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Allan Jones

Publications and source records attributed to Allan Jones.

12 recordsLinked to original sources
PubMed2006

The visualization of hepatic vasculature by X-ray micro-computed tomography.

In this study, X-ray micro-computed tomography (CT) was used to reconstruct the fine structure macro- and microvasculature in three dimensions in contrast-enhanced rat liver samples. The subsequent application in the experimental CC531s colorectal cancer model was concurrent with results obtained from confocal microscopy in earlier studies. The en bloc stains osmium tetroxide in combination with uranyl acetate provided an excellent contrasting result for hepatic tissue after a trial of several contrasting agents. X-ray micro-CT allowed us to image the large blood vessels together with the branching sinusoids of hepatic tissue in three dimensions. Furthermore, interruption of the microvasculature was noted when rats were injected with CC531s colorectal cancer cells indicating the presence of hepatic metastases.

Angiography↗
PubMed2006

Can standardized patients replace physicians as OSCE examiners?

BACKGROUND: To reduce inter-rater variability in evaluations and the demand on physician time, standardized patients (SP) are being used as examiners in OSCEs. There is concern that SP have insufficient training to provide valid evaluation of student competence and/or provide feedback on clinical skills. It is also unknown if SP ratings predict student competence in other areas. The objectives of this study were: to examine student attitudes towards SP examiners; to compare SP and physician evaluations of competence; and to compare predictive validity of these scores, using performance on the multiple choice questions examination (MCQE) as the outcome variable. METHODS: This was a cross-sectional study of third-year medical students undergoing an OSCE during the Internal Medicine clerkship rotation. Fifty-two students rotated through 8 stations (6 physician, 2 SP examiners). Statistical tests used were Pearson's correlation coefficient, two-sample t-test, effect size calculation, and multiple linear regression. RESULTS: Most students reported that SP stations were less stressful, that SP were as good as physicians in giving feedback, and that SP were sufficiently trained to judge clinical skills. SP scored students higher than physicians (mean 90.4% +/- 8.9 vs. 82.2% +/- 3.7, d = 1.5, p < 0.001) and there was a weak correlation between the SP and physician scores (coefficient 0.4, p = 0.003). Physician scores were predictive of summative MCQE scores (regression coefficient = 0.88 [0.15, 1.61], P = 0.019) but there was no relationship between SP scores and summative MCQE scores (regression coefficient = -0.23, P = 0.133). CONCLUSION: These results suggest that SP examiners are acceptable to medical students, SP rate students higher than physicians and, unlike physician scores, SP scores are not related to other measures of competence.

Alberta↗
PubMed2006

Upfront double high-dose chemotherapy with DICEP followed by BEAM and autologous stem cell transplantation for poor-prognosis aggressive non-Hodgkin lymphoma.

A single center, prospective clinical trial was conducted evaluating 2 cycles of induction high-dose chemotherapy for adults younger than 65 years of age with aggressive non-Hodgkin lymphoma (NHL) and 2 to 3 Age-Adjusted International Prognostic Index risk factors. Patients received one cycle of standard dose cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) followed by one cycle of dose-intensive cyclophosphamide 5.25 g/m(2), etoposide 1.05 g/m(2), cisplatin 105 mg/m(2) (DICEP), then underwent autologous blood stem cell collection, followed by one cycle of high-dose carmustine (BCNU) 300 mg/m(2), etoposide 800 mg/m(2), Ara-C 1600 mg/m(2), melphalan 140 mg/m(2) (BEAM), and autologous stem cell transplantation (ASCT) and radiotherapy to prior bulk. From June 1998 to August 2004, 55 patients aged 20 to 63 years (median 44 years) were accrued, 51 (92%) of whom had diffuse large B-cell NHL. Poor prognostic factors included stage 4 (n = 46), elevated lactate dehydrogenase (LDH; n = 47), Eastern Cooperative Oncology Group (ECOG) performance status 2 to 4 (n = 43), bulky mass more than 10 cm (n = 34), and marrow involvement (n = 16). Only one patient experienced nonrelapse mortality. With a median follow-up of 49 months, 4-year event-free survival (EFS) and overall survival (OS) rates for all 55 patients are 72% (95% confidence interval [CI] = 60%-84%) and 79% (95% CI = 69%-90%), respectively. In conclusion, CHOP-DICEP-BEAM is feasible and gave encouraging EFS and OS for patients with poor-prognosis aggressive NHL.

Adult↗
PubMed2006

The association between anxiety and chronic pain after whiplash injury: gender-specific effects.

OBJECTIVE: There is increasing evidence to suggest that anxiety is related more strongly to chronic pain experience in men relative to women. The aim of the present study was to examine for the first time gender-specific associations between anxiety and chronic pain experience in men and women exposed to whiplash trauma. METHOD: One thousand seven hundred and nine people with whiplash (1349 women, 360 men) belonging to the Danish Society for Polio, Traffic, and Accident Victims completed a battery of questionnaires measuring demographic, psychologic, and pain-related factors (including frequency of painful episodes, level of pain interference, number of anatomic regions in which pain was felt, and the level of general disability). RESULTS: Anxiety was found to be positively related to the level of general disability to a significantly stronger magnitude in men compared with women. A trend difference in correlation magnitude was also found between men and women when comparing anxiety with pain frequency, with the magnitude of correlation being higher in men. DISCUSSION: The stronger association between anxiety and symptoms of whiplash trauma in men compared with women may be due to gender differences in the attribution of anxiety-related autonomic arousal as symptoms of whiplash injury. Alternatively, anxiety may differentially affect the willingness of men and women to report pain and other health indices. Anxiety is an important factor in understanding gender differences in whiplash-related symptoms such as chronic pain and disability, and requires further investigation.

Adult↗
PubMed2004

Investigation of the interactive effects of gender and psychological factors on pain response.

OBJECTIVES: There is growing evidence to suggest that certain psychological modulators of pain sensitivity are dependent on gender. The aim of the present study was to examine further whether cognitive-affective factors (with specific focus on situational anxiety) shown to modulate pain report and behaviour have differential effects on men's and women's response to experimentally induced pain. METHOD: A sample of 80 healthy university students (40 women, 40 men) was assessed on subjective measures of anxiety (situational and dispositional), anxiety-sensitivity and attitudes toward the experimental pain procedure prior to being exposed to a cold pressor test (constant temperature + 1 degrees C; +/- 1 degrees C, cut-off limit 240 s). RESULTS: The present study produced three main findings: (1) No effect of gender was found on any of the pain measures; however, an interactive effect of anxiety and gender was found on measures of pain tolerance with low anxiety men displaying significantly higher pain tolerance than both low and high anxiety women. (2) Men classified as low-anxious tolerated cold pressor pain significantly longer than men classified as high-anxious, while no such effect of anxiety on pain response was observed in women. (3) Gender-specific associations were observed between other psychological variables (including anxiety-sensitivity and attitudes toward pain) and thermal pain response. CONCLUSION: Results from the present study suggest that there are important differences in the way cognitive-affective factors impact on the pain response of men and women. Further research is needed to explore potential psychosocial and physiological mechanisms that may underlie such differences.

Adult↗
PubMed2003

3-dimensional imaging of collagen using second harmonic generation.

Collagen is the most important structural protein of the animal body. Its unique triple-helix structure and extremely high level of crystallinity make it exceptionally efficient in generating the second harmonic of incident light, and we show here how this leads to a novel mode of microscopy of immediate practical significance in medicine and biology. In particular, it provides sensitive and high-resolution information on collagen distribution, discriminates between type I and type III collagen, and allows both a greater understanding of and a sensitive test for cirrhosis of the liver. Future research applications could include wound healing and hereditary collagen diseases such as osteogenesis imperfecta.

Animals↗
PubMed2003

Dispositional anxiety and the experience of pain: gender-specific effects.

AIM OF INVESTIGATION: Increased anxiety is believed to correlate with increased pain sensitivity in men and women. However, one laboratory-based study and one clinical-based study have offered evidence to suggest that the effect of anxiety in modulating pain sensitivity is specific to men only. The aim of the present study was to examine further whether anxiety differentially effects men and women's report of experimentally induced pain. METHODS: One hundred forty-four healthy university students (75 women, 69 men) were exposed to a contact heat pain procedure (ascending method of limits procedure, baseline temperature 30 degrees C, +/- 0.2 degrees C, rate of change 2.0 degrees C/s, cut-off limit 52 degrees C) and a cold pressor pain procedure (constant temperature +1 degrees C; +/-1 degrees C, cut-off limit 240 s). RESULTS: The results agreed with the previous two studies indicating a sex-specific effect of anxiety on pain report. Male participants scoring above the median on the Trait Anxiety Inventory reported significantly greater pain intensity, unpleasantness and showed lower pain tolerance compared to males scoring below the median on the cold pressor pain procedure, while no such differences in cold pressor pain report were found between high and low anxious women. No effect of anxiety was found on measures taken from the contact heat pain procedure, indicating that the sex-specific effect of anxiety on laboratory induced pain is dependent upon the method of stimulation used. CONCLUSION: Anxiety is an important factor when considering gender differences in pain perception and warrants further investigation.

Adult↗
PubMed2002

Early growth response transcription factors are required for development of CD4(-)CD8(-) thymocytes to the CD4(+)CD8(+) stage.

Progression of immature CD4(-)CD8(-) thymocytes beyond the beta-selection checkpoint to the CD4(+)CD8(+) stage requires activation of the pre-TCR complex; however, few of the DNA-binding proteins that serve as molecular effectors of those pre-TCR signals have been identified. We demonstrate in this study that members of the early growth response (Egr) family of transcription factors are critical effectors of the signals that promote this developmental transition. Specifically, the induction of three Egr family members (Egr1, 2, and 3) correlates with pre-TCR activation and development of CD4(-)CD8(-) thymocytes beyond the beta-selection checkpoint. Enforced expression of each of these Egr factors is able to bypass the block in thymocyte development associated with defective pre-TCR function. However, Egr family members may play somewhat distinct roles in promoting thymocyte development, because there are differences in the genes modulated by enforced expression of particular Egr factors. Finally, interfering with Egr function using dominant-negative proteins disrupts thymocyte development from the CD4(-)CD8(-) to the CD4(+)CD8(+) stage. Taken together, these data demonstrate that the Egr proteins play an essential role in executing the differentiation program initiated by pre-TCR signaling.

Animals↗
PubMed2002

The effect of situation-evoked anxiety and gender on pain report using the cold pressor test.

The aims of the present study were to investigate the influence of anxiety on pain perception and to test whether gender differences in pain perception are anxiety dependent. Sixty male and female university students exposed to situation-evoked anxiety or a control procedure were measured for their pain threshold, tolerance, and perceived intensity during a cold pressor test. Both subjective and autonomic responses indicated that anxiety was successfully induced in participants exposed to the anxiety condition. Increased situational anxiety had no significant effect on pain threshold or pain tolerance. Significant increases in pain intensity were found for the anxiety group. Levels of anxiety, however, did not correlate with this increased intensity, raising doubt as to the role of anxiety in producing this effect. No gender differences were found for pain tolerance or pain intensity. Gender differences were found for pain threshold in the anxiety group with, contrary to past findings, females showing significantly higher pain thresholds than males. The results are discussed in the light of related studies.

Adult↗
PubMed2002

Gender, anxiety, and experimental pain sensitivity: an overview.

Our objective was to review human experimental studies to see if anxiety had a differential impact on the pain perceptions of men and women. We searched MEDLINE and PsycINFO for studies of anxiety and pain sensitivity in men and women published from 1966 to 2001. Research indicated that women are more sensitive to pain than men, and that anxiety may be partly responsible for the observed differences. Anxiety may also differentially affect men's and women's report of pain. Anxiety may be an important factor when considering sex differences in pain perception and warrants further investigation.

Anxiety↗