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Biomedical subjects

P Coffey

Publications and source records attributed to P Coffey.

At least 19 recordsLinked to original sources

Women's participation in a cervical cancer screening program in northern Peru.

Cervical cancer is often the most common cancer among women in developing countries, yet current screening efforts have not been effective in reducing incidence and mortality rates in these settings. In an effort to increase knowledge about screening participation in low-resource settings, this study sought to identify key factors affecting women's participation in a cervical screening program in north central Peru. We studied women who were exposed to various health promotion educational activities and compared a total of 156 women who sought screening between July 2001 and October 2003 with 155 women who did not. Results from logistic regression identified four significant predictors of screening: higher relative wealth, knowing other screened women, seeking care from a health facility when sick and satisfaction with services at the health facility. When we restricted our analysis to women who had experienced screening in the past, two additional predictors emerged: having a husband who was supportive of screening participation and attending an awareness-raising session. These results have important programmatic value for tailoring outreach efforts for women and indicate that different strategies may be required to best reach women who have never been screened.

Adult↗

A low cost, colour coded, hand held spring scale accurately categorises birth weight in low resource settings.

AIMS: To determine the accuracy of a low cost, spring calibrated, hand held scale in classifying newborns into three weight categories (> or =2500 g, 2000-2499 g, <2000 g). METHODS: The test device was compared to a gold standard digital baby scale with precision to 2 g. In Sarlahi district, Nepal, 1890 newborns were eligible for the study. Measurements were collected for both the test device and the digital scale from 1820 (96.3%) newborns. RESULTS: The overall low birth weight (LBW) prevalence rate for the gold standard digital scale was 28.1% (511/1820). Sensitivity (93.7%) and specificity (97.6%) of the test device was high compared to LBW classifications based on digital weight measurements. Classification of infants into the <2000 g category was 5.0% and 4.7% for the gold standard and test device, respectively. Sensitivity and specificity of the test device in identifying infants <2000 g was 87.8% and 99.6%, respectively. Positive predictive values were high (>91%) for both weight categories CONCLUSIONS: This low cost, simple-to-use device classified infants into weight categories with a high degree of consistency and accuracy that exceeds that of surrogate measures. This new device is useful for identifying and targeting life saving interventions for LBW, high risk infants in settings where infants are born in the home and conventional weighing scales are unavailable.

Birth Weight↗

Involving the community in cervical cancer prevention programs.

Underutilization of cervical cancer prevention services by women in the high-risk age group of 30-60 years can be attributed to health service factors (such as poor availability, poor accessibility, and poor quality of care provided), to women's lack of information, and to cultural and behavioral barriers. The Alliance for Cervical Cancer Prevention (ACCP) partners have been working to identify effective ways to increase women's voluntary participation in prevention programs by testing strategies of community involvement in developing countries. The ACCP experiences include developing community partnerships to listen to and learn from the community, thereby enhancing appropriateness of services; developing culturally appropriate messages and educational materials; making access to high-quality screening services easier; and identifying effective ways to encourage women and their partners to complete diagnosis and treatment regimens. Cervical cancer prevention programs that use these strategies are more likely to increase demand, ensure follow-through for treatment, and ultimately reduce disease burden.

Ambulatory Care↗

Differentiation of an auditory neuronal cell line suitable for cell transplantation.

The auditory neuroblast cell line US/VOT-N33 (N33), which is conditionally immortal, was studied as an in vitro model for the differentiation of spiral ganglion neurons (SGNs) and as a candidate for cell transplantation in rodents. It expresses numerous molecular markers characteristic of auditory neuroblasts, including the transcription factors GATA3, NeuroD, Brn3a and Islet1, as well as the neuronal cytoskeletal protein beta3-tubulin. It displays active migratory behaviour in vitro and in vivo. In the presence of the fibroblast growth factors FGF1 or FGF2 it differentiates bipolar morphologies similar to those of native SGNs. In coculture with neonatal cochlear tissue it is repelled from epithelial surfaces but not from native SGNs, alongside which it extends parallel neuronal processes. When injected into the retina in vivo, EGFP-labelled N33 cells were traced for 1-2 weeks and migrated rapidly within the subretinal space. Cells that found their way into the retinal ganglion cell layer extended multiple processes but did not express beta3-tubulin. The ability of N33 to migrate, to differentiate, to localize with native SGNs in vitro and to survive in vivo suggests that they provide an effective model for SGN differentiation and for cell transplantation into the ear.

Animals↗

Oxytocin in prefilled Uniject injection devices for managing third-stage labor in Indonesia.

We assessed the use and acceptability of an injection device (Uniject) prefilled with oxytocin, as part of active management of third-stage labor (AMTL) by Indonesian midwives attending home births. We interviewed 140 village midwives (bidan di desa) and 2220 mothers whose deliveries they attended during the intervention period. We completed baseline and post-intervention assessments to determine their experiences and views of oxytocin Uniject use. Delivery logs and supervisory reports were reviewed. The assessment was done in three rural districts and one municipality in Lombok. Injection practices and oxytocin availability did not change dramatically, although dose accuracy, use of sterile injection equipment, and proper disposal improved when the Uniject device was used. Midwives had little difficulty using the Uniject device properly; they overwhelmingly preferred it to standard needles and syringes. Postpartum hemorrhage rates did not change substantially. Oxytocin via Uniject holds promise for safer, more convenient use of oxytocin by trained midwives attending home deliveries, thereby potentially reducing the incidence of postpartum hemorrhage.

Attitude of Health Personnel↗

Subretinal transplantation of genetically modified human cell lines attenuates loss of visual function in dystrophic rats.

Royal College of Surgeons rats are genetically predisposed to undergo significant visual loss caused by a primary dysfunction of retinal pigment epithelial (RPE) cells. By using this model, we have examined the efficacy of subretinal transplantation of two independent human RPE cell lines each exhibiting genetic modifications that confer long-term stability in vitro. The two cell lines, a spontaneously derived cell line (ARPE19) and an extensively characterized genetically engineered human RPE cell line (h1RPE7), which expresses SV40 large T (tumor) antigen, were evaluated separately. Both lines result in a significant preservation of visual function as assessed by either behavioral or physiological techniques. This attenuation of visual loss correlates with photoreceptor survival and the presence of donor cells in the areas of rescued photoreceptors at 5 months postgrafting (6 months of age). These results demonstrate the potential of genetically modified human RPE cells for ultimate application in therapeutic transplantation strategies for retinal degenerative diseases caused by RPE dysfunction.

Animals↗

Design and initial evaluation of a low-cost 3-Tesla research system for combined optical and functional MR imaging with interventional capability.

A 3-Tesla research system has been developed for functional and interventional magnetic resonance imaging (MRI) procedures on animal models based on a low field niche spectrometer. Use of two stages of fourth harmonic frequency multiplication has allowed us to produce a high-frequency spectrometer with good frequency stability based on a low-frequency direct digital synthesizer. The system has been designed with the ability to introduce interventional tools such as biopsy needles, radiofrequency (RF) electrodes, and fiber optics for optical spectroscopy and thermal ablation as well as drug infusions to allow function to be studied in the presence of external challenges. Full MR-compatible physiologic support capability allows animals to be maintained in a stable condition over extended periods of study. Functional MR images have been acquired by using gradient echoes (TR/TE = 40/12 msec) from the rat whisker barrel cortex using electrical stimulation (5-V, 1.5-mA, 1-msec pulses at 5 Hz via two needle electrodes inserted into the rat whisker pad). Initial results using respiratory gas challenges of 100% N(2), 100% O(2), and 10% CO(2) have shown excellent agreement between single wavelength (633 nm) optical and functional MR time series with subsecond time resolution. The 1-mm copper electrodes for interventional radiofrequency ablation procedures were easily visualized in the superior colliculus by using gradient echo sequences. This novel, low-cost, high field system appears to be a useful research tool for functional and interventional studies of rat brain and allows concurrent optical spectroscopy. J. Magn. Reson. Imaging 2001;13:87-92.

Animals↗

Pseudo-random procedures for rapid presentation rates using optical imaging and spectroscopy.

Optical imaging of rat barrel cortex has provided detailed spatio-temporal maps of functional cortical architecture. We describe an event-related procedure (ERP) for optical imaging based on selective signal averaging as reported by Burock et al., using an anti-correlative pseudo-random event sequence. The sequence used 1 s vibrissal stimulation at 5 Hz, with an interevent interval of 2 s. This rapid presentation rate allows for greater statistical power per unit time, and allows for direct comparison of event-related studies with other imaging modalities. The spatio-temporal characteristics of single wavelength and spectrographic results were found to be comparable with those obtained by standard techniques, although a general lessening of haemodynamic response function (HRF) was noted. We also describe a method of locating barrel activity by spectral analysis of summed event data. Using this technique, the power spectrum of remitted light from the barrel region was found to peak within +/- 0.12 Hz of the inter-event interval frequency.

Algorithms↗

Spectroscopic analysis of neural activity in brain: increased oxygen consumption following activation of barrel cortex.

This research investigates the hemodynamic response to stimulation of the barrel cortex in anaesthetized rats using optical imaging and spectroscopy (Bonhoeffer and Grinvald, 1996; Malonek and Grinvald, 1996; Mayhew et al., 1999). A slit spectrograph was used to collect spectral image data sequences. These were analyzed using an algorithm that corrects for the wavelength dependency in the optical path lengths produced by the light scattering properties of tissue. The analysis produced the changes in the oxy- and deoxygenation of hemoglobin following stimulation. Two methods of stimulation were used. One method mechanically vibrated a single whisker, the other electrically stimulated the whisker pad. The electrical stimulation intensity varied from 0.4 to 1.6 mA. The hemodynamic responses to stimulation increased as a function of intensity. At 0.4 mA they were commensurate with those from the mechanical stimulation; however, the responses at the higher levels were greater by a factor of approximately 10. For both methods of data collection, the results of the spectroscopic analysis showed an early increase in deoxygenated hemoglobin (Hbr) with no evidence for a corresponding decrease in oxygenated hemoglobin (HbO(2)). Evidence for increased oxygen consumption (CMRO(2)) was obtained by converting the fractional changes in blood volume (Hbt) into estimates of changes in blood flow (Grubb et al., 1974) and using the resulting time course to scale the fractional changes in Hbr. The results show an early increase CMRO(2) peaking approximately 2 s after stimulation onset. Using these methods, we find evidence for increased oxygen consumption following increased neural activity even at low levels of stimulation intensity.

Algorithms↗

Spectroscopic analysis of changes in remitted illumination: the response to increased neural activity in brain.

Imaging of neural activation has been used to produce maps of functional architecture and metabolic activity. There is some uncertainty associated with the sources underlying the intrinsic signals. It has been reported that following increased neural activity there was little increased oxygen consumption ( approximately 5%), although glucose consumption increased by approximately 50%. The research we describe uses a modification of the Beer-Lambert Law called path-length scaling analysis (PLSA) to analyze the spectra of the hemodynamic and metabolic responses to vibrissal stimulation in rat somatosensory cortex. The results of the PLSA algorithm were compared with those obtained using a linear spectrographic analysis method (we refer to this as LMCA). There are differences in the results of the analysis depending on which of the two algorithms (PLSA or LMCA) is used. Using the LMCA algorithm, we obtain results showing an increase in the volume of Hbr at approximately 2 s, following onset of stimulation but no complementary decrease in oxygenated haemoglobin (HbO(2)). These results are similar to a previous report. In contrast, after using the PLSA algorithm, the time series of the chromophore changes shows no evidence for an increase in the volume of deoxygenated haemoglobin (Hbr). However, after further analysis of the time series from the PLSA using general linear models (GLM) to remove contributions from low frequency baseline oscillations, both the HbO(2) and Hbr times series of the response to stimulation were found to be biphasic with an early decrease in saturation peaking approximately 1 s after onset of stimulation followed by a larger increase in saturation peaking at approximately 3 s. Finally, following the PLSA-then-GLM analysis procedure, we do not find convincing evidence for an increase in cytochrome oxidation following stimulation, though we demonstrate the PLSA algorithm to be capable of disassociating changes in cytochrome oxidation state from changes in hemoglobin oxygenation.

Algorithms↗

Prepulse facilitation of auditory startle response in hamsters.

A visual prepulse was applied just before a burst of white noise with various lead intervals ranging from 50 to 400 ms in hamsters. After habituation each hamster received 120 trials of the auditory noise with or without the prepulse. Amplitude of startle response increased significantly at 100 ms and 200 ms (n = 10). This enhancement disappeared in blind controls (n = 6). The amplitude of startle response decreased during exploratory behavior, grooming, sniffing or other movements. However, the facilitatory effects of the visual prepulse were consistent, regardless of the animal's behavioral states, except sniffing. The authors conclude that visual prepulse task is useful for studying the ability to detect visual signals in hamsters, and that further study is necessary to elucidate the factors affecting the enhancement of startle response in hamsters.

Acoustic Stimulation↗

Long-term psychological adjustment to witnessing interparental physical conflict during childhood.

A retrospective survey of undergraduate students was used to examine the long-term psychological impact of witnessing interparental physical aggression during childhood. Two hundred and three of 1,452 young adults surveyed (14%) reported witnessing as children at least one incident of physical aggression between their parents. Both men and women who witnessed interparental physical conflict reported higher levels of current psychological distress than a comparison group of young adults who never observed physical aggression between their parents. This group difference remained even after controlling for parental divorce, parental SES, physical abuse of the child, parental alcoholism, and nonphysical discord witnessed between parents. Additional analyses found that the negative effect of witnessing interparental aggression was intensified when the aggression was serious enough to warrant some type of outside assistance for the victim and when the parent of the same-sex was seen being victimized. Although these findings provided support for the theory that witnessing interparental physical aggression is a traumatic experience that may have long-term psychological ramifications, we also found that a substantial proportion of the variance accounted for in adult adjustment by interparental physical conflict was mediated through decreased parental caring and warmth during childhood. Implications for these results, limitations of the present study, and directions for further research are discussed.

Adolescent↗

Light induced EEG desynchronization and behavioral arousal in rats with restored retinocollicular projection by peripheral nerve graft.

Peripheral nerve (PN) was grafted to sectioned optic nerve and was bridged to the superior colliculus in adult rats. To test functional recovery of restored retinocollicular pathway, we examined cortical electroencephalogram (EEG) and behavioral arousal responses to light stimuli. In eight of 10 recording trials in PN grafted rats (n = 6) and in all of eight trials in normal rats (n = 5), cortical EEGs showed desynchronization to light stimuli. On the other hand, after bilateral sections of the optic nerve (n = 3) EEG desynchronization to light disappeared while it was induced by a white noise. Mean threshold duration of light for EEG desynchronization was significantly longer in the PN grafted rats (440 ms) than in normal rats (173 ms). In three of six trials in PN grafted rats (n = 4), and in four of eight trials in normal rats (n = 4), EEG desynchronization elicited by light stimulus was accompanied by behavioral arousal responses, whereas no behavioral arousal could be induced by light in blind rats (n = 3). These results strongly suggest that visual information processed through the restored retinocollicular pathway was further transmitted to the cerebral cortices and ultimately resulted in behavioral arousal of the PN grafted rats.

Animals↗

Mediators of the long-term impact of child sexual abuse: perceived stigma, betrayal, powerlessness, and self-blame.

Using a community sample of 192 adult women who had been sexually abused during childhood, the present study tested the hypothesis that perceived stigma, betrayal, powerlessness, and self-blame mediate the long-term effects of child sexual abuse. A path analysis indicated that the level of psychological distress currently experienced by adult women who had been sexually abused in childhood was mediated by feelings of stigma and self-blame. This result provides partial support for Finkelhor and Browne's (1985) traumagenic dynamics model of child sexual abuse. The limitations of the study are discussed.

Adult↗

The relation between methods of coping during adulthood with a history of childhood sexual abuse and current psychological adjustment.

With a community sample of 192 women who had been sexually abused during childhood, the investigators determined if methods of coping in adulthood with the aftermath of child sexual abuse were associated with current symptoms of psychological distress. Multiple regression analyses indicated that disengagement methods of coping with the sexual abuse accounted for unique variance in general psychological distress even after controlling for characteristics of the abuse and methods of coping with other stressors. Disengagement methods of coping were also used more often to deal with the stressful aspects of having been sexually abused than to deal with other stressful events. In contrast, engagement methods of coping were used more often to deal with the other stressors than with sexual abuse.

Adaptation, Psychological↗

Dating violence: the association between methods of coping and women's psychological adjustment.

The present study examined the psychological impact of dating violence and the relationship between methods of coping with dating violence and psychological adjustment in a nonclinical female student population. Analyses revealed that women who experienced dating violence were at significantly greater risk than a comparison group for experiencing psychological distress. More symptoms of psychological distress were observed even after controlling for differences between the groups in histories of sexual aggression since age 16 and violence experiences in childhood including physical abuse, sexual abuse, and witnessing physical conflict between one's parents. The dating violence group was also more prone to use disengagement methods of coping to deal with nondating violence stressful life events than was the comparison group. In addition, disengagement methods of coping with the dating violence per se accounted for unique variance in psychological adjustment even after controlling characteristics of dating violence and methods of coping with other stressors.

Adaptation, Psychological↗