Biomedical subjects

S Van Noorden

Publications and source records attributed to S Van Noorden.

At least 19 recordsLinked to original sources

PubMed2003

Purified malignant mammary epithelial cells maintain hormone responsiveness in culture.

Currently, the therapy for breast cancer is determined by immunohistochemical staining of the primary tumour for oestrogen receptor alpha (ERalpha). However, a proportion of ERalpha-positive patients fail to respond to tamoxifen and a proportion of ERalpha-negative patients show response. Here, we describe a novel procedure for the purification of malignant breast epithelial cells in an attempt to identify these patients at an early stage. Using this procedure, we are able to purify malignant cells to >90% purity as determined by immunohistochemical staining, cytology and fluorescent in situ hybridisation (FISH). While the malignant cells can be maintained in culture they do not proliferate in contrast to purified breast epithelial cells from reduction mammoplasties. Moreover, ERalpha and progesterone receptor (PR) expression is maintained in malignant cells, whereas normal epithelial cells rapidly lose ERalpha and PR. Functional studies were performed on the separated malignant cells in terms of their response to oestradiol and tamoxifen. Four out of the seven ERalpha-positive tumours showed a significant reduction in cell numbers after tamoxifen treatment compared to oestradiol, ERalpha negative tumours failed to show a response. We conclude that (a) it is possible to purify and maintain breast cancer cells for a sufficient period to permit functional studies and (b) ERalpha is retained in culture facilitating the use of these cells in studies of the mechanism of endocrine response and resistance in vitro.

Breast↗

PubMed2002

Rapid flow carbon dioxide laparoscopy disperses cancer cells into the peritoneal cavity but not the port sites in a new rat model.

BACKGROUND: The role of carbon dioxide (CO2) in the pathogenesis of tumor recurrence after laparoscopy remains controversial. Using a new rat model, we studied the effect of different CO2 flow rates on the dispersal of free cancer cells. METHODS: A novel model of desufflation without trocar was developed, and 55 Fischer rats were randomized into three flow groups: group A (rapid, 0.67 l/min; n = 20), group B (slow, 0.44 l/min; n = 20), and group C (gasless, n = 15). We vented CO2 via a portless surgical valve that filtered cells. After the abdominal wall had been suspended to create space, half of the animals in each group (nonrecovery) received 7.5 x 10(6) immunolabeled rat colon cancer cells (RCC2) intraperitoneally, whereas the other half (recovery) received 7.5 x l0(6) viable RCC2 before insufflation or gasless laparoscopy. Nonrecovery animals were killed after 20 l of insufflation. Parietal peritoneal and port-site specimens were examined for RCC2 by fluorescence microscopy (FM) and flow cytometry (FC). The recovery animals were killed at 4 weeks for evidence of wound recurrence. RESULTS: Nine of 10 nonrecovery animals in A had RCC2 on FM or FC, as compared with 2 animals in each of the nonrecovery groups B and C (p = 0.018, Fisher's exact test). Two of the nine animals in group A also had RCC2 in their portless valves. Two recovery (A) animals developed wound recurrence as compared with none in the other groups (p = 0.315). CONCLUSION: In this model, rapid CO2 flow dispersed free cancer cells into the peritoneal cavity, but not into the port sites, thus supporting a role for CO2 in the intraperitoneal dispersal of free cancer cells, but not in wound recurrence.

Abdominal Neoplasms↗

PubMed2002

Estrogen receptor beta in breast cancer.

Estrogen is essential for normal growth and differentiation in the mammary gland. It also supports growth of approximately 50% of primary breast cancers. For this reason, removal of estrogen or blocking of its action with the anti-estrogen, tamoxifen, is the main treatment for estrogen receptor alpha (ERalpha)-positive tumors. In 1996, when oncologists became aware of a second ER, ERbeta, there was some doubt as to whether this receptor would be of importance in breast cancer because the clinical consensus was that responsiveness to tamoxifen is related to the presence of ERalpha in breast cancer. Today we know that ERalpha and ERbeta have distinct cellular distributions, regulate separate sets of genes and can oppose each other's actions on some genes. We also know that ERbeta is widely expressed in both the normal and malignant breast and that there are proliferating cells in the breast which express ERbeta. In this review we summarize what is known about ERbeta in breast cancer and examine the possibility that ERbeta-selective ligands may well represent a useful class of pharmacological tools with a novel target, namely proliferating cells expressing ERbeta.

Animals↗

PubMed2001

Estrogen receptors and proliferation markers in primary and recurrent breast cancer.

To elucidate the clinical importance of estrogen receptor (ER) beta in breast cancer, 29 archival primary breast cancer specimens, six locally recurrent cancers, and five benign mammary tumors were examined histochemically for ERalpha, ERbeta and the proliferation markers Ki67 and cyclin A. In benign tumors, most epithelial cells contained ERbeta, but ERalpha was rare. In primary cancers, both ERalpha and ERbeta occurred in epithelial cells, the presence of ERbeta being associated with elevated expression of Ki67 and cyclin A, and ERalpha with decreased levels. Thus, the highest content of proliferation markers was seen in primary cancers that were ERalpha(-) ERbeta(+). Most Ki67-containing cells coexpressed ERbeta, but few showed ERalpha. In locally recurring cancers, ERalpha, ERbeta, and Ki67 were more highly expressed than in the corresponding primary tumors, and many cells containing ERbeta, but few with ERalpha, expressed Ki67. Surprisingly, ERbeta, but not ERalpha, was seen in the stromal cells of both primary and recurrent cancers. Because the response of breast cancers to tamoxifen therapy is correlated with the presence of ERalpha, cancer cells that lack ERalpha but contain ERbeta and proliferation markers represent a novel population of apparently proliferating cells that probably are not targeted by the current antiestrogens. Thus, appropriate ERbeta-specific ligands, perhaps in combination with tamoxifen, may be useful in improving the treatment of breast cancers.

Biomarkers, Tumor↗

PubMed2001

Enhanced susceptibility to superantigen-associated streptococcal sepsis in human leukocyte antigen-DQ transgenic mice.

Bacterial superantigens are believed to cause septic shock, although, because of the lack of superantigen-sensitive infection models, proof that superantigenicity underlies shock pathogenesis is lacking. This work demonstrates a clear superantigen effect in septic shock resulting from bacterial infection. Transgenic expression of human leukocyte antigen (HLA)-DQ, but not HLA-DR, specifically augments lymphocyte responses to streptococcal pyrogenic exotoxin A (SPEA). HLA-DQ transgenic mice had increased mortality after administration of SPEA or infection with Streptococcus pyogenes. Immune activation during infection was HLA-DQ transgene-dependent and was manifested by Vbeta-specific T cell repertoire changes and widespread lymphoblastic tissue infiltration. Unlike earlier models, which used toxin-induced shock, these T cell superantigen responses and lymphoblastoid changes were observed during invasive streptococcal sepsis. Lymphoid activation was undetectable in HLA-DQ mice infected with an isogenic SPEA(-) strain, which proves that a single superantigen can play a role in sepsis pathogenesis.

Animals↗

PubMed2000

Failure of ultrasonic vibration as a means of antigen retrieval in routine diagnostic immunocytochemistry.

It was recently reported that certain antigens can be retrieved from paraffin sections of formalin-fixed tissues by ultrasonication using either an expensive and sophisticated ultrasonic cell disrupter probe (cytokeratins 13 and 16) or an inexpensive and generally available ultrasonic cleaning bath (bcl-1). We wished to investigate the routine use of the latter method and therefore tried to retrieve from various tissues 11 antigens that usually require heat-mediated retrieval in citrate buffer. We applied ultrasonic vibration for periods of 30 seconds to 1.5 minutes in a cleaning bath containing citrate buffer or water, with and without the addition of heat, or for 1 minute in hot citrate buffer after microwaving for 10 minutes in the same buffer. Although a slight effect of ultrasound was noted for a few antigens, in no case did the immunostaining reach the level achieved after standard microwave heating in citrate buffer. We conclude that, under the conditions we used, ultrasonic antigen retrieval cannot be used for immunocytochemistry in a routine histopathology laboratory.

Antigens↗

PubMed1999

High expression of CD23 in the proliferation centers of chronic lymphocytic leukemia in lymph nodes and spleen.

Chronic lymphocytic leukemia (CLL) is a B-cell neoplasm composed of a heterogeneous mixture of cells, including small lymphocytes, prolymphocytes, and large transformed cells; these last cells appear to represent the proliferating compartment. CLL cells express, in addition to B cell markers, the transmembrane receptor CD23. CD23 functions as the receptor for IgE and also appears to play a role in controlling the growth and proliferation of lymphocytes. Its level of expression among the different cells in CLL has not been examined. In this study, we show that CD23 expression is much higher in the large transformed CLL cells than in the small lymphoid population. This may provide an explanation for the observed correlation between a circulating CD23 cleavage product (soluble CD23) and prognosis in CLL. In addition, we have shown that proliferation in splenic CLL occurs preferentially in the white pulp zones, even in cases in which both the white and red pulp are extensively infiltrated.

Aged↗

PubMed1997

The interaction of CGRP and adrenomedullin with a receptor expressed in the rat pulmonary vascular endothelium.

An abundant, seven trans-membrane domain receptor related to the calcitonin receptor has been studied by a number of groups without identification of its ligand. A recent report claimed that the receptor was a type 1 CGRP receptor (Aiyar et al J. Biol. Chem. 271 11325-11329 (1996)). We have studied the equivalent rat sequence in transfected cells. When expressed in 293 cells the receptor interacts with CGRP and adrenomedullin with KD values of 1.2 nM for CGRP and 11 nM for adrenomedullin. Both ligands cause an elevation of intracellular cAMP with EC50 values of 4 nM and 20 nM respectively and these effects are inhibited by the antagonist CGRP8-37. The receptor is expressed at high levels in the pulmonary vascular endothelium. Both the pharmacological data and the localisation are consistent with the conclusion that the orphan receptor is a type J CGRP receptor. However, when expressed in COS-7 cells, no receptor activity could be demonstrated suggesting that 293 cells contain a factor necessary for functional receptor expression.

Adrenomedullin↗

PubMed1996

Expression of the multifunctional extracellular matrix protein thrombospondin in crescentic glomerulonephritis.

Thrombospondin is a multifunctional 450 kD glycoprotein which may be secreted into the extracellular matrix by a wide variety of cells. Occasional foci of immunoreactive thrombospondin have previously been demonstrated within normal human glomeruli. A specific polyclonal antibody directed against thrombospondin 1 was used to examine the distribution of this regulatory glycoprotein in renal biopsies from patients with a variety of renal diseases, including rapidly progressive glomerulonephritis associated with circulating antibodies to neutrophils, active or quiescent systemic lupus erythematosus, and membranous nephropathy, together with normal renal tissue. The results demonstrated the marked up-regulation of thrombospondin expression in acutely inflamed renal tissue with strongly positive, predominantly extracellular staining of glomerular crescents, although cytoplasmic staining of epithelial cells was also seen, indicating that these cells may contribute to thrombospondin accumulation at these sites. Occasional segmental mesangial staining was seen in cases of active lupus and rapidly progressive glomerulonephritis, while some focal interstitial staining around peritubular capillaries was seen in all renal tissue examined. These results suggest that thrombospondin may play an important role in the regulation of cellular recruitment, proliferation, and function in crescentic glomerulonephritis.

Antibodies, Antineutrophil Cytoplasmic↗

PubMed1996

Acetyl cholinesterase is expressed in the follicular dendritic cells of germinal centres: differences between normal and neoplastic follicles.

Acetyl cholinesterase (AcChE) was demonstrated by histochemistry in the follicular dendritic cells (FDCs) of the germinal centres of lymph nodes, tonsils, and bowel lymphoid tissue. Its presence in the FDCs was confirmed by double immunostaining for CD21 or DRC-1. AcChE-positive FDCs are concentrated in the inner portion of the light zone of the germinal centre, being absent from the dark zone. In the lymphoid tissue surrounding the germinal centres are AcChE-positive blood vessels; double staining shows that the AcChE is present in the pericytes surrounding the endothelium of the blood vessels. In contrast to the reactive follicle, the AcChE reactivity in FDCs of follicle centre lymphoma is absent or minimally expressed, although the dense FDC mesh is well stained with CD21 or DRC-1. This suggests that the AcChE is not constitutively expressed in FDCs but that its expression is influenced by the state and activity of the lymphoid cells in the germinal centre. The reduced level of AcChE staining can be profitably employed in the diagnosis of follicle centre lymphoma.

Acetylcholinesterase↗

PubMed1996

Morphological interactions of human first trimester placental villi co-cultured with decidual explants.

Abnormalities of pregnancy such as pre-eclampsia and intrauterine growth retardation are characterized by shallow trophoblastic invasion of the placental bed, the precise molecular pathophysiology of which remains to be fully elucidated. An in-vitro model involving a co-culture of first trimester placental villi and decidua parietalis explants (of 8-12 weeks gestation) was developed and used to characterize the migration and local invasion of trophoblast cells. Trophoblast proliferation (confirmed by Ki-67 immunostaining), differentiation and loose attachment of placental villi to the underlying decidual epithelium or stroma occurred within the first 24 h of co-culture. This was followed by erosion of the syncytial layer of the placental villi and commencement of a progressive cytotrophoblast invasion after 48 h of co-culture, which continued until 120 h, when the experiments were terminated. E-cadherin was expressed at the interfaces between trophoblast cells within the villi, but expression of this adhesion molecule seemed to be down-regulated in the invasive trophoblast cells. Our results suggest that the model could be useful in investigating the factors that control early human placentation and the feto-maternal interface.

Antibodies, Monoclonal↗

PubMed1996

The intestine and endocrine pancreas of the African elephant: a histological immunocytochemical and immunofluorescence study.

Histological, immunocytochemical and immunofluorescence methods were employed to study the intestine and endocrine pancreas of the elephant. The histological findings were in line with those in monogastric mammals. In the mucosa of intestine, endocrine cells were immunoreactive to somatostatin, gastrin, CCK, GIP, secretin, motilin, glucagon and NPY. Nerve cells immunoreactive to somatostatin, substance P, VIP, PHI, NPY, bombesin and CGRP were detected. No immunoreactivity to neurotensin was observed, islets of the pancreas had insulin cells in their cores and glucagon and somatostatin cells in their mantles. The antisera employed failed to demonstrate PP cells in the pancreas, but NPY-immunoreactive cells were present.

Animals↗

PubMed1994

Virulence of Aspergillus fumigatus double mutants lacking restriction and an alkaline protease in a low-dose model of invasive pulmonary aspergillosis.

To investigate the pathogenicity of Aspergillus fumigatus mutants lacking putative virulence factors, we have developed a new murine model of invasive pulmonary aspergillosis based on neutropenia, the major factor predisposing patients to this infection. Mice were treated with cyclophosphamide and inoculated by the intranasal route with 5 x 10(3) conidia, a significant reduction from inoculum levels used in previous models. Evidence for the production of the extracellular alkaline protease (Alp) in lung tissue was obtained by using a fungal transformant harboring an alp::lacZ reporter gene fusion. The pathogenicities of single mutant strains lacking either Alp or the ribotoxin restrictocin and of a double mutant strain lacking both proteins were assessed in this infection model. There were no significant differences between the mutant and the wild-type strains in terms of mortality or histological-features. Inoculations with mixtures of conidia showed that the double mutant strain is slightly less virulent than the wild-type strain. We conclude that Alp and restrictocin are not important virulence determinants in pulmonary infection.

Allergens↗

PubMed1994

False positive immunoreaction in products of conception.

False positive immunostaining for cytomegalovirus in products of conception was revealed using an avidinbiotinylated peroxidase complex. The cause was shown to be endogenous biotin. The use of a non-avidin-biotin method avoided the problem.

Abortion, Missed↗

PubMed1994

The cell blot assay in analysis of rat anterior pituitary cell secretion.

We have investigated the efficacy of the cell blot assay in analysis of the secretion of hormones and peptides from rat anterior pituitary cells. The dissociated cells are cultured on pieces of translucent polyvinylidene difluoride membrane, on which their secretory products are adsorbed and subsequently immunostained. The area and integrated optical density of the stained 'halo' surrounding individual cells is measured by microscopical image processing and the values for basal secretion of a particular hormone or peptide are compared with those after application of secretagogues or inhibitors. Our experiments tested established responses of dissociated rat anterior pituitary cells; in general, the results were as expected. Double immunoenzymatic staining could be used to show secretion of two products from the same or different cells in one preparation, and immunofluorescence with fluorescein- and/or rhodamine-labelled antibodies could be used instead of enzyme-linked immunolabelling. Optimal dilutions of immunoreagents were much higher than those used for immunocytochemistry on tissue sections. Although the cell blot assay does not provide absolute quantification, since some of the secreted product escapes into the medium, it is a relatively easy and economical way for morphologists to compare secretion from individual cells under varying conditions.

Adrenocorticotropic Hormone↗

PubMed1994

The oesophagus and stomach of the African elephant: a histological, immunocytochemical and immunofluorescence study.

Histological, immunocytochemical and immunofluorescence methods were employed to study the oesophagus and stomach of the elephant. The histological findings were in line with the situation in monogastric species like swine and man. In the mucosa of the stomach, endocrine cells were immunoreactive to gastrin, somatostatin, chromogranin A and serotonin. Nerve cells immunoreactive to somatostatin, bombesin, VIP, PHI and CGRP were detected in the submucosal and myenteric plexus of the stomach. In the stomach, the absence of glucagon cells and the presence of endocrine cells immunoreactive to PYY, are in contrast to the situation in mammals and need further investigation. Small gastric ulcers were observed in some of the specimens.

Animals↗

PubMed1993

Protection of germinal centres from complement attack: decay-accelerating factor (DAF) is a constitutive protein on follicular dendritic cells. A study in reactive and neoplastic follicles.

The development of B-cell memory is linked to the presence of germinal centres. This process is dependent on the presence of antigen, usually in the form of immune complexes with antibody, on the surface of the follicular dendritic cells (FDCs) that form a network in the germinal centre. The presence of immune complexes poses a constant danger of activating complement. Decay accelerating factor (DAF, CD55) and the membrane attack complex (MAC) inhibitor (CD59) are two cell proteins whose sole function is to protect cells from the action of complement, the former affecting the earlier components of the complement cascade, and the latter the terminal ones; both are bound to the cell surface via a glycosylphosphatidylinositol link. DAF but not CD59 could be demonstrated on FDCs. DAF is also present on the FDCs in follicular lymphomas despite the absence of complement (C3) in neoplastic follicles. This indicates that DAF is constitutive to FDCs but does not preclude the possibility that its expression is increased when immune complexes are deposited.

Antigens, CD↗

PubMed1993

Modulation of galanin and neuromedin U-like immunoreactivity in rat corticotropes after alteration of endocrine status.

The localization of galanin in rat lactotropes and human corticotropes is well established. Neuromedin U immunoreactivity is present in rat corticotropes but radioimmunoassay of thyroid-manipulated rat pituitaries has also linked it to the thyroid axis. We found galanin immunoreactivity in some rat corticotropes, so we have re-examined rat anterior pituitary galanin- and neuromedin U-like immunoreactivity by use of immunocytochemistry and electron microscopy in rats in the normal state and after estrogen administration or adrenalectomy. In normal rats galanin immunoreactivity was present in a few corticotropes and lactotropes, females showing more than males; neuromedin U-like immunoreactivity was present in some thyrotropes and most corticotropes, in both sexes. Where galanin, neuromedin U and ACTH immunoreactivities were colocalized in corticotropes they were present in the same granules. Estrogen administration caused an increase in number of galanin immunoreactive lactotropes, as previously shown. The proportion of neuromedin U-positive corticotropes was not affected. After adrenalectomy, only females showed a significant increase in the proportion of galanin-positive corticotropes. Neuromedin U immunoreactivity was significantly increased in both sexes, as previously shown. Thus, in rat, as in man, galanin can be present in corticotropes and its expression appears to be sex-related. This finding, and the demonstration of thyrotrope neuromedin U (only examined in normal females), provide correlation with previous experiments. The influence of endocrine status on the expression of these novel peptides underlines the inherent plasticity of pituitary endocrine cells.

Adrenalectomy↗