Publications by authors named "Chambers A"

We have used the technique known as selected and amplified binding (SAAB) to isolate binding sites for the yeast transcription factor RAP1 from a degenerate pool of oligonucleotides. A total of 47 sequences were isolated, of which two were shown to be contaminating non-RAP1 binding sites. After excluding these two sequences the remainder of the sequences were used to derive a new consensus binding site for RAP1.

View Article and Find Full Text PDF

Inherited mutations of the p53 and neurofibromin genes are thought to cause two distinct neoplastic disorders in which gliomas occur, the Li-Fraumeni syndrome and neurofibromatosis type 1. We investigated the possibility that inherited mutations in specific regions of these genes also contributed to the clustering of gliomas in otherwise normal families. Twenty-six members of 16 families with glioma were screened for germline mutations of exons 5 through 9 of the p53 gene and exon 24 of the neurofibromin gene using a polymerase chain reaction-single-strand conformation polymorphism method.

View Article and Find Full Text PDF

To assess potential clinical applications for molecular genetic markers associated with human esophageal tumorigenesis, ten patients with primary esophageal adenocarcinomas were studied prospectively to evaluate expression of the p53 and H-ras genes. Total RNA was extracted from tumor, Barrett's epithelium, and histologically normal esophageal mucosa obtained at surgical resection, and gene expression investigated by Northern blot analysis. p53 was overexpressed, relative to normal tissue from the same patient, in seven tumor and six Barrett's specimens, whereas high levels of H-ras were found in only four tumor and one Barrett's specimen.

View Article and Find Full Text PDF

Farnesylamine, an analogue of farnesol, was shown to inhibit growth of PAP2 cells (ras-transformed NIH 3T3 cells) in a dose-dependent manner. This inhibition was overcome by adding farnesol to the culture medium, but not by adding geranylgeraniol, squalene, cholesterol, dolichol, myristic acid or palmitic acid. Farnesylamine inhibited both farnesyl/protein transferase and geranylgeranyl/protein transferase in whole cell extracts and also inhibited the prenylation of proteins, particularly ras p21, in PAP2 cells.

View Article and Find Full Text PDF

Biomechanical interactions of cancer cells with the microvasculature were studied using high resolution intravital videomicroscopy. We compared initial arrest of murine B16F10 melanoma and D2A1 mammary carcinoma cells fluorescently labelled with calcein-AM, in low pressure (liver) vs high pressure (cremaster muscle) microvascular beds. Cells were arrested due to size restriction at the inflow side of the microcirculation, penetrating further and becoming more deformed in muscle than liver [median length to width ratios of 3.

View Article and Find Full Text PDF

A decrease in stress tolerance of chorioamniotic membranes when exposed to meconium has previously been demonstrated. Clinically, variations in elastic qualities of membranes can be appreciated during their removal following spontaneous vaginal deliveries. The purpose of this study was to determine if there is a relationship between the presence of meconium-stained amniotic fluid and difficulty in removal of chorioamniotic membranes in spontaneous vaginal deliveries.

View Article and Find Full Text PDF

Two conflicting conclusions regarding the structure of the mouse osteopontin (OPN) gene were tested for their validity. Miyazaki et al. (Miyazaki, Y.

View Article and Find Full Text PDF

Data were collected from 814 clients attending anonymously for counselling before tests for human immunodeficiency virus (HIV) infection at the Burnett Clinic in Auckland. Just over 10 per cent of clients (n = 83) reported ever having injected drugs. This group was matched according to age, gender, ethnicity and sexual orientation with an equal sized control group drawn from clients who had not injected drugs.

View Article and Find Full Text PDF

We previously reported that H-ras-induced metastatic ability in murine NIH 3T3 cells is accompanied by increased expression of osteopontin (OPN). OPN is a secreted phosphoprotein that contains a GRGDS amino acid sequence, suggesting adhesive function, but the function of OPN in tumor cells remains poorly understood. Here we report that PAP2 cells (ras-transformed, metastatic NIH 3T3 cells) adhere and spread on OPN-coated substrates, while NIH 3T3 cells adhere and spread poorly on OPN.

View Article and Find Full Text PDF

We have examined tumor progression and metastatic properties of three clonal murine mammary tumor cell lines of recent origin (D2A1, D2.OR and D2.1).

View Article and Find Full Text PDF

Transfected ras oncogenes have been shown to induce metastatic properties in some cells. Clarification of the mechanisms by which ras is able to increase the metastatic ability in model systems will improve our understanding of tumor progression to metastasis, even in those cells in which ras activation has not been implicated. Many of the consequences of ras expression also have been detected in cells that have become metastatic in the apparent absence of an altered ras gene, suggesting that there is a set of common changes that can lead to metastasis with multiple signals capable of eliciting these changes.

View Article and Find Full Text PDF

We have isolated two members of the RSRF protein family, SL-1 and SL-2, in Xenopus laevis. Both proteins contain SRF-type DNA binding domains and are related to the human protein, RSRFC4. SL-1 constitutes a novel member of the RSRF family whilst SL-2 is similar to human RSRFC4 throughout its length.

View Article and Find Full Text PDF

Aims: To examine the incidence of sexually transmitted diseases according to gender, age, sexual orientation, sexual behaviour and drug use.

Methods: Data were collected from 814 clients attending anonymously for HIV testing at the Burnett Centre in Auckland. During pretest counselling clients were asked questions designed to assess their risk of HIV infection including a detailed history of sexually transmitted diseases (STDs).

View Article and Find Full Text PDF

Clonal B16-F10 cell lines with increased expression of tissue inhibitor of metalloproteinase-1 (TIMP-1) have been generated by transfection with a TIMP-1-containing expression vector. The parental B16-F10 and control 1-2 cells, and two TIMP-1 up-regulated clones (2-10, 6-5), were studied for their growth characteristics in tissue culture and their experimental metastatic ability in the chick embryo. Both of the TIMP-1 up-regulated clones showed slower in vitro growth and had lower saturation densities.

View Article and Find Full Text PDF

Anterior atlas clefts (AACs) are rare developmental variants that may mimic fractures. Due to the potential severe implications of craniocervical junction trauma, expeditious differentiation between a Jefferson burst fracture and a congenital cleft is essential in trauma patients. Three cases of AAC are presented.

View Article and Find Full Text PDF

Transfected ras oncogenes have been shown to induce metastatic properties in some cells. This altered behavior is likely due to changes in ras-mediated signal transduction pathways, resulting in altered expression of genes important to metastasis. Clarification of the mechanisms by which ras is able to induce metastatic ability in model systems will improve our understanding of tumor progression, even in those cells in which ras activation has not been implicated.

View Article and Find Full Text PDF

The chick embryo is a useful model for studying hematogenous metastasis. Cancer cells injected into veins of the chorioallantoic membrane (CAM) circulate briefly through all tissues but form metastases predominantly in the CAM. This respiratory organ is particularly suitable for intravital microscope because of its accessibility without the need for surgery and the density and planar configuration of its vessels (which we confirmed by microcorrosion casting).

View Article and Find Full Text PDF

Basement membrane-degrading enzymes of two clonal sublines of the murine Lewis lung carcinoma with distinct patterns of organ-selective metastasis were analyzed. Subline M-27 is highly metastatic to the lung and does not form liver metastases, while subline H-59 is highly metastatic to lymph nodes and liver, but not to lung. Qualitative and quantitative differences in the enzymatic profiles were found.

View Article and Find Full Text PDF

Background: There are few techniques that permit direct observation of tumor metastasis. The ability to observe steps in this process as they occur in experimental animals would complement studies on molecular mechanisms.

Purpose: We have developed a novel procedure using high-resolution intravital videomicroscopy to permit direct observation of cells as they arrest in the microcirculation, extravasate, and form micrometastases.

View Article and Find Full Text PDF

We previously found that the T24 Ha-ras oncogene induces metastatic ability in NIH 3T3 cells and that this change depends on expression of the ras oncogene. As part of our studies on mechanisms by which ras may induce metastasis, we investigated expression and activity of two cysteine proteinases, cathepsin L (major excreted protein) and cathepsin B, as well as cysteine proteinase inhibitor activity, in ras-transformed NIH 3T3 cells. In a series of cel lines that expressed differing amounts of ras, we found a good correlation between levels of ras expression and cathepsin L expression (r = 0.

View Article and Find Full Text PDF

We have previously shown that transfection of NIH 3T3 cells with the T24 H-ras oncogene converts the cells to a tumorigenic and metastatic phenotype, in proportion to levels of ras expression. We hypothesize that ras-induced increases in malignancy occur via altered expression of various genes. We have identified OPN (osteopontin; also known as Secreted Phosphoprotein, 2ar, Eta-1, and transformation-associated phosphoprotein) as a ras-induced gene in these cells.

View Article and Find Full Text PDF

To examine the relationship between the malignant behavior of rat glioma cells and expression of the differentiation antigen glial fibrillary acidic protein (GF), we assayed the tumorigenicity and metastatic ability of P635 and its GF+ or GF- clones. We injected P635 (GF+) and clone 45 (GF-) cells intramuscularly in nude mice. Both lines formed local tumors which metastasized to lungs with equal efficiency.

View Article and Find Full Text PDF

The relation between age, sleep disorders, nocturnal penile tumescence, and sexual behavior was investigated in 70 healthy married men aged 45-75 years. They had an extensive psychosexual interview, a medical and psychiatric evaluation, and were studied in the sleep laboratory for four nights. Electroencephalogram (EEG), eye movements, muscle tone, and penile tumescence were monitored continuously, and respiratory airflow and bilateral anterior tibialis recordings were obtained during the first sleep session.

View Article and Find Full Text PDF