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J Varley

Publications and source records attributed to J Varley.

31 records · Page 2Linked to original sources
PubMed1995

Allelic imbalance on chromosome 1 in human breast cancer. II. Microsatellite repeat analysis.

We have determined regions of allelic imbalance in human breast cancer cells using highly polymorphic microsatellite markers, which can be rapidly typed by the polymerase chain reaction (PCR) using very small amounts of DNA. It appears that there are several regions of chromosome I which may be the targets of allelic imbalance, including some regions which have been identified previously by different groups. The detail with which we have mapped these regions of imbalance is, however, much greater than has been previously reported, and we have been able to localise these regions to small intervals of the genome. In addition we have identified previously uncharacterised regions of allelic imbalance on chromosome arm 1p, one of which (at 1p22-31) is lost in a high proportion of malignant lesions. We are currently attempting to analyse this latter region in detail in order to identify and characterise the sequence(s) involved. Study of such regions should help us understand some of the mechanisms underlying the development and progression of breast cancer.

Alleles↗
PubMed1995

Loss of heterozygosity on the X chromosome in human breast cancer.

The analysis of loss of heterozygosity (LOH) in tumours can be a powerful tool for mapping the sites of tumour suppressor genes in the human genome. A panel of breast cancer patients was assembled as pairs of tumour and lymphocyte DNA samples and LOH studies carried out by Southern hybridisation with polymorphic loci mapping to the X chromosome with appropriate controls. Deletion mapping revealed a high frequency of small regionalised deletions, defining at least three independent regions, one of which is particularly well mapped to a 500 kb stretch of DNA in the distal portion of the pseudoautosomal region of Xp. A second region has been identified within the pseudoautosomal region close to the pseudoautosomal boundary, and there is a third discrete site of loss on distal Xq. Perturbations of sequences at these regions represent independent events in a number of patients. This study represents the first detailed analysis of LOH on the X chromosome in human breast tumours, the results of which indicate that at least three regions of this chromosome are involved in the disease.

Alleles↗
PubMed1995

Establishment of the marker order pter-NRAS-NGFB-D1S189-D1S252-D1S440-D1S453-D1S514-CEN-D1S442-D1S498-qte r in relation to the centromere on human chromosome 1.

Recent developments in genetic linkage mapping of the human genome have generated a large number of short tandem repeat polymorphic markers (Weissenbach et al. 1992, Gyapay et al. 1994), and eventual integration of these markers into a physical map is a logical progression. A number of Généthon microsatellite (CA repeat) markers have been provisionally localized to 1p13, but their exact position with respect to other sequences is unknown. In order to confirm the order of these markers and their position with respect to known genes within 1p13 and the centromere, we have isolated yeast artificial chromosomes (YACs) corresponding to the markers and have carried out double and triple fluorescence in situ hybridization (FISH) studies. Knowledge of both the order of microsatellite markers and their integration with a physical map of known genes can be an essential component in analysis of disease loci such as human cancer, where regions of chromosomes showing high levels of loss of heterozygosity need to be mapped in detail.

Centromere↗
PubMed1995

Confirmation of the copy number of chromosome 1 in interphase nuclei from paraffin sections of breast tumours by fluorescence in situ hybridization.

Fluorescence in situ hybridization (FISH) was used to establish the copy number of chromosome 1 in a set of nine breast tumours in which the chromosome had previously been shown to have undergone a variety of rearrangements by loss of heterozygosity studies. In each case, FISH with satellite III DNA from chromosome 1q12 confirmed the results obtained by Southern hybridization. Importantly, in all five cases with rearrangements thought not to involve the centromeric region, FISH showed that the events had not disrupted the gross chromosome structure. This study highlights the potential of using the two techniques together to obtain a clearer picture of both large- and small-scale alterations to chromosomes in solid tumours.

Alleles↗
PubMed1995

Detailed mapping and loss of heterozygosity analysis suggests a suppressor locus involved in sporadic breast cancer within a distal region of chromosome band 17p13.3.

The chromosome region 17p13.3 is thought to encode a tumour suppressor gene involved in sporadic breast cancer and other malignancies. Physical ordering of markers has been carried out by a series of multicolour fluorescent in situ hybridisation (FISH) experiments, using isolated yeast artificial chromosomes (YACs) and cosmids. Eight polymorphic markers ordered within this new physical map and one external marker were used to investigate the pattern of loss of heterozygosity in a panel of 40 sporadic breast tumour patients. The data revealed a region of high loss (60%) within distal 17p13.3, defined by markers D17S926, D17S695 and D17S849 which mapped close together. A contig of YACs was constructed physically linking these three markers.

Base Sequence↗
PubMed1994

Meconium analysis for improved identification of infants exposed to cocaine in utero.

We screened anonymously all mothers and infants born during a 3 1/2-month period to determine the prevalence of intrapartum cocaine use, test the maternal characteristics that are specific predictors of intrauterine cocaine exposure (IUCE), and compare the sensitivity of infant urine versus meconium samples for identification of IUCE. Of 1237 live births during the study period, a sample was obtained from 1201 mother-infant pairs. The overall prevalence of documented intrapartum cocaine exposure was 66 (5.5%) of 1201 pairs. Previously developed drug screening guidelines had a sensitivity of 89% for detecting IUCE in infants. Direct comparisons of samples from the same mother-infant pair revealed that there were no cases in which cocaine was found in infant urine but not in meconium; however, infant urine testing missed 25% of the infants who had positive findings in meconium. We conclude that (1) meconium testing was more likely than urine testing to identify an infant with IUCE, detecting an additional 33%; (2) there was significant maternal cocaine use (5.5%) in a teaching hospital with a mixed patient population; (3) maternal characteristics known to identify infants at risk of having IUCE were useful in our population; and (4) IUCE of neonates admitted to the neonatal intensive care unit was more common than that of infants admitted to the regular newborn nursery.

Cannabis↗
PubMed1991

Developmental regulation of a serum response element binding activity in amphibian embryos.

As part of our studies of transcriptional control during early development in vertebrates, we have examined embryos of the amphibian Xenopus laevis for the presence of sequence-specific DNA-binding proteins, using gel electrophoresis mobility-shift assays. Our analysis has focused on sequence elements in the cytoskeletal actin gene, whose embryonic transcription is initially activated at the gastrula stage, approximately 16 hours after fertilization. We detect activities capable of specific binding to two known transcriptional regulatory elements, the serum response element and the GC-box, located in the 5'-flanking region of the cytoskeletal actin gene. Binding activity specific for a region downstream of the transcriptional startsite is also detected, in a region which may be involved in controlling developmental activation of this gene. Serum response element-binding activity, as well as the downstream binding activity, is enriched in extracts from gastrula and neurula stage embryos, compared to egg extracts, suggesting that increased levels of one or both of these activities might play a role in developmentally timed transcriptional activation of the cytoskeletal actin gene in the embryo.

Actins↗
PubMed1990

T lymphocytes and eosinophils in allergen-induced late-phase asthmatic reactions in the guinea pig.

The kinetics and phenotype of T lymphocytes infiltrating the airways of guinea pigs undergoing late-phase asthmatic reactions (LAR) were studied with monoclonal antibodies, cytofluorimetry, and immunocytochemistry. Challenge of sensitized animals with aerosolized ovalbumin was followed by early (2 h) and late-phase (17 h) bronchoconstriction. The induction of hypersensitivity, by aerosolized antigen, was associated with an increase in mucosal T cell numbers, which consisted almost entirely of CD8+ T cells. Following allergen challenge of fully sensitized animals, a biphasic rise in total T cell (CD3+) numbers was observed in the bronchial mucosa, peaking at 17 and 48 h. A similar pattern of T cell accumulation was observed in the bronchial adventitia but with an extra early peak at 2 h. In contrast to the T cell influx of the sensitization phase, the postchallenge infiltrate consisted largely of CD3+, CD8- cells. Eosinophil numbers were elevated in both submucosa and adventitia, with a single broad peak between 17 and 48 h. T cell infiltration was compared with eosinophil accumulation; while correlations between T cell and eosinophil numbers varied over the 96 h of the experiment, strong associations were observed between CD8+ numbers and eosinophils in the adventitia at 6 h (r = 0.733, p less than 0.01) and between CD3+ numbers and eosinophils in the submucosa at 72 h (r = 0.88, p less than 0.001). No significant changes were detected in T cell or eosinophil numbers in the lung parenchyma. There was a postchallenge increase in eosinophils (but not T cells) in bronchoalveolar lavage (BAL).(ABSTRACT TRUNCATED AT 250 WORDS)

Airway Resistance↗
PubMed1988

Comparative vascular effects of histamine, prostaglandin (PG) D2 and its metabolite 9 alpha,11 beta-PGF2 in human skin.

In this double-blind study we have investigated the vascular effects of prostaglandin, (PG) D2, in normal skin and compared these effects with histamine and the initial PGD2 metabolite 9 alpha, 11 beta-PGF2. In eight healthy subjects the vascular response to intradermal injections of histamine, PGD2, a combination of histamine and PGD2, and 9 alpha,11 beta-PGF2, was assessed by measurement of the weal and flare area. Histamine caused dose-related increases in weal area (P less than 0.01). The weal response due to PGD2 was greater than saline control only at a dose of 71.0 and 710 nmol (P less than 0.05). Because of the small size of the weal produced by PGD2 when compared with histamine, it was not possible to determine their relative potencies. Histamine and PGD2 caused dose-related increases in flare area (P less than 0.05), and when compared at a response level of 10 cm2 and 15 cm2, histamine was 45 and 251 (P less than 0.01) times more potent than PGD2 in molar terms. Weal and flare responses due to 9 alpha,11 beta-PGF2 were similar to those observed with the equimolar concentration of PGD2. The weal and flare responses when PGD2 and histamine when combined were not significantly different from that predicted by a purely additive effect. We conclude that histamine is likely to be an important mediator contributing towards increased vascular permeability and vasodilatation following immunological activation of skin mast cells in vivo, while PGD2 and its metabolite 9 alpha, 11 beta-PGF2 play only a minor role.

Dinoprost↗
PubMed1987

Cholinergic-mediated bronchoconstriction induced by prostaglandin D2, its initial metabolite 9 alpha,11 beta-PGF2, and PGF2 alpha in asthma.

In this study, we have investigated the contribution of cholinergic-mediated bronchoconstriction in the airway response provoked by inhaled prostaglandin (PG)D2, its metabolite 9 alpha, 11 beta-PGF2, and PGF2 alpha, which are generated during mast cell activation in vivo and are potent bronchoconstrictor agonists in humans. The effect of prior inhalation of 1 mg ipratropium bromide (IB) on the bronchoconstrictor response to inhaled methacholine (MCh), PGD2, 9 alpha, 11 beta-PGF2, and PGF2 alpha was determined in 7 allergic asthmatic subjects by measuring changes in SGaw, FEV1, and Vmax30. Methacholine, PGD2, and 9 alpha, 11 beta-PGF2 caused concentration-related bronchoconstriction with PGD2 and 9 alpha, 11 beta-PGF2 being between 45 and 112 times more potent than MCh (p less than 0.05), depending on the method used to measure airway caliber. Preinhalation of IB displaced the concentration response curves to MCh between 69- and 196-fold to the right, and this was significantly greater than that observed with PGD2 (12- to 23-fold, p less than 0.02) and 9 alpha, 11 beta-PGF2 (12- to 22-fold, p less than 0.02). Ipratropium bromide inhibited the bronchoconstriction achieved with the highest concentration of agonist by 73 to 91% with MCh, 46 to 79% with PGD2, and 32 to 38% with 9 alpha, 11 beta-PGF2. Ipratropium bromide did not affect the bronchoconstriction pattern to inhaled PGF2 alpha, irrespective of the nature of the response. We conclude that although PGD2 and 9 alpha, 11 beta-PGF2 are potent contractile agonists of human smooth muscle in vitro, bronchoconstriction observed with these mediators in vivo results from a combination of both direct and cholinergic-mediated mechanisms.

Adult↗
PubMed1979

Effect of propranolol on the ventilatory response to hypercapnia in man.

1. The effect of a single oral dose of propranolol on the ventilatory response to hypercapnia has been studied in five healthy subjects. 2. Propranolol produced a small but significant reduction in the slope of the ventilation/end-tidal PCO2 regression line. 3. Propranolol did not significantly change vital capacity or forced expiratory volume in 1 s.

Adult↗
PubMed1978

Culturing anomalies associated with Mycoplasma recovered from the tissues of chicks and turkey poults experimentally infected with Mycoplasma gallisepticum or Mycoplasma gallinarum.

Tissues of mycoplasma infected chicks and turkey poults were cultured and subcultured on mycoplasma agar. Usually, colonies which grew on the agar initially inoculated could be subcultured, but sometimes they could not. At other times, colonies were not seen on the agar initially inoculated but appeared on the subcultured plate.

Animals↗