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Biomedical subjects

G Germano

Publications and source records attributed to G Germano.

At least 37 records · Page 2Linked to original sources
PubMed2000

The distribution and colocalisation of nicotinamide adenine dinucleotide phosphate reduced-diaphorase (NADPH-d)-/nitric oxide synthase (NOS)-containing neurons in the innervation of the duck ureter.

ensp;The distribution and colocalisation of nicotinamide adenine dinucleotide phosphate reduced-diaphorase (NADPH-d)-/nitric oxide synthase (NOS)-containing (nitrergic) neurons in the innervation of the duck ureter have been studied using histochemistry and immunohistochemistry. Quantitative analysis showed that nitrergic neurons made up 60% and 70% of the total intramural and adventitial neuronal populations, respectively. About 40% of intramural nitrergic neurons expressed VIP-immunoreactivity, and about 75% of nitrergic adventitial neurons expressed TH-immunoreactivity. The density of nitrergic adventitial neurons was significantly greater in the lower tract than in the upper and intermediate tracts. Nerve lesioning experiments showed that the majority of ureteral nitrergic innervation was extrinsic in origin; nitrergic adventitial neurons primarily projected caudocranially, whereas NOS-immunoreactive and NOS-/VIP-immunoreactive intramural neurons primarily projected craniocaudally. These findings suggest that, in birds, the nitrergic innervation plays a role in ureteral functions such as epithelial mucosecretion, muscular motility, and the closing and/or opening of the ureteral papilla.

Animals↗
PubMed2000

Good correlation between gated single photon emission computed myocardial tomography and contrast ventriculography in the assessment of global and regional left ventricular function.

PURPOSE: The purpose of this study was to determine the reliability of the measured left ventricular ejection fraction (LVEF) and wall motion analysis by the recently introduced quantitative electrocardiographically (ECG)-gated myocardial perfusion single-photon emission computed myocardial tomography technique (gated SPECT) (QGS). MATERIALS AND METHODS: We compared technetium-99 m tetrofosmin gated SPECT imaging and contrast ventriculography in the assessment of global and regional left ventricular function in 74 patients with undiagnosed chest pain of whom 27 sustained a previous myocardial infarction. RESULTS: Linear regression analysis demonstrated that gated SPECT determined LVEF correlated well with LVEF determined from contrast ventriculography (y = 0.95x + 1.9, r2 = 0.84, p < 0.0001). Bland-Altman plot analysis showed no systematic difference between the two sets of values derived from the two imaging approaches over a wide range of LVEF values. Exact agreement of segmental wall motion scores was 460 of 518 (89%) segments with a kappa value of 0.76 (p < 0.0001). CONCLUSION: We conclude that gated SPECT imaging is an accurate and reliable clinical tool to accurately measure global and regional left ventricular function.

Adult↗
PubMed2000

Enhanced prognostic stratification of patients with left ventricular hypertrophy with the use of single-photon emission computed tomography.

BACKGROUND: Patients with left ventricular hypertrophy (LVH) are at increased risk of future cardiovascular events. Little is known about risk stratification of these patients with the use of myocardial perfusion imaging. This study sought to assess the prognostic stratification of patients with LVH by using myocardial perfusion single-photon emission computed tomography (SPECT). METHODS AND RESULTS: We studied 633 consecutive patients with electrocardiographic evidence of LVH who underwent dual isotope myocardial perfusion SPECT (rest thallium 201/stress technetium 99m sestamibi) and were followed up for a mean period of 22 +/- 7 months. During the follow-up period, 67 events (35 cardiac deaths and 32 nonfatal myocardial infarctions) occurred (6% annual event rate). The results of the perfusion scan significantly risk-stratified the population; patients with normal scans had a low rate of nonfatal myocardial infarction and cardiac death (<1% per year of follow-up). The rates of cardiac events increased significantly as a function of the scan result: 4.9% in patients with mildly abnormal scans and 10. 3% in moderately to severely abnormal scans. Cox proportional hazards analysis demonstrated that after adjusting for pretest likelihood of coronary artery disease (the most predictive clinical variable; chi(2) = 15.5, P <.001), summed stress score (the most predictive nuclear variable; chi(2) = 18, P <.0001) added significant incremental prognostic information (global chi(2) increased from 15.5 to 36; P <.001). CONCLUSIONS: In patients with LVH with an overall high cardiac event rate, SPECT provided enhanced stratification by adding significant incremental prognostic information over clinical and historic variables.

Aged↗
PubMed2000

Liquid crystal director fluctuations and surface anchoring by molecular simulation

We propose a simple and reliable method to measure the liquid crystal surface anchoring strength by molecular simulation. The method is based on the measurement of the long-range fluctuation modes of the director in confined geometry. As an example, molecular simulations of a liquid crystal in slab geometry between parallel walls with homeotropic anchoring have been carried out using the Monte Carlo technique. By studying different slab thicknesses, we are able to calculate separately the position of the elastic boundary condition and the extrapolation length.

Journal Article↗
PubMed2000

Left ventricular function: correlation of quantitative gated SPECT and MR imaging over a wide range of values.

In 21 patients, the authors compared results with quantitative gated single photon emission computed tomography (SPECT) to results with magnetic resonance imaging in the assessment of left ventricular (LV) end-diastolic volume (LVEDV), end-systolic volume (LVESV), and ejection fraction (LVEF). Between the two methods, correlations were good for LVEF (r = 0.85), LVEDV (r = 0.94), and LVESV (r = 0.95). Quantitative gated SPECT can help determine LVEF, LVEDV, and LVESV.

Adult↗
PubMed2000

The clinical value of assessing left ventricular function from gated SPECT perfusion studies.

Gated myocardial perfusion SPECT is a technique that is rapidly becoming widespread in the nuclear cardiology arena, and it currently accounts for a majority of all perfusion SPECT acquisitions performed in the USA. Its main advantage is that of providing important incremental clinical information over SPECT perfusion assessment alone, at essentially no extra cost. With respect to the diagnosis of cardiac disease, gated SPECT has been demonstrated to improve specificity by helping identify attenuation artifacts in patients with suspected coronary artery disease, and is also key in identifying patients with non-ischemic cardiomyopathies. In prognostic assessment, gated SPECT-derived measurements of ejection fraction achieve substantial incremental stratification of patients at risk for cardiac death or myocardial infarction, compared to perfusion scores, and volume measurements further improve risk stratification. New quantitative algorithms allow the fast, accurate and reproducible measurement of parameters of global cardiac function (ejection fraction, end-systolic and end-diastolic volume) as well as regional cardiac function (myocardial wall motion and thickening), all of which have been validated against a wide variety of gold standards.

Coronary Disease↗
PubMed2000

A new algorithm for the quantitation of myocardial perfusion SPECT. I: technical principles and reproducibility.

UNLABELLED: We have developed a new, completely automatic 3-dimensional software approach to quantitative perfusion SPECT. The main features of the software are myocardial sampling based on an ellipsoid model; use of the entire count profile between the endocardial and epicardial surfaces; independence of the algorithm from myocardial shape, size, and orientation and establishment of a standard 3-dimensional point-to-point correspondence among all sampled myocardial regions; automatic generation of quantitative measurements and 5-point semiquantitative scores for each of 20 myocardial segments and automatic derivation of summed perfusion scores; and automatic generation of normal limits for any given patient population on the basis of data fractionally normalized to minimize hot spot artifacts. METHODS: The new algorithm was tested on the tomographic images of 420 patients studied with a rest 201TI (111-167 MBq, 35 s/projection)-stress 99mTc-sestamibi (925-1480 MBq, 25 s/projection) separate dual-isotope protocol on a single-detector camera, a dual-detector 90 degrees camera, and a triple-detector camera. RESULTS: The algorithm was successful in 397 of 420 patients (94.5%) and 816 of 840 image datasets (97.1%), with a statistically significant difference between the success rates of the 201TI images (399/ 420, or 95.0%) and the 99mTc images (417/420, or 99.3%; P < 0.001). Algorithm failure was caused by extracardiac uptake (10/24, or 41.7%) or inaccurate identification of the valve plane because of low count statistics (14/24, or 58.3%) and was obviated by simply limiting the image volume in which the software operates. Reproducibility of measurements of summed perfusion scores (r = 0.999 and 1 for stress and rest, respectively), global defect extent (r = 0.999 and 1 for stress and rest, respectively), and segmental perfusion scores (exact agreement = 99.9%, kappa = 0.998 for stress and 0.997 for rest) was extremely high. CONCLUSION: Automatic 3-dimensional quantitation of perfusion from 201Tl and 99mTc-sestamibi images is feasible and reproducible. The described software, because it is based on the same sampling scheme used for gated SPECT analysis, ensures intrinsically perfect registration of quantitative perfusion with quantitative regional wall motion and thickening information, if gated SPECT is used.

Algorithms↗
PubMed2000

A new algorithm for the quantitation of myocardial perfusion SPECT. II: validation and diagnostic yield.

UNLABELLED: This study validates a new quantitative perfusion SPECT algorithm for the assessment of myocardial perfusion. The algorithm is not based on slices and provides fully 3-dimensional sampling and analysis independent of assumptions about the geometric shape of the left ventricle. METHODS: Radiopharmaceutical- and sex-specific normal limits and thresholds for perfusion abnormality in 20 segments of the left ventricle were developed for separate, dual-isotope rest 201Tl-exercise 99mTc-sestamibi SPECT in 36 patients with <5% before-scanning likelihood of coronary artery disease (CAD) (group 1) and 159 patients with perfusion abnormalities (group 2). These thresholds were validated in 131 patients (group 3) by comparison with expert visual interpretation. Thresholds for automatic segmental scores were developed and validated for groups 2 and 3, respectively. The accuracy of CAD detection was assessed in 94 patients, who underwent coronary angiography (group 4). RESULTS: Overall sensitivity for detection of stress and rest segmental perfusion abnormality was 91% and 96%, respectively, for men and 89% and 79%, respectively, for women. Overall specificity for stress and rest was 87% and 90%, respectively, for men and 88% and 90%, respectively, for women. Agreement between automatic and visual scores was good (weighted K of 0.71 and 0.60 for stress and rest images, respectively). Sensitivity and specificity were 88% for the detection of > or =70% stenosis. For the detection of left anterior descending, left circumflex, and right coronary artery stenosis, sensitivity was 84%, 86%, and 88%, respectively, and specificity was 84%, 88%, and 81%, respectively. CONCLUSION: The new quantitative perfusion SPECT approach is highly sensitive and specific for the detection and localization of CAD, provides accurate automatic scores for the assessment of regional perfusion, and overcomes the low-specificity limitations of previous quantitative algorithms.

Algorithms↗
PubMed2000

Photon energy recovery for crosstalk correction in simultaneous 99mTc/201Tl imaging.

UNLABELLED: Simultaneous 99mTc sestamibi/201Tl imaging enables the acquisition of images of myocardial stress perfusion and myocardial viability in a single process. One of the major limits of this technique is the crosstalk of the 99mTc downscattered photons into the 201Tl window. We propose using the spectral deconvolution technique photon energy recovery (PER) for correcting this crosstalk. METHODS: A planar line phantom made of 99Tc vertical lines and 201Tl horizontal lines and a cardiac SPECT phantom including an anterior (2 mL) and an inferior (1.5 mL) myocardial fixed defect were used. The phantoms were filled with an initial 99mTc/201Tl ratio of 5:1. Several successive acquisitions were made from time t = 0 to time t = 48 h (99mTc/201Tl ratio approximately 0) without moving the phantoms. Total number of counts, contrast, and normalized SD (NSD) were calculated on the Tl-raw and the Tl-PER planar images. SPECT datasets were analyzed. The Tl-raw images recorded at 48 h were considered the reference "virgin" 201Tl images. RESULTS: Total number of counts, contrast, and NSD ranged from 336% to 201%, 15% to 29%, and 257% to 225% of the virgin 201Tl values, respectively, for Tl-raw planar images; whereas values for Tl-PER images ranged from 128% to 108%, 61% to 79%, and 154% to 108%, respectively. Anterior and inferior defect contrasts ranged from 1.18 to 1.22 and 1.12 to 1.16 for Tl-raw SPECT images, respectively; whereas for Tl-PER images, value ranges were 1.28-1.32 and 1.21-1.24, respectively. The corresponding reference virgin 201Tl values were 1.31 and 1.25 respectively. Summed score, average defect severity, and average defect extent ranges were 4-5, 0.4-0.52, and 4.7-5.9 for Tl-raw images, respectively, and 8-9, 0.59-0.79, and 7.4-8.8 for Tl-PER images. The reference virgin 201Tl values were 9, 0.73, and 8.7, respectively. CONCLUSION: PER is quantitatively efficient to remove 99mTc crosstalk photons from 201Tl images for 99mTc/201Tl ratios ranging from 5:1 to 2:1.

Heart↗
PubMed2000

Consensus Conference on Self-blood pressure measurement. Clinical applications and diagnosis.

The present study was aimed at reviewing the medical literature devoted to the clinical applications of self-blood pressure monitoring (SBPM) and at providing some recommendations regarding the use of SBPM for diagnostic purposes. The lack of reliability of conventional blood pressure (BP) measurement is largely related to the extreme variability of BP over time. SBPM provides a large number of readings and can be used to predict the results of repeated clinical measurements. The use of SBPM in the diagnosis of white coat hypertension can be proposed as a screening test: if it gives a positive result (a low home BP), it should be confirmed by ambulatory BP monitoring (ABPM). SBPM could improve patients' compliance with medication. Last, SBPM may be cost-effective for the management of hypertensive patients, by reducing costs of medication, number of clinic visits and costs of cardiovascular morbidity. Compared with ABPM, SBPM seems to have a less value for the initial diagnosis of hypertension and for predicting prognosis. In contrast, it should be of more value for the long term follow-up of patients with white coat hypertension and for the evaluation of treatment efficacy in patients with sustained hypertension. The use of SBPM in diabetic hypertensives, in pregnant women and in the elderly is encouraged, but needs further evaluation.

Blood Pressure Determination↗
PubMed2000

Postexercise lung uptake of 99mTc-sestamibi determined by a new automatic technique: validation and application in detection of severe and extensive coronary artery disease and reduced left ventricular function.

UNLABELLED: This study validated a new automatic algorithm for assessment of lung-to-heart ratio (L/H) of radiotracers in myocardial perfusion SPECT and assessed the diagnostic value of (99m)Tc-sestamibi L/H after exercise. METHODS: The new technique extracts a left ventricular region of interest (ROI) from a summed anterior projection image and generates a lung ROI by reshaping and translating the left ventricular ROI. This algorithm was applied to 230 patients who underwent exercise (99m)Tc-sestamibi SPECT (gated SPECT, n = 88) with first-pass ventriculography. Normal values were established in 26 patients in whom the likelihood of coronary artery disease (CAD) was 5% or less. An abnormality threshold for detecting severe and extensive CAD was defined in a subgroup of 109 patients who underwent coronary angiography and was validated in a prospective group (n = 72). RESULTS: The success rate of the automatic algorithm was 97%. Excellent correlation was found between automatic and manual L/H values (r = 0.95; P < 0.001). The mean L/H was higher in patients with a peak exercise ejection fraction (EF) less than 40% versus 40% or more (0.51 +/- 0.07 versus 0.43 +/- 0.05, P < 0.001) and in patients with a poststress EF less than 40% versus 40% or more (0.50 +/- 0.07 versus 0.44 +/- 0.06, P < 0.01). A threshold of L/H greater than 0.44 yielded a sensitivity and specificity of 63% and 81%, respectively, for identifying severe and extensive CAD in the prospective group and a sensitivity of 86% in identifying stenosis of 90% or more in the proximal left anterior descending artery. CONCLUSION: The new automatic algorithm for assessing L/H correlated well with manually derived L/H for (99m)Tc-sestamibi as well as (201)TI SPECT. An increased postexercise (99m)Tc-sestamibi L/H adds significant diagnostic value to study myocardial perfusion SPECT as a marker of severe and extensive CAD and reduced ventricular function.

Aged↗
PubMed1999

Incremental prognostic value of rest-redistribution (201)Tl single-photon emission computed tomography.

BACKGROUND: The incremental prognostic value of rest-redistribution (201)Tl compared with stress and rest perfusion abnormalities has not been defined. METHODS AND RESULTS: We identified 458 patients who underwent rest (201)Tl /stress (exercise or adenosine) (99m)Tc sestamibi single-photon emission computed tomography (SPECT) and had late (18 to 24 hours) (201)Tl imaging, were not revascularized within 60 days of SPECT, and were followed up at >1 year. SPECT images were visually analyzed with the use of a 20-segment model on a scale of 0 to 4. Thirty-seven cardiac deaths (CDs) and 17 nonfatal myocardial infarctions occurred. Univariate Cox proportional hazards analysis showed that the presence of a large amount of rest (201)Tl reversibility (rest-late summed difference score [SDS] of >8) was a significant predictor of CD (chi(2) = 5.77, P = 0.02) and CD or myocardial infarction (chi(2) = 5.3, P = 0.02). The CD rate was 9.3% y(-1) in patients with rest-late SDS of >8 compared with 3.6% y(-1) in patients with a mild/moderate amount of rest reversibility (rest-late SDS 3 to 8) and 3.4% y(-1) in patients with no rest reversibility (rest-late SDS <3) (P = 0.029). Kaplan-Meier survival analysis demonstrated significantly lower cumulative survival rates in patients with rest-late SDS of >8 (P = 0.01). Multivariate Cox proportional hazards analysis demonstrated that the presence of a large amount of resting reversibility was an independent and incremental predictor of CD after adjustment for stress and rest perfusion information. Multivariate logistic regression analysis demonstrated that resting reversibility was not an independent predictor of referral to coronary angiography and revascularization. CONCLUSIONS: The identification of a large amount of resting (201)Tl reversibility is an independent predictor of CD over stress and rest perfusion abnormalities.

Aged↗
PubMed1999

Incremental prognostic value of post-stress left ventricular ejection fraction and volume by gated myocardial perfusion single photon emission computed tomography.

BACKGROUND: The incremental prognostic value of post-stress left ventricular ejection fraction (EF) and volume over perfusion has not been investigated. METHODS AND RESULTS: We identified 1680 consecutive patients who underwent rest Tl-201/stress Tc-99m sestamibi gated single photon emission computed tomography (SPECT) and who were followed-up for 569+/-106 days. Receiver-operator characteristics analysis defined an EF<45%, an end-systolic volume (ESV) >70 mL, and an end-diastolic volume >120 mL as optimal thresholds, yielding moderate sensitivity and high specificity in the prediction of cardiac death. Patients with an EF> or = 45% had mortality rates <1%/year, despite severe perfusion abnormalities, whereas patients with an EF<45% had high mortality rates, even with only mild/moderate perfusion abnormalities (9.2%/year; P<0.00001). Similarly, an ESV< or = 70 mL was related to a low cardiac death rate (<1.2%/year), even for patients with severe perfusion abnormalities, whereas patients with an ESV>70 mL and only mild/moderate perfusion abnormalities had high death rates (8.2%/year; P<0.00001). Patients with an EF<45% and an ESV< or = 70 mL had low cardiac death rates (1.7%/year); those with an EF<45% but an ESV>70 mL had high death rates (7.9%/year; P<0.02). Multivariate Cox proportional hazards regression showed that perfusion variables and ESV were independent predictors of overall coronary events, whereas EF and ESV demonstrated incremental prognostic values over prescan and perfusion information in predicting cardiac death and cardiac death or myocardial infarction. CONCLUSIONS: Post-stress EF and ESV by gated-SPECT have incremental prognostic values over prescan and perfusion information in predicting cardiac death, and they provide clinically useful risk stratification.

Adenosine↗
PubMed1999

The role of nuclear cardiology in clinical decision making.

This review suggests that the field of nuclear cardiology is alive, well, and thriving, providing relevant information that aids in everyday clinical decision making for nuclear medicine and referring physicians alike. Despite the competition from other modalities, the clinically appropriate applications of nuclear cardiology techniques are likely to increase. The foundation of this optimism is based on the vast amount of data documenting cost-effective clinical applications for diagnosis, risk stratification, and assessing therapy in both chronic and acute coronary artery disease (CAD), the powerful objective quantitative analysis of perfusion and function provided by the technique, and the increasing general availability of the approach.

Algorithms↗
PubMed1999

Incremental prognostic value of myocardial perfusion single photon emission computed tomography in patients with diabetes mellitus.

BACKGROUND: Previous studies have shown that myocardial perfusion single photon emission computed tomography (SPECT) provides incremental prognostic information in the general population, but the prognostic efficacy of nuclear testing in patients with diabetes mellitus is unclear. METHODS: We conducted a study with 1271 consecutively registered patients with diabetes and 5862 patients without diabetes with known or suspected coronary artery disease undergoing rest thallium 201/stress technetium 99m sestamibi dual-isotope myocardial perfusion SPECT with exercise or adenosine pharmacologic testing. Patients were followed up for at least 1 year. The successful follow-up rate was 92.4% for patients with diabetes and 94.0% for subjects without diabetes. The mean follow-up period was 23.7 +/- 7.7 months for the former group and 21.5 +/- 6.1 months for the latter. RESULTS: Over the follow-up period, patients with diabetes had significantly higher rates of hard events (cardiac death or nonfatal myocardial infarction) (4.3% per year versus 2.3% per year, P <.001) and higher total event rates (hard events and late revascularization) (9.0% per year versus 5.3% per year, P <. 001) compared with rates among patients without diabetes. Cox proportional hazards analysis revealed that nuclear testing added incremental value over clinical and historical variables among patients with diabetes (global chi(2) increased 46% for the exercise group [n = 619] and 88% for the adenosine group [n = 461]; both P <. 001). The event rates rose significantly as a function of summed stress score and summed difference score among both patients with diabetes and patients without diabetes (P <.001). The patients with diabetes with normal scans had relatively low hard event rates (1% to 2% per year), those with mildly abnormal scans had intermediate hard event rates (3% to 4% per year), and those with moderately to severely abnormal scans had relatively high hard event rates (>7% per year). CONCLUSIONS: The results of this study indicated that exercise and adenosine stress myocardial perfusion SPECT are valuable for risk stratification and management of patients with diabetes.

Aged↗
PubMed1999

The innervation of the ureter in the duck (Anas platyrhynchos). A morphological and quantitative study.

The morphology and distribution of the innervation in the duck ureter were studied using AChE histochemistry and PGP 9.5 immunohistochemistry. The density of AChE positive ganglia and neurons was calculated in the adventitial and muscular layers both in young and adult birds. Moreover, in order to investigate regional differences in neuronal density, separate neuron counts and neuron density calculations were performed for the upper, intermediate and lower parts of the ureter, and the data were statistically evaluated. Three nerve plexuses located in the tunica adventitia, in the tunica muscularis and in the lamina propria respectively, were observed. Both in young and adult ducks, the density of adventitial neurons was significantly greater in the lower tract than in the upper and intermediate tracts. The findings of the present study suggest that, in birds, the innervation may play a role in ureteric functions such as epithelial mucosecretion, muscular motility, and closure and/or opening of the ureteric papilla.

Acetylcholinesterase↗