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R Carpenter

Publications and source records attributed to R Carpenter.

At least 91 records · Page 5Linked to original sources
PubMed1996

Molecular probes for sweeteners: immunorecognition of superpotent guanidinium compounds.

Monoclonal antibodies (MAb) were made to two different superpotent guanidino sweet tasting ligands, N-(p-cyanophenyl)-N'-(diphenylmethyl)-guanidineacetic acid and N-(p-cyanophenyl)-N'-(cyclooctyl)-guanidineacetic acid. In the present study we examined the binding specificity of three MAb clones (denoted as NC10.7, NC10.13, and NC37.3). The isotypes of these MAb were determined to be IgG1 kappa for NC10.7 and NC37.3, while NC10.13 was IgG2b, kappa. The dissociation constants for the MAb were 19 nM (NC10.7), 28 nM (NC10.13), and 16 nM (NC37.3). The binding specificity of each MAb was characterized by a competitive inhibition radioimmunoassay using related sweetener analogues. Antibodies to this family of sweet tasting compounds may be useful probes for the study of sweet taste chemistry and identification of novel sweet taste ligands.

Acetates↗
PubMed1996

Induction, recovery, and safety characteristics of sevoflurane in children undergoing ambulatory surgery. A comparison with halothane.

BACKGROUND: Sevoflurane is an inhalational anesthetic with characteristics suited for use in children. To determine whether the induction, recovery, and safety characteristics of sevoflurane differ from those of halothane, the following open-labeled, multicenter, randomized, controlled, phase III study in children undergoing ambulatory surgery was designed. METHODS: Three hundred seventy-five children, ASA physical status 1 or 2, were randomly assigned in a 2:1 ratio to receive either sevoflurance or halothane, both in 60% N2O and 40% O2. Anesthesia was induced using a mask with an Ayre's t piece or Bain circuit in four of the centers and a mask with a circle circuit in the fifth center. Maximum inspired concentrations during induction of anesthesia were 7% sevoflurane and 4.3% halothane. Anesthesia was maintained by spontaneous ventilation, without tracheal intubation. End-tidal concentrations of both inhalational anesthetics were adjusted to 1.0 MAC for at least 10 min before the end of surgery. Induction and recovery characteristics and all side effects were recorded. The plasma concentration of inorganic fluoride was measured at induction of and 1 h after anesthesia. RESULTS: During induction of anesthesia, the time to loss of the eyelash reflex with sevoflurane was 0.3 min faster than with halothane (P < 0.001). The incidence of airway reflex responses was similar, albeit infrequent with both anesthetics. The total MAC.h exposure to sevoflurane was 11% less than the exposure to halothane (P < 0.013), although the end-tidal MAC multiple during the final 10 min of anesthesia was similar for both groups. Early recovery as evidenced by the time to response to commands after sevoflurane was 33% more rapid than it was after halothane (P < 0.001), although the time to discharge from hospital was similar for both anesthetics. The mean ( +/- SD) plasma concentration of inorganic fluoride 1 h after discontinuation of sevoflurane was 10.3 +/- 3.5 microM. The overall incidence of adverse events attributable to sevoflurane was similar to that of halothane, although the incidence of agitation attributable to sevoflurane was almost threefold greater than that attributable to halothane (P < 0.004). CONCLUSIONS: Sevoflurane compared favorably with halothane. Early recovery after sevoflurane was predictably more rapid than after halothane, although this was not reflected in a more rapid discharge from the hospital. The incidence of adverse events was similar for both anesthetics. Clinically, the induction, recovery, and safety characteristics of sevoflurane and halothane are similar. Sevoflurane is a suitable alternative to halothane for use in children undergoing minor ambulatory surgery.

Ambulatory Surgical Procedures↗
PubMed1996

Origin of allelic diversity in antirrhinum S locus RNases.

In many plant species, self-incompatibility (SI) is genetically controlled by a single multiallelic S locus. Previous analysis of S alleles in the Solanaceae, in which S locus ribonucleases (S RNases) are responsible for stylar expression of SI, has demonstrated that allelic diversity predated speciation within this family. To understand how allelic diversity has evolved, we investigated the molecular basis of gametophytic SI in Antirrhinum, a member of the Scrophulariaceae, which is closely related to the Solanaceae. We have characterized three Antirrhinum cDNAs encoding polypeptides homologous to S RNases and shown that they are encoded by genes at the S locus. RNA in situ hybridization revealed that the Antirrhinum S RNase are primarily expressed in the stylar transmitting tissue. This expression is consistent with their proposed role in arresting the growth of self-pollen tubes. S alleles from the Scrophulariaceae form a separate group from those of the Solanaceae, indicating that new S alleles have been generated since these families separated (approximately 40 million years). We propose that the recruitment of an ancestral RNase gene into SI occurred during an early stage of angiosperm evolution and that, since that time, new alleles subsequently have arisen at a low rate.

Amino Acid Sequence↗
PubMed1996

Pathways for inflorescence and floral induction in Antirrhinum.

The presentation of flowers on a modified stem, the inflorescence, requires the integration of several aspects of meristem behaviour. In Antirrhinum, the inflorescence can be distinguished by its flowers, hairy stem, modified leaves, short internodes and spiral phyllotaxy. We show, by a combination of physiological, genetical and morphological analysis, that the various aspects of the inflorescence are controlled by three pathways. The first pathway, depends on expression of the floricaula gene, and is rapidly and discretely induced by exposure to long daylength. Activation of this pathway occurs in very young axillary meristems, resulting in a floral identity. In addition, the length of subtending leaves and hairiness of the stem are partially modified. The second pathway affects leaf size, internode length, and stem hairiness, but does not confer floral meristem identity. This pathway is induced by long daylength, but not as rapidly or discretely as the floricaula-dependent pathway. The third pathway controls the switch in phyllotaxy from decussate to spiral and is activated independently of daylength. The coordination of these three programmes ensures that apical and axillary meristem behaviour is integrated.

Base Sequence↗
PubMed1996

The prevalence of seat belt use in Jamaica. An observational study.

An observational cross-sectional survey showed that 21.1% of private motor vehicle drivers and 13.5% of front seat passengers voluntarily wore seat belts in Kingston, Jamaica, where there is no law requiring this. Rear passenger utilisation was not examined. Compared to males, females were significantly more likely to wear seat belts when driving but not as front seat passengers. Of all motor vehicles examined, 10.1% were not equipped with seat belts. The oldest group of vehicles were mostly not fitted with seat belts. Drivers of older vehicles were significantly less likely to use seat belts even when the vehicles were equipped with belts. Implementation of legislation can reduce mortality, morbidity and costs from road traffic accidents which are relatively frequent in Jamaica. Male drivers, drivers of older vehicles and all passengers may require specific targeting in an educational and enforcement campaign should legislation, which is highly desirable, be implemented.

Adult↗
PubMed1995

Cell lineage patterns and homeotic gene activity during Antirrhinum flower development.

BACKGROUND: Homeotic genes controlling the identity of flower organs have been characterized in several plant species. To determine whether cells expressing these genes are specified to follow particular developmental fates, we have studied the pattern of cell lineages in developing flowers of Antirrhinum. Each flower has four whorls of organs, and progenitor cells of these can be marked at particular stages of development using a temperature-sensitive transposon. This allows the cell lineages in the flower to be followed, as well as giving information about rates of cell division. RESULTS: We show here that, prior to the emergence of organ primordia, cells in the floral meristem have not been allocated organ identities. After this time, lineage restrictions arise between whorls, correlating with the onset of expression of genes that control organ identity. A further lineage restriction appears slightly later on, between the dorsal and ventral surfaces of the petal. Our results further suggest that the rates of cell division fluctuate during key stages of meristern development, perhaps as a consequence of meristem-identity gene expression. CONCLUSIONS: The patterns of lineage restriction and organ-identity gene expression in early floral meristems are consistent with some cells being allocated specific identities at about this stage of development. Plant cells cannot move relative to each other, so lineage restrictions in plants may reflect particular orientations and/or rates of growth at boundary regions.

Genes, Homeobox↗
PubMed1995

In vitro regulation of human breast cancer cell adhesion and invasion via integrin receptors to the extracellular matrix.

The extracellular matrix consists of the interstitium and the basement membrane. Cellular interaction with fibronectin, laminin and collagen provides a possible mechanism by which cancer cells adhere, invade and metastasize. The integrins are a major family of adhesion molecules that recognize epitopes on the extracellular matrix as ligands. These include the alpha 2 beta 1, alpha 3 beta 1, alpha v beta 1 and alpha v beta 5 integrins, most of which were found to be expressed on MCF-7, T47D, MDA-MB-231, ZR75-1 and Hs578T breast cancer cell lines. Each cell line adhered to the matrix proteins in a dose-dependent manner and was inhibited by monoclonal antibodies against relevant integrins. Only Hs578T was significantly invasive through fibronectin but both Hs578T and MDA-MB-231 invaded through laminin and type IV collagen in an in vitro assay. The invasive potential of these cell lines could be inhibited by integrin antibodies added to cells before incubation, but the addition of antibodies after cells were allowed to adhere to the matrix failed to inhibit invasion. Inhibition of cellular adhesion to the matrix reduced the invasive potential of breast cancer cell lines. As integrin antibodies inhibit cell invasion in vitro, the integrins may be of potential value as antitumour therapeutic agents.

Antibodies, Monoclonal↗
PubMed1995

Benign biopsies in the prevalent round of breast screening: a review of 137 cases.

In the first round of the National Health Service Breast Screening Programme, 35,533 women attended for screening at the two breast screening units served by St Bartholomew's Hospital. Further assessment was necessary in 2212 women (6.2%), of whom 412 (1%) subsequently underwent surgical biopsy. Of these 137 had benign lesions. The predominant mammographic abnormality leading to biopsy was microcalcification in 55, a mass in 48, parenchymal asymmetry in 18 and architectural distortion in 16. Histology revealed fibrocystic change in 66, fibroadenoma in 27, radial scar/complex sclerosing lesion in 23, atypical ductal hyperplasia only in eight, and a variety of unusual benign lesions in 13. In an attempt to determine criteria which would minimize unnecessary biopsy of benign lesions in future, the mammographic and cytological features of these benign lesions were reviewed and compared with the final histology. The most common diagnostic problems were clustered and variable microcalcification, the radial scar/complex sclerosing lesion, and mammographic features shown to be atypical hyperplasia on histology.

Biopsy↗
PubMed1995

Integrin expression in primary breast cancer and its relation to axillary nodal status.

BACKGROUND: Integrins are transmembrane receptors that modulate cell adhesion. Each is a heterodimer of varying alpha and beta subunits. In malignancy, loss of integrin expression may result in less adhesive cells more likely to metastasize. Our aim was to characterize the integrins in human breast tissue and to examine the relationship between integrin expression and nodal metastasis in breast cancer. METHODS: Cryostat sections from 12 benign and 61 malignant (50 ductal and 11 lobular) samples were stained by the avidin-biotin complex method with monoclonal antibodies to the beta 1, beta 3, beta 4, and beta 5 subfamilies. All slides were read by two independent assessors with consensus agreement. Integrin expression was compared to variables by using the chi-squared test with Yates' correction and multivariate analysis based on logistic regression. RESULTS: All integrin subunits studied were significantly reduced on breast cancer compared with benign cells (chi-squared test) but were not related to tumor differentiation. Loss of alpha 1 beta 1, alpha 2 beta 1, alpha 3 beta 1, alpha 6 beta 1, alpha v beta 1, and alpha v beta 5 were related to the presence of axillary metastasis. Independently the integrins were of limited clinical value as predictors of axillary spread. However, on multivariate analysis the combination of beta 1, alpha v, alpha 1, tumor size, and vascular invasion gave a cumulative overall accuracy in predicting nodal disease of 97%. CONCLUSIONS: Integrin expression is reduced in breast cancer and may explain tumor progression. Measuring the integrins might thus provide a means of selection for aggressive axillary treatment.

Adult↗
PubMed1995

Modulation of very late activation-2 laminin receptor function in breast cancer metastasis.

BACKGROUND: Very late activation-2 (VLA-2) is an integrin receptor for laminin that consists of an alpha 2- and a beta 1-subunit. In human breast cancer, down-regulation of VLA-2 expression is related to positive nodal status. The functional significance of altered integrin expression in individual patients has never been investigated. To test the hypothesis that less adhesive primary breast cancer cells were predisposed to metastasize, variation in VLA-2 modulation of cell attachment to laminin with nodal status was studied. METHODS: Integrin expression was measured by means of immunohistochemistry on cryostat sections. Primary breast cancer cells were isolated by enzymatic disaggregation and immunomagnetic separation. Cell adhesion to laminin was evaluated in an in vitro assay, and the effect of monoclonal antibodies against the component subunits of VLA-2 was assessed. RESULTS: Adhesion of primary breast cancer cells from women with positive nodes to laminin was significantly reduced compared with women with negative nodes (p < 0.001, Wilcoxon signed rank test). VLA-2 antibodies inhibited primary breast cancer cell attachment of women with negative nodes but not women with positive nodes. Strong adhesion to laminin was related to node-negative status (chi-squared, 16.33; p < 0.001) and to positive integrin expression (chi-squared, 31.54; p < 0.001). CONCLUSIONS: VLA-2-mediated adhesion of primary breast cancer cells to laminin differs with nodal status. Measurement of VLA-2 expression may thus be of clinical value as a prognostic indicator in the assessment of breast cancer.

Adult↗
PubMed1995

Perioperative pain management.

The clinical anesthesia, general surgery, and gynecology literature addressing the pathophysiology and management strategies for perioperative pain were reviewed. There are few prospective, randomized studies from which to draw meaningful conclusions. Nevertheless, a theoretical construct has been developed which may help the gynecologic surgeon optimizing pain management. The era of managed care and shorter hospital stays has focused physicians and, in particular, surgeons on elements of patient care that can be addressed and improved. Reducing or eliminating postoperative pain without excessive sedation promotes rapid mobilization and return to self-care. Strategies for pain management can be adopted that reduce postoperative ileus and other adverse reactions to analgesics.

Analgesics↗
PubMed1995

Control of flower development and phyllotaxy by meristem identity genes in antirrhinum.

The flower meristem identity genes floricaula (flo) and squamosa (squa) promote a change in phyllotaxy from spiral to whorled in Antirrhinum. To determine how this might be achieved, we have performed a combination of morphological, genetic, and expression analyses. Comparison of the phenotypes and RNA expression patterns of single and double mutants with the wild type showed that flo and squa act together to promote flower development but that flo is epistatic to squa with respect to early effects on phyllotaxy. We propose that a common process underlies the phyllotaxy of wildtype, flo, and squa meristem development but that the relative timing of primordium initiation or growth is altered. This process depends on two separable events: setting aside zones for potential primordium initiation and partitioning these zones into discrete primordia. Failure of the second event can lead to the formation of continuous double spirals, which are occasionally seen in flo mutants.

Base Sequence↗
PubMed1995

Transposon induced chimeras show that floricaula, a meristem identity gene, acts non-autonomously between cell layers.

Flower meristems comprise several distinct cell layers. To understand the role of cell interactions between and within these layers, we have generated plants chimeric for a key floral homeotic gene, floricaula (flo). These chimeras arose in Antirrhinum by excision of a transposon, restoring flo gene function. Activity of flo in a subset of cell layers gives fertile flowers with an abnormal morphology. This shows that flo can act non-autonomously between layers, although some aspects of its function are impaired. In addition, we show that flo exhibits some cell-autonomy within layers.

Cell Communication↗
PubMed1995

Expression of floricaula in single cell layers of periclinal chimeras activates downstream homeotic genes in all layers of floral meristems.

We show that the flowering sectors on plants mutant for floricaula (flo), a meristem identity gene in Antirrhinum majus, are periclinal chimeras expressing flo in either the L1, L2 or L3 cell layer. Flower morphology is almost normal in L1 chimeras, but altered in L2 and L3 chimeras. Expression of flo in any one cell layer results in the expression of organ identity genes, deficiens (def) and plena (ple) in all three cell layers of the chimeras, showing that flo acts inductively to promote gene transcription. The activation of both def and ple is delayed, and the expression domain of def is reduced, accounting for some of the phenotypic properties of the chimeras. Furthermore, we show that flo exhibits some cell-autonomy with respect to autoregulation.

Amino Acid Sequence↗
PubMed1995

Clinical audit of a specialist symptomatic breast clinic.

The efficient delivery of health care requires vigilant quality assurance. We describe the audit of our symptomatic breast clinic, which includes the option of a one-stop diagnostic service. A total of 134 new and 386 follow-up patients attended over four consecutive clinics. The majority of new referrals (68%) were seen by a consultant surgeon. Urgent referrals were seen significantly sooner than routine referrals (P < 0.001, chi 2-test), and the mean wait from designated appointment to seeing the surgeon was 37.6 (range-68 to 171) min. One-stop investigations were offered to 50 patients; of these, 36 women (72%) had a total wait of less than 2 h. For those not investigated at the same clinic, the mean time until investigations was 6.1 (range 0-36) days and mean recall was 2.7 (range 1-8) weeks. Patients undergoing definitive surgery for cancer (n = 5) were operated on average 14.2 (range 7-27) days after the decision was made in outpatients, while the mean waiting time for non-cancer operations was 49.7 (range 15-98) days. Objective audit on outpatient services is possible and can lead to improvement of services.

Adult↗
PubMed1995

One-stop diagnosis for symptomatic breast disease.

A consultant-led one-stop diagnostic service has been available at a busy symptomatic breast clinic each week at St Bartholomew's Hospital for 18 months. Women can be investigated appropriately using mammography, ultrasonography and cytology with immediate reporting. The aim is to achieve a diagnosis and management plan for each patient at the initial outpatient visit. A prospective audit of four consecutive clinics was undertaken to assess the impact of this service on clinical practice. Fifty patients out of 134 new and 386 follow-up clinic attenders had one-stop investigations. As a result of immediate reporting, 48 (96%) patients had a management decision made at the first outpatient visit, 9 (18%) were offered surgery, and 18 (36%) were discharged with a benign diagnosis and no dominant mass. Four symptomatic cancers were detected and evaluated on a one-stop basis, constituting 8% of the workload of this clinic. The mean wait from designated appointment until surgical consultation was 37.7 min (range -68-171 min) and that for investigation until subsequent clinical review was 56.9 min (range -4-191 min). Thirty-six (72%) one-stop patients had a total wait of less than 2 h and 95% were seen in under 3 h. It is felt that the one-stop clinic allows optimum patient management, minimises anxiety associated with symptomatic breast disease, and maximises utilisation of hospital outpatient resources.

Adult↗