum on cancer cells in a culture system and in cases of cervical cancer using monoclonal antibody of BrdU]

Flow cytometric analyses were done in cervical squamous cell carcinoma cell line (SKG-IIIa) and in cancer cells of cervical cancer cases treated with CDDP using monoclonal antibody of BrdU. 1) In fundamental studies using culture system, accumulation of late S phase cells and of mid S phase cells was observed after 48 hours at the dose of 0.2 micrograms/ml and 0.5 micrograms/ml of CDDP, respectively. 2) Accumulation of early S phase cells was observed at the condition of 1 microgram/ml and 3 micrograms/ml of CDDP. All S phase cells decreased gradually thereafter 3) In clinical studies, accumulation of early S phase cells was observed in cancer cells of cervical cancer cases after intra-arterial infusion of CDDP. However, cell cycle recycling was observed in tumor cells which retained their low sensitivity to CDDP after 21-day treatment with intra-arterial infusion of CDDP.

[Astrocytic proliferation in the brain adjacent to infarcted lesion: immunohistochemical study of astroprotein (GFAP) and bromodeoxyuridine (BrdU)]

Although cerebral infarction is a destructive process of nerve cells and brain tissue, the nature is not exclusively disintegrating but also includes active cellular reaction which may modify the progression of tissue damage. Most prominent cellular reaction in the area surrounding infarction can be recognized as a trophic or proliferative change of glial cells. In the present study we produced a focal cerebral ischemia in Mongolian gerbils and investigated the dynamic change of astrocytes in the brain adjacent to thalamic infarction. Using immunohistochemical methods, astrocytes were identified with the antibody to astroprotein (GFAP) and the DNA synthesizing (S phase) cells were detected with the antibody to bromodeoxyuridine (BrdU). The posterior communicating artery of a gerbil was occluded by coagulation through the trans-tympanic bulla approach under general anesthesia with ketamine hydrochloride (80 mg/kg, i.p.). Thirty min after intravenous administration of BrdU (200 mg/kg), animals were sacrificed by transcardiac perfusion with 75% ethanol on days 1, 2, 3, 5 and 7 post-infarction. Ethanol-fixed, paraffin-embedded blocks were cut coronally into 6 microns-thick sections at the level of dorsal hippocampus. Double-labeled immunohistochemical technique (avidin biotin peroxidase-complex method) was carried out with each antibody using 3,3'-diaminobenzidine tetrahydrochloride and 4-chloro-1-naphthol as chromogens. The population of GFAP-positive cells and their S-phase fraction (the number of BrdU-positive nuclei divided by the number of GFAP-positive cells expressed in per cent, %) were examined. The data demonstrated that the regional GFAP-positive cells increased continuously between days 1 to 5 (105.9 to 528.8 cells/mm2) postinfarction (44.6 cells/mm2 in normal brain).(ABSTRACT TRUNCATED AT 250 WORDS)

Rapid S-phase determination of non-Hodgkin's lymphomas with the use of an immunofluorescence bromodeoxyuridine labeling index procedure

Cell kinetic measurements are currently being investigated to determine if they are useful in the clinical management of patients with non-Hodgkin's lymphomas (NHLs). Although the tritiated thymidine labeling index (TLI) is the standard method of S-phase measurement, it is difficult to perform. The authors describe a slide-based immunofluorescence labeling index (LI) method that uses 5-bromo-2-deoxyuridine (BrdUrd) as the pulsing medium and a monoclonal antibody (BU-1) to BrdUrd. The BrdUrd LI was performed on 217 NHLs and compared with routine histologic results. The authors found a median BrdUrd LI of 0.9% for low-grade NHLs; 7.5% for intermediate-grade; 10.4% for high-grade; and 2.2% for T-cell NHLs. This method provides a rapid, reliable S-phase measurement that can be easily performed in the clinical laboratory. It should replace the TLI and allow wider application of S-phase measurements in the NHL.

[Evaluation of proliferating activity of pleomorphic adenoma arising from the salivary glands--using anti BrdU monoclonal antibody]

Salivary gland tumors present diverse histopathological aspects and show various biological behavior. At present, the immunohistological method using anti-BrdU monoclonal antibodies, which was originated in the field neurosurgery, has been tried extensively in various fields of medicine. Using this method, the authors have attempted to detect biological characteristics of salivary gland tumor tissues, especially those of pleomorphic adenomas. The labelling index (L.I.) is defined as the percentage of the labelled cells (proliferating cells) in the tumor tissue. In order to confirm the usefulness of the L.I. for measuring the proliferating activity of tumor tissue, an investigation was conducted with respect to squamous cell carcinomas of the head and neck, excluding salivary gland tumors. The results indicate that the L.I. is highly correlated with the differentiation of these carcinomas. In salivary gland tumors, values of the L.I. are also higher for benign tumors than for normal or inflammatory tissues and the values were even higher for malignant tumors. Values of the L.I. are low for pleomorphic adenomas, which are the majority of salivary gland tumors, as well as for other benign tumors. However considerable individual variabilities, are bound for pleom. ad. and the values of the L.I. are markedly high in some cases. These high values are particularly common in patients with whom strong positivity in Ga scintigraphy, or primary growth in the submandibular glands are found. The localization of proliferating cells shows a characteristic pattern in each type of tumor tissue. In pleomorphic adenomas, proliferating cells are sporadically distributed but the main growth is located at the site of the epithelioid proliferative region, excluding the duct-forming locus. However, the overall proliferating activity of myxochondromatous tumors is not generally low, and the proliferating activity is not particularly high in the region of infiltrating is the capsule.

[Cell kinetic study of human carcinomas using bromodeoxyuridine and immunohistochemistry]

Cell kinetics of human carcinomas was studied in vivo using immunohistochemical technique with bromodeoxyuridine (BrdU). Relationship between tumor growth and DNA synthesis was analysed in 7 human tumor xenografts serially transplanted into nude mice by in vivo administration of BrdU. The specimens were processed in immunohistochemical staining of ABC method using anti-BrdU monoclonal Ab. The labeling index (LI) was determined as the ratio of stained cells to tumor cells. It was found that LI tended to increase transiently at the initial stage of exponential growth phase and remained stable thereafter. Correlation between tumor doubling time and LI was observed with statistical significance. In 29 cancer patients including 24 gastric and 5 colorectal cancers, LI was also determined in vivo. In advanced gastric cancers, LIs were higher at the site of invasion than the central area. LIs of gastric cancers in stage I were lower than those in stage II, III and IV. Considering the data of human tumor xenografts, it was suggested that the stage II, III and IV gastric cancers might be biologically different types of cancers compared to stage I gastric cancers.

Immunocytochemical demonstration of S phase cells by anti-bromodeoxyuridine monoclonal antibody in human prostate adenocarcinoma

Using a monoclonal antibody to bromodeoxyuridine and immunohistochemistry, we measured the incorporation of this thymidine analogue into the deoxyribonucleic acid of human prostate adenocarcinoma cells exposed in situ. Fifteen patients with prostate cancer were given an intravenous infusion of 500 mg. bromodeoxyuridine at needle biopsy to label tumor cells in the deoxyribonucleic acid synthesis phase (S phase). The tumor specimens were fixed with 70 per cent ethanol, embedded in paraffin, sectioned and stained by an indirect immunoperoxidase method using anti-bromodeoxyuridine monoclonal antibody as the first antibody. The results showed that this method demonstrated bromodeoxyuridine-labeled nuclei satisfactorily in tissue section. The bromodeoxyuridine labeling index, S phase fraction, was determined by counting the number of bromodeoxyuridine-labeled cells in the tissue sections. Grade 3 tumors averaged 4.37 +/- 0.48 per cent labeling versus 2.41 +/- 0.49 per cent in grade 2 tumors, and grade 1 tumor in the series had an S phase fraction of 1.36 +/- 0.39 per cent. The average S phase fractions for single gland, cribriform, fused and medullary were 1.16, 2.30, 3.74 and 4.95 per cent, respectively. The results obtained with S phase fraction measured with bromodeoxyuridine labeling proved to be comparable to the results of histological grade and growth pattern. Thus, the higher S phase fraction may indicate biological malignancy. Moreover, the degree of heterogeneity concerning S phase fraction distribution within prostate cancer tissue could be compared to the morphological appearance. Our preliminary results suggest that the measurement of bromodeoxyuridine labeling index in prostate cancer may prove to be a new objective and quantitative assay of biological potential of individual tumor.

[Biological activity of hepatocellular carcinoma by analysing nuclear DNA ploidy patterns and using anti BrdU monoclonal antibody]

Cell nuclear DNA ploidy patterns were examined using cytofluorometry in hepatocellular carcinomas (HCC) induced by diethylnitrosamine (DEN) in rat and human HCC. These ploidy patterns were compared with histopathological and/or immunohistochemical studies of HCC using anti-bromodeoxyuridine monoclonal antibody. The results are summarized as follows. HCC of rats induced by DEN was occurred in 74(65.5%) of 113 rats. Intravascular invasion of the livers were seen in 31 of 74(41.9%). Metastasis was in 25 of 74(33.8%). The ploidy patterns of HCC in rats were classified into three types (types I, II and III). These ploidy patterns were closely connected with histological types of HCC in Edmondson's classification, and in order of types changing from type I to type III, 6c over polyploid cells, mitotic indices (MI) and labeling indices (LI) had a tendency to increase. In human HCC, cell nuclear DNA ploidy patterns were classified into three types similarly to experimental HCC. These ploidy patterns were closely related to histological types in Edmondson's classification. MI and 6c over polyploid cells were tendency to increase similarly to HCC of experimental rats. From the above results, measurement of DNA ploidy patterns and LI are considered a valuable parameter in examining the biological activity of HCC.

Immunospecific targeting of cytosine arabinonucleoside-containing liposomes to the idiotype on the surface of a murine B-cell tumor in vitro and in vivo

A new tumor model is described that is suitable for the evaluation of antibody-directed drug-delivery protocols and a modification in the procedure for covalently coupling antibody to the surface of drug-containing liposomes is presented. These immunospecific liposomes containing cytosine arabinonucleoside (Ara-C) have been tested in vitro and in vivo for their ability to kill a B-cell tumor. The target of the immunospecific-Ara-C liposomes is the idiotype associated with an antigen-specific immunoglobulin receptor on the cell surface of a murine B-cell hybrid (2C3). Affinity-purified antibodies specific for the idiotype were covalently coupled to modified lipid on the surface of the large unilamelar liposomes containing drug. These liposomes were shown to kill idiotype-positive 2C3 cells in vitro, but not idiotype-negative variants of this same cell line. It was also established in vitro that the drug-containing liposomes were at least 40 times more efficient than free Ara-C in the killing of the tumor cells. The 2C3 tumor was also propagated in vivo following the i.p. administration of tumor cells. The tumor grew initially as multiple foci within the peritoneum and subsequently spread to the spleen. Tumor-bearing mice were treated either with free Ara-C or with immunospecific liposomes containing Ara-C. Tumor growth in the primary tumor nodules and in the spleen was monitored by the administration of bromodeoxyuridine to the tumor-bearing animals followed by the immunofluorescent staining of cells with a monoclonal anti-bromodeoxyuridine antibody to estimate the proportion of cells in S phase. Our data from five out of seven animal experiments shows that the immunospecific-Ara-C liposomes, but not free drug, reduced tumor growth in the spleen. However, neither the liposomes containing drug nor the free drug were able to alter the growth of the primary tumor nodules growing in the peritoneal cavity. These results suggest that immunospecific-Ara-C containing liposomes may be useful in conjunction with other cytoreductive protocols in controlling tumor growth or preventing the spread of the tumor to other sites, but that immunospecific-Ara-C containing liposomes by themselves are not likely to eliminate an established tumor in vivo. We also demonstrate here that the administration of immunospecific-Ara-C containing liposomes in an animal having high levels of circulating tumor-associated antigen (i.e., IgG containing the idiotype) represents a potential clinically relevant hazard which must be considered when designing antibody-directed drug-delivery protocols.

Immunoelectron microscopic study of nucleolar DNA during mitosis in Ehrlich tumor cells

In order to investigate the DNA localization within Ehrlich tumor cell nucleoli during mitosis, two recent immunocytochemical methods using either an anti-DNA or an anti-bromodeoxyuridine (BrdU) monoclonal antibody have been applied. In both cases, the immunogold labeling has been performed on ultrathin sections of cells embedded either in Lowicryl K4M or in Epon, respectively. Identical results are observed with both immunocytochemical approaches. In the interphase nucleolus, besides the labeling of the perinucleolar chromatin shell and of its intranucleolar invaginations which penetrate into the nucleolar body and often terminate at the fibrillar centers, a few gold particles are also preferentially found towards the peripheral region of the fibrillar centers. In contrast, the dense fibrillar component and the granular component are never labeled. During mitosis, the fibrillar centers persist at the chromosomal nucleolus organizing regions (NOR's) and can be selectively stained by the silver method. However, these metaphase fibrillar centers are no longer decorated by the DNA- or BrdU antibodies. These results indicate that until the end of prophase, rRNA genes are present inside the fibrillar center material, disappear during metaphase and reappear in reconstituting nucleoli during telophase. Thus, fibrillar centers appear to represent structures sui generis, which are populated by rRNA genes only when the nucleolus is functionally active. In segregated nucleoli after actinomycin D treatment, the DNA labeling is exclusively restricted to the perinucleolar chromatin blocks. These findings also suggest that the DNA content of the fibrillar center material varies according to the rRNA transcription level of the cells. The results are discussed in the light of the present knowledge of the functional organization of the nucleolus.

[Effect of ACNU against experimental brain tumor--immunohistochemical study using anti-BrdU monoclonal antibody]

We have studied the efficacy of intrathecal ACNU against experimental leptomeningeal tumors. In the present report, the effect of ACNU on the growth kinetics of the tumor was evaluated by the immunohistochemical technique using anti-BrdU monoclonal antibody. The experimental leptomeningeal tumor was developed by inoculation of Walker 256 carcinosarcoma cells into the cisterna magna of rats. Seven days after the inoculation of tumor cells, the animals were treated either by intravenous (15 mg/kg) or intrathecal (1.5 mg/kg) ACNU. Four, 12, 24, 48, 96 or 144 hours after treatment, the animals received intravenous BrdU (200 mg/kg). Thirty minutes thereafter, they were sacrificed and the brain was removed. L. I. was calculated by counting the immunoreactive tumor cells. L. I. of the tumor without treatment on the seventh day after inoculation was over 40%. L. I. began to decrease 24 hours after intravenous ACNU, and remained 11% up to 96 hours. On the other hand, L. I. already decreased to 20% 4 hours after intrathecal ACNU and remained to be low (17%) up to 48 hours. However, L. I. increased to 38% at 96 hours. Thus, the effect on the growth kinetics of the tumor differs between intravenous and intrathecal ACNU. These results are considered to be useful informations for determining the optimal dosage of the antineoplastic agent against the brain tumor and developing the effective combination chemotherapy.

Cell kinetics studies of human brain tumors by in vitro labeling using anti-BUdR monoclonal antibody

Since the development of a specific monoclonal antibody against the thymidine analogue bromodeoxyuridine (BUdR), many investigators have used intravenous infusion of BUdR to estimate the proliferative potential of human brain tumors. However, side effects such as the induction of cell mutation, latent virus promotion, or inhibition of cytodifferentiation cannot be ignored, and thus many workers hesitate to use it in patients, especially those with hepatic disease or of reproductive age. Furthermore, if BUdR remains in the deoxyribonucleic acid of tumor cells after injection, analysis of the effect of chemical and radiation therapy may not be evaluated correctly. In this report, in vitro BUdR labeling with an anti-BUdR antibody is compared with the in vivo methods described by previous authors. This method appears to be useful for determining the S-phase fraction of human brain tumor. It was more rapid, and was simple, safe, and reproducible as compared to the intravenous infusion method.