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Biomedical subjects

C Bryant

Publications and source records attributed to C Bryant.

At least 19 recordsLinked to original sources
PubMed2005

Power Doppler 'blanching' after the application of transducer pressure.

The aim of this study was to determine if transducer pressure modifies power Doppler assessments of rheumatoid arthritis synovium at the metacarpophalangeal joints and metatarsophalangeal joints. Five rheumatoid arthritis patients of varying degrees of 'disease activity' and damage were assessed with power Doppler ultrasound scanning of the dominant hand second to fifth metacarpophalangeal joints. Two rheumatoid arthritis patients had their dominant foot first to fifth metatarsophalangeal joints assessed with power Doppler ultrasound. Ultrasonography was performed with a high frequency transducer (14 MHz) with a colour mode frequency of 10 Mhz, and a standard colour box and gain. In the joint that showed the highest power Doppler signal, an image was made. A further image was taken after transducer pressure was applied. In all patients, there was increased flow to at least one joint. After pressure was applied, power Doppler signal intensity markedly reduced in all images and in some there was no recordable power Doppler signal. Increased transducer pressure can result in a marked reduction or obliteration in power Doppler signal. This power Doppler 'blanching' shows the need for further studies to evaluate sources of error and standardization before power Doppler ultrasound becomes a routine measure of 'disease activity' in rheumatoid arthritis.

Adult↗
PubMed2002

Footstrike is the major cause of hemolysis during running.

There is a wide body of literature reporting red cell hemolysis as occurring after various forms of exercise. Whereas the trauma associated with footstrike is thought to be the major cause of hemolysis after running, its significance compared with hemolysis that results from other circulatory stresses on the red blood cell has not been thoroughly addressed. To investigate the significance of footstrike, we measured the degree of hemolysis after 1 h of running. To control for the potential effects of oxidative and circulatory stresses on the red blood cell, the same subjects cycled for 1 h at equivalent oxygen uptake. Our subjects were 10 male triathletes, who each completed two separate 1-h sessions of running and cycling at 75% peak oxygen uptake, which were performed in random order 1 wk apart. Plasma free hemoglobin and serum haptoglobin concentrations were measured as indicators of hemolysis. We also measured methemoglobin as a percentage of total hemoglobin immediately postexercise as an indicator of red cell oxidative stress. Plasma free hemoglobin increased after both running (P < 0.01) and cycling (P < 0.01), but the increase was fourfold greater after running (P < 0.01). This was reflected by a significant fall in haptoglobin 1 h after the running trials, whereas no significant changes occurred after cycling at any sample point. Methemoglobin increased twofold after both running and cycling (P < 0.01), with no significant differences between modes of exercise. The present data indicate that, whereas general circulatory trauma to the red blood cells associated with 1 h of exercise at 75% maximal oxygen uptake may result in some exercise-induced hemolysis, footstrike is the major contributor to hemolysis during running.

Adult↗
PubMed2001

The antiosteoporotic efficacy of intravenous pamidronate in men with prostate carcinoma receiving combined androgen blockade: a double blind, randomized, placebo-controlled crossover study.

BACKGROUND: Prostate carcinoma therapy with combined androgen blockade may result in high bone-turnover with significant bone loss. This study was undertaken to evaluate the antiosteoporotic efficacy of intravenous pamidronate in a double blind, randomized, placebo-controlled, crossover study. METHODS: Twenty-one consecutive men with metastatic prostate carcinoma who were receiving combined androgen blockade with a long-acting gonadotropin-releasing hormone agonist (gosarelin acetate) and an androgen antagonist (flutamide or bicalutamide) were evaluated at baseline and at 6 and 12 months after therapy. They were randomly assigned to receive a single intravenous infusion of 500 mL of normal saline solution diluted with either pamidronate (90 mg) or placebo at baseline and with a crossover at 6 months. Lumbar-spine bone-mineral densities (BMDs) were measured by spinal quantitative computed tomography (QCT), femoral neck BMDs were measured by dual-energy X-ray absorptiometry (DXA), and markers of bone turnover were measured by noninvasive methods. Data on 10 men with localized prostate carcinoma who were treated with radiotherapy alone, over the same period, was collected for comparison studies. RESULTS: The mean age of the men was 75.1 years +/- 1.6 years. One man withdrew from the study because of deteriorating health, and two died from metastatic disease within the first 6 months. Combined androgen blockade normalized serum prostate-specific antigen activities (from an initial mean value of 86.2 ng/mL +/- 10.1 ng/mL) and maintained serum free testosterone concentrations in the hypogonadal range (< 2.2 pmol/L) in all men throughout the study. Treatment with pamidronate resulted in a 7.8% +/- 1.5% increase in mean lumbar spine QCT from 79.4 mg/cm(3) (95% confidence interval [CI], 64-94 mg/cm(3)) to 85.6 mg/cm(3) (95% CI, 70-101 mg/cm(3)) (P = 0.0005) and a 2% +/- 0.9% increase in mean total femoral neck DXA from 0.98 g/cm(2) (95% CI, 0.90 -1.05 g/cm(2)) to 1.0 mg/cm(2) (95% CI, 0.91-1.08 g/cm(2)) (P = 0.02). Conversely, treatment with placebo, resulted in a 5.7% +/- 1.6% decrease in mean lumbar spine QCT and a 2.3% +/- 0.7% decrease in mean total femoral neck DXA (P = 0.0001 and P = 0.0007 for the comparison of percentage change between the pamidronate and placebo treatments). After pamidronate therapy, serum bone Gla-protein concentrations decreased by 16.8% +/- 5.9%, and urinary deoxypyridinoline excretion rates decreased by 18.5% +/- 12.8% (P < 0.01 respectively for the comparison between pamidronate and placebo treatment). CONCLUSIONS: This study demonstrated that a single intravenous infusion of pamidronate (90 mg) significantly reduced the high bone turnover and bone loss (for at least 6 mos) in men with prostate carcinoma who had been rendered hypogonadal with combined androgen blockade therapy.

Aged↗
PubMed2001

Nuclear factor kappa B is involved in lipopolysaccharide-stimulated induction of interferon regulatory factor-1 and GAS/GAF DNA-binding in human umbilical vein endothelial cells.

1. In this study we examined the signalling events that regulate lipopolysaccharide (LPS)-stimulated induction of interferon regulatory factor (IRF)-1 in human umbilical vein endothelial cells (HUVECs). 2. LPS stimulated a time- and concentration-dependent increase in IRF-1 protein expression, an effect that was mimicked by the cytokine, tumour necrosis factor (TNF)-alpha. 3. LPS stimulated a rapid increase in nuclear factor kappa B (NFkappaB) DNA-binding activity. Pre-incubation with the NFkappaB pathway inhibitors, N-alpha-tosyl-L-lysine chloromethyl ketone (TLCK) or pyrrolidine dithiocarbamate (PDTC), or infection with adenovirus encoding IkappaBalpha, blocked both IRF-1 induction and NFkappaB DNA-binding activity. 4. LPS and TNFalpha also stimulated a rapid activation of gamma interferon activation site/gamma interferon activation factor (GAS/GAF) DNA-binding in HUVECs. Preincubation with the Janus kinase (JAK)-2 inhibitor, AG490 blocked LPS-stimulated IRF-1 induction but did not affect GAS/GAF DNA-binding. 5. Preincubation with TLCK, PDTC or infection with IkappaBalpha adenovirus abolished LPS-stimulated GAS/GAF DNA-binding. 6. Incubation of nuclear extracts with antibodies to RelA/p50 supershifted GAS/GAF DNA-binding demonstrating the involvement of NFkappaB isoforms in the formation of the GAS/GAF complex. 7. These studies show that NFkappaB plays an important role in the regulation of IRF-1 induction in HUVECs. This is in part due to the interaction of NFkappaB isoforms with the GAS/GAF complex either directly or via an intermediate protein.

Adenoviridae↗
PubMed2001

Functional magnetic resonance imaging of odor identification: the effect of aging.

BACKGROUND: Sense of smell declines with age and impairment in olfaction has been observed in some neurodegenerative disorders such as Alzheimer's disease. Functional neuroimaging techniques enable researchers to observe brain regions activated by olfactory stimuli. METHODS: We gave three mainly olfactory-mediated odors (limonene, methylsalicylate, and eugenol) to six young and six elderly subjects and observed the areas activated by using blood oxygen level dependent contrast functional magnetic resonance imaging. RESULTS: The group mapping of young subjects showed extensive activation in the orbitofrontal cortex, commonly believed to be the olfactory cortex, some limbic areas (the hippocampus and the thalamus), regions involved with gustatory sensation (the anterior insula and the inferior postcentral gyrus), superior and inferior temporal gyri, and cerebellum. In the elderly group, only the left inferior temporal gyrus and the primary visual cortex reached accepted significance levels. CONCLUSIONS: We have therefore confirmed previous reports of brain regions involved in olfactory processing in young volunteers and demonstrated decreased activation in elderly volunteers.

Adult↗
PubMed2001

Generation and characterization of a defined mutant of Streptococcus suis lacking suilysin.

A defined allelic-replacement mutant of the sly gene, encoding a thiol-activated cytolysin, from a European isolate of Streptococcus suis serotype 2 was generated and characterized. Unlike the parental strain, it is nonhemolytic, noncytotoxic for cultured macrophage-like cells, avirulent in a mouse infection model, yet only slightly attenuated in a porcine model of systemic infection.

Animals↗
PubMed2001

Implementing a community-based social marketing project to improve agricultural worker health.

The Together for Agricultural Safety project is a community-based social marketing project working to reduce the adverse health effects of pesticide exposure among fernery and nursery workers in Florida. In 3 years, the collaboration between university and community researchers has embodied many of the principles of community-based research while completing multiple stages of formative data collection required for a social marketing project. This hybrid approach to developing a health intervention for a minority community has been successful in its early stages because the community partners are organized, empowered, and motivated to execute research activities with the assistance of academic partners. However, this work has also been labor intensive and costly. This article describes the lessons learned by project partners and considers the limitations of this approach for agricultural health research.

Adult↗
PubMed2000

Attitudes to vaginal/urethral touching and device placement in women with urinary incontinence.

Because of recent development of a number of intravaginal and urethral occlusive devices for the treatment of urinary incontinence, we aimed to develop a linear analog scale that measured women's attitudes to becoming familiar with their genital anatomy and to placing devices into or upon the vagina or urethral orifices. We also investigated whether such attitudes were affected by previous tampon or diaphragm use, or were age dependent. After pilot studies, a 10-item questionnaire was given to 104 consecutive incontinent women, only 30% of whom were quite comfortable about the concept of touching their genitalia: this attitude was age dependent. Only 21% were quite willing to insert a continence device into their vagina: this attitude varied weakly with age but was significantly affected by previous tampon or diaphragm usage. Only 15% felt very comfortable about placing a continence device on to their urethra, but the likelihood of a positive response to this concept was not at all affected by age and was only slightly more common in previous tampon users. Thus older women are less likely to understand the anatomy of their genitalia or to be comfortable about the idea of exploring it, but age is no barrier to willingness to employ urethral or vaginal continence devices per se. We suggest that such a linear analog questionnaire may help gynecologists determine which patients might respond well to the use of vaginal or urethral continence devices.

Adult↗
PubMed2000

Influence of sucrose on the thermal denaturation, gelation, and emulsion stabilization of whey proteins.

The influence of sucrose (0-40 wt %) on the thermal denaturation and functionality of whey protein isolate (WPI) solutions has been studied. The effect of sucrose on the heat denaturation of 0.2 wt % WPI solutions (pH 7.0) was measured using differential scanning calorimetry. Sucrose increased the temperature at which protein denaturation occurred, for example, by 6-8 degrees C for 40 wt % sucrose. The dynamic shear rheology of 10 wt % WPI solutions (pH 7.0, 100 mM NaCl) was monitored as they were heated from 30 to 90 degrees C and then cooled to 30 degrees C. Sucrose increased the gelation temperature and the final rigidity of the cooled gels. The degree of flocculation in 10 wt % oil-in-water emulsions stabilized by 1 wt % WPI (pH 7.0, 100 mM NaCl) was measured using a light scattering technique after they were heated at fixed temperatures from 30 to 90 degrees C for 15 min and then cooled to 30 degrees C. Sucrose increased the temperature at which maximum flocculation was observed and increased the extent of droplet flocculation. These results are interpreted in terms of the influence of sucrose on the thermal unfolding and aggregation of protein molecules.

Emulsions↗
PubMed2000

Programmed cell death (apoptosis) as a possible pathway to metalloproteinase activation and fetal membrane degradation in premature rupture of membranes.

OBJECTIVE: Increased matrix metalloproteinase 2 expression and activity are associated with premature rupture of fetal membranes. A proapoptotic protein produced in response to deoxyribonucleic acid fragmentation, p53, can bind to the matrix metalloproteinase 2 gene promoter and cause increased gene expression. It promotes apoptosis by inducing the expression of the proapoptotic bax gene and inhibiting the antiapoptotic bcl-2 gene. This study was undertaken to investigate the expression pattern of apoptotic elements in pregnancy complications that may cause increased expression of the gene for matrix metalloproteinase 2. STUDY DESIGN: Amniochorial membranes were collected from the following groups of women: (1) women with premature rupture of fetal membranes, (2) women with preterm labor and intact membranes, and (3) women with term labor after vaginal delivery. Deoxyribonucleic acid fragmentation was tested with ligation-mediated polymerase chain reaction and the terminal deoxynucleotidyl transferase-mediated biotinylated deoxyribonucleoside triphosphate end-labeling assay. Matrix metalloproteinase 2, p53, bcl-2, and bax gene expression patterns were studied with quantitative competitive polymerase chain reaction. Statistical analysis was performed with the Tukey-Kramer multiple comparison test. RESULTS: Quantitative competitive polymerase chain reaction documented a 10-fold increase in the expression of the gene for matrix metalloproteinase 2 in premature rupture of fetal membranes with respect to term and preterm labor. This induction coincided with an increase in the expressions of the proapoptotic genes p53 and bax and a drop in the expression of the antiapoptotic gene bcl-2. Ligation-mediated polymerase chain reaction revealed deoxyribonucleic acid fragmentation in specimens from premature rupture of fetal membranes and not in those from preterm labor or labor at term. Histochemical analysis documented fragmented deoxyribonucleic acid in chorionic and amniotic cells. CONCLUSION: This study suggests that apoptosis is associated with premature rupture of fetal membranes. Deoxyribonucleic acid fragmentation, associated with elevations in the levels of the two proapoptotic gene products evaluated (p53 and bax ) and a drop in the level of the antiapoptotic bcl-2, was seen in premature rupture of the fetal membranes. Induction of matrix metalloproteinase 2 may be a function of p53 gene expression increase in premature rupture of fetal membranes.

Apoptosis↗
PubMed2000

Identification of novel polymorphisms in the 5' flanking region of CYP1A2, characterization of interethnic variability, and investigation of their functional significance.

CYP1A2 activity has been demonstrated to be bimodally or trimodally distributed in several populations, consistent with a codominant or recessive functional genetic polymorphism. However, studies aimed at identifying polymorphisms in CYPIA2 have not yet adequately accounted for this distribution pattern. To search for functional polymorphisms, we performed genome-walking, polymerase chain reaction (PCR) sequencing, and cloning, and identified three novel polymorphisms in the 5' flanking region of CYP1A2: a T-3591G substitution, a G-3595T substitution, and a T-3605 insertion. The frequency of the T-3591G substitution was determined by a PCR-restriction fragment length polymorphism assay, and found to be significantly higher (P < 0.0001) in Taiwanese (allele frequency 0.128, n = 125) compared to Caucasians (0.017, n = 87) or African Americans (0.024, n = 104). The functional consequence of the T-3591G and the G-3595T substitutions was determined by site-directed mutagenesis followed by transient transfection experiments. The T-3591G mutation was shown to be nonfunctional, while although the G-3595T mutation appeared to result in an increase in promoter activity, this was only to a small degree and therefore unlikely to be important in vivo. In addition, we report 532 bases of 5' flanking sequence further upstream than that reported to date, and four sequence discrepancies compared to the original published sequence (G-3649C, deltaT-3650, deltaA-4072, and C-4093 ins).

Black or African American↗
PubMed1999

Ovarian steroid cell tumors, not otherwise specified: a case report and literature review.

Steroid cell tumors, not otherwise specified, are rare ovarian sex cord-stromal tumors with malignant potential. The majority of these tumors produce steroids with testosterone being the most common. A case of a 46-year-old woman who presented with sudden onset of virilization and a pelvic mass is reported. Various aspects of the presentation, diagnosis, and treatment of these tumors are discussed.

Female↗
PubMed1999

Immunology and biochemistry of Hymenolepis diminuta.

This review is an account of modern research into the immunology and biochemistry of the rat tapeworm, Hymenolepis diminuta. The first half of the review is devoted to the immunological responses of the host to the parasite. It describes the specific responses that occur when the host is exposed to a primary infection, and the changes that occur when further infections are superimposed on the primary one. The aquisition of immunity to the tapeworm and its persistence in the absence of the infection are also discussed, as well as the non-specific responses of the host to the parasite. The second half of the review is concerned with biochemistry, summarizing the early biochemical work that has been carried out on the tapeworm and describing the metabolic pathways now thought to be characteristic of the parasite. What little information that exists on intermediary metabolism in eggs and larvae is summarized here. Much of this section is concerned with the role of mitochondria in H. diminuta, especially the control of the critical branchpoint (PK/PEPCK), which partitions carbon into either the cytosol or the mitochondrion. The role of 5-hydroxytryptamine in controlling both worm behaviour and metabolism is discussed, followed by a brief look at some other effectors that may prove in the future to have great significance in regulating the parasite. Finally, there is a detailed consideration of strain variation within H. diminuta and of the impact on the tapeworm of components of the immune system, formerly described as the 'crowding effect'. The review concludes with a brief discussion of evolutionary aspects of the rat-tapeworm relationship and a comprehensive bibliography.

Animals↗
PubMed1999

Three-dimensional treatment planning for central lymphatic irradiation.

The purpose of this study was to investigate the applicability of 3-dimensional (3D) treatment planning for central lymphatic irradiation (CLI). CLI requires more than 1 course of treatment with large, highly blocked, overlapping beams, and careful planning is required to ensure that such treatments are delivered safely and effectively. Three patients were selected for this study. Each patient completed at least 1 course of radiation therapy for CLI and was scheduled to receive irradiation to an adjacent area with overlapping beams. Two treatment plans were generated for each patient: a standard, 2-dimensional (2D) treatment plan and a 3D treatment plan designed to mimic the standard plan, taking advantage of unique 3D features. The time required to complete the treatment plans and differences in the treatment planning processes were noted. The time required to generate a 3D treatment plan was approximately the same as the time required to generate a standard 2D treatment plan; however, the 3D planning process required less redundancy of data entry than the 2D process. The 3D treatment plan was qualitatively similar to the standard 2D treatment plan; however, differences in beam penumbra and beam junctions were noted, and are most likely due to differences in the dose-calculation models used in these 2 treatment planning systems. Dose-volume histograms (DVHs) were calculated for the spinal cord and were found to be useful to the physicians for quickly and accurately evaluating the presence or absence of hot spots in the junction region. 3D treatment-planning has some advantages over 2D treatment planning for CLI; the main advantage of the 3D treatment plan is that it provides a single plan for each patient with multiple views of the data, including different planar cross-sections and DVHs. For the 2D system, a separate plan was generated for each view, requiring redundant data entry. The quality of the output of the 3D treatment plans is superior to that of 2D treatment plans, but the clinical utility is about the same. Currently, the time required for 2D and 3D treatment plans is similar. However, as dosimetrists become more familiar with 3D treatment planning systems, we expect this familiarity and regularity of use to translate into a significant time advantage.

Humans↗
PubMed1999

Efficacy and user acceptability of the urethral occlusive device in women with urinary incontinence.

PURPOSE: We determine the efficacy and user acceptability of the urethral occlusive device (FemAssist) for incontinence for 1 month and identify factors that may predict successful use of the device. MATERIALS AND METHODS: Baseline and posttreatment outcome measures included a 1-hour pad test, frequency volume chart (leakage, voiding and number of pads per 24 hour), visual analog scale for incontinence impact and quality of life (Urogenital Distress Inventory). The last 36 consecutive women also completed a linear analog scale about attitudes toward touching the genitalia. RESULTS: The device was offered to 100 consecutive incontinent women of whom 3 did not enroll in the study and 57 (57%) completed the 1-month trial. Age, incontinence type or severity and attitudes about touching the genitalia were not significantly different between dropouts and participants. Only 13% of recruits were disinclined to place the device on the urethra. Significant reduction of incontinence was observed for all outcome measures with the device in situ. Pad testing revealed that 47% of the patients became continent and 33% had more than 50% benefit, while 9% had worse leakage. Those with severe baseline leakage were equally likely to respond as those with mild or moderate pad test loss. Women with stress, urge or mixed incontinence appeared to respond equally well. CONCLUSIONS: The urethral occlusive device provides a further nonsurgical treatment option which is useful for a range of incontinence types.

Aged↗
PubMed1998

The effect of combined androgen blockade on bone turnover and bone mineral densities in men treated for prostate carcinoma: longitudinal evaluation and response to intermittent cyclic etidronate therapy.

BACKGROUND: Androgen receptor blocking agents have become an established form of therapy for men with disseminated prostate carcinoma. The purpose of this study was to evaluate markers of bone turnover and to measure bone mineral densities (BMD) in men with disseminated prostate carcinoma treated with combined androgen blockade prior to and after 6 months of intermittent cyclic etidronate therapy. METHODS: Twelve consecutive men with disseminated prostate carcinoma were evaluated at 0, 6, and 12 months after treatment with a long acting gonadotropin-releasing hormone agonist (goserelin acetate) and an androgen antagonist (flutamide). During the 6-12 month period, patients were treated with adjuvant intermittent cyclic etidronate therapy and calcium supplementation. Lumbar spine BMD was measured by spinal quantitative computed tomography (QCT) and femoral neck BMD by dual energy X-ray absorptiometry (DXA). RESULTS: Combined androgen blockade resulted in all men achieving serum free testosterone concentrations of <2.2 pmol/L (normal range, 38-114 pmol/ L). The mean serum prostate specific antigen activities decreased from 130.8+/-46 to 6.9+/-4.4 ng/mL (P < 0.05). Although serum calcium, parathyroid hormone, and 25-hydroxyvitamin D measurements remained unchanged, serum bone Gla-protein concentrations and urinary deoxypyridinolene excretion rates increased significantly (P < 0.01, respectively). Mean lumbar spine QCT decreased by 6.6+/-1.5% from 76.5 mg/cm3 (95% confidence interval [95% CI, 57-96 mg/cm3) to 73.9 mg/cm3 (95% CI, 55-93 mg/cm3) (P < 0.001) and mean femoral neck DXA decreased by 6.5+/-1.3% from 0.94 g/cm2 (95% CI, 0.81-1.07 g/cm2) to 0.91 g/cm2 (95% CI, 0.79-1.04 g/cm2) (P < 0.001). After treatment with adjuvant intermittent cyclic etidronate, mean lumbar spine QCT increased by 7.8+/-3.7% to a final value of 75 mg/cm3 (95% CI, 48.7-101 mg/cm3) (P=0.001 compared with the initial 6 months without intermittent cyclic etidronate therapy). Significant increases in BMD also were observed in the femoral neck and Ward's triangle. CONCLUSIONS: Androgen receptor blocking agents have an established role in the treatment of disseminated prostate carcinoma. However, combined androgen blockade in elderly men with disseminated prostate carcinoma results in high bone turnover with significant cancellous bone loss. The results of this study show that adjuvant therapy with intermittent cyclic etidronate may prevent these changes and decrease the risk of spinal fractures.

Absorptiometry, Photon↗