Global revascularization

Percutaneous endovascular intervention has revolutionized the treatment of peripheral vascular disease by allowing successful treatment of patients who are not good surgical candidates. Cardiologists with peripheral vascular training are more readily able to identify patients with concomitant peripheral arterial disease. It has been our experience that the technical skills necessary to perform coronary angioplasty are transferable to the peripheral vasculature. However, an understanding of the natural history of peripheral disease and of patient and lesion selection criteria, and the knowledge of other treatment alternatives are essential elements required to perform these procedures safely and effectively. There are inherent advantages for patients when the interventionalist performing the procedure is also the clinician responsible for the pre- and post-procedure care, analogous to the vascular surgeon who cares for patients before and after surgical procedures. In view of the increased incidence of coronary artery disease in patients with atherosclerotic peripheral vascular disease, the participation of a cardiologist in their care seems appropriate.

Provisional stenting for symptomatic intracranial stenosis using a multidisciplinary approach: acute results, unexpected benefit, and one-year outcome

Percutaneous techniques have dramatically changed our approach to coronary and peripheral revascularization. Intracranial atherosclerosis is a highly morbid disease; however, techniques for revascularization are still in evolution. The authors comprise a multidisciplinary team of neurologists, neuroradiologists, and interventional cardiologists who have collaborated in treating fifteen patients with symptomatic intracranial stenosis who have failed medical therapy. The acute success rate (100%) and one-year freedom from death and stroke (93.4%) using balloon angioplasty and provisional stenting are encouraging. A surprising observation in this patient cohort was that 53% of patients had improvement or resolution of a deficit that was chronic and presumed to be permanent and irreversible. This type of chronic but reversible deficit is termed "brain angina". The background, rationale for a multidisciplinary team, techniques, and preliminary results of intracranial angioplasty with provisional stenting are presented.

Percutaneous profundaplasty in the treatment of lower extremity ischemia: results of long-term surveillance

PURPOSE

To assess the procedural and long-term clinical outcomes of balloon angioplasty of the profunda femoris artery in patients with severe limb ischemia.

METHODS

Thirty-one consecutive patients were evaluated for severe ischemia in 32 limbs: 13 (41%) were categorized Fontaine class 2B, and 19 (59%) were class 3 or 4. The superficial femoral artery was occluded in 20 (62%) limbs; an additional vessel was treated in 22 (69%) limbs.

RESULTS

Procedural success was achieved in 91% (31/32) of limbs. The ankle-brachial index increased from 0.5 +/- 0.2 at baseline to 0.7 +/- 0.2 after intervention (p < 0.01). In-hospital limb salvage was 94% (30/32), and in-hospital event-free survival was 90% (28/31). At a mean follow-up of 34 +/- 20 months, no additional amputations were necessary; 3 patients required repeat revascularization, and 5 patients died. Freedom from revascularization was 88% in the 25 survivors. At follow-up, 88% of the patients had Fontaine class 1 or 2A symptoms, and only 12% had Fontaine class 2B or higher (p < 0.001 compared with baseline).

CONCLUSIONS

These data suggest that percutaneous profundaplasty is safe, effective, and may be considered as an alternative to surgical therapy in patients with anatomically suitable lesions.

Calcium signalling--an overview

Calcium (Ca2+) is an almost universal intracellular messenger, controlling a diverse range of cellular processes, such as gene transcription, muscle contraction and cell proliferation. The ability of a simple ion such as Ca2+ to play a pivotal role in cell biology results from the facility that cells have to shape Ca2+ signals in the dimensions of space, time and amplitude. To generate the variety of observed Ca2+ signals, different cell types employ components selected from a Ca2+ signalling 'toolkit', which comprizes an array of signalling, homeostatic and sensory mechanisms. By mixing and matching components from the toolkit, cells can obtain Ca2+ signals that suit their physiology.

A comparison of fluorescent Ca2+ indicator properties and their use in measuring elementary and global Ca2+ signals

Quantifying the magnitude of Ca2+ signals from changes in the emission of fluorescent indicators relies on assumptions about the indicator behaviour in situ. Factors such as osmolarity, pH, ionic strength and protein environment can affect indicator properties making it advantageous to calibrate indicators within the required cellular or subcellular environment. Selecting Ca2+ indicators appropriate for a particular application depends upon several considerations including Ca2+ binding affinity, dynamic range and ease of loading. These factors are usually best determined empirically. This study describes the in-situ calibration of a number of frequently used fluorescent Ca2+ indicators (Fluo-3, Fluo-4, Calcium Green-1, Calcium Orange, Oregon Green 488 BAPTA-1 and Fura-Red) and their use in reporting low- and high-amplitude Ca2+ signals in HeLa cells. All Ca2+ indicators exhibited lower in-situ Ca2+ binding affinities than suggested by previously published in-vitro determinations. Furthermore, for some of the indicators, there were significant differences in the apparent Ca2+ binding affinities between nuclear and cytoplasmic compartments. Variation between indicators was also found in their dynamic ranges, compartmentalization, leakage and photostability. Overall, Fluo-3 proved to be the generally most applicable Ca2+ indicator, since it displayed a large dynamic range, low compartmentalization and an appropriate apparent Ca2+ binding affinity. However, it was more susceptible to photobleaching than many of the other Ca2+ indicators.

Acute renal failure after redo thoracoabdominal aortic aneurysm repair in a patient with a solitary kidney: successful percutaneous treatment

PURPOSE

To report the successful percutaneous treatment of renal artery stenosis that precipitated renal failure following surgical repair of a thoracoabdominal aortic aneurysm (TAAA).

METHODS AND RESULTS

A 70-year-old woman with a solitary kidney became anuric 2 hours after urgent repair of a symptomatic true aneurysm of the Carrel patch from an 8-year-old TAAA repair. After medical treatment failed, aortography was performed, identifying complete occlusion of the solitary renal artery. Balloon dilation and implantation of a Palmaz stent restored renal perfusion and improved function. At 6-month follow-up, she was normotensive and her creatinine within normal limits.

CONCLUSIONS

Renal artery stenosis or occlusion is a treatable cause of acute renal failure after TAAA repair. Percutaneous treatment options are likely to be better tolerated than surgical revascularization in this patient population.

Inositol 1,4,5-trisphosphate-induced Ca2+ release is inhibited by mitochondrial depolarization

We investigated the consequences of depolarizing the mitochondrial membrane potential (Deltapsi(mit)) on Ca(2+) signals arising via inositol 1,4,5-trisphosphate receptors (InsP(3)R) in hormone-stimulated HeLa cells. Carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP) or a mixture of antimycin A+oligomycin were found to rapidly depolarize Deltapsi(mit). Mitochondrial depolarization enhanced the number of cells responding to a brief application of a Ca(2+)-mobilizing hormone and prolonged the recovery of cytosolic Ca(2+) after washout of the hormone; effects consistent with the removal of a passive Ca(2+) buffer. However, with repeated application of the same hormone concentration both the number of responsive cells and peak Ca(2+) changes were observed to progressively decline. The inhibition of Ca(2+) signalling was observed using different Ca(2+)-mobilizing hormones and also with a membrane-permeant Ins(1,4,5)P(3) ester. Upon washout of FCCP, the Ca(2+) signals recovered with a time course similar to the re-establishment of Deltapsi(mit). Global measurements indicated that none of the obvious factors such as changes in pH, ATP concentration, cellular redox state, permeability transition pore activation or reduction in Ca(2+)-store loading appeared to underlie the inhibition of Ca(2+) signalling. We therefore suggest that local changes in one or more of these factors, as a consequence of depolarizing Deltapsi(mit), prevents InsP(3)R activation.

Primary stenting in acute myocardial infarction: influence of diabetes mellitus in angiographic results and clinical outcome

BACKGROUND

The outcome of patients with diabetes after myocardial infarction (MI) has traditionally been worse than in their nondiabetic counterparts before and during the thrombolytic therapy era. Whether the fate of patients with diabetes might improve with mechanical intervention, particularly with primary stenting, has not previously been studied.

METHODS

We compared the angiographic and clinical outcome of 76 nondiabetic patients (aged 61 +/- 14 years; 66% male) and 28 patients with diabetes (aged 65 +/- 12 years; 64% male) consecutively treated with primary stenting for acute MI. Coronary Thrombolysis In Myocardial Infarction grade 3 flow was restored in 96% of diabetic and 97% of nondiabetic patients.

RESULTS

Angiographic results after stent deployment were similar in the 2 groups. At 1-month follow-up, all patients in both groups were alive. Patients with diabetes had a much higher incidence of stent thrombosis (18% vs 1%; P =.003), which accounted for the majority of the major cardiac events at 1 month (21% vs 4%; P =.009). At a mean follow-up of 315 +/- 13 days, 99% of nondiabetic and 89% of patients with diabetes were alive (P =.04). Overall freedom from a major cardiac event (death, MI, target vessel revascularization) at 315 +/- 13 day follow-up was 88% for nondiabetics and 54% for patients with diabetes (P =.0003). By multivariate analysis, diabetes mellitus was the most important predictor for development of 1-month (RR 9.89; 95% confidence interval, 1.6-30) and late major cardiovascular events (RR 8.39; 95% confidence interval, 2.93-24).

CONCLUSIONS

Primary stenting in acute MI is highly effective in restoring immediate TIMI 3 coronary flow in nondiabetic patients and patients with diabetes. This procedure may improve benefit in terms of mortality rate to both groups, particularly in patients with diabetes, compared with previous reports with thrombolytic therapy. Nevertheless, stent thrombosis and major cardiovascular events at 1 month and late follow-up are more frequent in patients with diabetes.

Predictors of stent thrombosis after primary stenting for acute myocardial infarction

The aim of the study was to determine if a hypercoagulable state that may persist for several months after an acute myocardial infarction may contribute to an increased incidence of stent thrombosis. Primary stenting was performed in 104 consecutive patients with acute myocardial infarction using 147 coronary stents. Twenty-eight patients (27%) were diabetic and 55 patients (53%) were smokers. A single stent was placed in 63%, two stents in 33%, and more than two stents in 4% of the patients. Procedural success was obtained in 97% of the patients. All stents were deployed using high-pressure balloon inflation. The reference vessel diameter and minimal lumen diameter after stent deployment were 3.30 +/- 0.42 and 3.23 +/- 0.42 mm, respectively. Six patients (5.7%) developed stent thrombosis within 1 month after the procedure complicated by reinfarction in five of the six patients. At 1-month follow-up, all patients remained alive. On multivariate analysis, independent predictors of stent thrombosis were diabetes mellitus (relative risk [RR] 5.2; 95% confidence interval [CI] 1.8, 25.1), tobacco use (RR 4.5; 95% CI 1.3, 24.5), number of stents: 1 vs. > 1 (RR 3.7; 95% CI 1.1, 15.9), minimal lumen diameter poststent placement (RR 0.03; 95% CI 0.0002, 0.74), and duration of chest pain before intervention (RR 1.1; 95% CI 1.01, 1.25). Stent thrombosis had not been associated with diabetes mellitus and tobacco use previously but is in agreement with the enhanced platelet aggregability, coagulation factor abnormalities, and impaired fibrinolysis characteristic of these patients.

Differential expression of gonadotropin and prolactin antigens by GHRH target cells from male and female rats

There is a 2- to 3-fold increase in luteinizing hormone-beta (LHbeta) or follicle-stimulating hormone-beta (FSHbeta) antigen-bearing gonadotropes during diestrus in preparation for the peak LH or FSH secretory activity. This coincides with an increase in cells bearing LHbeta or FSHbeta mRNA. Similarly, there is a 3- to 4-fold increase in the percentage of cells that bind GnRH. In 1994, we reported that this augmentation in gonadotropes may come partially from subsets of somatotropes that transitionally express LHbeta or FSHbeta mRNA and GnRH-binding sites. The next phase of the study focused on questions relating to the somatotropes themselves. Do these putative somatogonadotropes retain a somatotrope phenotype? As a part of ongoing studies that address this question, a biotinylated analog of GHRH was produced, separated by HPLC and characterized for its ability to elicit the release of GH as well as bind to pituitary target cells. The biotinylated analog (Bio-GHRH) was detected cytochemically by the avidin-peroxidase complex technique. It could be displaced by competition with 100-1000 nM GHRH but not corticotropin-releasing hormone or GnRH. In cells from male rats exposed to 1 nM Bio-GHRH, 28+/-6% (mean+/-s.d) of pituitary cells exhibited label for Bio-GHRH (compared with 0.8+/-0.6% in the controls). There were no differences in percentages of GHRH target cells in populations from proestrous (28+/-5%) and estrous (25+/-5%) rats. Maximal percentages of labeled cells were seen following addition of 1 nM analog for 10 min. In dual-labeled fields, GHRH target cells contained all major pituitary hormones, but their expression of ACTH and TRH was very low (less than 3% of the pituitary cell population) and the expression of prolactin (PRL) and gonadotropins varied with the sex and stage of the animal. In all experimental groups, 78-80% of Bio-GHRH-reactive cells contained GH (80-91% of GH cells). In male rats, 33+/-6% of GHRH target cells contained PRL (37+/-9% of PRL cells) and less than 20% of these GHRH-receptive cells contained gonadotropins (23+/-1% of LH and 31+/-9% of FSH cells). In contrast, expression of PRL and gonadotropins was found in over half of the GHRH target cells from proestrous female rats (55+/-10% contained PRL; 56+/-8% contained FSHbeta; and 66+/-1% contained LHbeta). This reflected GHRH binding by 71+/-2% PRL cells, 85+/-5% of LH cells and 83+/-9% of FSH cells. In estrous female rats, the hormonal storage patterns in GHRH target cells were similar to those in the male rat. Because the overall percentages of cells with Bio-GHRH or GH label do not vary among the three groups, the differences seen in the proestrous group reflect internal changes within a single group of somatotropes that retain their GHRH receptor phenotype. Hence, these data correlate with earlier findings that showed that somatotropes may be converted to transitional gonadotropes just before proestrus secretory activity. The LH and FSH antigen content of the GHRH target cells from proestrous rats demonstrates that the LHbeta and FSHbeta mRNAs are indeed translated. Furthermore, the increased expression of PRL antigens by these cells signifies that these convertible somatotropes may also be somatomammotropes.

Cold stress and corticotropin-releasing hormone induced changes in messenger ribonucleic acid for the alpha(1)-subunit of the L-type Ca(2+) channel in the rat anterior pituitary and enriched populations of corticotropes

In response to stress, adrenocorticotropin (ACTH) is secreted from anterior pituitary corticotropes. Corticotropin-releasing hormone (CRH) is a potent stimulator of ACTH secretion. The CRH stimulation of secretion is mediated by cAMP and is largely dependent on Ca(2+) influx through voltage-gated L-type Ca(2+) channels. This study was designed to investigate whether the expression of L-type Ca(2+) channels in the rat anterior pituitary and in corticotropes is regulated by acute stress and CRH. RNase protection assays were used to quantify alpha(1C) mRNA of the L-type Ca(2+) channel. The alpha(1C) mRNA levels from stressed rats increased by 31% in anterior pituitaries of rats after 30 min of exposure to cold stress. Neither 60 min cold stress nor 30 min restraint stress had an effect on alpha(1C) mRNA levels. When alpha(1C) mRNA was detected by in situ hybridization in a population of corticotropes enriched to 90%, 0.5 nM CRH (3 h) stimulated a 36% increase in the average area of label/cell and a 10% increase in the average density of label. Our results suggest that (1) the expression of alpha(1C) subunit mRNA of L-type Ca(2+) channels is increased in the rat anterior pituitary with a stress-specific response that might reflect an increase both in thyrotropes and corticotropes (both are known to be stimulated by cold stress), and (2) the CRH-mediated increase in alpha(1C) mRNA expression in individual rat corticotropes, in vitro, supports the hypothesis that some of the increase in vivo is due to changes in corticotropes.

Rheolytic thrombectomy: a new treatment for stent thrombosis

Coronary stent thrombosis, a rare complication after stent deployment, carries major morbidity and mortality. Traditional treatments for stent thrombosis include local or systemic delivery of thrombolytic agents and balloon angioplasty, both with far from optimum results. We report on two cases of coronary stent thrombosis successfully treated with rheolytic thrombectomy as an adjunct to balloon angioplasty.

Rheolytic thrombectomy in the treatment of acute limb-threatening ischemia: immediate results and six-month follow-up of the multicenter AngioJet registry. Possis Peripheral AngioJet Study AngioJet Investigators

We tested the efficacy of rheolytic thrombectomy in treating 21 patients (mean age 68+/-12 years; 66% male) and 22 vessels (limbs) who presented to the hospital within 2 weeks of the development of limb-threatening ischemia. Fifty-two percent had contraindications to use thrombolytics, and 57% had severe comorbidities. All of the vessels were occluded with thrombus on the initial angiogram. Procedural success was achieved in 20 limbs (91%). Three patients expired in the hospital, and one expired at follow-up due to nonvascular causes. Acute limb salvage was achieved in 18 of 19 limbs (95%) in the 18 survivors, and 6-month limb salvage was achieved in 16 of 18 limbs (89%) in the 17 survivors. Rheolytic thrombectomy is effective in restoring immediate blood flow in acute limb-threatening ischemia, especially in high-risk surgical patients or patients with contraindications to thrombolytic therapy.

Acute coronary occlusion and in-stent thrombosis in a patient with essential thrombocythemia

We describe a case of essential thrombocythemia in a 34-year-old male who presented with acute anterior wall myocardial infarction and a platelet count of 2,100,000/mm3. Primary percutaneous coronary angioplasty and stenting were performed. Postangioplasty course was complicated by stent thrombosis requiring repeat coronary angioplasty and persistent femoral arterial bleeding that was treated with surgical exploration and repair. The patient was subsequently treated with platelet pheresis, acetylsalicylic acid, ticlopidine, hydroxyurea, and anagrelide without further complications.

Coronary stenting in cardiac allograft vasculopathy

OBJECTIVE

The purpose of this study was to evaluate acute angiographic success, in-hospital complications and long-term outcome after intracoronary stenting in patients with cardiac allograft vasculopathy.

BACKGROUND

The application of conventional interventional modalities to treat discrete lesions in patients with cardiac allograft vasculopathy is associated with higher procedural morbidity, mortality and higher restenosis compared to atherosclerotic coronary artery disease. Elective coronary stenting has been shown to lower restenosis rates and improve long-term outcome in selected patients with native coronary artery disease; however, its safety and efficacy in reducing restenosis in patients with cardiac allograft vasculopathy is unknown.

METHODS

Ten patients with 19 discrete lesions in a major coronary artery without diffuse distal disease underwent intracoronary stenting using Palmaz-Schatz stents. The average stent size was 3.4 mm, and the stent/artery ratio was 0.99+/-0.07. Eight of ten (80%) patients received antiplatelet therapy (aspirin plus ticlopidine) only.

RESULTS

Procedural success was 100% with no in-hospital stent thrombosis, Q-wave myocardial infarction or death. Minimal luminal diameter increased from 0.83+/-0.38 mm to 3.23+/-0.49 mm after stenting. Diameter stenosis decreased from 74.91+/-11.52% to 5.90+/-4.09% after stenting. Follow-up angiography was performed in 8 of 10 (80%) patients and 16 of 19 (84%) lesions. Target lesion revascularization was required in 2 of 10 (20%) patients and 3 of 16 (19%) lesions. Allograft survival was 7 of 10 (70%) at the end of 22+/-11 months follow-up.

CONCLUSIONS

Intracoronary stenting can be performed safely with excellent angiographic success in selected patients with cardiac allograft vasculopathy. The restenosis rate appears to be low despite the aggressive nature of the disease. A multicenter study with a larger number of patients is required to assess its efficacy in reducing restenosis and improving allograft survival.

Morphologic comparison of atherosclerotic lesions in native coronary arteries and saphenous vein graphs with intracoronary angioscopy in patients with unstable angina

BACKGROUND

Coronary vein grafts develop accelerated atherosclerosis after aortocoronary bypass surgery. Previous pathologic studies have suggested that the morphologic appearance of atherosclerotic lesions in saphenous vein grafts may have subtle differences compared with those of native coronary arteries and may be more prone to disruption and thrombus formation. However, a comparative in vivo assessment of the angioscopic morphology differences between these two types of vessels has not been reported previously. We compared the angioscopic lesion morphology of native coronary arteries and saphenous vein grafts in patients with unstable angina.

METHODS AND RESULTS

Percutaneous coronary angioscopy was performed in 60 consecutive patients with unstable angina. Plaque color, texture, friability, and the presence of atherosclerotic plaque ulceration or intracoronary thrombus were noted in the culprit lesion. The culprit lesion was located in native coronary arteries in 42 (70%) patients and in a saphenous vein graft in 18 (30%) patients. There were no significant differences in age, sex, and coronary risk factors including tobacco use, hypertension, hypercholesterolemia, or diabetes mellitus between the two populations. There were also no significant differences between the two groups in terms of plaque color, surface texture, or the incidence of complex plaque morphology (plaque ulceration and intracoronary thrombosis). Loosely adherent, friable plaque, detected by angioscopy, was absent in native coronary arteries and was present in 44% of the saphenous vein grafts (p < 0.0001).

CONCLUSIONS

The results of our angioscopic study indicate that other than a high incidence of plaque friability in vein grafts, the surface morphology of culprit lesions in unstable angina patients is quite similar for saphenous vein grafts and native coronary arteries.

Permeability, cytotoxicity, and genotoxicity of chromium (V) and chromium (VI) complexes in V79 Chinese hamster lung cells

The genotoxicity of Cr(V) complexes in mammalian cells (V79 Chinese hamster lung cells) has been studied for the first time using the in vitro micronucleus assay. Two complexes were investigated, [CrO(ehba)2]-, which undergoes ligand-exchange and disproportionation reactions in the cell growth medium, and [CrO(mampa)]-, which is chemically inert in the medium for the duration of the exposure period. Results of in vitro micronucleus assays show that both complexes are genotoxic and exhibit similar potencies to that of [Cr2O7]2-. The permeabilities of the Cr(V) complexes were also investigated for the first time using particle-induced X-ray emission (PIXE) analysis of individual cells. The Cr uptake increased in the order: [Cr(phen)2-(H2O)2]3+ < [CrO(ehba)2]- < [CrO(mampa)]- < [Cr2O7]2-. Clonal assays showed that Cr(VI) exhibits an expectedly higher cytotoxicity than the Cr(V) complexes. While the genotoxicities of the Cr(V) and Cr(VI) complexes increase according to their permeabilities, the genotoxicities of the Cr(V) complexes are equal to, if not greater than, that of Cr(VI) in terms of the amount of Cr entering the cell. This supports other evidence that Cr(V), produced as a metabolic intermediate from the intracellular reduction of Cr(VI), may be important in Cr-induced cancers.

Renal artery stent placement: utility in lesions difficult to treat with balloon angioplasty

OBJECTIVES

We assessed the safety and efficacy of stent placement in patients with poorly controlled hypertension and renal artery stenoses, which are difficult to treat with balloon angioplasty alone.

BACKGROUND

Preliminary experience with stent placement suggests improved results over balloon angioplasty alone in patients with atherosclerotic renal artery stenosis.

METHODS

Balloon-expandable stents were placed in 100 consecutive patients (133 renal arteries) with hypertension and renal artery stenosis. Sixty-seven of the patients had unilateral renal artery stenosis treated and 33 had bilateral renal artery stenoses treated with stents placed in both renal arteries.

RESULTS

Angiographic success, as determined by quantitative angiography, was obtained in 132 (99%) of 133 lesions. Early clinical success was achieved in 76% of the patients. Six months after stent placement, the systolic blood pressure was reduced from 173 +/- 25 to 147 +/- 23 mm Hg (p < 0.001); the diastolic pressure from 88 +/- 17 to 76 +/- 12 mm Hg (p < 0.001); and the mean number of antihypertensive medications per patient from 2.6 +/- 1 to 2.0 +/- 0.9 (p < 0.001). Angiographic follow-up at a mean of 8.7 +/- 5.0 months in 67 patients revealed restenosis (>50% diameter narrowing) in 15 (19%) of 80 stented vessels.

CONCLUSIONS

Renal artery stenting is an effective treatment for renovascular hypertension, with a low angiographic restenosis rate. Stent placement appears to be a very attractive therapy in patients with lesions difficult to treat with balloon angioplasty such as renal aorto-ostial lesions and restenotic lesions, as well as after a suboptimal balloon angioplasty result.

Effects of renal artery stent implantation in patients with renovascular hypertension presenting with unstable angina or congestive heart failure

This study evaluates the effect of renal artery stent implantation in patients with renovascular hypertension presenting with unstable angina (n = 20) or congestive heart failure (n = 28). There was a significant improvement in the Canadian Cardiovascular Society angina class and the New York Heart Association functional class, and at 8.4 +/- 6.4 month follow-up.

Allograft aortopathy: an in vivo study of donor aorta involvement in cardiac allograft vasculopathy

Limited histopathologic studies of failed cardiac allografts have demonstrated that cardiac allograft vasculopathy extends into the donor aorta; however, no study has examined the development of allograft aortic intimal proliferation in vivo in conjunction with coronary intimal hyperplasia. By using simultaneous intracoronary and intraaortic ultrasound, we studied 20 consecutive heart transplant recipients at 2.5 +/- 2.1 years after transplantation. The degree of coronary intimal thickening was strongly correlated with the development of intraaortic intimal hyperplasia (r = 0.90; p < 0.0001). Multivariate predictors of aortic intimal thickening included years after transplant (r = 0.47; p = 0.03), serum cholesterol level (r = 0.65, p = 0.003), and serum triglyceride level (r = 0.51; p = 0.03). Allograft aortopathy occurs in a similar manner to allograft coronary disease, thus providing support for the notion that an immunologic stimulus operating across the allograft vascular bed may be responsible for the development of cardiac allograft vasculopathy. Furthermore, this investigation provides insight into the putative role of hyperlipidemia in allograft vascular disease.

Microprobe X-ray absorption spectroscopic determination of the oxidation state of intracellular chromium following exposure of V79 Chinese hamster lung cells to genotoxic chromium complexes

The oxidation state of intracellular chromium has been determined directly in mammalian lung cells exposed to mutagenic and carcinogenic chromium compounds. Microprobe X-ray absorption spectroscopy (XAS) experiments on single V79 Chinese hamster lung cells showed that Cr(VI) and Cr(V) complexes were reduced completely (>90%) to Cr(III) within 4 h of exposure of the cells. This result provides direct evidence for the hypothesis that these genotoxic oxidants react rapidly with intracellular reductants.