Biomedical subjects

J Ge

Publications and source records attributed to J Ge.

At least 55 records · Page 3Linked to original sources

PubMed1999

Stepwise intravascular ultrasound (IVUS) guidance of high-pressure coronary stenting does not result in an improved acute or long-term outcome: a randomized comparison to "final-look" IVUS assessment.

The objective of this study was to evaluate the potential benefit of stepwise intravascular ultrasound (IVUS)-guided coronary stent deployment compared to angiographic stent implantation with final IVUS assessment only. Acute procedural success and 6-month angiographic follow-up were compared in both groups. Intravascular ultrasound was performed using a 20- or 30-MHz mechanically rotated catheter in 85 patients who were prospectively randomized to group A (n=42; IVUS-guided) and group B (n=43; angiography +/- final IVUS assessment). There was no difference in the number of stents implanted (1.5+/-0.9 stents/lesion in group A and 1.3+/-0.6 stents/lesion in group B), the duration of the procedure, or the amount of contrast medium used. Defined criteria of optimal stent deployment (stent apposition, stent symmetry, complete coverage of dissections, >90% in-stent lumen area/reference lumen area) were achieved in 54.2% in group A and 56.6% in group B (NS). Angiographic follow-up was 87.1% at 6+/-2 months, and clinical follow-up was 100% at 8+/-1 months. There was no significant difference in restenosis rate (33.3% vs. 34.9%) applying a binary >50% diameter stenosis criterion for both groups. There was no significant difference in minimal in-stent lumen area at both baseline (7.91+/-2.64 mm2 vs. 7.76+/-2.21 mm2) and follow-up (5.84+/-2 mm2 vs. 5.52+/-1.87 mm2). With regard to immediate procedural lumen gain and rate of restenosis, multiple IVUS examinations during the procedure showed no advantage compared to final IVUS assessment only.

Coronary Angiography↗

PubMed1999

Role of intravascular ultrasound imaging in identifying vulnerable plaques.

UNLABELLED: A plaque that has a large lipid core and a thin fibrous cap may undergo rupture. Once it ruptures, it may lead to thrombus formation and subsequent vessel occlusion. To identify unstable plaques before they rupture is essential for clinical management and patient's prognosis. Intravascular ultrasound (IVUS) opens a new window for the assessment of plaque morphology to identify vulnerable plaques and plaque rupture. We examined 144 patients with angina and ischemic ECG changes using IVUS. Ruptured plaques, characterized by a plaque cavity and a tear on the thin fibrous cap, were identified in 31 patients (group A) of which 23/31 (74%) clinically presented as unstable angina. Plaque rupture was confirmed by injecting contrast medium filling the plaque cavity during IVUS examination. Of the patients without plaque rupture (group B, n = 108), only 19 (18%) had unstable angina. No significant differences between the 2 groups were found concerning the vessel and plaque areas (p > 0.05). The percent stenosis in group A (56.2 +/- 16.5%) was significantly lower than in group B (67.9 +/- 13.4%) (p < 0.001). Area of the plaque cavity in group A (4.1 +/- 3.2 mm2) was significantly larger than the echolucent zone in group B (1.32 +/- 0.79 mm2) (p < 0.001). The plaque cavity/plaque ratio in group A (38.5 +/- 17.1%) was larger than the echolucent area/plaque ratio in group B (11.2 +/- 8.9%) (p < 0.001). The thickness of the fibrous cap in group A (0.47 +/- 0.20 mm) was significantly thinner than that (0.96 +/- 0.94 mm) in group B (p < 0.001). CONCLUSIONS: Plaques seem to be prone to rupture when the echolucent area is larger than 1 mm2, the echolucent area/plaque ratio greater than 20% and the fibrous cap thinner than 0.7 mm. IVUS has the capacity of identifying plaque rupture and vulnerable plaques. This may have potential influence on patients management and therapy.

Adult↗

PubMed1999

Prevalence of microvascular disease in patients with significant coronary artery disease.

Coronary flow velocity reserve (CFVR) measurement using intracoronary Doppler techniques has been increasing accepted for the assessment of physiological significance of epicardial stenosis and the functional changes after coronary interventions. However, large discrepancy exists concerning the acute changes of CFVR immediately after intervention. The purpose of this study was to investigate the prevalence of microvascular dysfunction in patients with significant coronary artery disease. Intracoronary Doppler flow measurements were performed in a total of 212 patients who underwent coronary interventions because of significant epicardial stenosis using 0.014" Doppler flow wire (Cardiometrics, Inc, Mountain View, CA). Intracoronary bolus injection of adenosine (12 micrograms for the right coronary and 18 micrograms for the left coronary arteries) was used to induce hyperemic reaction. CFVR was registered as the ratio of average peak velocity during hyperemia (hAPV) to at baseline (bAPV). Successful coronary interventions either by percutaneous transluminal coronary balloon angioplasty (PTCA) or by stenting could significantly improve the CFVR. In 80 patients with PTCA, the bAPV elevated from 16.6 +/- 2.1 cm/s to 20.6 +/- 13.4 cm/s and hAPV from 30.1 +/- 15.9 cm/s to 45.2 +/- 17.7 cm/s (both p < 0.001) with PTCA and the CFVR increased from 1.94 +/- 0.78 to 2.58 +/- 0.87 correspondingly (p < 0.001). Significant elevation of coronary flow parameters were also found in 132 patients with subsequent stent implantation (bAPV from 15.3 +/- 6.7 cm/s to 18.7 +/- 9.1 cm/s, hAPV from 28.7 +/- 14.4 cm/s to 44.3 +/- 17.7 cm/s and CFVR from 1.90 +/- 0.70 to 2.59 +/- 0.87, all p < 0.001). Reduction of CFVR (< 3.0) after intervention still existed in 46 (61.3%) of 80 patients after PTCA and 88 (66.7%) of 132 patients after stenting. Moreover, CFVR < 3.0 were found in 50 (45.9%) of 109 reference vessels in patients with single vessel disease. Significant improvement of coronary flow velocity and coronary flow velocity reserve could be obtained after successful angioplasty. However, microvascualr dysfunction existed in a large proportion of patients either in normal reference vessels or in target vessels after interventions.

Adult↗

PubMed1999

Malignant transformation of an optic disk melanocytoma.

PURPOSE: To report a case of malignant transformation of an optic disk melanocytoma with a second melanocytoma in the ciliary body. METHODS: Clinical data including visual acuity, visual fields, color fundus photographs, fluorescein angiogram, and ultrasonogram and histopathologic studies of this case were reviewed. RESULTS: The right eye of a 65-year-old white woman was diagnosed with melanocytoma of the optic nerve. Four years later, the tumor became significantly larger. The best-corrected visual acuity declined from 20/40 to counting fingers and the size of the tumor increased fourfold in 2 years. The right globe was enucleated. Histopathologic studies demonstrated moderately pigmented spindle-B malignant melanoma cells adjacent to and within a population of large, polyhedral, heavily pigmented melanocytoma cells that extended to the lamina cribrosa and optic nerve. There was also a deeply pigmented melanocytoma in the ciliary body. CONCLUSION: This is a rare case of malignant melanoma transformed from an optic disk melanocytoma. Periodic follow-up of the patient with optic disk melanocytoma is necessary.

Aged↗

PubMed1999

Does remodeling occur in the diseased human saphenous vein bypass grafts? An intravascular ultrasound study.

BACKGROUND: Coronary artery remodeling is a common phenomenon in human atherosclerotic arteries. Controversies exist concerning the presence of absence of the remodeling process in diseased human coronary saphenous vein bypass grafts. The purpose of the study was to observe the vessel and lumen dimensions in patients who had undergone saphenous vein grafting with intravascular ultrasound to find out whether the remodeling process exists in the diseased human saphenous vein bypass grafts. METHODS: A total of 43 saphenous vein bypass grafts from 43 patients (39 males, 4 females, mean age 63+/-8 years); 1-16 years (mean 9.3+/-4.0 years) after grafting, who had not undergone previous catheter intervention, were studied using intravascular ultrasound. The vessel, lumen and plaque area were measured at the lesion segment as well as in the proximal and distal reference segments. The percent stenosis was calculated. RESULTS: In 43 bypass grafts having severe stenosis before intervention, plaque was eccentric in 69.4% and concentric in 30.6%. No calcification was detected in 75% cases and 25% cases has mild-moderate intimal calcification. The vessel area in the lesion segment was 19.0+/-9.7 mm2, significantly larger than the proximal reference segment 12.8+/-4.0 min2 as well as the distal reference segment 12.9+/-3.6 mm2 (p < 0.001). It was also larger than that of the average area of the proximal and distal reference segments (p < 0.001). The vessel area increased in accordance with plaque area (p < 0.001). A weak relationship existed between vessel area and percent stenosis (r = 0.37, p = 0.04). CONCLUSION: In contrary to previous findings, diseased human saphenous vein bypass grafts undergo focal compensatory enlargement (remodeling) in the presence of plaque formation. The underlying mechanism is probably similar to that in de novo atherosclerosis.

Adaptation, Physiological↗

PubMed1999

Cytogenetic studies of infant acute lymphoblastic leukemia: poor prognosis of infants with t(4;11) - a report of the Children's Cancer Group.

Infants less than 1 year of age at diagnosis of acute lymphoblastic leukemia (ALL) have a poor prognosis, which has been attributed primarily to a breakpoint in chromosomal band 11q23 or the MLL gene. Most infants with an 11q23 breakpoint have a t(4;11)(q21 ;q23). We studied the cytogenetics of the leukemia cells of 56 infants on CCG-1883, a single-arm clinical treatment protocol for infant ALL. Twenty-one patients had t(4;11)(q21;q23), seven had other rearrangements with breakpoints in 11q23 (other 11q23), 16 had normal chromosomes, two had t(1;19)(q32;p13), one had >50 chromosomes, and nine had non-recurring structural abnormalities. To determine whether there is a difference in outcome for infants with t(4;11), other 11q23 and the remaining patients, we compared event-free survival (EFS) and other clinical and laboratory features of the above infants. Infants without t(4;11) and those with other 11q23 rearrangements had significantly better EFS than those with t(4;11) (P= 0.007 and P= 0.02, respectively). t(4;11) correlated with age less than 6 months and with CD10 negativity, both of which also were poor prognostic indicators. After adjustment for age, there was still a significant difference in EFS between patients with t(4;11) and those with other 1lq23 rearrangements (P=0.02), and between patients with t(4;11) and those without t(4;11) (P=0.04). Among CD10 negative patients, t(4;11) was associated with a worse EFS (P=0.01). Multivariate analysis showed that after adjusting for a variety of clinical and laboratory features, t(4;11) was the most important prognostic factor for poor outcome, and patients with other 11q23 rearrangements had as good an outcome as the remaining patients without t(4;11).

Chromosomes, Human, Pair 11↗

PubMed1999

Vaccination of mice with gamma-irradiated Schistosoma japonicum cercariae.

gamma-irradiated cercarial vaccines induce high levels of protection in mice against Schistosoma mansoni infection, however, the same has not been well established for S. japonicum. Here we describe vaccination studies in mice with gamma-irradiated S. japonicum cercariae testing the effectiveness of different irradiation doses, number of vaccinations, and mouse strains. In CBA/Ca mice, a single percutaneous exposure to 500 S. japonicum cercariae previously attenuated by 10, 20, 30, 40 or 50 krad gamma-irradiation induced significant, but comparable levels of protection (34-46%) against challenge infection. In a repeat experiment in C57Bl/6 mice, only groups vaccinated with 10 or 20 krad gamma-irradiated cercariae showed statistically significant, but lower levels of resistance (20-24%). Multiple vaccination of CBA/Ca mice with 500 20 krad gamma-irradiated cercariae did not improve the resistance level (40%). Analysis of IgG responses showed no clear correlation between antibody levels and levels of protection. Western blot analysis suggested that recognition of a 200-kDa antigen might be correlated with protection, that antigens of 42 and 50 kDa may be involved in the protection induced by single vaccination, but that different antigens might be protective in single vs multiple vaccinations. Sera from mice vaccinated with gamma-irradiated cercariae recognized many fewer antigens than more protective sera from mice vaccinated with UV-attenuated cercariae. These results suggest that the mouse may not be a suitable host for studies involving gamma-irradiated S. japonicum vaccines.

Animals↗

PubMed1999

New signs characteristic of myocardial bridging demonstrated by intracoronary ultrasound and Doppler.

BACKGROUND: Large discrepancies exist concerning the incidence of myocardial bridging. This has been reported to be 0.5%-2.5% following coronary angiography but 15%-85% following autopsy. The purpose of the study was to use intravascular ultrasound and intracoronary Doppler to study the morphology and flow characteristics of myocardial bridging in order to find feasible parameters of this syndrome. METHODS AND RESULTS: Intravascular ultrasound was performed in 62/69 patients in whom typical angiographic 'milking effects' were present. In 48 patients, intracoronary Doppler was performed. A specific, echolucent 'half moon' phenomenon surrounding the myocardial bridge was found in all the patients. The thickness of the half moon area was 0.47 +/- 0.19 mm in diastole and 0.52 +/- 0.23 mm in systole. There was systolic compression of the myocardial bridge with a lumen reduction during systole of 36.4 +/- 8.8%. Using intracoronary Doppler, a characteristic early diastolic 'finger tip' phenomenon was observed in 42 (87%) of the patients. All patients showed no or reduced antegrade systolic flow. Coronary flow velocity reserve was 2.03 +/- 0. 54. After intracoronary nitroglycerin injection, retrograde systolic flow occurred in 37 (77%) of the 48 patients, with a velocity of -22. 2 +/- 13.2 cm. s(-1). Intravascular ultrasound revealed atherosclerotic involvement of the proximal segment in 61 (88%) of the 69 patients, with an area stenosis of 42 +/- 13%. No plaques were found in the bridge or distal segments in the 62 patients in whom it was possible to introduce the ultrasound catheter throughout the bridging segment. CONCLUSION: Myocardial bridging is characterized by the following morphological and functional signs: a specific, echolucent half moon phenomenon over the bridge segment, which exists throughout the cardiac cycle; systolic compression of the bridge segment of the coronary artery; accelerated flow velocity at early diastole (finger-tip phenomenon); no or reduced systolic antegrade flow; decreased diastolic/systolic velocity ratio; retrograde flow in the proximal segment, which is provoked and enhanced by nitroglycerin injection.

Blood Flow Velocity↗

PubMed1999

Intravascular ultrasound classification of atherosclerotic lesions according to American Heart Association recommendation.

BACKGROUND: Intravascular ultrasound (IVUS) offers a new modality by which to image the vessel wall in high resolution. The aim of the study was to classify atherosclerotic lesions using IVUS according to American Heart Association (AHA) recommendation. METHODS: IVUS was performed using a 20 or 30 MHz mechanically rotated catheter in 190 patients (aged from 35 to 75 years, mean 59 +/- 9 years) who presented with suspicion of coronary artery disease based on clinical examination. RESULTS: Of the 190 patients, 49 (26%) (group A) were found to have normal or nearly normal coronary arteries, whereas the other 141 (74%) (group B) had significant angiographic stenosis (> 50% luminal narrowing). IVUS image interpretation was based on the recommendation of the Committee on Vascular Lesions of the Council on Atherosclerosis (AHA). In group A, a total of 822 segments were evaluated with IVUS; 444 (54%) were found to have plaque formation. Among these 444 segments, type II lesions were found in 145 (33%), type III lesions in 110 segments (25%), type IV and Va lesions in 169 segments (38%), and type Vb in 18 segments (4%). The severity of plaque area stenosis increased from type II to IV. In group B, only the most stenotic segments (n = 141) on angiography were selected for analysis. No significant differences were found among different lesion types with respect to the severity of plaque area stenosis. Type Vb and Vc lesions presented mainly, but not exclusively, as stable angina, whereas type VI lesions presented mainly as unstable angina. Some patients (12%) with stable angina had complicated lesions (type VIa-VIc). CONCLUSIONS: It is now possible to use intravascular ultrasound to classify atherosclerotic lesions according to the AHA recommendations that were based on histological examination. Standardized reports of IVUS can now be based on these recommendations. Even in angiographically normal coronary arteries, advanced atherosclerotic lesions are found, explaining the potential risk of acute coronary syndromes in this group of patients. In patients with angiographically severe coronary disease, clinical symptoms correlate mainly with plaque characteristics, rather than with the severity of stenosis.

Adult↗

PubMed1999

Screening of ruptured plaques in patients with coronary artery disease by intravascular ultrasound.

AIM: To visualise the characteristics of ruptured plaques by intravascular ultrasound (IVUS) and to correlate plaque characteristics with clinical symptoms to establish a quantitative index of plaque vulnerability. METHODS: 144 consecutive patients with angina were examined using IVUS. Ruptured plaques, characterised by a plaque cavity and a tear on the thin fibrous cap, were identified in 31 patients (group A), of whom 23 (74%) presented with unstable angina. Plaque rupture was confirmed by injecting contrast medium filling the plaque cavity during IVUS examination. Of the patients without plaque rupture (group B, n = 108), only 19 (18%) had unstable angina. RESULTS: No significant differences were found between groups A and B in relation to plaque and vessel area (p > 0.05). Mean (SD) per cent stenosis in group A was less than in group B, at 56.2 (16.5)% v 67.9 (13.4)%; p < 0.001. Area of the emptied plaque cavity in group A (4.1 (3.2) mm2) was larger than the echolucent zone in group B (1.32 (0.79) mm2) (p < 0.001). The plaque cavity to plaque ratio in group A (38.5 (17.1)%) was larger than the echolucent area to plaque ratio in group B (11.2 (8.9)%) (p < 0.001). The thickness of the fibrous cap in group A was less than in group B, at 0.47 (0.20) mm v 0.96 (0.94) mm; p < 0.001. CONCLUSIONS: Plaques seem to be prone to rupture when the echolucent area is larger than 4.1 (3.2) mm2, when the echolucent area to plaque ratio is greater than 38.5 (17.1)%, and when the fibrous cap is thinner than 0.7 mm. IVUS can identify plaque rupture and vulnerable plaques. This may influence patient management and treatment.

Adult↗

PubMed1999

Worldwide ethnic distribution of the G protein beta3 subunit 825T allele and its association with obesity in Caucasian, Chinese, and Black African individuals.

Recently, it was demonstrated that one allele (825T) of the gene encoding the G protein beta3 subunit (GNB3) is associated with hypertension in Germans. This study investigates a possible association with obesity in young male Germans, Chinese, and black South Africans with low, intermediate, and high 825T allele frequencies, respectively. In each of these three distinct cohorts, the 825T allele frequency was increased significantly in overweight (body mass index [BMI] > or =25 kg/m2) and obese individuals (BMI >27 kg/m2) compared to those with normal weight. The 825T allele frequencies in these three BMI groups were, respectively, 29.5, 39.3, and 47.7% in Germans, 46.8, 53.9, and 58.6% in Chinese, and 83.1, 87.7, and 90.9% in South Africans. In each of these three distinct groups, the 825T allele was significantly associated with obesity with odds ratios between 2 and 3. More urban than rural black Africans were overweight despite similar 825T allele frequencies in both populations, which underscores the role of both genetic and environmental factors. BP values in young male whites increased significantly with increasing BMI values but were independent of the C825T polymorphism, suggesting that hypertension associated with the 825T allele could be a consequence of obesity. Genotyping of 5254 individuals from 55 native population samples from Africa, the Americas, Europe, Asia, Australia, and New Guinea demonstrated highest 825T allele frequencies in black Africans (82%) and intermediate values in east Asians (47%). It is anticipated that high frequencies of the 825T allele in Africans and Asians may contribute to an obesity and hypertension epidemic if Westernization of lifestyles continues.

Adolescent↗

PubMed1999

[Polymorphism of HLA-DRB1, DQB1 in the Hans of north China].

OBJECTIVE: To understand polymorphism of HLA-DRB1, DQB1 in the Hans of north China and obtain more comprehensive and accurate data on genetics at DNA level. METHODS: Polymerase chain reaction-sequence specific primers (PCR-SSP) were used to determine HLA-DRB1, DQB1 alleles in 107 unrelated healthy Han individuals of north China. RESULTS: The authors determined 14 DRB1, 9 DQB1 alleles, which included not only the allele frequencies that corresponded to the gene frequencies of DR, DQ loci determined by other 9 cooperating labs but also the allele frequencies of DRB1*15, DRB1*16, DQB1*0301, DQB1*0302, DQB1*0303, DQB1*05, DQB1*0601, DQB1*0602, and DQB1*0604 that other serology labs did not report. CONCLUSION: This study has obtained a more comprehensive and accurate data set of the normal allele frequencies and linkage disequilibrium parameters of HLA-DRB1, DQB1 in the Hans of north China, which may be of significance in the studies on population genetics and disease association.

Alleles↗

PubMed1999

[Analysis on characteristics and risk factors of acute myocardial infarction in younger adults].

OBJECTIVE: To investigate the risk factors and characteristics related to acute myocardial infarction (AMI) in younger adults. METHODS: Clinical data were analyzed in 55 patients under 40 years old with AMI and compared with 1,097 controls of older age group (> or = 40 years). RESULTS: Results showed that the family history of coronary heart disease, smoking and alcohol intake were more frequently seen in younger age group than those in control group with odds ratios OR = 1.4, OR = 1.6 and OR = 1.6, respectively. Younger age group had a higher rate of noticeable inducing cause and the major causes were exhaustion and physically over-hurdened. A higher percentage of typical chest pain was found in younger patients. CONCLUSION: Smoking, alcohol drinking and genetic factor made up major risk factors of coronary heart disease in younger adults in this study, however reducing the amount of smoking and alcohol drinking, prevention of fatigue and over excitement might have some preventive impact on the prevalence of AMI in younger population.

Adolescent↗

PubMed1999

[The experimental research of purification and character of cultured retinal ganglion cell].

OBJECTIVE: To establish a cell line and purification model of retinal ganglion cells (RGCs) in vitro. METHOD: RGCs from Sprague Dawley neonatal rats (postnatal 1 - 3 days) were cultured in basal medium eagle (BME) basal medium. The growth regularity of RGCs in vitro was observed under phase-contrast microscope. RGCs were purified by Thy 1.1 with FITC antibody and detected under fluorescent microscope and phase-contrast microscope. RESULTS: Higher density of retinal cells and tectal extract facilitate cultured RGCs to survive. The purification rate of retinal ganglion cells in the experiment arrived at 95 percent. CONCLUSION: Cytokine and trophic factors from other cells in the retina and tectal extract can promote RGCs to survive, and they can be purified by Thy 1.1 antibody.

Animals↗

PubMed1998

Pharmacokinetics and pharmacodynamics of oral methotrexate and mercaptopurine in children with lower risk acute lymphoblastic leukemia: a joint children's cancer group and pediatric oncology branch study.

We prospectively assessed the pharmacokinetics of methotrexate, mercaptopurine, and erythrocyte thioguanine nucleotide levels in a homogenous population of children with lower risk acute lymphoblastic leukemia and correlated pharmacokinetic parameters with disease outcome. The maintenance therapy regimen included daily oral mercaptopurine (75 mg/m2) and weekly oral methotrexate (20 mg/m2). One hundred ninety-one methotrexate doses and 190 mercaptopurine doses were monitored in 89 patients. Plasma drug concentrations of both agents were highly variable. The area under the plasma concentration-time curve (AUC) of methotrexate ranged from 0.63 to 12 micromol*h/L, and the AUC of mercaptopurine ranged from 0.11 to 8 micromol*h/L. Drug dose, patient age, and duration of therapy did not account for the variability. Methotrexate AUC was significantly higher in girls than boys (P =.007). There was considerable intrapatient variability for both agents. Erythrocyte thioguanine nucleotide levels were also highly variable (range, 0 to 10 pmol/g Hgb) and did not correlate with mercaptopurine dose or AUC. A Cox regression analysis showed that mercaptopurine AUC was a marginally significant (P =.043) predictor of outcome, but a direct comparison of mercaptopurine AUC in the remission and relapsed patient groups failed to show a significant difference. Methotrexate and mercaptopurine plasma concentrations and erythrocyte thioguanine nucleotide levels were highly variable, but measurement of these pharmacokinetic parameters at the start of maintenance will not distinguish patients who are more likely to relapse.

Administration, Oral↗

PubMed1998

Improved assessment of coronary stenosis severity using the relative flow velocity reserve.

BACKGROUND: Myocardial fractional flow reserve (FFR) is based on pressure measurements. We have now sought to establish a Doppler-based concept of relative flow velocity reserve (RFVR) for the functional assessment of stenosis severity in epicardial coronary arteries. A clear threshold value to discriminate the functional severity of a coronary stenosis does not exist for coronary flow velocity reserve (CVR) based on intracoronary Doppler measurements. In contrast, the concept of FFR, which is based on intracoronary pressure measurements, has been extensively validated. An FFR value below 0.75 reliably indicates a significant stenosis. METHODS AND RESULTS: RFVR is calculated as the ratio between distal CVR in the stenosed target vessel and distal CVR in a nonstenotic reference vessel. In 21 patients, RFVR was determined in 24 target vessels by use of intracoronary adenosine and correlated to the FFR, determined as the ratio of mean poststenotic to aortic pressures, in the target vessel. Stenosis severity was classified according to quantitative coronary angiography analysis. Reference diameter was 3.0+/-0.4 mm (mean+/-SD), and area stenosis was 74+/-15% (range, 40% to 95%). CVRs in the target and reference vessels were 2.1+/-0.5 and 2.6+/-0.7, respectively. FFR ranged from 0.49 to 0.99 (mean, 0.81+/-0.15) and RFVR from 0.53 to 1.0 (mean, 0.82+/-0.13). Poststenotic CVR did not correlate with either percent area stenosis (r=0.27, P=NS) or FFR (r=0.33, P=NS). In contrast, FFR as well as RFVR showed a curvilinear relation to percent area stenosis (r=0.89, P<0.0001 and r=0.79, P<0.0001, respectively). There was a close linear correlation between FFR and RFVR (r=0.91, P<0.0001). CONCLUSIONS: RFVR correlates closely to FFR and to percent area stenosis, whereas the correlation of CVR with FFR and percent area stenosis is rather poor. RFVR is a promising new concept for assessment of coronary stenosis severity and clinical decision making based on Doppler measurements.

Aged↗

PubMed1998

Central 5-HT3 receptors in P and in AA alcohol-preferring rats: An autoradiographic study.

Considerable evidence exists for an involvement of serotonergic mechanisms in the control of alcohol consumption. In the present study, an extensive 5-hydroxytryptamine (5-HT3) receptor autoradiographical investigation was performed using two genetically selected rat strains, alcohol preferring (P) and Alko alcohol (AA) alcohol-preferring rats, as well as the corresponding alcohol nonpreferring (NP) and Alko nonalcohol (ANA) alcohol-nonpreferring rats. The aim was to determine if there are any differences in 5-HT3 binding levels that may illuminate mechanisms of alcohol preference in these animals. For quantitating 5-HT3 binding sites, [3H]S(-)zacopride (0.5 nM) was used. Non-specific binding was measured in the presence of granisetron 10(-6) M. The [3H]S(-)zacopride binding density was measured in two subregions of the amygdaloid nucleus, frontal cortex, piriform cortex, cingulate laminae, parietal anterior cortex, parietal medial cortex, hippocampus CA1, hippocampus CA3, and entorhinal cortex. In all the brain areas investigated, the results showed no differences between AA and ANA rats. In P rats, compared to NP controls, there was a 30% lower 5-HT3 binding level in the lateral nucleus and the posteromedial cortical nucleus of the amygdala. These findings suggest that the expression of high alcohol preference in genetically selected P and AA rats is not associated with a general alteration of central 5-HT3 receptors, although a lower 5-HT3 receptor level in the amygdala of P rats may contribute to the phenotype of this strain of animals.

Alcohol Drinking↗

PubMed1998

Role of intravascular ultrasound in the evaluation of mechanisms of coronary interventions and restenosis.

Intravascular ultrasound (IVUS) has emerged from being a research tool to becoming an intrinsic part of modern invasive cardiology. The main reason is its ability to obtain "in vivo" microanatomy. For the first time it is possible to base decisions not only on lumenograms but also on vessel wall assessment. The intervention-associated potential of IVUS includes the ability to allow optimal device selection, i.e., rotablators in calcified lesions or atherectomy devices in large plaque burden. The effects of percutaneous transluminal coronary angioplasty (PTCA) on vessel-wall morphology can be studied in great detail and the effect on luminal gain can be assessed almost on-line. Several groups have showed that the residual plaque area, even after angiographically successful PTCA, still lies in the range of 60%. A significant reduction of this percentage may influence long-term outcome after PTCA. Minimal luminal areas and residual plaque area after PTCA seem to be an indicator of restenosis, whereas the presence or absence of dissections seem to be less predictive. The main mechanism of restenosis after PTCA is vessel shrinkage, not intimal hyperplasia. Intravascular monitoring of stent expansion led to high-pressure stent deployment with a significant increase in postprocedural luminal diameters and finally the ability to withhold anticoagulation in patients with optimal stent deployment.

Angioplasty, Balloon, Coronary↗