Biomedical subjects

C G Pantazis

Publications and source records attributed to C G Pantazis.

At least 37 records · Page 2Linked to original sources

PubMed1991

Cellular localization of müllerian inhibiting substance messenger ribonucleic acid during human ovarian follicular development.

Müllerian inhibiting substance is expressed in the human reproductive system and has been associated with oocyte meiotic arrest. In situ hybridization was used to selectively localize ovarian cells containing high levels of müllerian inhibiting substance messenger ribonucleic acid, a müllerian inhibiting substance precursor, during different stages of human follicular development. Müllerian inhibiting substance transcript was noted in the granulosa cells of primordial, primary, and antral follicles. Surprisingly, transcript was also identified within the cytoplasm of oocytes and throughout the ovarian stroma. Controls included sense oligoprobe, positive and negative tissue controls, and treatments minus the detection antibody. Localization of transcript within the cytoplasm demonstrates that active transcription of müllerian inhibiting substance messenger ribonucleic acid occurs within both fetal and adult human female gonads. The presence of müllerian inhibiting substance messenger ribonucleic acid within oocyte cytoplasm could implicate an autocrine role for müllerian inhibiting substance-derived peptides in the establishment of oocyte competence.

Adult↗

PubMed1991

Flow cytometric analysis of granulosa cells from developing rat follicles.

Immature rats were treated with diethylstilboestrol (DES) or pregnant mares' serum gonadotropin (PMSG) and forward angle light-scatter (FALS) and 90 degrees light-scatter (90 degrees LS) signals were used to measure the size and the granularity (internal organization) of the granulosa cells, respectively. The results confirmed the presence of two major populations of granulosa cells in the ovaries of both groups of rats, with the same percentage of larger cells in both treatments (52.3% in DES, 49.5% in PMSG). Since DES treatment brings about granulosa cell growth while PMSG treatment causes growth and differentiation, it is evident that there is heterogeneity in granulosa cell sizes during different states of growth and differentiation. There was also heterogeneity in sizes of granulosa cells harvested from follicles of small (less than 210 microns), medium (210-420 microns) and large (greater than 420 microns) diameter. Quadrant analysis of granulosa cells in various fractions collected from Percoll gradients suggested an increase in granularity in the small and large granulosa cell populations. Cell cycle analysis of small and large granulosa cell populations collected from large follicles of rats treated with PMSG indicated that each population was distributed in G0/G1, S and G2/M phases. These results demonstrate that populations of small and large granulosa cells exist in rat ovarian follicles during various stages of growth and differentiation.

Animals↗

PubMed1991

Flow cytometric analysis of induced human graafian follicles. I. Demonstration and sorting of two luteinized cell populations.

STUDY OBJECTIVE: To test the hypothesis that induced human graafian follicles consist of different steroidogenic cell types on the basis of their light scatter characteristics as determined by flow cytometry. DESIGN: Cross-sectional, observational study. SETTING: Flow cytometry laboratory. PATIENTS: Thirty-six follicular aspirates from nine consecutive patients undergoing in vitro fertilization for tubal factor infertility were evaluated. RESULTS: Two distinct luteal cell populations were recovered. Both populations were positive by Oil Red O staining, suggesting the presence of intracellular lipid. Neither population stained positively for the presence of HLe-1/CD45, an antigen present on all human leukocytes. CONCLUSIONS: Cellular heterogeneity exists within the granulosa cell compartment.

Antigens, CD↗

PubMed1991

Differential expression of c-myc and H-ras oncogenes in Barrett's epithelium. A study using colorimetric in situ hybridization.

To determine the role of c-myc and H-ras in progressive, dysplastic Barrett's mucosa (BM), and the usefulness of these oncogenes as markers for dysplastic lesions at high risk for malignant transformation, sequential formaldehyde solution-fixed, paraffin-embedded biopsy specimens that were obtained from 12 patients with BM were evaluated by in situ hybridization with the use of biotinylated complimentary DNA probes. Nine of the patients were taken from a previous prospective study. Four of these nine patients had dysplasia, and adenocarcinoma had developed in two of them; five had nondysplastic BM only. Two additional patients had adenocarcinoma, but their initial biopsy specimens had revealed dysplasia. One additional patient had intermediate-grade dysplasia. The intensity of oncogene expression was quantified by computerized color-image analysis. Enhanced c-myc expression of approximately equal intensity was consistently observed in all grades of dysplasia and carcinoma. H-ras was also consistently expressed in higher grades of dysplasia and carcinoma but not in low-grade dysplasia. Neither c-myc nor H-ras expression was detected in nondysplastic BM. The expression of H-ras in dysplastic BM appears to be a helpful marker for identifying which dysplastic lesions will progress to carcinoma.

Chronic Disease↗

PubMed1990

Chemosensitivity testing of human gliomas using a fluorescent microcarrier technique.

This report describes a new fluorescent microcarrier cytostasis assay. Human glioma cell lines and primary cultures were attached to microcarrier tissue culture beads and treated with various chemotherapeutic drugs. After treatment, the cells were labelled with two vital fluorescent dyes in order to measure cellular viability. The uptake of hydroethidine and Hoechst 33342 was evaluated alone and in combination as probes for determining metabolic activity and cellular proliferation. Hydroethidine was found to be superior when compared to trypan blue and tritiated thymidine. The use of the microcarrier technique allows for the direct cellular measurement of fluorescence without the need of extensive extraction procedures. The fluorescent assay is a sensitive, rapid and an effective way to screen for potential antiproliferative compounds.

Antineoplastic Agents↗

PubMed1990

Intermediate structures in nuclear morphogenesis following metaphase from HeLaS3 cells can be isolated and temporally grouped.

Previously nuclear reformation following metaphase in HeLaS3 cells was conceptualized in terms of a stepwise process which was continuous throughout anaphase and telophase. This concept was based on a three-dimensional visualization by scanning electron microscopy (SEM) of individual, organically prepared chromatid structures (prenuclei) which could be sequentially arranged. Morphologic analysis revealed unique topographies and morphometric properties which suggested that it should be possible to isolate populations of prenuclei aqueously. Such an isolation using detergents and density centrifugation is presented which yields metaphase plates and two populations of prenuclei with distinctive morphology. Essentially, prenuclei are freed from late mitotic cells in suspension cultures of synchronized HeLaS3 cells by treatment with 0.1% Nonidet-P40 followed by treatment with a mixture of Tween 40-desoxycholate (0.5%). Critical for the isolation is the presence of a divalent cation (5 mM Mg(+)+) and an acid pH (approximately 5.8). After density centrifugation, 2N decondensing structures (late intermediates) are recovered from 42% Percoll, and a mixture of 2N predecondensing (early intermediates) and 4N metaphase plates are recovered from 52% Percoll. The latter intermediates can be further separated into highly enriched populations (greater than 94% pure) by fluorescence-activated sorting. Predecondensing structures are of the same overall morphology as prenuclei isolated previously by organic means, can also be ordered sequentially to demonstrate nuclear morphogenesis, and retain centromere/kinetochore loci. These chromosomal loci based on immunostaining of individual structures appear to be positioned centrally during chromatid reassociation and then appear to be dispersed prior to structural rearrangements leading to formation of a disc-like prenucleus.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell Fractionation↗

PubMed1990

Use of verapamil to enhance the antiproliferative activity of BCNU in human glioma cells: an in vitro and in vivo study.

The authors have evaluated the antiproliferative activity of verapamil, alone or in combination with 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) in brain-tumor cells. These effects were studied in vitro using four human glioma cell lines and in vivo using glioblastoma multiforme cells transplanted to athymic nude mice. The results showed that verapamil when used alone produced inhibition of tumor growth; however, when verapamil was used in combination with BCNU (in vitro), significant dose-dependent suppression of proliferation occurred in all four cell lines. The in vivo results were far more dramatic. Mice treated with BCNU (25 mg/kg) plus verapamil (50 mg/kg) achieved a 200-fold decrease in tumor growth with a greater than 80% regression in tumor size. Complete cures were achieved in 80% of the mice observed for at least 50 days following the completion of therapy. These findings support the use of verapamil in overcoming drug resistance in malignant brain tumors.

Animals↗

PubMed1990

Enhanced expression of c-myc and H-ras oncogenes in Letterer-Siwe disease. A sequential study using colorimetric in situ hybridization.

Tissues from two patients with disseminated histiocytosis X (Letterer-Siwe disease) in which histiocytosis X cells exhibited histologic and cytologic features of malignancy were evaluated by in situ hybridization with the use of biotinylated nucleic acid probes to c-myc and H-ras oncogenes. Enhanced expression of these oncogenes was observed in mononucleated and multinucleated cells of histiocytosis X in the terminal proliferative phase but not in the early quiescent phase of Letterer-Siwe disease in both patients. Our findings indicate that deregulation of c-myc and H-ras in histiocytosis X are late events that likely confer a selective growth advantage to histiocytosis X cells.

DNA Probes↗

PubMed1989

Immunocytochemical study of ras and myc proto-oncogene polypeptide expression in the human menstrual cycle.

The human endometrium is a unique and dynamic tissue model system characterized by cyclic processes of cellular proliferation, differentiation, and menstrual desquamation. Both the glandular epithelial and stromal mesenchymal components work in synchronous response to the mitogenetic effect of estradiol and the antimitogenetic effect of progesterone. Mechanisms whereby estradiol and progesterone exert their effects are not completely understood. This study was undertaken to evaluate the expression and localization of the polypeptide products of the ras and myc proto-oncogenes sequentially during the menstrual cycle. Sixteen endometrial biopsy specimens were evaluated. Immunocytochemical quantitation of ras and myc expression was done by use of color image analysis (CoreScan). There was no cyclic variation in the ras polypeptide product, but the expression of myc polypeptide was low in the secretory phase and high in the proliferative phase.

Cell Division↗

PubMed1989

Immunocytochemical study of transforming growth factor expression in benign and malignant gliomas.

Immunocytochemical studies using polyclonal antibodies to epidermal growth factor (EGF) and transforming growth factor (TGF) alpha and beta were performed on 20 cases of human gliomas. EGF immunoreactive material was detected in both benign and malignant glial tumors. In addition, EGF immunoreactive material was detected in normal brain. TGF-beta was detected in both benign and malignant tumors, but was not detected in normal brain. In contrast, TGF-alpha was highly conserved in its expression, occurring predominantly in malignant compared with benign or normal brain tissue (P less than 0.0001). In malignant gliomas, glioblastomas contained 76% TGF-alpha reactivity (immunoreactive product), and anaplastic types contained 85% reactivity. Benign gliomas contained only 13% TGF-alpha reactivity. These findings support the role of TGF-alpha as an oncoprotein marker in brain neoplasms.

Brain Neoplasms↗

PubMed1989

The vacuolated glycogen-laden leukemic lymphocytes of a T-cell lymphoproliferative disorder.

In this report, we present a case of peripheral T-cell leukemia/lymphoma having mostly small- to medium-sized cells with abundant clear cytoplasmic vacuoles. The presentation at the time of diagnosis was one of leukemia/lymphoma. The phenotype of the leukemic cells of the peripheral blood was T1+, T11+, TQ1+, interleukin-2+, T3-, T4-, and T8-. The cells in the peripheral blood as well as those obtained from lymph node biopsy were strongly periodic acid-Schiff positive; the positivity was diastase sensitive. Electron microscopy confirmed the presence of glycogen in the cytoplasmic vacuoles. Serologic tests were negative for human T-cell lymphotropic virus type 1 antibody. The data presented in this article support the existence of a vacuolated variant of peripheral T-cell leukemia/lymphoma and further expand the morphological spectrum of T-cell lymphoproliferative disorders.

Aged↗

PubMed1988

Down's syndrome and acute myelofibrosis. Time study of DNA content during the progression to leukemia.

Flow cytometry (FCM) for the determination of cellular DNA content was performed on multiple bone marrow biopsy specimens from a 3-year-old boy with Down's syndrome and myelofibrosis. A rapidly fatal acute nonlymphocytic leukemia developed within 3 months after initial bone marrow evaluation. The clinical and morphologic changes corresponded to the development of aneuploidy as determined by FCM and cytogenetic analysis. These findings support the clinical observations of the premalignant potential of myelofibrosis in Down's syndrome.

Antibodies, Monoclonal↗

PubMed1988

Flow cytometry shows recurrent aneuploid clone after remission in megakaryocytic leukemia.

Flow cytometry using a DNA label can quantitate aneuploid clones in malignant tissue. We illustrated the clinical value of this technique in a 71-year-old woman with acute megakaryocytic leukemia, which was diagnosed by staining of the blasts with factor VIII antigen and their morphologic resemblance to megakaryoblasts. Marrow cells were removed from needle biopsies by vortexing in RPMI medium, centrifuged in Ficoll-Hypaque, stained with a propidium-iodide/NP-40 mixture, and analyzed at 488 nm using an argon laser. During 3 weeks of low-dose cytosine arabinoside (ara-c) infusion therapy, hyperdiploid peak A dropped from 35% (day 0) to 2.3% (day 14) to 0% (day 21), with development of marrow hypoplasia. Similarly, hyperdiploid peak B, went from 7.6% to 9.1% to 3.5%. Subsequently, her marrow recovered normal morphology and lost the aneuploid peaks. Her blood counts recovered to near normal. Four months later, she relapsed and had a return of the day-21, incompletely eradicated peak B. There was no evidence of peak A. Repeated treatment with ara-c resulted in temporary suppression of the disease, but she died 3 months later with progressive hepatosplenomegaly. Analysis of cells from her enlarged liver, heavily infiltrated with blasts, showed a large hyperdiploid peak B. In this patient, ara-c therapy induced a remission with permanent eradication of one clone, but incomplete eradication of a second clone, which ultimately led to her relapse and death.

Aged↗

PubMed1988

Ganglioglioma, a malignant tumor? Correlation with flow deoxyribonucleic acid cytometric analysis.

This study describes the flow cytometric deoxyribonucleic acid (DNA) analysis of a resected ganglioglioma. The initial histopathological analysis revealed a benign tumor characterized by a predominance of mature ganglion cells. The flow cytometric DNA analysis of the necrotic areas, however, demonstrated an aneuploid population of cells. Further examination by histological analysis of the tumor revealed both benign and atypical foci. The retrospective DNA analysis performed from paraffin sections of tissue with benign-histological findings demonstrated euploid populations of cells consistent with a benign, slow-growing lesion. In contrast, DNA analysis performed from tissue with atypical histological findings revealed aneuploid populations of cells consistent with a malignant phenotype. Our analysis provides additional data supporting the existence of tumor progression in some gangliogliomas. Results support the concept of tumor cell heterogeneity and the importance of adequate tumor sampling. The finding of aneuploid populations with unfavorable histology further supports the use of flow cytometry as an adjunct method in assessing tumor biology.

Adolescent↗

PubMed1988

Examination of differentiation, proliferation and distribution of lymphoid cells in mice by immunohistochemical analysis post in vivo administration of recombinant interleukin-II.

Augmentation of lymphoid cell activity has been observed after administration of a variety of biological response modifiers (BRM) in both preclinical and clinical studies. Little is known of in vivo control of the proliferation and early differentiation of lymphoid cells after administration of a BRM in lymphoid tissues. In view of the role that lymphoid activity plays in resistance of the host to disease and the recent demonstration that Interleukin II (IL-2) has a profound effect on regulation of immune function both in vitro by activation of cytolytic cells and in vivo by augmenting lymphoid cell activity, studies to evaluate possible morphological changes in differentiation, proliferation and distribution in lymphoid organs after in vivo administration of IL-2 were performed in conjunction with evaluation of cellular immune response modification using a functional cytolytic assay. Our findings indicate increased activation of cytolysis by spleen cells with no observed apparent corresponding changes in lymphoid morphology in either lymph node, thymus, or splenic organs. In contrast to this, marked thymic medullary proliferation was observed in animals receiving 100,000 units of IL-2, i.p., 1 thru 5 days. No thymic changes were observed after only a single i.p. injection of IL-2. Augmentation of cytolytic activity by thymic cells was not observed.

Animals↗

PubMed1987

Acute megakaryocytic leukemia. Flow cytometric analysis of DNA content at diagnosis and during the course of therapy.

Flow cytometry (FCM) for the determination of DNA content and cell cycle analysis was performed on multiple bone marrows from a case of acute megakaryocytic leukemia in a 71-year-old woman. Two aneuploid (multiploid) peaks were present at diagnosis. This multiploidy was a stable characteristic when studied temporally. The disappearance of the peaks in the bone marrow specimens directly correlated with complete remission morphologically. These findings further support the concept of FCM as an adjunct to morphologic study in identifying residual tumor burden.

Aged↗

PubMed1987

Identification of a low molecular weight polypeptide of pregnant bovine uterine origin (LMW-UDF): influence on coagulation system in vitro. Part I.

Acidified extracts of pregnant bovine uterus were found to contain a heparin-affinity polypeptide(s). The eluted peak was assayed in the Chandler loop method for whole blood and fibrin thrombus generation. Significant differences in the mean weight and size of whole blood thrombi (243.5 +/- 50 mg and 3.5 cm +/- 0.6 cm) occurred with 1 microgram of purified polypeptide when compared to control samples containing albumin (47.87 +/- .30 g and 0.8 cm +/- 0.3 cm). This activity was detected by the Chandler loop method with 100 ng to 10 micrograms of protein when analyzed in a dose-response fashion. When tested for fibrin thrombus formation this activity persisted. Experiments with 125I fibrinogen revealed no net increase or decrease of uptake into whole blood thrombi when purified polypeptide was added. The heparin-affinity polypeptide(s) possessed a molecular weight of approximately 6-4 kDa when examined by SDS-PAGE. We have therefore designated this polypeptide as low molecular weight-uterine derived factor (LMW-UDF).

Animals↗

PubMed1987

Metastasis-stimulating activity in the mouse uterus.

Mouse uterine luminal proteins are thought to play important roles in inducing diapausing blastocysts to implant into the uterine wall. Employing a syngeneic teratocarcinoma cell line (402AX), we demonstrate that neoplastic cells are better able to invade and metastasize if they are coinjected with uterine fluid from pregnant or estrogen-primed mice. This metastasizing activity of uterine fluid was partially purified by using disc polyacrylamide electrophoresis and gel filtration chromatography. Preliminary experiments indicate that the post-albumin and albumin bands contain most of the bioactivity. Furthermore, these bands contain smaller molecular weight proteins (less than 14,000) than can be separated by detergent and mild acetic acid (0.1 N) treatment.

Animals↗