Advantage of stents in the most proximal left anterior descending coronary artery

OBJECTIVES

Balloon angioplasty of the proximal left anterior descending artery is associated with a high rate of restenosis. We hypothesized that the significant reduction in restenosis rates demonstrated by stent implantation in the coronary arteries in general would be especially prominent in the most proximal left anterior descending coronary artery.

METHODS

We reviewed 65 consecutive patients in whom stents were placed in the most proximal left anterior descending artery between March 1990 and July 1995 and compared them with 56 consecutive patients with angioplasty. Minimum luminal diameter was measured angiographically before, after, and 6 months after the intervention. We compared the change in minimum luminal diameter and restenosis rate between the patients with stents and the patients with angioplasty to clarify the response of this important artery to these different procedures.

RESULTS

There was 6-month angiographic follow-up of the treated lesion in 99% of the patients. The postprocedure minimum luminal diameter, acute gain, and minimum luminal diameter at follow-up were greater in arteries treated with stents than in those treated with balloons. Of importance, late loss was not significantly different between the two groups after treatment at this site. Thus the restenosis rate after angioplasty was 52% compared with 20% after stent implantation (p < 0.001).

CONCLUSIONS

Stent implantation in the most proximal left anterior descending artery is associated with an even greater reduction in restenosis rate than implantations elsewhere in the coronary arteries. This enhanced reduction in restenosis appears to be due to an unusually large amount of late loss after angioplasty at this site.

Differentiation-dependent expression of transgenes in engineered astrocyte cell lines

The utility of transgenes for both basic and applied studies has been augmented by the recent advent of versions that can be regulated by the addition of suitable activators. However, still more convenient would be transgenes whose expression responded appropriately to endogenous signals. The promoter of the glial fibrillary acidic protein (GFAP) gene is a candidate for this role in the central nervous system (CNS) since the GFAP gene is specifically expressed in astrocytes in the CNS and its activity is upregulated in response to almost any CNS injury. As a feasibility study, we isolated a C6 rat glioma cell line stably transfected with a lacZ reporter gene driven by the gfa2 human GFAP promoter fragment. We find that the activity of the transgene indeed responds to an environmental signal, forskolin, that induces astrocyte-like differentiation of C6 cells. We also isolated a C6 line carrying a transgene in which the gfa2 promoter directs expression of a cDNA for tyrosine hydroxylase (TH), the rate-limiting enzyme for catecholamine synthesis. This transgene should be of considerable interest for gene therapy for Parkinson's disease. We show that in this cell line both TH mRNA and protein are upregulated by forskolin. Finally, we note that the growth rate of C6 cells is severely depressed by forskolin, suggesting that predifferentiation of these cells prior to implant may retard their tumor forming capacity, prolonging the time that they can be used in animal models in vivo.

Aortic dissection occurring during coronary angioplasty: angiographic and transesophageal echocardiographic findings

A localized acute aortic dissection was produced in 2 patients, complicating coronary angioplasty. In both cases a coronary dissection provided the entry door, with subsequent retrograde progression of the dissection into the aortic root. After sealing the entry door, both patients could be managed conservatively using transesophageal echocardiography to accurately define the location of the intimal flap and to rule out dissection progression.

Angioscopic evaluation of angiographically complex coronary lesions

Coronary angioscopy (CA) provides direct visualization of the endoluminal surface of coronary vessels. The usefulness of CA during coronary angioplasty of angiographically complex lesions remains to be established. This study was designed to determine the value of CA to elucidate the underlying substrate of angiographically complex lesions. Forty-seven consecutive patients with angiographically complex lesions were studied with CA before coronary intervention. Mean age of the group was 59 +/- 9 years; six patients were women. Forty (85%) patients had unstable angina. Complex angiographic lesions included coronary occlusions (n = 23) (14 with Thrombolysis in Myocardial Infarction coronary flow grade 0 and nine with flow grade 1), lesions with intraluminal filling defects suggestive of thrombus or ulceration (n = 8), and lesions that were highly eccentric (n = 16). Items analyzed with CA included red thrombus (lining or protruding) and plaque color (yellow, white, or mixed). In all patients, CA visualized the protruding material causing the angiographic appearance. At this site CA detected red thrombus in 34 (72%) patients (14 protruding, 20 lining) and atherosclerotic plaque in 45 (96%) patients. At the site of the angiographically complex lesion, plaque was classified as predominantly yellow in 24 patients, mixed in 12, and white in nine. The incidence of thrombus on CA was higher for occluded vessels (91%) or lesions with intraluminal filling defects or ulceration (87%) than in eccentric lesions (37%) (p < 0.05). However, plaque coloration was not significantly different among these three angiographic subgroups. Initial procedural success (without stent requirement) was lower in lesions showing protruding thrombus on CA (64% vs 91 %, p < 0.05). Thus most angiographically complex lesions contain thrombus. On CA red thrombus was more frequently identified on occluded vessels and lesions with filling defects or ulceration than in eccentric lesions. Yellow or mixed plaques are common in these patients, suggesting lipid-laden plaques as the underlying pathologic substrate of angiographically complex lesions.

Angioscopic characteristics of coronary narrowing in patients with recurrent myocardial ischemia after myocardial infarction

Coronary angioscopy was used to elucidate the underlying substrate of the culprit lesion in 20 patients with postinfarction ischemia and in 19 patients with other types of unstable angina. Plaque characteristics were similar in both groups, but red thrombi and occlusive thrombi were more frequently seen in patients with postinfarction ischemia.

Clinical and angiographic implications of coronary stenting in thrombus-containing lesions

OBJECTIVES

This study sought to determine the results of coronary stenting in thrombus-laden lesions.

BACKGROUND

The angiographic evidence of intracoronary thrombus has classically been considered a formal contraindication to stent implantation. However, with increasing use of stenting, the indications for this technique have widened to include treatment of patients who have an acute coronary syndrome or lesions with adverse anatomic features.

METHODS

We studied 86 consecutive patients (mean age +/- SD 61 +/- 11 years, 14 women) undergoing coronary stenting of a thrombus-containing lesion; the procedure was performed electively in 39% and after angioplasty failure in 61%. Sixty-four patients (75%) were treated for unstable angina, and 19 (22%) underwent the procedure during an acute myocardial infarction. A specific protocol that included clinical and late angiographic follow-up was used.

RESULTS

Angiographic success was obtained in 83 patients (96%). Five patients (6%) died during the hospital stay despite angiographic success; four of these had cardiogenic shock, and one (1%) had subacute stent thrombosis. Non-Q wave myocardial infarction developed in five additional patients (6%), and four of these five had data consistent with distal embolization. Of the 78 patients discharged with angiographic success, 67 (86%) were event-free and clinically improved at last follow-up visit (12 +/- 11 months). During the follow-up period, eight patients required repeat angioplasty, one patient required heart transplantation, and two patients died. Quantitative angiography demonstrated excellent angiographic results after stenting (minimal lumen diameter 0.31 +/- 0.4 vs. 2.77 +/- 0.6 mm). Late angiographic follow-up (5.5 +/- 1 months) was obtained in 50 patients with 54 lesions (93% of eligible), revealing a minimal lumen diameter of 2.0 +/- 1 mm and restenosis (lumen narrowing > 50%) in 18 lesions (33%).

CONCLUSIONS

Coronary stenting constitutes an effective therapeutic strategy for patients with thrombus-containing lesions, either after failure of initial angioplasty or electively as the primary procedure. Coronary stenting in this adverse anatomic setting results in a high degree of angiographic success, a low incidence of subacute thrombosis and an acceptable restenosis rate.

Effects of Palmaz-Schatz stents on angled coronary arteries

This review of consecutive, single Palmaz-Schatz stent implantations reveals that coronary lesion angulation does not result in suboptimal results or increased restenosis after stenting. The implantation of a rigid stent at an arterial hinge point is associated with an increased restenosis rate.

Intracoronary ultrasound before coronary interventions: a prospective comparison of two different catheters

Intravascular ultrasound (IVUS) provides unique information about the coronary arterial wall that can be used to guide transcatheter therapy. In this prospective study, two different IVUS systems were compared with respect to feasibility of imaging before intervention and angiographic changes induced by the simple advancement of the catheter across the lesion. Eighty-five patients (mean age 59 +/- 10 yr, 11 female) were studied with IVUS before intervention. In 34 patients, a 4.8 F (1.6-mm) IVUS catheter was used (Group I), whereas in the remaining 51 patients, a 3.5 F (1.2-mm) IVUS catheter was used (Group II). Quantitative angiography was performed before and after the IVUS study to determine potential changes in lumen diameter. Clinical and angiographic characteristics were similar in the two groups. A successful IVUS interrogation of the target lesion was obtained more frequently in Group II (45/51 (88%) vs. 19/34 (56%) patients, P < 0.01). After the IVUS study, a change in minimal lumen diameter was seen in Group I (baseline 0.84 +/- 0.2 vs. final 1.17 +/- 0.2 mm, P < 0.001) and Group II patients (baseline 0.80 +/- 0.3 vs. final 1.03 +/- 0.4 mm, P < 0.01). In the 64 lesions successfully crossed, the absolute gain in lumen diameter was significantly higher in Group I (0.40 +/- 0.2 vs. 0.23 +/- 0.2 mm, P < 0.05). In addition, an inverse correlation was found between baseline minimal lumen diameter and the absolute lumen gain induced by the IVUS study in Group I (r = -0.47, P < 0.05) but not in Group II patients (r = -0.16, NS). Neither angiographic nor echogenic lesion characteristics were associated with the change in lumen diameter. When multivariate analysis was applied, catheter size was the only independent predictor of lumen gain induced by IVUS after adjustment. Thus, the advancement of IVUS catheters across severe coronary lesions induces significant angiographic changes consistent with plaque remodeling and a Dotter effect. The use of smaller catheters not only allows a higher number of lesions to be studied before intervention, but also lessens the mechanical disruption of the plaque, yielding a more accurate and veracious picture of baseline plaque characteristics.

[The role of non-angiographic observations (IVUS, angioscopy, doppler) in coronary stenting]

Coronary stenting is increasingly used during transcatheter coronary therapy. Coronary angiography, mainly since the advent of quantitative angiography, provides an effective tool to obtain excellent clinical results with coronary stenting. However, during this procedure some limitations inherent to the angiographic techniques may become apparent. Accordingly, great enthusiasm has been generated regarding the potential value of alternative diagnostic techniques to guide coronary stenting. Intravascular ultrasound is able to study the arterial wall and provides a unique tool to assess stent expansion, apposition and symmetry. Therefore, this technique is increasingly used to optimize stent deployment. Coronary angioscopy directly visualizes stent expansion and is able to precisely recognize protrusion of redundant fronds of tissue or residual dissections within the stent struts. In addition, this technique is the procedure of choice to identify intracoronary thrombus. Intracoronary Doppler permits the application in the catheterization laboratory of sophisticated methods of functional assessment of lesion severity. Coronary stenting allows a faster and complete normalization of coronary flow reserve than balloon angioplasty. Thus, all these new techniques of intracoronary diagnosis provide unique and useful information, which is complementary to that obtained with angiography, potentially useful during coronary stenting.

Arterial perforation during optimization of coronary stents using high-pressure balloon inflations

Angiographic optimization of coronary stents, using high-pressure balloon inflation, was complicated by vessel rupture in 3 patients. The risk of this potentially life-threatening complication should be considered during stent optimization.

Percutaneous mitral valvuloplasty for rheumatic mitral stenosis associated with cor triatriatum

A patient with rheumatic mitral stenosis associated with cor triatriatum is described. The anomalies were detected by two-dimensional echocardiography and confirmed by transesophageal echocardiography. Percutaneous mitral valvuloplasty was successfully performed with the inoue technique. The clinical and technical implications during the procedure of this previously unreported association are discussed.

Beta-adrenergic receptor activation promotes process outgrowth in an embryonic rat basal forebrain cell line and in primary neurons

A clonal cell line, AS583-8.E4.22, from the embryonic day 15 rat basal forebrain was established using retrovirus-mediated transduction of a temperature-sensitive mutant of the simian virus 40 (SV40) large tumour antigen. The cell line expresses cytoskeletal and neurotransmitter features indicative of neuronal commitment. In response to agents that increase intracellular cAMP, including forskolin and catecholamines, the cell line exhibits rapid process outgrowth and growth cone formation that does not require new gene expression or protein synthesis. The neurite outgrowth induced by catecholamines is mediated by beta 2-adrenergic receptors and is characterized by a rapid, reversible redistribution of filamentous actin. Neurons from primary cultures of embryonic day 15 basal forebrain were also found to respond to beta-adrenergic receptor agonists by enhancing growth cone formation. These results suggest that catecholamines provide cues that induce cytoskeletal rearrangements leading to neuronal process outgrowth and growth cone formation in the developing basal forebrain and possibly other neuronal progenitor cell populations. The neuronal basal forebrain cell line provides an ideal model to study the signalling mechanisms underlying the catecholamine-induced process outgrowth.

Stent embolization during intracoronary stenting

Nine patients with systemic embolization complicating intracoronary stenting (incidence 1.8%) are described. Although this rare complication was not associated with any clinical sequelae, great care should be taken to prevent this possibility, especially in patients with unfavorable anatomic characteristics, including lesions in the left circumflex artery, at bend points, and calcified lesions.

Percutaneous mitral valvuloplasty with the Inoue technique in a patient with heavily calcified interatrial septum

A 75-year-old woman with severe rheumatic mitral stenosis was admitted for percutaneous mitral valvuloplasty. Two-dimensional echocardiography disclosed severe calcification of the posterolateral left atrial wall and interatrial septum. Percutaneous mitral valvuloplasty, using the inoue technique, was successfully performed after a transseptal puncture through the calcified interatrial septum, avoiding the need for surgical intervention.

[Coronary angioscopy: initial experience during coronary interventions]

BACKGROUND AND OBJECTIVE

Percutaneous coronary angioscopy (CAG) provides in vivo visual information about the luminal aspect of the vessel. In this report we describe our initial experience with CAG during coronary angioplasty (PTCA).

METHODS

Fifty-five patients (age 60 +/- 9 years), 8 female, were included. Most patients, 42 (76%) were treated for unstable angina.

RESULTS

In 49 patients (89%) CAG was performed prior to PTCA, and in all cases the intraluminal material responsible of the stenosis was recognized. This included plaque associated to thrombus in 29 patients (59%), isolated plaque in 15 (31%) and isolated thrombus in 5 (10%). Of these plaques, 25 (57%) were yellow, 14 (32%) were yellow and white and 5 (11%) were white. Of the 34 thrombi, 23 (68%) were mural and 11 (32%) protruding. CAG post-PTCA was performed in 43 patients (78%). CAG visualized residual plaque in 41 patients (95%) and residual thrombus in 34 (79%). In addition, CAG recognized dissections in 30 patients (70%). CAG was more sensitive than angiography for the detection of thrombus (pre-PTCA 34 [69%] vs 11 [22%]; p < 0.05, and post-PTCA 34 [79%] vs 5 [12%]; p < 0.05]) and coronary dissections (post-PTCA 30 [70%] vs 19 [44%]; p < 0.05). CAG before intervention caused angina in 39 patients (80%), ventricular fibrillation (successfully managed with DC cardioversion) in 1, and AV block in another patient. The angiographic result deteriorated in 4 patients (9%) immediately after the CAG performed following PTCA. A repeat balloon PTCA was required in these patients.

CONCLUSIONS

CAG provides unique information on coronary lumen surface that complements angiographic data. As compared with angiography, CAG is more sensitive in the detection of intracoronary thrombi and dissections. Further studies are required to determine whether the additional information provided by CAG may be used, to select coronary interventions according to specific lesion characteristics, to optimize dilation results and, eventually, to improve the clinical outcome of these patients.

Findings of coronary angioscopy in angiographically normal coronary segments of patients with coronary artery disease

Compared with pathologic studies coronary angiography is a relatively insensitive technique to detect early atherosclerosis. Coronary angioscopy is a new technique providing direct information on luminal vessel surface. To determine whether coronary angioscopy may detect the presence of atherosclerotic disease on angiographically normal coronary segments, 52 patients underwent a study with coronary angioscopy before coronary angioplasty. The mean age was 59 +/- 10 years; 46 patients were men and 6 were women. The reason for coronary angioplasty was unstable angina in 36 patients, stable angina in 8 patients, and silent ischemia in 8 patients. In seven patients angiography revealed luminal irregularities on the coronary segment proximal to the culprit lesion, and all these patients also had proximal disease as demonstrated by coronary angioscopy. In the remaining 45 (87%) patients angiography revealed a smooth-vessel contour proximal to the target lesion. On quantitative angiography these "normal" coronary segments measured 2.8 +/- 0.4 mm in luminal diameter. In 30 (67%) of these patients angioscopy revealed proximal disease on the vessel wall, but in 15 (33%) patients the luminal surface of these segments also appeared normal on angioscopy. Disease as detected by angioscopy in angiographically normal segments included yellow plaque in 19 patients, mural thrombus in 5, mixed plaques in 4, and small flaps in 2 patients. In eight patients coronary angioscopy detected that atherosclerotic disease extended proximally from the target lesion, but in the remaining 22 patients the angioscopic findings appeared to be discrete and well separated from the angiographic lesion. All these plaques were relatively small and did not protrude into the coronary lumen.(ABSTRACT TRUNCATED AT 250 WORDS)

Angioscopic findings during coronary angioplasty of coronary occlusions

OBJECTIVES

This study sought to elucidate angioscopic findings in totally occluded vessels before and after intervention.

BACKGROUND

Coronary angioscopy allows direct visualization of the lumen surface of the coronary arteries; however, the utility of coronary angioscopy during coronary angioplasty of vessels with a total occlusion is unknown.

METHODS

Twenty-one consecutive patients (mean [+/- SD] 58 +/- 9 years, range 39 to 77; 3 women, 18 men) undergoing dilation of an occluded vessel were studied with coronary angioscopy. Occlusions were classified as functional in 8 patients (Thrombolysis in Myocardial Infarction [TIMI] flow grade 1) and anatomic in 13 (TIMI flow grade 0). Once the guide wire had crossed the occlusion, coronary angioscopy was attempted before and after angioplasty.

RESULTS

In all patients, coronary angioscopy before dilation visualized protruding material occluding the coronary lumen where the guide wire was wedged. The occlusion consisted of red thrombus in 19 patients (90%) (2 with isolated occlusive thrombus, 17 with thrombus associated with atherosclerotic plaque) and protruding yellow plaque in 2 patients (10%). However, on angiography only 7 occlusions (33%) had data consistent with thrombus (p < 0.01 vs. coronary angioscopy). Successful dilation was obtained in 20 patients. After dilation, coronary angioscopy was repeated in 18 patients, revealing residual thrombus with plaque in 16 (89%) and a residual yellow plaque in 2. In addition, coronary angioscopy revealed coronary dissections in 13 patients (72%); however, angiography revealed dissections only in 10 patients (55%) and residual thrombus in 2 (10%) (p < 0.001). In one patient, coronary angioscopy visualized silent distal embolization of a red thrombus not previously recognized on angiography.

CONCLUSIONS

Before intervention, coronary angioscopy provides unique insights into the pathologic substrate of occluded coronary vessels. An occlusive plaque with thrombus is the most common underlying substrate in these lesions. After successful dilation, angiographically silent mural thrombus is seen in most patients. This information could be used to assist in the selection of candidates and type of coronary interventions and could also prove to be of prognostic value in patients with occluded vessels.

Intracellular increases of cAMP induce opposite effects in glutamic acid decarboxylase (GAD67) and glial fibrillary acidic protein immunoreactivities in C6 cells

C6 is a cell line that expresses glial and neuronal markers. Treatments that increase intracellular cAMP levels induce the differentiation of these cells. We had previously demonstrated that forskolin, an agent that activates adenylate cyclase, produced changes in gene expression in C6 cells. As a consequence of this treatment, glutamic acid decarboxylase (GAD) activity and the mRNA for GAD67, one of the isoforms of the enzyme, decreased. In contrast, this treatment increased the transcription of the glial fibrillary acidic protein (GFAP) gene. We now show, by immunocytochemistry, that the changes in gene expression are phenotypically reflected by corresponding changes in the levels of the proteins encoded by the GAD67 and GFAP genes. Computer-assisted image analysis demonstrated that both the increase in GFAP immunofluorescence, and the decrease in GAD67 immunofluorescence are statistically significant. The changes in gene expression and in protein immunoreactivity are part of the differentiation process of the C6 cells towards a more mature glial phenotype.

[Clinical characteristics and natural history of human immunodeficiency virus infection. Study in a Chilean population served at a multiprofessional pilot center]

Four hundred and eighty six infected adults (90.7% men) were prospectively followed from 1988 to 1993 at a multiprofessional center in Santiago, Chile. 87.8% of male patients (pts)--84% of them homo/bisexual--and 64.4% of women acquired the infection sexually. At the beginning of the follow up (F/U) 51% of men and 71% of women were asymptomatic and 30% of the total group had AIDS. (AIDS definition: CDC 1993, excluded CD4 lymphocyte count < 200 x mm3). 240/486 (49.4%) had developed AIDS at the end of the study (12/31/93). AIDS defining events (ADE) were: interstitial pneumonia (confirmed or suggestive as caused by P. carinii [PCP]), 25%; tuberculosis (all forms), 22.1%; wasting, 13.8%; Kaposi Sarcoma, 9.2%; esophageal candidiasis, 6.7%; isosporiasis, 5.4%. Of all PCP cases, 72% were ADE, the rest, post.AIDS'. As expected, AIDS pts continued having major complications (mainly bacterial pneumonias, PCPs, esophagitis, tuberculosis and diarrhea due to I. belli and Cryptosporidium. Less frequently, but also observed, were toxoplasmic encephalitis and cryptococcal meningitis). Known mortality (excluded abandonment of F/U) was 27% for the whole group and varied from 5.8%, 51.6% to 69.2% for the first, 4th and 6th year of F/U respectively. For II-III CDC pts the mortality was 5% and 57% and for IV CDC pts it was 38% and 100% during the first and 6th year of F/U respectively. 36%, 53%, 74% and 85% of the pts followed for 1, 3, 5 and 6 years respectively had developed AIDS by the end of 1993. Multifactorial causes with either diarrhea, wasting or both were responsible for the death in half the pts in whom this was known, 15% died of respiratory complications and 5.7% of cryptococcal meningitis. 80% of AIDS pts survived their ADE. This study has provided information about the clinical profile of the HIV infection and natural history of the disease in Chile.

Comparison of the effectiveness of lovastatin therapy for hypercholesterolemia after heart transplantation between patients with and without pretransplant atherosclerotic coronary artery disease

With the aim of assessing the effectiveness and safety of lovastatin in patients with hypercholesterolemia after heart transplantation, as well as the potential differences in the lipid-lowering effect of lovastatin between patients with or without pretransplant coronary artery disease (CAD), we studied 63 heart transplant patients who had serum total cholesterol > 250 mg/dl in spite of dietary therapy. Mean age of subjects was 47 +/- 2 years. Triple-drug immunosuppressive therapy consisted of cyclosporine, azathioprine, and steroids. Thirty-nine patients (62%) had pretransplant CAD and 24 (38%) did not. Pretreatment serum lipid levels were: total cholesterol, 302 +/- 32 mg/dl; low-density lipoprotein (LDL) cholesterol, 201 +/- 35 mg/dl; high-density lipoprotein (HDL) cholesterol, 60 +/- 19 mg/dl; triglycerides, 205 +/- 86 mg/dl; and total/HDL cholesterol ratio, 5.4 +/- 1.6. Patients received 10 to 40 mg/day of lovastatin (mean dose 17 +/- 6) for 13 +/- 4 months. There were no serious adverse events. At 3 months, lovastatin decreased total cholesterol by 15% (p < 0.001), LDL cholesterol by 21% (p < 0.001), triglycerides by 17% (p < 0.05), and total/HDL cholesterol ratio by 17% (p < 0.001), and increased HDL cholesterol by 3% (NS). Although lovastatin was effective in both patients with pretransplant CAD and non-CAD, analysis of its effect in each subgroup (CAD and non-CAD) revealed that its lipid-lowering effect was higher for non-CAD patients (-20% vs -12% for total cholesterol, and -27% vs -17% for LDL cholesterol, both p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Cyclic AMP decreases the expression of a neuronal marker (GAD67) and increases the expression of an astroglial marker (GFAP) in C6 cells

C6 cells express proteins and mRNAs that are characteristic of both glia and neurons. Agents that increase intracellular levels of cyclic AMP (cAMP) decrease the enzymatic activity of glutamate decarboxylase (GAD), a neuronal marker, and the mRNA levels for one of the two GAD isoenzymes, GAD67. This reduction is accompanied by increased levels of glial fibrillary acidic protein (GFAP) mRNA, an astrocyte marker. Transient transfection assays, in which a 2-kb upstream regulatory region of the human GFAP gene was linked to a reporter gene, indicate that at least some of the cAMP-mediated increase of GFAP mRNA levels is due to increased transcription. Increases in intracellular cAMP appear to induce differentiation of C6 cells toward a more mature astrocyte phenotype.

Coronary stenting for acute coronary dissection after coronary angioplasty: implications of residual dissection

OBJECTIVES

The aim of this study was to assess the implications of residual coronary dissections after stenting.

BACKGROUND

Coronary stenting is currently used in selected patients with coronary dissection after angioplasty. However, in some patients the total length of the dissection may not be completely covered with the device.

METHODS

Forty-two consecutive patients (mean [+/- SD] age 58 +/- 11 years; 39 men, 3 women) undergoing stenting for a major coronary dissection after angioplasty were studied.

RESULTS

Thirty (67%) coronary dissections were small (< or = 15 mm), and 29 (64%) were occlusive (Thrombolysis in Myocardial Infarction [TIMI] flow grade < or = 2). In 3 patients, coronary stenting was unable to open large occlusive dissections, but a good angiographic result was obtained in 39 patients (93%). After stenting, 22 of these patients (56%) had no visible residual dissections, and 13 (33%) had small and 4 (10%) had large residual dissections. These residual dissections were stable and did not compromise coronary flow. In a repeat angiogram (24 h later) the stent was patent in all 39 patients. However, two patients experienced a subacute stent occlusion. Of the remaining 37 patients, 36 (97%) had a late angiogram after stenting. Quantitative angiography revealed a reduction in minimal lumen diameter at the stent site (2.6 +/- 0.4 vs. 2 +/- 0.7 mm, p < 0.05) and a trend toward improvement in vessel diameter at the site of the previous residual dissection (1.7 +/- 0.6 vs. 1.9 +/- 0.5 mm, p < 0.1). The angiographic image of residual dissection disappeared in all patients. These factors provided a rather smooth angiographic appearance at follow-up. The four patients with large residual dissections after stenting did not have restenosis and were asymptomatic at last visit.

CONCLUSIONS

Coronary stenting is effective in the management of acute coronary dissections after angioplasty. In this setting, small residual dissections are frequently seen but have a good outcome and disappear at follow-up. Large residual dissections may have a good outcome if coronary flow is not impaired and no residual stenosis is visualized.

Prenatal haloperidol induces a selective reduction in the expression of plasticity-related genes in neonate rat forebrain

Haloperidol, a dopamine receptor antagonist clinically used as an antipsychotic drug, induces long-term deleterious effects in offspring development when administered prenatally. However, the basis for this overall response to the drug remains unknown. Here we describe that prenatal administration of haloperidol in rats induces a drastic and selective reduction in the expression of plasticity-related genes in neonate forebrain, but not in mesencephalon. GABAergic and enkephalinergic markers such as glutamic acid decarboxylase activity and mRNA, and preproenkephalin mRNA were also diminished in forebrain. However, the expression of other genes such as epidermal growth factor-receptor, glial fibrillary acidic protein, and several proto-oncogenes (src, fos and myc), and a cholinergic marker such as choline acetyltransferase activity were unaltered. In addition, haloperidol promoted a significant decrease in mitotic cell number and cellular density in the striatum, one of the forebrain regions with the highest dopamine receptor density. These findings suggest that prenatal dopamine receptor occupancy may be a critical factor in controlling the development of forebrain target cells through mechanisms involving changes in the expression of plasticity-related genes.

Acute coronary closure complicating intravascular ultrasound examination

A patient with an excellent angiographic result after directional atherectomy suffered an acute coronary closure during an intravascular ultrasound study performed after the intervention. Intravascular ultrasound revealed a large medial dissection which could be successfully managed only with intracoronary stenting. The pathogenesis and implications of this rare major complication are discussed.

Determinants of coronary compliance in patients with coronary artery disease: an intravascular ultrasound study

OBJECTIVES

The aim of this study was to elucidate determinants of coronary compliance in patients with coronary artery disease.

BACKGROUND

Intravascular ultrasound potentially enables in vivo evaluation of coronary artery compliance.

METHODS

Twenty-seven patients (mean age [+/- SD] 57 +/- 11 years, three women) undergoing coronary angioplasty were studied with intravascular ultrasound imaging. A mechanical intravascular ultrasound system (4.8F, 20 MHz) was used. A total of 58 different coronary segments (proximal to the target angiographic lesion) were studied. Of these, 35 were located in the left anterior descending, 9 in the left main, 8 in the left circumflex and 6 in the right coronary arteries. During intravascular ultrasound imaging, 22 segments (38%) appeared normal, but 36 (62%) had plaque (24 fibrotic, 3 lipidic and 9 calcified). Systolic-diastolic changes in area (delta A) and pressure (delta P) with respect to vessel area (A) were used to study normalized compliance (Normalized compliance = [delta A/A]/delta P [mm Hg-1 x 10(3)]).

RESULTS

Lumen area and plaque area were 12.6 +/- 5.7 and 3 +/- 3 min2, respectively. Plaque was concentric (more than two quadrants) at 10 sites, but the remaining 26 plaques were eccentric. Compliance was inversely related to age (r = -0.34, p < 0.05) but was not related to other clinical variables. Compliance was greater in the left main coronary artery (3.9 +/- 2.1 vs. 1.8 +/- 1.2 mm Hg-1, p < 0.05) and in coronary segments with normal findings on ultrasound imaging (2.9 +/- 1.9 vs. 1.6 +/- 1.1 mm Hg-1, p < 0.01). Moreover, at diseased coronary segments compliance was lower in calcified plaques than in other types of plaques (1.2 +/- 0.7 vs. 2.3 +/- 1.6 mm Hg-1, p < 0.01) but was similar in concentric and eccentric plaques (1.6 +/- 1.5 vs. 1.6 +/- 0.9 mm Hg-1). Plaque area (r = -0.38, p < 0.01) was inversely correlated with compliance. On multivariate analysis, only age and plaque area were independently related to compliance.

CONCLUSIONS

Intravascular ultrasound may be used to evaluate compliance in patients with coronary artery disease. Compliance is reduced with increasing age and is mainly determined by the arterial site and by the presence, size and characteristics of plaque on intravascular ultrasound imaging.

Rhodococcus equi: first case in a heart transplant recipient

Rhodococcus equi is a gram-positive diphtheroid that occasionally affects immunocompromised patients, usually causing a chronic respiratory infection with cavitating pulmonary opacities on chest radiograph that resemble mycobacterial or fungal disease. Etiologic diagnosis presents a number of pitfalls, because Rhodococcus equi isolates mimic many of the characteristics of other microorganisms more familiar to the laboratory staff. The treatment of choice for this disease has not yet been established, and its mortality rate is greater than 50% in individuals with human immunodeficiency virus and 20% to 25% among the remaining patients. We describe here the first case of Rhodococcus equi infection in a heart transplant recipient. Clinical presentation was typical, and treatment with a sensitivity-based combination of antibiotics resulted in resolution of both the clinical and radiologic picture.

Heart transplantation for cardiac angiosarcoma: should its indication be questioned?

Two men, aged 31 and 32 years, respectively, underwent orthotopic heart transplantation, in both cases to treat primary cardiac angiosarcoma of the right atrium. Total removal of the tumor was performed, and no evidence was found of distant dissemination at the time of surgery. Their postoperative progress was good; however, the patients died 8 and 9 months after transplantation, respectively, of multiple brain metastases. We do not consider heart transplantation to be indicated in the management of malignant cardiac tumors.

Heart transplantation in a patient with liver hydatidosis

The human can serve as an accidental intermediate host to Echinococcus granulosus, a parasite that targets dogs as its definitive hosts. We present the case of a 27-year-old man with liver hydatidosis, who underwent heart transplantation because of ischemic cardiomyopathy. The immunosuppressor treatment had no effect on the size of the cysts, which were removed surgically 14 months after heart transplantation; good results persist after 3 years of follow-up.

[Etiologic diagnosis of pneumonia in HIV-AIDS patients. Usefulness of fibrobronchoscopy]

AIM

to assess the usefulness of fiberoptic bronchoscopy in the etiologic diagnosis of pulmonary infiltrates in patients with AIDS.

PATIENTS AND METHODS

in 25 patients with AIDS and pneumonia, 31 fiberoptic bronchoscopies with bronchoalveolar lavage were performed; in 11 occasions, a transbronchial biopsy was also performed.

RESULTS

in 24 of the 31 procedures (77%) an etiologic diagnosis was made. There were 7 false negative results; in two of these patients, a repeated examination allowed an etiologic diagnosis. The etiologies of the infiltrates were pyogenic bacteria in 14 cases. Pneumocystis carinii in 9, mycobacteria in 3, cytomegalovirus in one and a lymphocytic interstitial pneumonia in one. In 5 patients, the association of two or more etiological agents was observed. Except one case, all patients had a good response to specific treatments. There were no complications attributed to the bronchoscopic procedure.

CONCLUSIONS

fiberoptic bronchoscopy and bronchoalveolar lavage are safe and effective procedures for the etiologic diagnosis of pulmonary infiltrates in patients with AIDS.

Transplants of fetal substantia nigra regulate glutamic acid decarboxylase gene expression in host striatal neurons

Lesions of the dopaminergic innervation to the striatum result in increased activity of glutamic acid decarboxylase (GAD) and increased GAD mRNA in striatal GABAergic neurons. Here we show that solid transplants of dopamine-containing fetal mesencephalic tissue placed adjacent to the striatum can completely reverse the elevation of GAD mRNA in the striatum of adult rats with complete lesions of the nigrostriatal dopamine projections. The ability of the fetal transplants to re-establish control over gene expression in host target neurons indicates that there is a significant transneuronal influence of the transplanted neurons. Furthermore, striatal GAD mRNA levels appear to be a good marker of the functional impact of dopamine-producing transplants.

Health status and health practices--Alameda and beyond

Using the population of St John's, Newfoundland, we did a constructive replication of previous studies testing the association between health practices and health status. A telephone questionnaire was applied to all adults in a probabilistic sample of households (3300 subjects, 85% response rate). Several health practices and preventive behaviours indexes were developed and tested. An additive index of six practices (breakfast, sleeping, drinking, smoking, weight and exercise) using the Alameda County definitions, and an additive score of five practices (excluding breakfast and with revised definitions for smoking, drinking and exercise) were analysed using log-linear models; there was association between the indexes and self-assessed health status when controlling for sex, age and education, with the exception of the six-practice index in males. The association between these two indexes and several variables and constructs of health status showed that the best relationships were with self-assessed health status and with a construct including variables measuring subjective health.

Striatal glutamic acid decarboxylase immunoreactivity is increased after dopaminergic deafferentation: densitometric analysis

Several lines of evidence suggest that dopamine exerts a chronic inhibitory action on GABAergic cells in the striatum, and striatal glutamic acid decarboxylase (GAD) mRNA levels are increased after ipsilateral dopaminergic denervation. In the present study we have used GAD immunocytochemistry to assess whether dopaminergic denervation results in an increase in GAD protein synthesis. In three 6-hydroxydopamine-lesioned animals, there was a perceptible increase in the density of GAD-immunoreactive (ir)staining on the side ipsilateral to the lesion. Computer-assisted densitometric analysis showed a significant increase in GAD-ir staining in the ipsilateral striatum compared to the contralateral (control) side. These data suggest that removal of striatal dopaminergic innervation results in an increase in the amount of immunoreactive GAD, the rate limiting enzyme in the synthesis of GABA.

Parallel increases in striatal glutamic acid decarboxylase activity and mRNA levels in rats with lesions of the nigrostriatal pathway

Adult male rats were lesioned with 6-hydroxydopamine in order to destroy the nigrostriatal dopaminergic projections. In rats with such a lesion, we found a parallel increase in glutamic acid decarboxylase (GAD) activity and GAD mRNA in the striatum ipsilateral to the lesion at 4 weeks and 4 months after the lesion. These observations support the proposal that nigral dopaminergic neurons exert a tonic inhibitory control over the striatal GABAergic neurons. Our observations also suggest that the dopaminergic neurons can inhibit gene expression in striatal GABAergic neurons and that the enhanced striatal GAD activity following lesions of the dopaminergic projections is due to 'de novo' synthesis of the enzyme.

Effect of dopaminergic denervation and transplant-derived reinnervation on a marker of striatal GABAergic function

Solid grafts of dopamine-containing fetal mesencephalon were placed adjacent to the striatum of rats with 6-hydroxydopamine lesions of ascending dopaminergic projections. These grafts resulted in a significant, although partial, reversal of the lesion-induced increase in striatal glutamic acid decarboxylase (GAD) when measured 3-4 months after the lesion. These results suggest that the grafted neurons can partly restore inhibitory control over striatal GABA neurons. In the same rats, the grafts partially reversed apomorphine-induced turning although amphetamine-induced turning was nearly abolished. It is likely that both apomorphine-induced behavior and striatal GAD activity reflect the sustained chronic influence of the graft on target neurons in striatum.

Hippocampal membranes contain a neurotrophic activity that stimulates cholinergic properties of fetal rat septal neurons cultured under serum-free conditions

Primary cultures of fetal rat septal neurons were used to identify a membrane-associated cholinergic neurotrophic activity. Under serum-free culture conditions, approximately 98% of the septal cells are neurons, and approximately 6% of the neurons are cholinergic as determined immunocytochemically. Crude membranes prepared from rat hippocampal homogenates stimulate choline acetyltransferase (ChAT) activity in treated septal neurons. The membrane-associated trophic activity is apparent at lower protein concentrations than activity present in the soluble fraction and is unevenly distributed in various brain regions; it is highest in hippocampus and striatum and negligible in cerebellum. Membrane trophic activity is developmentally regulated, is heat and trypsin sensitive, and increases the rate of expression of ChAT in septal neurons. Upon gel filtration chromatography of a high-salt membrane extract, trophic activity elutes as a broad peak in the 500 kilodalton (kD) molecular mass range. Stimulation of septal neuronal ChAT activity by either crude membranes or partially purified preparations is not inhibited by antibodies against nerve growth factor (NGF), and its maximal activity is additive to maximally active doses of NGF. The results indicate that hippocampal membranes contain cholinergic neurotrophic activity which may be important for the development of septal cholinergic neurons.

Tissue levels and in vivo release of tachykinins and GABA in striatum and substantia nigra of rat brain after unilateral striatal dopamine denervation

Brain tissue levels and in vivo release of substance P (SP) and neurokinin A (NKA) and GABA were measured bilaterally in striatum and substantia nigra of the rat, after a unilateral 6-hydroxydopamine lesion of the nigro-striatal dopamine pathway. Sham injected animals served as controls. The dopamine denervation decreased the tissue levels of SP in striatum (-38%) ipsilateral to the lesion and in substantia nigra both ipsi- (-54%) and contralateral (-38%) to the lesion. NKA was not significantly changed in the striatum, but decreased (like SP) in the substantia nigra both ipsi- (-50%) and contralateral (-40%) to the lesion. GABA tissue levels increased in the denervated striatum (+20%) and remained unchanged in substantia nigra at both sides. The extracellular levels of SP, NKA and GABA were measured with microdialysis in vivo at basal conditions and during stimulation with potassium administered locally via the microdialysis probe. The stimulated release of SP and NKA in the substantia nigra ipsilateral to the lesion was compared to in sham operated animals reduced with 39% and 64%, respectively, while no change in SP or NKA release was detected in the striatum. The basal release of GABA in the striatum was increased with 296% and with 76% during stimulation in the dopamine denervated striatum, while no change in GABA basal or stimulated release was detected in the substantia nigra. We suggest that the increased GABA release in the dopamine denervated striatum may be due to a decreased dopamine mediated inhibition of local GABA neurons.(ABSTRACT TRUNCATED AT 250 WORDS)

An empirical analysis of the dimensions of health status measures

The objective of this study is to verify empirically the existence of separate dimensions in the overall concept of health status by analyzing 10 variables included in a questionnaire that was applied to all adults in a simple random sample of households in St John's, Newfoundland. The response rate was 85% for a total of 3300 subjects. These data were analyzed by frequencies and by associations with sex, age and education. Nonparametric correlation, factor and cluster analyses on variables were used to verify if health status had identifiable dimensions. All these methods produced similar results showing five distinct factors. The first factor is composed of variables related to disease (disability/chronic conditions/worry about health); the second, to happiness (happiness/emotional); the third, to subjective appraisal of health (physical condition/comparative level of energy/self-rated health status). Finally, the fourth and fifth factors were single variables; restriction of normal activities and social contacts. An interesting finding was that self-rated health status was distributed with almost equal weight in both the first and third factors. A validation of the 10 variables and the 5 factors was undertaken by studying their association with health care utilization. Two measures of utilization were used; number of physicians' visits in a year and number of hospital days in a 4-year period. Number of chronic conditions, disability and self-rated health status were associated with both measures of utilization; factor 1 was the only summary construct showing association with utilization. This paper demonstrates that self-rated health status is valid as a single measure of overall health status in this sample, being associated with both disease and subjective assessment components.

The association between self-assessed health status and individual health practices

We report the association between single health practices and self-assessed health status. Data were collected by telephone survey applied to all adults in a sample of households in metropolitan St. John's; questionnaires were completed for 3,300 subjects. Five health practices--smoking, exercise, sleep, weight and drinking--as defined by previous studies were compared with self-assessed health status--good or poor--using logistic regression; linear and quadratic functions were fitted, plots were prepared and the direction and strength of the associations studied using odds and odds ratios. For sleep, smoking, weight and exercise, our results confirm the definitions used in previous studies. Current non-drinkers in our sample do not report good health as frequently as moderate drinkers. Breakfast--which was analyzed by conventional cross-tabulation--showed no association with health status.