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Biomedical subjects

N D Pugh

Publications and source records attributed to N D Pugh.

At least 19 recordsLinked to original sources
PubMed2006

Power Doppler in the assessment of pelvic masses in a low risk group.

Discrimination between benign and malignant adnexal masses aids in optimising the management of women with pelvic tumours. A grading system incorporating grey-scale and power Doppler measurements might increase the accuracy of pre-operative assessment. The present study aimed to assess the sensitivity and specificity of a grading system including grey-scale and power Doppler findings. A total of 179 women who had undergone power Doppler Ultrasound for a pelvic mass between April 2001 and March 2003 were identified. Masses were surveyed by grey-scale and power Doppler and graded in relation to the estimated risk of malignancy. Clinicians were provided with the findings. The results were compared with the findings at surgery. A total of 74.3% were premenopausal. Some 94.4% (n = 169) had benign; 1.7% borderline and 3.9% malignant histology. A total of 69% underwent surgery. Specificity was 72.2 - 95.9%; sensitivity 55.6 - 88.9% and negative predictive value 97.6 - 99.2%. Power Doppler as an additional diagnostic aid may help the clinician in the management of pelvic masses. Further research is needed to clarify sensitivity and specificity.

Adolescent↗
PubMed2005

Development and validation of an in vivo analysis tool to identify changes in carotid plaque tissue types in serial 3-D ultrasound scans.

We have developed a three-dimensional (3-D) B-mode acquisition system suitable for imaging carotid plaques in vivo. A texture classification system using 157 statistical and textural algorithms, previously developed in our laboratory and shown to predict the contents of in vitro carotid plaques, was applied to in vivo 3-D image sets obtained from patients with both symptomatic and asymptomatic carotid artery plaques. Delineation of plaque boundaries is more difficult using in vivo images than in vitro images of excised plaques embedded in agar. This study has examined inter- and intraobserver variability studies to assess the degree of selectivity of the plaque region-of-interest (ROI) and assess the degree of repeatability for potential use in comparing serial scans. An interobserver limit of agreement of +/-12.9% and an intraobserver limit of repeatability of <2% were obtained. These results show that the plaque ROI selection is subjective, but is repeatable within acceptable limits.

Carotid Arteries↗
PubMed2003

Post-sternotomy internal mammary arteriovenous fistula.

Arteriovenous fistula from the mammary artery is a rare complication following cardiac surgery. The fistula usually develops within the first 2 weeks after surgery and is initially asymptomatic. Typically, a continuous machinery murmur is heard along the parasternal border of the chest wall. A patient with an arteriovenous fistula between the right internal mammary artery and mammary vein following a combined aortic valve and coronary bypass operation is described. A transthoracic colour Doppler scan led to the diagnosis of the fistula. Because of potential late complications endovascular embolisation of the fistula was successfully performed.

Aged↗
PubMed2001

The effect of head rotation on the diameter of the internal jugular vein: implications for free tissue transfer.

PURPOSE: To determine the effects of medial (inwards) and lateral (outwards) rotation of the head on the transverse diameter of the internal jugular vein. MATERIAL: The original study sample included 26 patients. Duplex ultrasound was used to measure the transverse diameter of the internal jugular vein at a fixed point on either side of the neck. Measurements were taken with the head central (neutral position), rotated laterally and medially. RESULTS: Using Student's t-test we found that lateral rotation of the head produced a reduction in the mean of the transverse diameters of the left and right ipsilateral vein from 6.9 mm to 5.4 mm (p < 0.03) and 5.9 mm to 5.0 mm (p = 0.2173) respectively. One patient excluded from the study because of previous neck surgery showed complete occlusion of the ipsilateral internal jugular vein on lateral rotation of the head. CONCLUSION: There is a possibility that patency of the vein could be compromised if the head is turned laterally. This situation may arise immediately after surgery in the ventilated and paralysed patient when the head may be unsupported. It could be of particular importance if the vein has been used as a recipient vein for free tissue transfer.

Adult↗
PubMed2001

The potential effect of controlled ovarian hyperstimulation on follicular vascular perfusion: a study applying power Doppler ultrasonography within a treatment programme using donor sperm.

This was a prospective observational study to evaluate the effect of controlled ovarian hyperstimulation on follicular vascularity. A subjective grading system was applied to assess vascularity using transvaginal power Doppler ultrasonography on the day of insemination (32-36 hours post-HCG administration) in donor treatment cycles undergoing either controlled ovarian hyperstimulation (COH group) with gonadotrophin and intrauterine insemination or intracervical insemination with/without clomiphene stimulation (non-COH group). The incidence of follicles (81% vs. 53%; P < 0.05) as well as cycles (63% vs. 49%; P < 0.05) with uniformly high grade vascularity was significantly higher in treatments that had controlled ovarian hyperstimulation compared with unstimulated or clomiphene induced donor cycles. Pregnancy rates were higher and early pregnancy loss rates lower, in cycles with uniformly high grade follicular vascularity in both treatment groups compared with other vascularity grades. Using multiple logistic regression analysis, the only independent variable that was significantly related to pregnancy rates in this treatment programme was follicular vascularity. Controlled ovarian hyperstimulation appears to have an effect on follicular vascularity and this may contribute to improved outcome in donor insemination treatment programmes.

Journal Article↗
PubMed2001

Perifollicular vascularity as a potential variable affecting outcome in stimulated intrauterine insemination treatment cycles: a study using transvaginal power Doppler.

BACKGROUND: The aim of the present study was to assess any potential relationship between perifollicular vascularity and outcome in an in-vivo environment following human chorionic gonadotrophin (HCG) administration. METHODS: A total of 182 unselected consecutive patients undergoing stimulated intrauterine insemination (IUI) cycles was recruited where the perifollicular vascularity of follicles > or =16 mm was studied using a subjective grading system and transvaginal power Doppler ultrasonography, 36 h after HCG administration. RESULTS: A total of 601 follicles was studied. The incidence of follicles showing high-grade perifollicular vascularity (3 and 4) was higher than those with low-grade vascularity (1 and 2) (80 versus 20%). Treatment cycles were divided according to uniformity of vascularity grades of follicles > or =16 mm on the day of IUI [55% all high (3/4) grade; 33% mixed (1/2 and 3/4) and 12% all low (1/2) grade]. The mean age and duration of subfertility were significantly higher (P < 0.05), whereas the number of follicles > or =16 mm pre/post HCG, serum oestradiol and incidence of ultrashort gonadotrophin-releasing hormone (GnRH) agonist use were all significantly lower (P < 0.05) in treatment cycles with uniformly low follicular vascularity grades compared with mixed or uniformly high-grade cycles. However, on subjecting the data to multiple logistic regression analysis, the only independent variables that affected pregnancy rates appeared to be serum oestradiol (OR 1.28, 1.01--1.62) and high-grade follicular vascularity (OR 2.41, 1.08--5.40). CONCLUSION: These data would suggest that perifollicular vascularity has an important role to play in the outcome of IUI cycles, and that power Doppler has the potential to refine the management of assisted reproduction treatment cycles.

Adult↗
PubMed1999

The use of transvaginal power Doppler ultrasonography to evaluate the relationship between perifollicular vascularity and outcome in in-vitro fertilization treatment cycles.

The aim of this prospective study of the use of transvaginal power Doppler ultrasound was to assess the subjectivity of the grading system and to elucidate, on a much larger series (200) of treatment cycles, the findings of previous authors. Vascular perfusion was studied using a grading system based on the percentage of follicular circumference (grade 1 < 25%, grade 2 < 50%, grade 3 < 75% and grade 4 > 75%) that depicted an echo signal. Interobserver variation was low (k = 0.81 + 0.08). A total of 1285 follicles were studied, of which 64% were of high (grades 3 or 4) and 36% were of low (grades 1 or 2) grade vascularity. Mean follicular diameter, oocyte retrieval rate, number of mature oocytes recovered and fertilization rates were all significantly higher (P < 0.05) and triploidy rate significantly lower (P < 0.05) from the cohort of follicles with high grade vascularity. There was no correlation between embryo morphology and vascularity grade. The pregnancy rate for cycles where the embryos transferred were derived from follicles with uniformly high grade (3 or 4 only) vascularity was significantly higher than for those cycles where the embryos transferred were derived from mixed (1 to 4) or low (1 or 2 only) grade follicles [24/72 (34.7%) versus 22/122 (18%); P < 0.05]. There were no significant differences in uterine artery or intraovarian pulsatility index values between the pregnant and non-pregnant treatment cycles. This study suggests that follicles with high grade vascularity are associated with better outcome variables. Thus, follicular assessment may be used prospectively to improve the outcome in in-vitro fertilization treatment cycles.

Female↗
PubMed1998

The haemodynamic effects of iodinated water soluble radiographic contrast media: a review.

All classes of iodinated water-soluble radiographic contrast media (RCM) are vasoactive with the iso-osmolar dimers inducing the least changes in the vascular tone. The mechanisms responsible for RCM-induced changes in the vascular tone are not fully understood and could be multifactorial. A direct effect on the vascular smooth muscle cells causing alterations in the ion exchanges across the cell membrane is thought to be an important factor in RCM-induced vasodilatation. The release of the endogenous vasoactive mediators adenosine and endothelin may also play a crucial role in the haemodynamic effects of RCM particularly in the kidney. In addition, the effects of RCM on blood rheology can cause a reduction in the blood flow in the microcirculation. The purpose of this review is to discuss the pathophysiology of the haemodynamic effects of RCM and to offer some insight into the biology of the endothelium and vascular smooth muscle cells as well as the pharmacology of the important vasoactive mediators endothelin and adenosine.

Adenosine↗
PubMed1998

Power Doppler in breast tumours: a comparison with conventional colour Doppler imaging.

OBJECTIVE: Tumour vascularity can be assessed in-vivo using Doppler ultrasound. The purpose of this study was to determine whether Power Doppler imaging (PDI) better differentiates benign from malignant breast masses than conventional colour doppler imaging (CDI) on the basis of assessment of tumour vascularity. METHODS: One-hundred women with solid breast lumps (51 malignant lesions, 49 benign lesions) were investigated using a Toshiba SSA-270A ultrasound machine with a 5.0 MHz (3.75 MHz Doppler reference frequency) or a 7. 5 MHz (5.0 MHz Doppler reference frequency) linear array probe. The vascularity within or at the periphery of the mass was subjectively assessed from the CDI and Power Doppler images by two independent observers. It was assumed that the absence of vascularity indicated benignity and the presence of flow malignancy. RESULTS: CDI showed sensitivities of 62 and 42% and specificities of 62 and 62% using the 5 and 7.5 MHz probes respectively. PDI showed sensitivities of 76 and 51% and specificities of 56 and 48% using the 5 and 7.5 MHz probes respectively. A comparison of images of the 59 lesions investigated with both probes on both CDI and PDI concluded that the 5 MHz (3.75 MHz DRF) probe displayed equal vascularity to the 7.5 MHz (5.0 MHz DRF) probe in 76% of cases and greater vascularity in 24% of cases on CDI, and 68 and 31% of cases respectively on PDI. CONCLUSION: Power Doppler imaging with a 5 MHz (3.75 MHz DRF) probe increases the sensitivity of Doppler ultrasound to malignant breast tumours but the sensitivity achieved is not high enough to propose it as a screening investigation.

Adult↗
PubMed1997

Follicular vascularity--the predictive value of transvaginal power Doppler ultrasonography in an in-vitro fertilization programme: a preliminary study.

The aim of this prospective study was to investigate the ability of transvaginal power Doppler ultrasonography to assess the relationship between follicular vascularity and outcome in women undergoing in-vitro fertilization. Each of 38 subjects underwent a single transvaginal power Doppler ultrasound scan on the day of oocyte collection, where the vascularity of individual ovarian follicles was assessed, using a subjective system, and graded 1 to 4. In addition, conventional pulsatility indices (PI) of the uterine and intra-ovarian (stromal) arteries were calculated, which showed no significant differences between the pregnant and non-pregnant groups. Using power Doppler ultrasonography, a total of 188 follicles was studied. The follicular vascularity grade was found to be independent of follicular size and there was no significant difference in fertilization rates with different degrees of vascularity, although there was a trend towards higher fertilization rates with higher grade vascularity. There were 10 pregnancies, giving a pregnancy rate of 26.3% per embryo transfer. Pregnancies were confined to those women whose embryos were derived from follicles with grade 3 and 4 vascularity (pregnancy rates per embryo transfer of 12.5 and 61.5% respectively), with only those from grade 4 follicles resulting in livebirths. This preliminary study suggested that high grade follicular vascularity is associated with increased pregnancy rate and that there is a possible link between follicular vascularity and implantation potential.

Adult↗
PubMed1997

Dynamic obstruction of the external iliac artery in endurance athletes and its relationship to endothelial function: the case of a long distance runner.

There have been recent reports of exercise induced claudication in endurance trained athletes attributed to narrowing of the external iliac artery. Most patients have been competitive cyclists, and intimal hyperplasia has been cited as the cause. The case is reported here of a long distance runner who presented with similar symptoms.

Adult↗
PubMed1996

Haemodynamic and rheological effects of contrast media: the role of viscosity and osmolality.

All currently available iodinated contrast media (CM) produce some form of haemodynamic or rheological change when injected. These effects are thought to be due primarily to the osmolality and viscosity of the CM. The new hexa-iodinated contrast agent Visipaque has the advantage of being iso-osmotic with blood at all clinically relevant concentrations, but is more viscous than the monomers at equivalent iodine concentrations. The purpose of this review is to discuss the relative importance of osmolality and viscosity in the clinical situation.

Animals↗
PubMed1996

Duplication of the superficial femoral vein: recognition with duplex ultrasonography.

Duplication of the superficial femoral vein (SFV) is a normal variant seen in 20% of contrast phlebograms. Failure to identify thrombus in one limb of a SFV may lead to inappropriate management and subsequent complications. Colour Doppler imaging (CDI) is now the imaging technique of choice in the diagnosis of a deep vein thrombosis (DVT). The purpose of this study was to identify the prevalence of duplication of the SFV at CDI and to compare this with the known prevalence at contrast phlebography. CDI was performed on 58 healthy volunteers (116 limbs examined). Duplication of the SFV was present in 29 examinations (25%). Ultrasonic measurement of the diameter of the SFV was performed in all patients. In the presence of duplication a significant reduction in the diameter of both limbs of the SFV was noted when compared with an unduplicated vessel. The prevalence of duplication of the SFV at CDI is comparable to that at contrast phlebography. Recognition of this variant may help reduce false negative CDI examinations.

Adult↗
PubMed1995

Carotid artery duplex scanning: does plaque echogenicity correlate with patient symptoms?

In this study we have investigated the relationship between plaque sonolucency and ipsilateral hemispheric symptoms in 116 patients at risk of cerebrovascular disease (75 symptomatic patients, 41 asymptomatic patients). Our results indicate that plaque sonolucency is significantly associated with the incidence of patient symptoms at presentation. Twice as many symptomatic vessels contained the predominantly sonolucent plaque types (types 1 and 2) compared to contralateral asymptomatic vessels (p = 0.039, odds ratio = 2.9). Vessel stenosis also had a significant association with patient symptoms. No significant interaction was shown between vessel stenosis and plaque sonolucency (p = 0.15, odds ratio = 1.0). A model using vessel stenosis and plaque echogenicity as independent variables showed that degree of vessel stenosis had a closer association with incidence of symptoms (p = 0.03, odds ratio = 1.04) than plaque type (p = 0.13, odds ratio = 0.51).

Aged↗
PubMed1995

Stress reduction and preventing hypertension: preliminary support for a psychoneuroendocrine mechanism.

Our objective was to identify endocrine-related mechanisms capable of mediating preventive effects of stress reduction in hypertensive heart disease. Since beneficial effects of stress reduction accrue over time, this cross-sectional, descriptive study sought differences between healthy students not practicing a systematic technique for reducing stress (the average stress, or AS, group, n = 33) and a similar group who for 8.5 years had practiced the Transcendental Meditation (TM) technique, used widely to reduce stress (the low stress, or LS, group, n = 22). The two groups of students, matched for age and area of study, performed timed collections of urine that included (separately) the entire waking and sleeping portions of 1 day. They also completed the Profile of Mood States and the State-Trait Anxiety Inventory, self-report instruments sensitive to subjective level of stress. Urine samples were analyzed for adrenocortical steroids by radioimmunoassay, for Na+, K+, Mg2+, Ca2+, and Zn2+ by atomic absorption spectrometry, and for neurotransmitter metabolites by reverse-phase, high-performance, liquid chromatography, and spectrophotometry. The two groups differed significantly on most measures. Specifically, the LS group was lower in cortisol and aldosterone and higher in dehydroepiandrosterone sulfate (DS) and the serotonin metabolite, 5-hydroxyindoleacetic acid (5-HIAA). Excretion of sodium, calcium, zinc, and the norepinephrine metabolite, vanillylmandelic acid (VMA), was also lower in this group, as were Na+/K+ ratio, mood disturbance, and anxiety. In women practicing TM, cortisol correlated inversely and DS directly with number of months of TM practice. The results identify improvements in mood state, adrenocortical activity, and kidney function as probable factors in the preventive and treatment effects of stress reduction. Because suboptimal levels of these parameters result from chronic, subjective stress, the findings add mechanistic support to the contention that hypertensive heart disease is avoidable, even in modern industrialized societies.

Adrenal Cortex Hormones↗
PubMed1995

Effects of iodinated contrast media on peripheral blood flow.

All types of clinically employed iodinated roentgen contrast media (CM) cause vasodilatation after i.a. and i.v. administration, regardless of precise molecular structure. It is now apparent, however, that at iodine concentrations which provide equivalent angiographic contrast, this is significantly less with newer hexa-iodinated dimers, such as iodixanol and iotrolan, than older generations of compounds. The cellular mechanisms that underly the vasodilator effects of CM still remain to be fully elucidated but may include a) effects attributable to hyperosmolality; b) stimulation of the release of endogenous vasoactive mediators; and c) direct relaxant effects upon vascular smooth muscle. This review will discuss the possible contributions of these mechanisms to the vasodilatation observed in the clinical situation.

Animals↗
PubMed1995

Angiographic contrast media relax isolated rabbit aorta through an endothelium-independent mechanism that may not depend on the presence of the iodine atom.

Systemically administered iodinated angiographic contrast media evoke vasodilatation through mechanisms that are at present poorly understood. In the current investigation we have evaluated the role of the vascular endothelium in responses to an iso-osmolar formation of the non-ionic dimer iodixanol and a hyperosmolar formulation of the non-ionic monomer iopromide. Isolated rabbit aortic ring preparations with endothelium intact or removed by gentle abrasion were mounted in organ baths containing oxygenated Holman's solution, and cumulative concentration-response curves for relaxation to the contrast media were constructed after pre-constriction by phenylephrine (300 nM) in the presence of indomethacin to inhibit prostaglandin synthesis. Endothelial denudation did not influence the ability of either iodixanol or iopromide to relax the aortic ring preparations. Iopromide was significantly more potent than iodixanol when expressed in terms of iodine concentration (mg I ml-1), but both agents were equipotent when expressed in terms of molarity (mM). We conclude that relaxation of isolated rabbit aortic rings to iodixanol and iopromide under conditions where there is no fluid flow is endothelium-independent, and therefore not mediated by release of the potent endogeneous nitrovasodilator endothelium-derived relaxing factor (EDRF). Furthermore, their relaxant activity under the in vitro experimental conditions employed is attributable to a direct action on vascular smooth muscle by factors in addition to osmolality, and may depend on features that are not specifically associated with the presence of the iodine atom.

Angiography↗