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Biomedical subjects

C A Glass

Publications and source records attributed to C A Glass.

At least 19 recordsLinked to original sources
PubMed2006

A multicenter international study on the Spinal Cord Independence Measure, version III: Rasch psychometric validation.

BACKGROUND: A third version of the Spinal Cord Independence Measure (SCIM III), made up of three subscales, was formulated following comments by experts from several countries and Rasch analysis performed on the previous version. OBJECTIVE: To examine the validity, reliability, and usefulness of SCIM III using Rasch analysis. DESIGN: Multicenter cohort study. SETTING: Thirteen spinal cord units in six countries from North America, Europe, and the Middle-East. SUBJECTS: 425 patients with spinal cord lesions (SCL). INTERVENTIONS: SCIM III assessments by professional staff members. Rasch analysis of admission scores. MAIN OUTCOME MEASURES: SCIM III subscale match between the distribution of item difficulty grades and the patient ability measurements; reliability of patient ability measures; fit of data to Rasch model requirements; unidimensionality of each subscale; hierarchical ordering of categories within items; differential item functioning across classes of patients and across countries. RESULTS: Results supported the compatibility of the SCIM subscales with the stringent Rasch requirements. Average infit mean-square indices were 0.79-1.06; statistically distinct strata of abilities were 3 to 4; most thresholds between adjacent categories were properly ordered; item hierarchy was stable across most of the clinical subgroups and across countries. In a few items, however, misfit or category threshold disordering were found. CONCLUSIONS: The scores of each SCIM III subscale appear as a reliable and useful quantitative representation of a specific construct of independence after SCL. This justifies the use of SCIM in clinical research, including cross-cultural trials. The results also suggest that there is merit in further refining the scale.

Activities of Daily Living↗
PubMed2006

The anti-angiogenic VEGF isoform VEGF165b transiently increases hydraulic conductivity, probably through VEGF receptor 1 in vivo.

Vascular endothelial growth factor (VEGF) is the principal agent that increases microvascular permeability during physiological and pathological angiogenesis. VEGF is differentially spliced to form two families of isoforms: VEGF(xxx), and VEGF(xxx)b. Whereas VEGF(165) stimulates angiogenesis, VEGF(165)b is anti-angiogenic. To determine the effect of VEGF(165)b on permeability, hydraulic conductivity (L(p)) was measured in individually perfused microvessels in the mesentery of frogs and rats. As with VEGF(165), VEGF(165)b increased L(p) in amphibian (2.4 +/- 0.3-fold) and mammalian (1.9 +/- 0.2-fold) mesenteric microvessels. A dose-response relationship showed that VEGF(165)b (EC(50), 0.65 pm) was approximately 25 times more potent than VEGF(165) (EC(50), 16 pm) in amphibian microvessels. VEGF(165) has been shown to increase permeability through VEGF receptor 2 (VEGF-R2) signalling. However, VEGF(165)b increased L(p) of frog vessels to the same extent in the presence of the VEGF-R2 inhibitor ZM323881, indicating that it does not increase permeability via VEGF-R2 signalling, and was inhibited by the VEGF receptor inhibitor SU5416 at doses that are specific for VEGF receptor 1 (VEGF-R1). VEGF(165)b, in contrast to VEGF(165), did not result in a sustained chronic increase in L(p). These results show that although VEGF(165)b is anti-angiogenic in the mesentery, it does signal in endothelial cells in vivo resulting in a transient, but not sustained, increase in microvascular L(p), probably through VEGF-R1.

Angiogenesis Inhibitors↗
PubMed2005

Cytosolic Ca2+ concentration and rate of increase of the cytosolic Ca2+ concentration in the regulation of vascular permeability in Rana in vivo.

Vascular permeability is assumed to be regulated by the cytosolic Ca(2+) concentration ([Ca(2+)](c)) of the endothelial cells. When permeability is increased, however, the maximum [Ca(2+)](c) appears to occur after the maximum permeability increase, suggesting that Ca(2+)-dependent mechanisms other than the absolute Ca(2+) concentration may regulate permeability. Here we investigate whether the rate of increase of the [Ca(2+)](c) (d[Ca(2+)](c)/dt) may more closely approximate the time course of the permeability increase. Hydraulic conductivity (L(p)) and endothelial [Ca(2+)](c) were measured in single perfused frog mesenteric microvessels in vivo. The relationships between the time courses of the increased L(p), [Ca(2+)](c) and d[Ca(2+)](c)/dt were examined. L(p) peaked significantly earlier than [Ca(2+)](c) in all drug treatments examined (Ca(2+) store release, store-mediated Ca(2+) influx, and store-independent Ca(2+) influx). When L(p) was increased in a store-dependent manner the time taken for L(p) to peak (3.6 +/- 0.9 min during store release, 1.2 +/- 0.3 min during store-mediated Ca(2+) influx) was significantly less than the time taken for [Ca(2+)](c) to peak (9.2 +/- 2.8 min during store release, 2.1 +/- 0.7 min during store-mediated influx), but very similar to that for the peak d[Ca(2+)](c)/dt to occur (4.3 +/- 2.0 min during store release, 1.1 +/- 0.5 min during Ca(2+) influx). Additionally, when the increase was independent of intracellular Ca(2+) stores, L(p) (0.38 +/- 0.03 min) and d[Ca(2+)](c)/dt (0.30 +/- 0.1 min) both peaked significantly before the [Ca(2+)](c) (1.05 +/- 0.31 min). These data suggest that the regulation of vascular permeability by endothelial cell Ca(2+) may be regulated by the rate of change of the [Ca(2+)](c) rather than the global [Ca(2+)].

Animals↗
PubMed2004

The role of endothelial cell Ca2+ store release in the regulation of microvascular permeability in vivo.

Microvascular permeability is regulated by changes in intracellular calcium concentration. The mechanism by which this increase in calcium determines permeability under normal conditions and during stimulation with agonists remains to be elucidated. In order to determine whether calcium release from intracellular stores could contribute towards the regulation of vascular permeability, hydraulic conductivity (Lp) was measured in frog mesenteric microvessels during stimulation of the endothelial cells of these vessels with agonists that release calcium from the intracellular stores. ATP (which acts through activation of inositol 1,4,5-trisphosphate (IP3) receptors) increased Lp in the absence of calcium influx across the plasma membrane 2.3 +/- 0.3 fold (mean +/- s.e.m., P < 0.01, n = 8), which was less than the increase in the presence of calcium influx (3.1 +/- 1.1 fold). Caffeine (which acts through activation of ryanodine receptors) also increased Lp in the absence of calcium influx across the plasma membrane 3.8 +/- 1.0 fold (P < 0.01, n = 9), but by at least as much as it does in the presence of calcium influx (2.8 +/- 0.5 fold). It is surprising that there was a strong positive correlation between the size of the response during store release and the baseline permeability (r = 0.91 for ATP, r = 0.75 for caffeine). This suggests that the filling state of the stores may regulate the baseline permeability of the microvessels.

Animals↗
PubMed2003

Role of endothelial Ca2+ stores in the regulation of hydraulic conductivity of Rana microvessels in vivo.

Vascular permeability is regulated by endothelial cytosolic Ca(2+) concentration ([Ca(2+)](i)). To determine whether vascular permeability is dependent on extracellular Ca(2+) influx or release of Ca(2+) from stores, hydraulic conductivity (L(p)) was measured in single perfused frog mesenteric microvessels in the presence and absence of Ca(2+) influx and store depletion. Prevention of Ca(2+) reuptake into stores by sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA) inhibition increased L(p) in the absence of extracellular Ca(2+) influx. L(p) was further increased when Ca(2+) influx was restored. Depletion of the Ca(2+) stores with ionomycin and SERCA inhibition increased L(p) in the presence and the absence of extracellular Ca(2+) influx. However, store depletion in itself did not significantly increase L(p) in the absence of active Ca(2+) release from stores into the cytoplasm. There was a significant positive correlation between baseline permeability and the magnitude of the responses to both Ca(2+) store release and Ca(2+) influx, indicating that the Ca(2+) regulating properties of the endothelial cells may regulate the baseline L(p). To investigate the role of Ca(2+) stores in regulation of L(p), the relationship between SERCA inhibition and store release was studied. The magnitude of the L(p) increase during SERCA inhibition significantly and inversely correlated with that during store release by Ca(2+) ionophore, implying that the degree of store depletion regulates the size of the increase on L(p). These data show that microvascular permeability in vivo can be increased by agents that release Ca(2+) from stores in the absence of Ca(2+) influx. They also show that capacitative Ca(2+) entry results in increased L(p) and that the size of the permeability increase can be regulated by the degree of Ca(2+) release.

Animals↗
PubMed2001

Community-care waiting list for persons with spinal cord injury.

OBJECTIVES: To disseminate the concept of community care waiting lists for spinal cord injury (SCI) patients with particular reference to carer support for management of neuropathic bladder by a regime of intermittent catheterisation. METHODOLOGY: The surgical waiting list focuses only on operative procedures, and ignores the wider requirements for ensuring satisfactory rehabilitation of people with spinal cord injury in the community. A community-care waiting list for individuals with spinal cord injury should include the following aspects of community care: (1) Home adaptation; (2) Provision of appropriate mobility needs (including wheelchair and cushion); (3) Equipment for comfortable living (including provision of hoist, pressure relieving mattress); (4) Psychological support for spinal cord injury patients and their partners; (5) Nursing home or residential care placement where appropriate; (6) Carer support for global management of complex needs associated with spinal cord injury (eg neuropathic bladder and bowel). RESULTS: Whereas full physical adaptation of the home can wait for some time after discharge, carer support for intermittent catheterisation is required from the first day after discharge from a spinal unit. Lack of such support means that some SCI patients are discharged with long-term indwelling urinary catheters, even though clean intermittent catheterisation is known to be the safest regime for managing the neuropathic bladder. Therefore, the absence of a community care waiting list means that best practice cannot be achieved for some tetraplegic subjects. CONCLUSION: We believe that a community care waiting list for bladder management will help to provide optimum care for neuropathic bladder and, hopefully, reduce the complications related to long-term indwelling catheters in spinal cord injury patients.

Adult↗
PubMed2001

Doctor-patient communication: do people with spinal cord injury wish to receive written information about their medical condition from the physicians after an outpatient visit or after a readmission in the spinal unit?

STUDY DESIGN: A survey of spinal cord injury patients attending a follow-up clinic in a Regional Spinal Injuries Centre. OBJECTIVES: To investigate whether spinal cord injury patients wish to receive written information about any changes in their medical condition after an outpatient visit or, following readmission in a spinal unit. SETTING: Regional Spinal Injuries Centre, Southport, United Kingdom. METHODS: A questionnaire was developed to assess the following: (1) Whether spinal cord injury patients wished to receive written information about changes in their medical condition after an outpatient visit or following readmission in a spinal unit; and (2) Whether provision of such written information would cause needless anxiety to patients and/or their relatives/carers. RESULTS: A total of 128 adults with spinal cord injury filled in this questionnaire. One hundred and six persons (83%) wished to receive written information about any changes in their medical condition after an outpatient visit, whereas eight (6%) felt that provision of such written information was not required. 115 individuals with spinal cord injury (90%) preferred to receive a copy of the MRI scan report, with interpretation of the findings, while 11 (9%) would be happy not to receive such information. 115 persons with spinal cord injury (90%) felt that written information about their medical condition would be valuable for showing to a locum General Practitioner (GP), if necessary, who may not be acquainted with their medical status. Only eight (6%) did not perceive a need for written information to appraise a locum GP. One hundred and twenty-two persons with spinal cord injury (95%) did not feel that provision of written information would cause needless anxiety to them; only four (3%) felt the other way. One hundred and nineteen (93%) individuals with spinal cord injury wished to receive written information about changes in their medical condition after a readmission to the spinal unit, while six (5%) did not wish to receive such information. CONCLUSION: Although the vast majority of people with spinal cord injury reported they wished to receive written information, a small proportion of patients did not wish to receive such information. Acceptance of written information is not universal and clinicians must ensure that provision of written information to people with spinal cord injury should be tailored to the needs of individual patients.

Adult↗
PubMed1999

The pharmacological and functional characteristics of the serotonin 5-HT(3A) receptor are specifically modified by a 5-HT(3B) receptor subunit.

While homomers containing 5-HT(3A) subunits form functional ligand-gated serotonin (5-HT) receptors in heterologous expression systems (Jackson, M. B., and Yakel, J. L. (1995) Annu. Rev. Physiol. 57, 447-468; Lambert, J. J., Peters, J. A., and Hope, A. G. (1995) in Ligand-Voltage-Gated Ion Channels (North, R., ed) pp. 177-211, CRC Press, Inc., Boca Raton, FL), it has been proposed that native receptors may exist as heteromers (Fletcher, S., and Barnes, N. M. (1998) Trends Pharmacol. Sci. 19, 212-215). We report the cloning of a subunit 5-HT(3B) with approximately 44% amino acid identity to 5-HT(3A) that specifically modified 5-HT(3A) receptor kinetics, voltage dependence, and pharmacology. Co-expression of 5-HT(3B) with 5-HT(3A) modified the duration of 5-HT(3) receptor agonist-induced responses, linearized the current-voltage relationship, increased agonist and antagonist affinity, and reduced cooperativity between subunits. Reverse transcriptase-polymerase chain reaction in situ hybridization revealed co-localization of both 5-HT(3B) and 5-HT(3A) in a population of neurons in the amygdala, telencephalon, and entorhinal cortex. Furthermore, 5-HT(3A) and 5-HT(3B) mRNAs were expressed in spleen and intestine. Our data suggest that 5-HT(3B) might contribute to tissue-specific functional changes in 5-HT(3)-mediated signaling and/or modulation.

Amygdala↗
PubMed1999

A two-part pilot study of sildenafil (VIAGRA) in men with erectile dysfunction caused by spinal cord injury.

STUDY DESIGN: This was a two-part pilot study in men with erectile dysfunction (ED) due to spinal cord injury (SCI: cord level range T6-L5). Part I was a randomised, double-blind, two-way cross-over study comparing a single dose of sildenafil 50 mg or placebo. Part II was a randomised, double-blind, parallel-group evaluation of sildenafil 50 mg or placebo, taken as required (not more than once daily) approximately 1 h prior to sexual activity, over a period of 28 days. OBJECTIVES: To assay the efficacy and safety of sildenafil 50 mg and placebo. SETTING: Clinic- and home-based assessments in the United Kingdom. METHODS: A total of 27 subjects who were able to achieve at least a grade 2 erection (hard, but not hard enough for penetration) in response to penile vibratory stimulation (PVS) were recruited. In Part I, the reflexogenic response of the penis to PVS was evaluated in the clinic while in Part II, the response to treatment was assessed in the home (global efficacy. questionniare, diary). RESULTS: In Part I, 17/26 (65%) subjects had erections of >60% rigidity at the penile base (median duration 3.5 min) after sildenafil compared with 2/26 (8%) (median duration 0 min) alter placebo (P=0.0003). In Part II, 9/12 (75%) subjects on sildenafil and 1/14 (7%) subjects on placebo reported that the treatment had improved their erections (P<0.005), and 8/12 (67%) and 2/13 (15%) men, respectively, indicated that they wished to continue treatment (P<0.02). An analysis of diary data showed no difference between the groups with respect to the mean number of erections hard enough for penetration (P = 0.08). The mean proportion of attempts at sexual intercourse that were successful was 30 and 15%, respectively (P=0.21). Similarly, responses to the end-of-treatment questionnaire indicated that there were no significant differences between the groups with respect to the frequency of erections hard enough for sexual intercourse (P=0.47) or that lasted as long as the subject would have liked (P=0.11). No subject discontinued sildenafil due to adverse events. CONCLUSION: Sildenafil is an effective, well-tolerated oral treatment for ED in SCI subjects.

Adult↗
PubMed1999

Correlates of stress in long-term spinal cord injury.

STUDY DESIGN: Longitudinal. OBJECTIVES: To characterize long-injured SCI persons with high reported stress; to assess the relationship between severity of disability and perceived stress; to identify correlates of future stress and outcomes of previous stress. SETTING: Two SCI centres in England: Stoke Mandeville Hospital in Aylesbury, and the District General Hospital in Southport. METHODS: In 1990, 1993 and 1996 187 persons who sustained spinal cord injuries prior to 1971 underwent comprehensive physical evaluations and health status interviews and completed a battery of tests to measure psychosocial functioning. Using mean scores on the Perceived Stress Scale (PSS) as the reference, a range of outcomes were analyzed to identify concurrent, previous, and future variables that were significantly correlated with perceived stress. RESULTS: No associations were found between stress and any of the proxy variables that represented injury severity. Such common SCI-related medical conditions as pressure sores and upper extremity pain were not related to stress; not even fatigue was significantly associated with stress in both time periods studied. However, depressive symptoms, poorer life satisfaction, and poorer perceived well being were associated with future stress and were outcomes that appeared to be related to earlier stress. CONCLUSION: Perceived stress in long-term SCI is not closely related to the severity of the disability or physical independence. It is, however, related to scores on several measures of adjustment and coping. Though mean stress scores in this sample did not appear to differ substantially from scores in the general nondisabled population, further controlled study is needed to definitively answer the question: Do SCI survivors report more stress than their nondisabled counterparts?

Adaptation, Psychological↗
PubMed1999

A biomimetic controller for a multifinger prosthesis.

A novel controller for a multifinger hand prosthesis was developed and tested to measure its accuracy and performance in transducing volitional signals for individual "phantom" fingers. Pneumatic sensors were fabricated from open-cell polymeric foam, and were interposed between the prosthetic socket and superficial extrinsic tendons associated with individual finger flexion. Test subjects were prompted to move individual fingers or combinations thereof to execute either taps or grasps. Sensor outputs were processed by a computer that controlled motions of individual fingers on a mechanical prosthesis. Trials on three upper-limb amputees showed that after brief training sessions, the TAP controller was effective at producing voluntary flexions of individual fingers and grasping motions. Signal energies were between 5 and 25 dB relative to noise from all sources, including adjacent sensors, indicating high degrees of both sensitivity and specificity for tendon-associated transduction. Finger flexions at up to three repetitions per second, and rhythmic tapping of sequential fingers were readily transduced. One amputee subject was able to play a short piano piece with three fingers, at approximately one-quarter normal tempo. TAP sensors responded linearly to graded forces from individual fingers, indicating proportional force control. Our results demonstrate the feasibility of restoring some degree of finger dexterity by noninvasive sensing of extrinsic tendons.

Amputees↗
PubMed1999

Oral care in the adult intensive care unit.

BACKGROUND: Nurses have not been formally trained in assessing the oral status of patients in intensive care units, and no oral care protocols for these patients are available. OBJECTIVES: To assess the oral status of patients in an intensive care unit, evaluate the effects of a defined oral care protocol on the oral health status of patients in an intensive care unit, and compare oral assessments of a dental hygienist with those of intensive care nurses. METHODS: A nonequivalent comparison group, longitudinal design with repeated measures was used. In phase 1, oral assessment data on the comparison group were collected by a dental hygienist. In phase 2, nurses were instructed in oral assessment and an oral care protocol. In phase 3, the oral care protocol was implemented in the treatment group, and oral assessment data were collected separately by the dental hygienist and by nurses. RESULTS: The mean inflammation score was significantly lower (t test P = .03) in the treatment group (mean, 3.9; SEM, 3.0) than in the comparison group (mean, 12.4; SEM, 2.2). Although not significant, the mean scores of the treatment group were also lower than those of the comparison group on scales of candidiasis, purulence, bleeding, and plaque. Correlations between scores for individual items on the oral assessment tool obtained by the dental hygienist and those obtained by nurses were all greater than 0.6386. CONCLUSION: Implementation of a well-developed oral care protocol by bedside nurses can improve oral health of patients in the intensive care unit.

Adult↗
PubMed1998

Application of an artificial neural network to predict specific class I MHC binding peptide sequences.

Computational methods were used to predict the sequences of peptides that bind to the MHC class I molecule, K(b). The rules for predicting binding sequences, which are limited, are based on preferences for certain amino acids in certain positions of the peptide. It is apparent though, that binding can be influenced by the amino acids in all of the positions of the peptide. An artificial neural network (ANN) has the ability to simultaneously analyze the influence of all of the amino acids of the peptide and thus may improve binding predictions. ANNs were compared to statistically analyzed peptides for their abilities to predict the sequences of K(b) binding peptides. ANN systems were trained on a library of binding and nonbinding peptide sequences from a phage display library. Statistical and ANN methods identified strong binding peptides with preferred amino acids. ANNs detected more subtle binding preferences, enabling them to predict medium binding peptides. The ability to predict class I MHC molecule binding peptides is useful for immunolological therapies involving cytotoxic-T cells.

Amino Acids↗
PubMed1998

Efficacy and safety of oral sildenafil (Viagra) in men with erectile dysfunction caused by spinal cord injury.

OBJECTIVE: To evaluate the efficacy and safety of 50-mg doses of sildenafil during a 28-day period in patients with erectile dysfunction caused by spinal cord injury (cord level range, T6 through L5). BACKGROUND: Sildenafil is an orally active, potent, and selective inhibitor of phosphodiesterase type 5, an important regulator of cyclic guanosine monophosphate in the human corpus cavernosum. METHODS: To be included in this double-blind, placebo-controlled study, all patients had to be able to achieve at least a partial reflexogenic erectile response to penile vibratory stimulation. The study utilized a single triangular sequential trial design. A total of 27 patients were randomized to receive 50 mg of sildenafil or placebo, taken orally as required (not more than once daily) approximately 1 hour before sexual activity. RESULTS: After 28 days of treatment, nine of 12 patients (75%) on sildenafil and one of 14 patients (7%) on placebo reported that treatment had improved their erections (p=0.0043). Furthermore, eight of 12 patients (67%) on sildenafil and two of 13 patients (15%) on placebo indicated that they wished to continue treatment (p=0.018). A significant improvement in satisfaction with their sex life was reported by patients taking sildenafil (p=0.012). No patients discontinued treatment due to adverse events. CONCLUSION: Oral sildenafil, taken as required (not more than once daily), significantly improves the quality of erections and satisfaction with sex life in men with erectile dysfunction caused by a spinal cord injury between T6 and L5.

Administration, Oral↗
PubMed1997

Estimating social adjustment following spinal trauma--I: Who is more realistic--patient or spouse? A statistical justification.

Whilst assessment of functional independence has been accomplished, to a greater extent, following spinal trauma, assessing social adjustment remains an area requiring considerable further investigation. Providing premorbid estimation of adjustment is an area which presents a number of methodological difficulties both in the collection and interpretational of longitudinal data. Such analyses tend to allow overall estimates of adjustment to be made but which lack individual specificity. Analyses are presented of over 250 individuals, and their closest relative's assessment, of social adjustment to their spinal cord injury. Using a modification of an established scale for assessing social adjustment it has been possible to establish the statistical level of agreement and address the hypothesis of differential perception of the extent of adjustment problems by the injured person and their closest relative. The study allows for the conclusion that an injured person's perception of adjustment is at least as reliable as their closest relative, and that there is further evidence to support the essential accuracy of their estimations of premorbid and current levels of adjustment. Both issues are of clinical importance, particularly in relation to any medico-legal compensation aspects.

Adult↗
PubMed1997

Estimating social adjustment following spinal trauma--II: Population trends and effects of compensation on adjustment.

Adaptation to, or acceptance of, acquired spinal cord injury is accepted as an essentially longitudinal process. Changes in an individual's social, financial and domestic positions in turn affect issues concerning quality of life and self-image. The responses of 302 individuals with spinal cord injury in the United Kingdom and United States of America are presented to produce individual profiles of social adjustment. The differences between the UK and USA groups are presented, together with a combined analysis which addresses, in particular, the effects which being involved in litigation has on the process of social adjustment. Individual data concerning social adjustment, provided through a scale developed by the authors, and the utility of graphical presentation of the data is also presented. Such presentation has been found to have particular importance in clinical interview, situations by providing a framework for further exploration of individual adjustment difficulties, and in legal settings.

Adult↗
PubMed1996

The internal mammary artery and vein as a recipient site for free-flap breast reconstruction: a report of 110 consecutive cases.

The most common recipient site for free-flap breast reconstruction is the subscapular system. Because of a number of problems we encountered using this recipient site, we became interested in revisiting the internal mammary vessels. This paper reports the use of the internal mammary artery and vein as a recipient site in 110 consecutive cases of breast reconstruction in 87 patients. We also report the technical details of recipient-vessel dissection and vessel size in our series. Complications encountered in the series are discussed, and the advantages of using the internal mammary vessels are enumerated. Our experience of a 99 percent successful flap transfer rate supports the reliability of these recipient vessels in breast reconstructions.

Breast↗