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At least 577 records · Page 32Linked to original sources
PubMed1987

[Augmentation, by naloxone, of the frequency and amplitude of LH-RH pulses in hypothalamo-hypophyseal portal blood in the castrated ram].

The effect of naloxone administration on the LH-RH secretion in hypophyseal portal blood and LH secretion in peripheral blood was studied in four short term castrated rams (between 2 to 4 days after castration). For two animals (A and B) given a single naloxone injection, an increase of LH-RH pulse amplitude was observed (A, 22.3 to 80.5 pg/ml and B, 22.5 to 34.5 pg/ml) with only a small (nonsignificant) increase in LH-RH pulse frequency. For animals C and D given four injections of naloxone, both LH-RH pulse amplitudes and LH-RH pulse frequency were increased. Means of LH-RH pulse amplitude increase from 29.3 to 65.1 pg/ml and from 34.6 to 50.8 pg/ml for animals C and D respectively and the number of LH-RH pulses detected during the 3 hrs. before and after the first injection of naloxone were respectively 3 vs. 5 and 3 vs. 7. Whereas all LH pulses were preceded with a LH-RH pulse in animals A and B, after the multiple naloxone injections in animals C and D, a rapid LH-RH pulse frequency was associated with a sustained increment of LH secretion in peripheral blood in such a way that individual LH pulses were not clearly defined. The present report is the first documentation on naloxone increasing the release of LH-RH secretion in hypophyseal portal blood of conscious, unrestrained, short-term castrated rams. The results indicate: (1) that the opiate antagonist naloxone is able to increase both the amplitude and the frequency of LH-RH discharge by the hypothalamus and (2), when the LH-RH pulse frequency exceeds one pulse every 30 min., discrete LH secretory episodes are not observed in peripheral blood.

Animals↗
PubMed1998

Skin resurfacing of facial rhytides and scars with the 90-microsecond short pulse CO2 laser. Comparison to the 900-microsecond dwell time CO2 lasers and clinical experience.

BACKGROUND: Carbon dioxide lasers that produce either short pulses or scanned continuous beams have been used for skin resurfacing to improve wrinkles or scars. Using a high peak power, short pulse CO2 laser can produce clinically effective results with minimal thermal damage. OBJECTIVE: To evaluate the effectiveness of skin resurfacing using the 90-microsecond pulse duration CO2 laser compared to other laser systems. Erythema, healing time, complications, and histological measurement of the depth of ablation and thermal damage per pass with this system were also assessed. METHODS: Forty-one patients with facial rhytides and scars underwent resurfacing with a 90 microseconds pulse duration CO2 laser. Using patient survey, patients were evaluated for effectiveness of therapy, healing time, and complication rates. Comparisons of histologic and clinical findings were made with different short pulse CO2 lasers. RESULTS: Healing time, duration of erythema, and post-operative pain were less with the 90 microseconds pulse CO2 laser than with the 900-microsecond dwell time and 950-microsecond pulse duration lasers, while effectiveness was comparable. Complications were few with the 90-microsecond pulse laser, including three patients (9.1%) developing hyperpigmentation. One pass with the 90-microsecond pulse duration CO2 laser produced 100 microns of ablation with 17 microns of thermal damage. Ablation and damage were additive so that, by six passes, ablation depth was 350 microns and depth of thermal damage was 63 microns. This thermal damage is less than that reported with lasers having a longer pulse duration or dwell time with comparable depths of vaporization. CONCLUSION: Treatment with the 90-microsecond pulse duration laser results in a more rapid healing time and shorter duration erythema. The clinical improvements in wrinkles and sun damage were comparable. The 90-microsecond pulse duration laser provides an effective, predictable, and safe means of improving facial rhytides and scars.

Adult↗
PubMed2006

Baseline wander correction in pulse waveforms using wavelet-based cascaded adaptive filter.

Pulse diagnosis is a convenient, inexpensive, painless, and non-invasive diagnosis method. Quantifying pulse diagnosis is to acquire and record pulse waveforms by a set of sensor firstly, and then analyze these pulse waveforms. However, respiration and artifact motion during pulse waveform acquisition can introduce baseline wander. It is necessary, therefore, to remove the pulse waveform's baseline wander in order to perform accurate pulse waveform analysis. This paper presents a wavelet-based cascaded adaptive filter (CAF) to remove the baseline wander of pulse waveform. To evaluate the level of baseline wander, we introduce a criterion: energy ratio (ER) of pulse waveform to its baseline wander. If the ER is more than a given threshold, the baseline wander can be removed only by cubic spline estimation; otherwise it must be filtered by, in sequence, discrete Meyer wavelet filter and the cubic spline estimation. Compared with traditional methods such as cubic spline estimation, morphology filter and Linear-phase finite impulse response (FIR) least-squares-error digital filter, the experimental results on 50 simulated and 500 real pulse signals demonstrate the power of CAF filter both in removing baseline wander and in preserving the diagnostic information of pulse waveforms. This CAF filter also can be used to remove the baseline wander of other physiological signals, such as ECG and so on.

Algorithms↗
PubMed1997

Relationship between ocular pulse pressures and retinal vessel velocities.

PURPOSE: The authors quantified the relationship between ocular pulse pressures and retinal vessel velocities. METHOD: The blood velocity in the ophthalmic artery (OA), the central retinal vein (CRV), and artery (CRA) was measured by pulsed Doppler sonography (4-Mhz probe). The pulse curve of the intraocular pressure (IOP) was evaluated by pneumotonometry. With multichannel data acquisition and storage software, the velocity pulse curve of the OA, the CRV and CRA, the IOP-pulse curve, the arterial blood pressure, and the electrocardiogram were recorded simultaneously in real-time mode. The relationships between the pulse curves of the blood velocity in the OA, the CRV and CRA, and the IOP were calculated off-line. The onset time, the time of half maximum, and the time to the maximum of the pulse curves were evaluated. A relative retinal venous outflow resistance index (R') was calculated by R' = deltaIOP/deltaVcrv. We examined 23 eyes of 23 healthy subjects. The mean age of the group was 46 +/- 16 years. RESULTS: In all eyes, the outflow in the CRV was pulsatile and ran in synchrony with the IOP pulsation. The CRV velocity- and IOP-pulse curve showed a significant mean delay of 0.024 second compared with the CRA and OA velocity-pulse curve. The relative resistance index R' for venous outflow was 1.0 +/- 0.44 mmHg/cm/seconds. CONCLUSION: In all eyes, the authors found a significant linear relationship between the blood velocity in the CRV and the IOP pulsation. The CRV velocity- and IOP-pulse curve were significantly delayed compared with the CRA and OA velocity-pulse curve.

Adult↗
PubMed2000

Favourable effects on arterial wave reflection and pulse pressure amplification of adding angiotensin II receptor blockade in resistant hypertension.

OBJECTIVE: Angiotensin-converting enzyme (ACE) inhibitors have beneficial effects on arterial compliance and distensibility and favourably modify the arterial pressure waveform in hypertensive patients. The objective of our study was to explore the possible effects of adding an ATII AT1 receptor antagonist to an ACE inhibitor on augmentation pressure, a measure of arterial stiffness, and pulse pressure amplification in patients with poorly controlled essential hypertension. DESIGN AND METHODS: We studied a group of 18 patients with poorly controlled hypertension, despite at least three antihypertensive drugs including an ACE inhibitor, before, at 2 h and 2 weeks following the administration of 80 mg of valsartan, an ATII AT1 receptor antagonist. Haemodynamic responses were measured by cuff sphygmomanometry, arterial pulse-wave analysis and the pulse pressure gradient was calculated as the difference between the brachial pulse pressure (cuff sphygmomanometry) and derived aortic pulse pressure (arterial pulse wave analysis). RESULTS: Blood pressure decreased significantly (P<0.001) and the effect was more pronounced on central (aortic) pulse pressure than peripheral (brachial) pulse pressure. The pulse pressure amplification increased significantly (from 8+/-3 at baseline vs 12+/-7 at 2 h to 14+/-5 mm Hg at 2 weeks, P<0.01) and the augmentation pressure decreased from a baseline value of 21+/-8 to 11+/-7 at 2 h and 10+/-5 at 2 weeks, (P<0.01) following valsartan. CONCLUSION: The results of our study show that in a group of poorly controlled hypertensives, combining an ATII AT1 receptor blocker to an ACE inhibitor induced a significant fall in blood pressure. The decrease in blood pressure was accompanied by a decrease in augmentation pressure in the ascending aorta with a greater decrease in the central pulse pressure than in the peripheral, favourably increasing pulse pressure amplification between central and peripheral arteries. This effect on arterial stiffness and amplification suggests that combined angiotensin II blockade by adding an AT1 receptor blocker to an ACE inhibitor may have more beneficial effects on the blood pressure curve than simple blood pressure reduction.

Aged↗
PubMedDate not supplied

Radial pulse character relationships to systolic blood pressure and trauma outcomes.

BACKGROUND: Patient measurements that do not require monitoring equipment may be the only way to evaluate casualties in austere conditions to determine treatment and transport priority. Objective. To test the hypothesis that palpable pulse characteristics in the radial artery would estimate systolic blood pressure (SBP) and predict outcome in trauma patients. METHODS: Data were analyzed from the medical records of 342 trauma patients ranging from 18 to 50 years of age. Prehospital data were collected by helicopter emergency medical personnel at the scene of the injury. Based on radial pulse character, patients were divided into normal (n = 313) and weak (n = 29) groups. Those whose medical records did not describe pulse characters were not considered. Differences in SBP, mortality, and medical interventions between the radial-pulse-character groups were evaluated. RESULTS: The SBP taken at the scene was a mean of 26 mm Hg lower in those patients with weak radial pulse characters (102 mm Hg versus 128 mm Hg). Similarly, the lowest mean SBPs recorded in the field between the normal- and weak-pulse-character groups were 112 mm Hg and 99 mm Hg, respectively. Patient mortality increased with weak pulse character such that the mortality rats were 3% for the normal-pulse-character group and 29% for the weak-pulse-character-group (odds ratio = 15.2). CONCLUSIONS: These preliminary data suggest that a weak radial pulse may be an acceptable method for initial rapid evaluation of trauma patients. This simple and rapid method of pulse evaluation should be considered for the triage of trauma patients in field conditions with limited instrumentation.

Adolescent↗
PubMed1993

Pulse pressure gradient along the aortic tree in normotensive Wistar-Kyoto and spontaneously hypertensive rats: effect of nicardipine.

BACKGROUND: In large animals pulse pressure increases from central to peripheral arteries whereas mean arterial pressure decreases slightly. This haemodynamic pattern has not been verified in small animals, particularly in hypertensive rats before and after administration of antihypertensive drugs. DESIGN: The intra-arterial blood pressure of normotensive Wistar-Kyoto (WKY) rats and spontaneously hypertensive rats (SHR) was determined along the aorta in anaesthetized and conscious rats. In anaesthetized rats the study was performed before and after acute intravenous nicardipine administration (30 micrograms/kg). RESULTS: Mean arterial pressure was significantly higher in untreated SHR than in WKY rats, and within each strain was quite similar along the aortic tree. Pulse pressure increased significantly from the central to the terminal aorta in WKY rats, principally due to an increase in systolic blood pressure. In SHR pulse pressure did not differ along the aortic tree. Compared with in WKY rats, aortic pulse pressure in SHR was significantly elevated whereas femoral pulse pressure was quite similar. Acute nicardipine administration re-established the pulse pressure gradient in SHR, due to a significant decrease in central aortic pulse pressure with no significant change in femoral pulse pressure. CONCLUSIONS: These results suggest, first, that since there are large differences in pulse pressure in the proximal aorta of SHR and WKY rats but only small or negligible differences in the distal aorta, the measurement of pulse pressure may be an available index to differentiate normotensive and hypertensive rats, and secondly, that increased aortic pulse pressure in SHR participates in the increase in cardiac afterload independently of mean arterial pressure, and may be a preferential site of action of antihypertensive agents.

Animals↗
PubMed2001

Changes in the derived central pressure waveform and pulse pressure in response to angiotensin II and noradrenaline in man.

Peripheral pulse pressure provides a surrogate measure of arterial stiffness. Analysis of the central pressure waveform allows assessment of central pulse pressure and arterial stiffness. The aim of the present study was to assess the effect of vasoconstrictor drugs on pulse pressure amplification and arterial stiffness in vivo. Eight healthy male subjects (mean age 30 years) received an infusion of angiotensin II (1, 3, 6 and 10 ng kg(-1) min(-1)), noradrenaline (10, 30, 60 and 100 ng kg(-1) min(-1)) and matching placebo, in random order, on separate occasions. Peripheral blood pressure and cardiac index were recorded non-invasively. Pulse wave analysis was used to determine augmentation index (AIx), which provides a measure of systemic arterial stiffness, aortic stiffness and central arterial pressure. Infusion of both active drugs resulted in a significant increase in peripheral mean arterial pressure (PMAP), peripheral vascular resistance, AIx, aortic stiffness and central pulse pressure, but only angiotensin II reduced cardiac index. Peripheral pulse pressure was unaffected by infusion of angiotensin II but increased with noradrenaline, which also produced a greater reduction in pulse pressure amplification than angiotensin II. However, the linear relationship of PMAP with both AIx and aortic stiffness did not differ significantly between drugs. These results demonstrate that intravenous infusion of angiotensin II and noradrenaline increase aortic and systemic arterial stiffness. Despite a similar effect on both parameters, for a given change in PMAP, the two drugs had divergent effects on peripheral pulse pressure and pulse pressure amplification. These data reveal that assessment of peripheral pulse pressure does not always reliably predict changes in central pulse pressure or arterial stiffness.

Adult↗
PubMed2002

The reliable measurement of radial pulse characteristics.

The use of the radial pulse as a diagnostic tool is an integral part of the Traditional Chinese Medicine (TCM) patient evaluation. In spite of its long history of use, there is little systematic information available to support the many claims about the relationship between pulse qualities and physiological condition contained in the ancient Chinese texts and echoed in modern pulse terminology. This study reports the development of a reliable means of measuring and recording pulse characteristics. This was achieved by reporting on the physical sensations that are detected under the fingertips when the radial pulse is palpated, rather than attempting to translate these into the complex and typically ambiguously defined TCM pulse qualities. The study involved development of a standardised pulse taking procedure and development of concrete operational definitions for each of the characteristics of the pulse being measured. The inter-rater reliability of the pulse taking procedure and operational definitions was assessed by determining agreement levels between two independent pulse assessors for each characteristic. Inter-rater agreement averaged 80% between the two assessors in both the initial data collection (66 subjects) and in a replication collection (30 subjects) completed two months later. Demonstrating reliability of the procedure represents an essential first step for examining the validity of TCM pulse diagnosis assumptions.

Adult↗
PubMed1994

Presenting pulse pressure predicts thrombolytic therapy-related intracranial hemorrhage. Thrombolytic Predictive Instrument (TPI) Project results.

BACKGROUND: In selecting patients with acute myocardial infarction for thrombolytic therapy, it is important to identify patients who are at high risk for intracranial hemorrhage, for whom thrombolytic therapy is ill advised. We hypothesized that presenting pulse blood pressure, representing the "hammer" effect on cerebral vessels and the effects of age on arterial compliance, might predict thrombolysis-related intracranial hemorrhage better than systolic, diastolic, or mean arterial blood pressures. METHODS AND RESULTS: Of 3483 Thrombolytic Predictive Instrument (TPI) Project subjects receiving thrombolytic therapy for acute infarction, we identified and obtained detailed clinical data on the 19 with treatment-related intracranial hemorrhages confirmed by computed tomography and on 175 matched controls. Systolic, diastolic, mean arterial, and pulse blood pressures were each significantly related to the occurrence of intracranial hemorrhage, with pulse pressure most highly related. The mean pulse pressure in patients who developed intracranial hemorrhage was 63 mm Hg, 34% higher than the 47 mm Hg mean value for those not developing hemorrhage (P = .0001). Excess pulse pressure, defined as the extent to which a patient's pulse pressure exceeded 40 mm Hg for systolic blood pressures of at least 120 mm Hg, was even more strongly related: its mean value of 23 mm Hg for patients was 130% higher than its mean value of 10 mm Hg for controls (P < .0001). With logistic regression models to estimate the relative risks (odds ratios) for intracranial hemorrhage conferred by each form of blood pressure, the relative risk for hemorrhage was greatest for excess pulse pressure: for each 10-point pulse pressure excess, the relative risk for intracranial hemorrhage was increased by 1.85 (P = .0002; 95% confidence interval [CI], 1.34 to 2.55) by itself and 1.76 (P = .001; 95% CI, 1.26 to 2.46) when adjusted for age. In this sample, excess pulse pressure by itself predicted hemorrhage as well as systolic pressure and age together. When excess pulse pressure was combined with age to make a logistic regression model predicting intracranial hemorrhage, age contributed less to the prediction than when combined with the other blood pressure forms, even though this model predicted better than any other combination of age and pressure (receiver-operating characteristic curve area, 0.82 versus 0.77 with systolic pressure and age, 0.75 with mean arterial pressure, 0.71 with diastolic pressure, and 0.81 with both systolic and diastolic pressures). CONCLUSIONS: We found that excess pulse blood pressure predicted thrombolysis-related intracranial hemorrhage better than other forms of pretreatment blood pressure, perhaps better describing the pathophysiology of intracranial hemorrhage, including the effect of age. These findings will need confirmation in larger studies with comparable clinical detail.

Aged↗
PubMed1999

Isolated systolic hypertension : prognostic information provided by pulse pressure.

Increased arterial stiffness results in increased characteristic impedance of the aorta and increased pulse wave velocity, which increases systolic and pulse pressures. An association between increased pulse pressure and adverse cardiovascular events has been found in normotensive and hypertensive patient populations. Increased pulse pressure has also been associated with thickening of the carotid intima and media. However, the relationship between pulse pressure and stroke has not previously been evaluated. In this study, we examined the hypothesis that pulse pressure is an independent predictor of stroke in elderly patients with systolic hypertension entered in the Systolic Hypertension in the Elderly Program. Differences in baseline characteristics were examined by tertiles of pulse pressure. The independent prognostic value of pulse pressure and mean arterial pressure for predicting either stroke or total mortality was assessed with Cox proportional hazards models that included pulse pressure, mean arterial pressure, and other variables that were significant on univariate analysis. This analysis demonstrated an 11% increase in stroke risk and a 16% increase in risk of all-cause mortality for each 10-mm Hg increase in pulse pressure. Each 10-mm Hg increase in mean arterial pressure was independently associated with a 20% increase in the risk of stroke and a 14% increase in the risk of all-cause mortality. These data provide strong evidence of an association of increased conduit vessel stiffness, as indicated by increased pulse pressure, with stroke and total mortality, independent of the effects of mean arterial pressure, in elderly patients with isolated systolic hypertension.

Aged↗
PubMed2005

Effect of high dose methylprednisolone pulse therapy followed by oral prednisolone administration on the production of anti-TSH receptor antibodies and clinical outcome in Graves' disease.

Little is known about the immunosuppressive effect of glucocorticoids on TSH receptor antibodies. We observed the long-term prognosis and serum TSH binding inhibitor immunoglobulin (TBII) levels in patients with Graves' ophthalmopathy who had received intravenous methylprednisolone pulse therapy (pulse therapy) followed by oral prednisolone administration in order to ascertain how long the immunosuppressive effect of glucocorticoids continued. This is the first report on the effect of pulse therapy on Graves' disease outcome. We observed 67 patients who were treated by antithyroid drugs (ATD) alone for 2 years after pulse therapy. TBII was evaluated before and 3, 6, 12, 18, and 24 months after pulse therapy. The mean TBII decreased significantly 3 months after pulse therapy (p<0.001), and was maintained until 24 months. There were 24 patients whose TBII was positive (>15%) at 24 months, in whom the mean TBII decreased significantly 3 to 6 months after pulse therapy (p<0.001), but increased again at 12 to 24 months (p<0.05). Thus, the immunosuppressive effect of glucocorticoids may be lost at 12 months after pulse therapy in these patients. The remission rate in the pulse therapy group was 40.98%, and that of the control patient group was 48.57%. There was no significant difference between the two. These results suggest that the immunosuppressive effect of pulse therapy was temporary, and that pulse therapy did not increase remission rate of Graves' disease.

Administration, Oral↗
PubMed2004

[Different left ventricular geometric patterns and ambulatory pulse pressures in essential hypertensive patients].

OBJECTIVE: To explore the relationship between different left ventricular geometric patterns and ambulatory pulse pressures in essential hypertension patients. METHODS: Left ventricular geometric patterns were identified according to the results of left ventricular mass index and relative left ventricular thickness assessed by echocardiography in 130 hypertension patients. The average levels of 24-hour pulse pressure, daytime pulse pressure, and nighttime pulse pressure were analyzed by ambulatory blood pressure monitoring. The method of multiple stepwise regression analysis was applied to identify the independent determinants of ambulatory pulse pressures. After controlling or adjusting the effects of agr and the 24-hour mean arterial pressure, the average levels of 24-hour, daytime, and nighttime pulse pressure among different left ventricular geometric patterns were compared. Forty normotensive subjects served as controls. RESULTS: The age and the level of 24-hour mean arterial pressure were the independent determinants of 24-hour, daytime, and nighttime pulse pressure. After adjusting the effects of age and 24-hour mean arterial pressure, the average levels of 24-hour pulse pressure and daytime pulse pressure in concentric remodeling, concentric hypertrophy, and eccentric hypertrophy pattern groups were higher than those in the control group and normal geometric pattern group, whereas there were not significant differences among different left ventricular remodeling patterns at the average levels of 24-hour, daytime, and nighttime pulse pressure. CONCLUSION: Pulse pressure is an important risk factor in the development of cardiac remodeling in essential hypertension.

Adult↗
PubMed1996

Assessment of noninvasive lower extremity arterial testing versus pulse exam.

Palpation of pedal pulses was compared to noninvasive testing in 100 patients referred to a vascular laboratory. Subjects were 65 +/- 13 (mean +/- s.d.) years old. The right dorsalis pedis (DP) artery served as the reference artery for comparison of Doppler studies with physical examination of the pulses. Absolute Doppler pressures in the right DP were 129 +/- 50 mm Hg. The right ankle:brachial index (ABI) was 0.86 +/- 0.32. There were significant differences in ABI in those with (0.68 +/- 0.28) vs without (0.95 +/- 0.31) claudication in either extremity (p < 0.001). Rest pain was also associated with lower ABI (P < 0.04). Diabetics, hypertensives, claudicants and those with ischemic rest pain were less likely to have palpable pulses (P < 0.035). With right DP pressure >/= 118 mm Hg, 63 per cent of subjects had a palpable DP pulse, whereas 68 per cent with ABI > 0.82 had a palpable right DP. Of those (n = 35) with a right DP pressure < 118 mm Hg, only 6 per cent (n = 2) had a palpable pulse, whereas 5 per cent (2/40) with ABI </= 0.82 had palpable DP pulses. Based on these findings, it was predicted that a pulse would likely not be palpable in the left DP with a pressure < 118 mm Hg or with AB </= 0.82. The prediction based on systolic ankle pressures was correct, with 66 per cent sensitivity and 91 per cent specificity. The predication that a left DP pulse would not be palpable with AB </= 0.82 was more accurate (78% sensitive, 97% specific). Presence of a palpable DP pulse suggests the presence of a Doppler pressure >/= 188 mm Hg and ABI > 0.82. The range of ankle pressures with palpable right DP pulses was 64-220 mm Hg, whereas the range with nonpalpable DP was 42-300 mm Hg. Given the frequent disparity of pulse exam and ankle pressures, noninvasive Doppler testing may be necessary for many patients to accurately assess the vascular status of the leg.

Adult↗
PubMed1995

Influence of applied brachial recording forces on pulse wave velocity and transmission in the brachio-radial arterial segment.

Arterial stiffness in hypertension and heart failure may increase afterload on the left ventricle. Pulse wave velocity and transmission ratio measurements are noninvasive methods to assess arterial stiffness. Since noninvasive pressure pulse recording requires sufficient applied force to distort the vessel wall, we hypothesized that the pulse wave velocity, transmission ratios, and distal pulse amplitudes and contours may be altered by the recording technique. Brachial and radial arterial pressure pulses were recorded simultaneously using a piezoelectric pulse transducer in 14 young, normal, male subjects using 10 brachial artery recording forces (0.35-3.58N, approximately equal to 0.36N increments) applied in a random order and a constant radial force (2.35N). Pulses were Fourier analyzed. One subject was excluded from analysis because of improper transducer positioning over the brachial artery. In 8 subjects, no significant changes occurred in any variable over all brachial recording forces. In the remaining 5 subjects, the measured variables remained constant until brachial artery recording forces exceeded 2.42 +/- 0.03N. The pulse wave velocity (p < 0.04), transmission ratios (harmonics 2-5, p < 0.0001), radial pulse amplitude (p < 0.0003), and relative powers (harmonics 2-5, p < 0.02) then decreased. In these subjects, brachial artery depths were less than the other subjects (5.9 +/- 0.4 vs. 7.7 +/- 0.4 mm, p < 0.05). The brachial and radial artery recording forces normally used during clinical measurements by 2 investigators were 1.43 +/- 0.01N (95% confidence intervals (CI) = 1.23N, 1.62N) and 1.88 +/- 0.11N (95% CI = 1.65N, 2.10N), respectively. Therefore, at forces normally used by clinical investigators, the pulse wave velocity, harmonic transmission ratios, and pulse amplitudes and contours obtained at the brachial and radial artery are not significantly influenced by forces applied at the brachial artery. However, these variables may be decreased in subjects with more superficial arteries when higher recording forces are used.

Adult↗
PubMed1996

Pulse wave analysis.

PULSE WAVE ANALYSIS IN HISTORICAL TIMES: Interpretation of the arterial pulse has been an important part of the medical examination from ancient times. Graphic methods for clinical pulse wave recording were introduced by Marey in Paris and by Mahomed in London last century. Mahomed showed how such recordings could be used to detect asymptomatic hypertension, and used them to chart the natural history of essential hypertension and to distinguish between this condition and chronic nephritis. Interest in arterial pulse analysis, as applied by Mahomed, lapsed with the introduction of the cuff sphygmomanometer 100 years ago. MODERN PULSE WAVE ANALYSIS: Analysis of the arterial pulse is now regaining favour as limitations of the cuff sphygmomanometer are better recognized (including the ability only to measure extremes of the pulse in the brachial artery). In addition, high-fidelity tonometers have been introduced for very accurate, non-invasive measurement of arterial pulse contour, and there is now a better understanding of arterial hemodynamics, and appreciation of disease and aging effects in humans. It is now possible to record the pulse wave accurately in the radial or carotid artery, to synthesize the ascending aortic pulse waveform, to identify systolic and diastolic periods and to generate indices of ventricular-vascular interaction previously only possible with invasive arterial catheterization. Pressure pulse wave analysis now permits more accurate diagnosis and more logical therapy than was ever possible in the past.

Aging↗
PubMed1990

Laser sclerostomy by pulsed-dye laser and goniolens.

We describe an ab-interno laser sclerostomy procedure using the method termed dye-enhanced ablation with a slit-lamp delivery system and special goniolens such that only the laser light beam penetrates the anterior chamber. The procedure uses a microsecond-pulsed-dye laser emitting at 666 nm and iontophoresis of methylene blue dye (absorption of 668 nm) into the sclera at the limbus to enhance the absorption of the laser light. We compared the number of pulses needed to perforate excised human sclera at pulse durations of 1.5, 20, and 300 microseconds. Pulse durations of 1.5 and 20 microseconds required 20 pulses or fewer to perforate excised human sclera with pulse energies of 75 to 100 mJ. The ab-interno laser sclerostomy procedure was performed in 54 eyes of Dutch-belted rabbits with pulse durations of 1.5 or 20 microseconds and a 100- or 200-microns incident spot diameter delivered using a CGF goniolens. Full-thickness fistulas were successfully created at both pulse durations in approximately 80% of eyes treated. A range of three to 25 pulses was required to perforate sclera with slightly fewer pulses and lower pulse energies at 1.5 microseconds compared with 20 microseconds. There were no significant complications from the procedure. This technique could permit filtration surgery to be performed on an outpatient basis.

Animals↗
PubMed2000

Design of improved spectral-spatial pulses for routine clinical use.

Spectral-spatial pulses (spsp pulses) selectively excite spins at spatial location z and spectral frequency (due to chemical shift and/or field inhomogeneity) v. In this work we discuss the design of improved spsp pulses for fat signal suppression. Optimal pulses are designed as optimal constant ripple FIR filters using the inverse SLR transform. Spsp pulses with thin slices are obtained by modifying the phases between subpulses, thereby eliminating unwanted magnetization lobes. Robust spsp pulses at off-center slices are obtained with a prescan calibration. These pulses are used either for selective fat saturation or for selective water excitation. It is shown that spsp pulses suppress fat signal better than conventional fat saturation pulses. Using the techniques presented in this article, we replaced all the fat saturation pulses on our systems with spsp pulses and obtained a significant improvement in image quality.

Adipose Tissue↗