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Biomedical subjects

P Payne

Publications and source records attributed to P Payne.

At least 19 recordsLinked to original sources
PubMed2005

Determining a diagnostic dose for imidacloprid susceptibility testing of field-collected isolates of cat fleas (Siphonaptera: Pulicidae).

The susceptibility of four laboratory strains of cat fleas, Ctenocephalides felis (Bouche), to imidacloprid was determined by three different laboratories, by using a standardized bioassay protocol. The probit lines generated by the different laboratories were very similar, with LC50 values ranging from 0.32 to 0.81 ppm. Based on these data, a diagnostic dose (DD) of 3 ppm imidacloprid in larval rearing media was provisionally identified for detecting shifts in tolerance, possibly as a consequence of incipient imidacloprid resistance. None of the larvae from the susceptible laboratory strains survived the DD. Eighteen field-collected isolates were evaluated for their susceptibility to imidacloprid and to validate a DD of 3 ppm. Probit lines from 18 field-collected isolates were very similar, with LC50 values ranging from 0.14 to 1.52 ppm. When exposed to the DD, between 3 and 10% of the exposed larvae emerged as adults from only three of the 18 isolates. All other field isolates gave 100% mortality at the DD. Under the criteria established (>5% survivorship at 3 ppm), two isolates would be established on mammalian hosts and more extensive tests conducted to exclude or confirm the presence of resistance. The DD of 3 ppm is robust enough to eliminate most of the susceptible isolates collected until today, yet low enough to identify possible isolates for further testing.

Animals↗
PubMed2004

Molecular phylogeny of isolates of Ctenocephalides felis and related species based on analysis of ITS1, ITS2 and mitochondrial 16S rDNA sequences and random binding primers.

The phylogenetic relationships among 31 different flea isolates representing seven different species were studied by nucleotide sequence comparison of the internal transcribed spacer 1 (ITS1), internal transcribed spacer 2 (ITS2) and/or mitochondrial 16S ribosomal RNA gene (mt16S-rDNA) to examine the patterns of variation. Results show that all regions are useful in discriminating among flea species. In Ctenocephalides felis and Tunga penetrans, some differences in these gene regions occurred among different isolates within the same species. In the latter case, the differences are in the mt16S-rDNA region, with one isolate showing 48% divergence in nucleotide sequence. The taxonomic implications of this result are unclear at present. The gene regions revealed differences between C. felis isolates only after DNA sequencing the PCR products. Further differentiation among C. felis isolates was obtained using four different random binding primers (decamers) and primers for mammalian aldolase to amplify narrow differences in the genome. Using these primers we were able to discriminate between different C. felis isolates and determine that some of the genetic variation coincided with minor differences in response to the control agent imidacloprid. However, overall findings do not support the existence of subspecies of C. felis.

Animals↗
PubMed2002

Reagentless biosensing using electrochemical impedance spectroscopy.

The use of electrochemical impedance spectroscopy (EIS) and the conducting polymer, poly (pyrrole), as an integrated recognition and transduction system for reagentless biosensor systems was demonstrated with two different systems. The first system being an immunoassay for detection of luteinising hormone (LH) with the antibody being entrapped with in the poly (pyrrole) matrix and the second, a construct for DNA hybridisation discrimination able to differentiate single- and double-stranded DNA based on the interaction of the DNA with poly (pyrrole).

Biosensing Techniques↗
PubMed2002

Development of a larval bioassay for susceptibility of cat fleas (Siphonaptera: Pulicidae) to imidacloprid.

Strategies for controlling cat fleas, Ctenocephalidesfelisfelis (Bouché), have undergone dramatic changes in the past 5 yr. With the advent of on-animal treatments with residual activity the potential for the development of insecticide resistance increases. A larval bioassay was developed to determine the baseline susceptibility of field-collected strains of cat fleas to imidacloprid. All four laboratory strains tested showed a similar level of susceptibility to imidacloprid. Advantages of this bioassay are that smaller numbers of fleas are required because flea eggs are collected for the test. Insect growth regulators and other novel insecticides can also be evaluated. Using a discriminating dose, the detection of reduced susceptibility in field strains can be determined with as few as 40 eggs.

Acetone↗
PubMed1998

Malignancy associated changes in bronchial epithelial cells and clinical application as a biomarker.

A total of 74 bronchial brushing specimens, 24 from patients with advanced stage cancer, eight from patients with CIS, 31 from patients with atypical metaplasia and 11 from normal subjects were examined for the existence of malignancy associated changes (MAC). Conventional fiberoptic bronchoscopy and fluorescence endoscopy was carried out on every case. Each case was classified according to the highest grade of abnormality diagnosed by bronchial biopsy of the suspect areas. During the endoscopy examination, a bronchial brushing specimen was obtained from a visually normal area very remote from the abnormal area as possible such as the opposite lung or another lobe. The bronchial brushing specimens were fixed, mounted and stained by a DNA specific method and approximately 1500 images of individual nuclei per case were captured by an automated high resolution image cytometry. For each of these images, more than 100 nuclear features such as size, shape and chromatin spatial organization were calculated. Discriminant function analysis revealed nuclear features which differentiated between normal bronchial cell nuclei from the normal subjects and ostensively normal nuclei (MAC cell nuclei) from the lung cancer patients. The best discrimination was achieved when the frequency of individual cells expressing MAC was 50% or greater. With this threshold, 75% of the patients with invasive cancer and CIS were correctly classified. Fifty percent of those with severe or moderate atypia and 35% with mild atypia were also MAC positive. The frequency of cells expressing MAC also increased as the degree of abnormality of the groups increased. MAC may be a useful criterium to determine biological behavior of the intra-epithelial (pre-invasive) neoplasia.

Aged↗
PubMed1997

Molecular follow-up of a preinvasive bronchial lesion treated by 13-cis-retinoic acid.

We report the result of the follow-up molecular analysis of a bronchial carcinoma in situ treated by 13-cis-retinoic acid, which relapsed 9 months after cessation of drug therapy. Loss of heterozygosity at 3p21 and 9p22 genomic sequences were assessed by polymerase chain reaction (PCR) after microdissection of the dysplastic epithelia. Despite a transient regression of the lesion to a lower grade with treatment, molecular analysis showed the persistence of a 3p and 9p deletion in all the bronchial biopsies taken in the same area during a 1 year follow-up, preceding by 9 months the recurrence of the carcinoma in situ. Our findings suggest that molecular follow-up analysis can help to assess the persistence of a malignant clone within a bronchial epithelium that displays a more benign phenotype under retinoid treatment on follow-up. Molecular analysis may be of great importance to evaluate the effects of chemoprevention and to determine the duration of such intervention in responder patients.

Bronchial Neoplasms↗
PubMed1997

A smile a day.

Explore the source record for details and available documents.

Canada↗
PubMed1995

Evidence of cumulative gene losses with progression of premalignant epithelial lesions to carcinoma of the bronchus.

Human bronchial carcinoma is thought to develop through progressive stages from basal cell hyperplasia to squamous metaplasia, dysplasia, carcinoma in situ, and finally invasive cancer. In this study, we used tissue microdissection to examine loss of heterozygosity of chromosomes 3p21, 5q21, and 9p21 at each stage of the epithelial progression to invasive cancers. Forty-eight premalignant/malignant bronchial sites were biopsied from 13 patients (including 9 subjects without cancer) using fluorescence bronchoscopy. Eighteen sites with moderate/severe dysplasia in 6 patients were subjected to bronchoscopic and molecular follow-up during a 3-month to 2-year period. Seven separate cases of advanced non-small cell bronchial cancers were also analyzed. From the baseline biopsies, the prevalence of 3p and 9p deletions increased significantly from no deletion in the hyperplasia/metaplasia samples (n = 9) to 37 and 31% of the informative cases, respectively, in the dysplasia samples (n = 29), to 100 and 83%, respectively, for the carcinomas in situ (n = 6), and 100% in the invasive cancers (n = 11). Chromosome 5q deletion was significantly more frequent in invasive cancers (70% of the informative cases) as compared to carcinoma in situ (40%), dysplasias (33%), and hyperplasia/metaplasia samples (11%). The number of chromosome alterations also increased significantly from the lowest to the highest grade lesions, showing evidence of accumulation of genetic damage from one group to another. The molecular follow-up analysis showed that the same genomic alteration can persist in a given dysplastic bronchial area for several months or years, and that the persistence or the regression of the molecular abnormality is well correlated with the evolution of the disease on follow-up. Our results suggest that molecular analysis of bronchial biopsies obtained by fluorescence bronchoscopy may be a very useful means to study the natural history of preinvasive bronchial lesions and the outcome of interventions, such as with chemopreventive treatment.

Aged↗
PubMed1993

Cervicography: an intermediate triage test for the evaluation of cervical atypia.

BACKGROUND: A substantial number of abnormal Papanicolaou (Pap) smears are reported as demonstrating "cytologic atypia." This finding may actually represent premalignant cervical disease. Some of these patients may not be able to afford definitive colposcopic examinations, and simply repeating cytologic testing may result in missed treatable disease. The purpose of this study was to evaluate the use of cervicography as an intermediate triage test for women with atypical cervical cytology. METHODS: Women with a recent smear demonstrating cytologic atypia were evaluated using colposcopy, biopsy, and cervicography. RESULTS: Colposcopically directed cervical biopsies were obtained from 224 of 685 women with cytologic atypia. The histologic specimens confirmed evidence of cervical dysplasia for 166 women. Of these women, cervicography detected 74.7% of those who had mild dysplasia, 87.5% of those who had moderate dysplasia, 75% of those who had severe dysplasia, and the one patient who had cervical cancer. Most (93%) of the women with dysplasia that was undetected by cervicography had mild dysplasia. CONCLUSIONS: Cervicography may be an effective intermediate triage test for the evaluation of young women with Pap smears demonstrating cytologic atypia.

Acetates↗
PubMed1993

Cervicography: adjunctive cervical cancer screening by primary care clinicians.

BACKGROUND: Cervicography is an adjunct method of cervical cancer screening intended to complement cervical cytologic sampling, ie, Papanicolaou (Pap) smear. Cervicography involves obtaining and evaluating a photographic image of the cervix. The purpose of this investigation was to evaluate the screening use of cervicography as an adjunct to clinical cytologic screening. METHODS: Women presenting at four clinical sites for annual cervical cytologic screening or for follow-up evaluation after receiving an abnormal Pap smear result were enrolled in the study. Each patient received a Pap smear and a cervigram. Those women in whom abnormalities were detected by either test subsequently underwent colposcopy, and when appropriate, histologic specimens were obtained. RESULTS: Pap smear and cervigram data were obtained for 1449 women. When premalignant or malignant histologic test results were considered as a true positive, the Pap smear correctly identified 25.6% of subjects with dysplasia and 37.5% with severe dysplasia. The Pap smear failed to identify the one patient with invasive cancer. The cervigram detected 50.5% of the subjects with dysplasia and 77.8% of the subjects with severe dysplasia, and it identified the one patient with invasive cancer when a positive cervigram was considered a true positive. When the results were combined, the two tests identified 62.9% of subjects with histologically confirmed dysplasia, 81.3% of subjects with severe dysplasia, and 100% (one patient) with cancer. CONCLUSIONS: The cervigram detected twice the number of patients with premalignant disease as the Pap smear alone, and correctly identified the invasive cancer. Cervicography improved the detection of cervical disease.

Adolescent↗
PubMed1988

Effect of a CVIS instructional program regarding therapeutic communication on student learning and anxiety.

This quasi-experimental, pretest-posttest design study explored the effect of a computer video-interactive system (CVIS) instructional program regarding therapeutic communication on senior baccalaureate nursing students' learning and anxiety as they anticipated interaction with patients in psychiatric settings. The 75 subjects were randomly divided into two groups. Group I received a basic lecture and a supplementary CVIS instructional program on therapeutic communication, while Group II received the same lecture discussion on therapeutic communication and a videotape. Two hypotheses were tested, using analyses of covariance. Hypothesis I, that Group I would score significantly higher on a therapeutic communication posttest than would Group II, was supported (P less than .001). This finding validates previous observations that computer-video interaction programs do enhance learners' application of knowledge. Hypothesis II, that Group I would evidence significantly less state anxiety at posttest than would Group II, was not supported. Although there were no significant differences for state anxiety scores between the groups at either pretest or posttest, these scores remained higher than reported normative state anxiety scores. This finding suggests that anticipated interaction with psychiatric patients is an anxiety-inducing situation for nursing students.

Anxiety↗
PubMed1988

Conformational determinants of high affinity delta receptor binding of opioid peptides.

Detailed conformational analysis of linear and cyclic delta-selective opioid peptides was performed in conjunction with computer-analyzed receptor binding studies with the aim of determining conformational requirements for high affinity binding of peptides to the delta-receptor. The four linear delta-selective hexapeptides included in this study were: DSLET (Tyr-D-Ser-Gly-Phe-Leu-Thr) and its D-Thr2 analog (DTLET) and two t-butyl ether analogs. In one analog an O-t-butyl group replaces the D-Ser2OH and in the other a second O-t-butyl group replaces the D-Thr6OH group as well. This study also includes seven cyclic pentapeptides of the type: Tyr-Cys(Pen-Gly-Phe-Cys(Pen) with various combinations of DL-cysteine and DL-penicillamine (beta-dimethyl cysteine) as the second and fifth residues resulting in varying delta affinities and selectivities. Four (DPLPE, DPDPE, DPLCE, and DCLPE) have both high delta affinity and selectivity; two (DCDCE and DCLCE) have high affinity at both delta- and mu-receptors, and one (LCLCE) has low affinity for both receptors. Our investigation has shown that all analogs that have high affinity at the delta receptor have a unique common low energy conformer. This compact conformer contains intramolecular H-bonds and is very different from the beta II-turn-type structure associated with high affinity mu-receptor binding deduced in our previous work.

Computer Graphics↗
PubMed1986

Conformational studies and receptor binding of delta selective opioid peptides.

Detailed energy-conformation studies of a linear (DTLET) and four cyclic (DPDPE, DPLPE, DPLCE,DCLPE), delta-selective opioid peptides were combined with computer assisted detailed receptor binding studies. The results of these studies have allowed the identification of a low energy conformer common to all of these analogs which could be responsible for their high affinity delta-receptor binding. This conformer contains multiple intramolecular H-bonds and is very different from the beta-II type structure previously postulated to lead to high affinity mu-receptor binding. This mu-binding conformer was found either to have higher energies or be greatly distorted in these delta selective analogs.

Animals↗
PubMed1983

Prematurity and the obstetrician. A regional neonatal intensive care nursery is not enough.

Modern-day perinatal care has resulted in dramatically improved outcomes of premature infants, particularly those weighing 750 to 1,500 gm or of 27 to 32 weeks' gestational age. Assuming that the birth is not traumatic, the infant asphyxiated, or made hypothermic at birth, the chances of the very small premature baby developing normally are great. The delivery of an infant of less than or equal to 32 weeks' gestational age or weighing less than 1,500 gm should occur at a perinatal center when possible.

Delivery, Obstetric↗
PubMed1981

Comparison of xeroradiographic and ultrasound detection of corticosteroid induced dermal thinning.

A pulsed ultrasound technique was shown to have a high degree of correlation with the established xeroradiographic method for the determination of dermal thickness both in normal skin and corticosteroid treated skin, although xeroradiography consistently gave a higher value than ultrasound. Using the pulsed ultrasound technique, an early onset of dermal thinning could be detected 2 days following treatment with creams containing 0.05% clobetasol propionate and 0.1% beta-methasone 17-valerate. The amount of dermal thinning produced by the clobetasol propionate preparation was significantly greater than that produced by cream base, clobetasone butyrate 0.05% cream and hydrocortisone 1% cream as determined by both techniques. The pulsed ultrasound technique is an accurate, noninvasive and safe method for determining dermal thickness.

Adrenal Cortex Hormones↗