Silent healing of spontaneous plaque disruption demonstrated by intracoronary ultrasound

Intracoronary ultrasound was performed at diagnostic coronary angiography and 10 days later in a 45-year-old patient with a 3-day history of acute inferior myocardial infarction. Coronary angiography showed considerable stenosis (80%) in the distal right coronary artery (RCA) (pre the crux) and what appeared to be a dissection in the middle RCA. Intracoronary ultrasound identified this as plaque disruption. Coronary balloon angioplasty was then performed in the distal stenotic segment. Follow-up angiography 10 days after coronary intervention revealed that the flap in the lumen had disappeared. Intracoronary ultrasound imaging showed that the ruptured plaque had resealed and had the appearance of layering in the atheroma similar to thrombus formation. In summary, plaque disruption and subsequent thrombus formation can be demonstrated in vivo by intracoronary ultrasound. Monitoring this process may have important clinical significance in patient management and in assessing clinical prognosis.

Acute coronary artery closure following intracoronary ultrasound examination

Two patients undergoing intracoronary ultrasound examination were complicated by acute coronary artery closure. One of the complications was thought to be caused by intimal dissection and thrombus formation and the other was thought to be caused by intimal dissection and subsequent embolization. The complications were successfully managed conservatively in both cases.

Initial experience with a steerable intravascular ultrasound catheter in the aorta and pulmonary artery

The aim of this protocol was to test the feasibility and safety of a prototype steerable intravascular ultrasound (IVUS) catheter (Boston Scientific, Waterton, MA) in comparison with standard IVUS catheters. A 3.5F, 20-MHz mechanical echo transducer was incorporated into a bendable sheath with a blunt tip. The flexible IVUS catheter was compared with a standard IVUS catheter in 13 patients. Seven patients underwent catheterization of the left side of the heart, and six patients had catheterization of the right side of the heart for suspected recurrent pulmonary embolism. In the aorta, three lumen area measurements were made: (1) midway between the aortic arch and the aortic root, (2) at the most cranial part of the aorta, and (3) in the descending aorta at the level of the diaphragm. Evaluation of the accuracy of luminal dimension measurements by both types of catheters in perpendicular positions to the vessel wall was evaluated in a hollow rubber cast of an human aorta and its side branches, representing luminal diameters from 3 to 26 mm. We performed 20 measurements with each type of catheter. The results were compared with ruler measurements, after the cast had been cut in slices. The equation for the standard 3.5F IVUS catheter was: y = 0.89x + 0.15; SE = 0.17; r = .97; for the 4.8F 20-MHz standard IVUS catheter: y = 0.97x + 0.05; SE = 0.18; r = .98; and for the steerable catheter, y = 0.94x + 0.09; SE = 0.12; r = 0.97.(ABSTRACT TRUNCATED AT 250 WORDS)

Improvement of coronary morphology and blood flow after stenting. Assessment by intravascular ultrasound and intracoronary Doppler

Intravascular ultrasound (IVUS) and intracoronary Doppler (ICD) were performed in eight patients (54.3 +/- 6.5 years, 6 male) immediately after PTCA and after stenting. ICD was also performed before PTCA. After PTCA, IVUS has demonstrated intimal rupture in all patients. After stenting, IVUS revealed wall wrapping of the intimal flap with a free lumen in all patients. The lumen diameter was 2.42 +/- 0.55 mm after PTCA and was 2.74 +/- 0.49 mm after stenting (p < 0.001). The cross-sectional area increased from 4.70 +/- 1.99 mm2 post-PTCA to 6.40 +/- 2.15 mm2 post-stent (p < 0.005). Coronary flow velocity reserve, calculated by the ratio of mean flow velocity at rest and after intracoronary papaverine administration, increased from 2.05 +/- 1.01 to 2.99 +/- 1.14 after PTCA (p = 0.015); and increased to 4.51 +/- 1.33 after stenting (p < 0.001). The morphological data derived from IVUS correlated with the functional information obtained with ICD. In addition to its established role in bail out situations, stent implantation may be considered when a suboptimal morphological and functional result has been demonstrated.

[The study of correlation between hemorrheology and fluorescein angiography in open-angle glaucoma]

PURPOSE

To observe the correlation between hemorrheology and arm-retinal filling time of fluorescein angiogaphy in patients with primary open-angle glaucoma.

METHODS

The whole blood apparent viscosity in high (125 S-1), moderate (23 S-1) and low (1.2435 S-1) shear rates, plasma viscosity and hematocrit were measured in 50 cases (50 eyes) with primary open-angle glaucoma whose intraocular pressures were controlled. They also underwent fluorescein angiography. The duration from arm to retina arteria filling was named arm-retinal arteria filling time.

RESULTS

There were positive correlation between the whole blood apparent viscosity in high and moderate shear rates, hematocrit and arm-retinal arteria filling time (P < 0.05-0.005). The higher blood viscosity, the longer arm-retinal arteria filling time.

CONCLUSION

The blood viscosity in patients with primary open-angle glaucoma can affect the arm-retinal arteria filling time of fluorescein angiography. So, the increasing blood viscosity in patients with primary open-angle glaucoma can reduce the blood supply to the optic disc.

Identification of high-risk subgroups in infective endocarditis and the role of echocardiography

The outcome of infective endocarditis remains poor. It has an overall mortality of around 30%, rising in high-risk subgroups to 50% and 100%. The prognosis can be improved by identification of high-risk patients and special management. Patients with infective endocarditis are found to be at high risk for death or serious complications when one or more of the following factors exist: old age (especially > 60 years old), delayed diagnosis, staphylococcal infection, aortic valve endocarditis, large valvular vegetation, congestive heart failure, embolization in the central nervous system or coronary artery, prosthetic valve infection, recurrent events, and failed antibiotic therapy. These factors often coexist and interrelate with one another. Early diagnosis and active treatment are critical for a better clinical outcome. However, infective endocarditis is difficult to diagnose because of the atypical clinical manifestations and frequent negative results from blood culture. Echocardiography plays an indispensable role in the diagnosis and management of suspected or known infective endocarditis. By detecting and monitoring certain pathological changes associated with the disease, e.g. vegetation, abscess formation, or valvular destruction, echocardiography helps to diagnose the disease early, to identify patients at high risk, to monitor the patients, and to optimize the timing and mode of surgical intervention. Serious complications can thus be avoided or cured at an early stage and the prognosis significantly improved.

High wall shear stress proximal to myocardial bridging and atherosclerosis: intracoronary ultrasound and pressure measurements

BACKGROUND

Studies have shown that myocardial bridging may prevent coronary atherosclerosis and that the segment proximal to the bridge is often sclerosed. The underlying mechanism is still unknown.

METHODS

Intracoronary ultrasound and pressure measurements were performed in a patient with myocardial bridging in the left anterior descending coronary artery. A 3.5 F, 20 MHz probe was used to measure the change in cross sectional area of the lumen during the cardiac cycle. Intracoronary pressure was measured with a Double tip, end mounted pressure transducer system, the catheter having two pressure sensors located at the end of the catheter 3 cm apart. Intracoronary pressure was recorded as the catheter was slowly advanced and pulled back through the left anterior descending coronary artery.

RESULTS

Systolic compression of the bridge segment was clearly visualised on ultrasonography and an eccentric plaque with calcium deposit was found in the segment proximal to the bridge. The pressure in the segment proximal to the bridge (160/26 mm Hg) was higher than that of the proximal normal segment (126/68 mm Hg). The pressure distal to the bridge was 68/30 mm Hg. A highly characteristic "sucking effect" was found in the bridge segment. The pressure in the bridge segment was 102/-40 mm Hg.

CONCLUSION

The pressure in the segment proximal to the myocardial bridging was higher than aortic pressure. Disturbance of blood flow and high wall stress proximal to myocardial bridging was a main contributor to the development of atherosclerosis in the segment proximal to the bridge.

[Alternative methods in interventional therapy of coronary heart disease]

Percutaneous high-frequency coronary rotablation using the rotablator is able to remove arteriosclerotic material from the vessel wall. A diamond-coated (30-80 microns) brass burr drill fastened to a flexible drive shaft rotating and tracking along a drill coaxial guide wire is used. The turbine rotates the drive shaft in excess of 150,000-190,000 rpm. High-frequency rotational angioplasty was successful in > 90% of patients, but in about 90% additional PTCA is necessary. No increase of bypass surgery compared to PTCA is observed. CK and CR-MB elevation is more often found than after PTCA. Vessel perforation is rarely observed. All vessels were open at 24-h control. The restenosis rate seems not be increased. The main indications for high-frequency rotational angioplasty are rigid and calcified sclerotic lesions which cannot be passed by conventional balloon catheters. Whether the restenosis rate can be reduced by this method will be judged in part by the COBRA study. In order to avoid acute complications of PTCA and to reduce restenosis rate, coronary stents were developed. Self-expandable and balloon expandable stents are available. It could be demonstrated that these stents can be used as a bail-out system and can block elastic recoil of coronary arteries. The major remaining problem is subacute closure of coronary vessels. In order to prevent thrombosis treatment with coumarine, acetylsalicylic acid, and dipyridamol is necessary. Coronary stents can be successfully delivered in more than 90% of the patients. In a highly selected patient group using single stents restenosis rate could be significantly reduced.

Regression of pre-existing coronary artery disease in a donor heart after cardiac transplantation

This report is about the angiographic follow-up, over 5 years, in a patient with urgent heart transplantation grafted with an atherosclerotic donor heart because of severe congestive heart failure due to dilative cardiomyopathy. Sequential quantitative angiography documented a regression of the luminal narrowing of a focal lesion in the right coronary artery with a minimal luminal diameter of 1.38 mm (56% diameter stenosis) in 1988 to 2.78 mm (13%) in 1993. During this catheterization in 1993 intravascular ultrasound imaging illustrated almost no atherosclerotic vessel wall abnormalities at the site of the previous angiographic luminal narrowing as well as in the adjacent segments. These findings might promote the potential acceptance of heart transplant donors with a certain extent of coronary artery disease in the case of urgent organ request, if close follow-up and strict guidance of the patient by the transplanting team is feasible.

A human hybridoma monoclonal antibody (TrJ11) recognizing a new HLA-DR epitope shared by DR4, DR8, DR11, and DRB1*1303

The cytotoxic IgM lambda human hybridoma mAb TrJ11 reacts with lymphoblastoid B-cell lines expressing DR4, DR8, DR11, and DRB1*1303. However, TrJ11 was monospecific when normal B cells freshly isolated from blood served as targets in that it only killed HLA-DR4-positive cells. Thus, of 235 HLA-typed persons TrJ11 was strongly cytotoxic for normal B cells of all 90 DR4-positive individuals, but it did not react with B cells from any of the 145 DR4-negative donors. Hence, mAb TrJ11 proved to be suitable for routine DR4 typing. The specific binding of TrJ11 to a DR4-positive cell line was profoundly blocked by the mouse HLA-DR beta chain-specific monomorphic mAb TAL 14.1, indicating that the epitope recognized by TrJ11 is located in the DR beta chain. The possibility that amino acids located in the floor of the peptide-binding site are critical for the TrJ11 epitope is discussed.

[The comparative study of pattern visual evoked potential in the normal infants and adults]

This paper presents the pattern visual evoked potential (PVEP) results and comparative study between the two groups of 65 normal infants at the age of 3, 6, 9, 12 months and 18 normal adults. The different pattern spatial frequency stimulations (74', 25', 6') were given to the infants and adults. In the infant group, the latencies of P1 components of PVEP delayed significantly and amplitudes of PVEP decreased significantly between 74' and 6' spatial frequency with the spatial frequency of stimulation increasing. In the same spatial frequency stimulation, when 3 months infant group was compared with the 6, 9, 12 months infant and adult groups, the latencies of N1 and P1 waves showed significant difference, but no difference was found in the amplitudes of P1 wave. Our results might indicate that the visual function expressed by low, medium, and high spatial frequency in infants from 6 to 12 months could reach the level in adults, and in 3 months infants, not maturely develop.

Identification of the gene encoding a novel HLA-B39 subtype. Two amino acid substitutions on the beta-sheet out of the peptide-binding floor form a novel serological epitope

Serological analysis suggests the existence of a novel HLA-B39 subtype (HLA-B39N) in the Japanese population. To identify this novel allele, a gene encoding HLA-B39N was cloned and the exons were sequenced. A gene encoding HLA-B39N (B*3904) and B*39011 differs by two nucleotide substitutions at codons 11 and 12 whereas B*3904 and B*39013 differ by three nucleotide substitutions at codons 11, 12, and 312. One nucleotide difference at codon 11 produces a change from serine in B*3901 to alanine in B*3904 whereas another difference at codon 12 changes valine in B*3901 to methionine in B*3904. The residues 11 and 12 are located on the beta-sheet out of the peptide-binding floor and are completely buried in the molecule. These results suggest that the substitutions at these residues alter the conformation of other residues forming epitopes of alloantibodies. Analysis of HLA-B*3901 genes in the Japanese population showed that both B*39011 and B*39013 were observed in the Japanese population. The present study suggests that B*3904 may have evolved from B*39011 rather than B*39013.

[Therapy of cardiogenic shock in acute myocardial infarct]

Cardiogenic shock in acute myocardial infarction patients is the most common cause of in-hospital death. Various studies showed, that 60 to 100% of patients in cardiogenic shock will die, if no early reperfusion of their coronary artery could be established. The incidence of cardiogenic shock has decreased during the last years, most likely due to early thrombolytic therapy and administration of nitroglycerin. Reasons for cardiogenic shock are either necrosis of 40% or more of the left ventricular wall, right heart infarction, or complications which can be treated by the surgeon, like papillary muscle rupture, ventricular septal defect or rupture of the free ventricular wall. Diagnosis is based on clinical criteria, echocardiography, and on hemodynamic monitoring. The hemodynamic criteria for cardiogenic shock are a cardiac index of < 2.2/l, and an increased wedge pressure of > 18 mm Hg; additionally, diuresis is usually < 20 ml/h. Therapy can be divided into the following categories: a) pharmaceutical interventions to increase cardiac output like vasodilators or positive inotrope drugs; b) mechanical support systems; c) acute interventions with the aim of reperfusion; d) acute surgical interventions addressing complications like papillary muscle rupture, ventricular septal defect or rupture of the free ventricular wall. While steps a) and b) are able to stabilize the hemodynamical situation in patients with cardiogenic shock, they are rarely the definitive treatment. Point c), reperfusion of the coronary artery, can be divided in thrombolysis or acute PTCA. Thrombolysis failed to show a beneficial effect in most studies, either after intravenous or intracoronary application. On contrast, acute PTCA showed to be of great benefit in various studies with a technical success rate of 54 to 100% and a survival rate of patients from 58 to 100%. Thus, emergency PTCA is the treatment of choice in cardiogenic shock. Point d), surgical interventions can be divided in acute bypass grafting, which should be reserved for patients with severe multivessel disease, left main involvement, or failed PTCA. Furthermore, acute heart transplantation is effective, but will be possible in a minority of patients only. The last part of surgically manageable complications are surgery of papillary muscle rupture and ventricular septal defect. Results of early surgery in papillary muscle rupture or ventricular septal defects are much better than delayed interventions. Rupture of the free wall is usually a fatal event. In summary, the most successful therapy of cardiogenic shock is early emergency PTCA.(ABSTRACT TRUNCATED AT 400 WORDS)

A novel HLA-A determinant recognized by a cytotoxic human hybridoma IgG1 monoclonal antibody (TrJ14)

TrJ14 is a cytotoxic human IgG1 lambda hybridoma mAb that recognized a novel HLA-A epitope expressed by lymphoblastoid B cells that are homo- or heterozygous for A2, A3, A11, A30, A31, A33, A68 and A69. Based on these results, the HLA type of cell line TEM (10w9057) was retyped as A66. When peripheral blood T cells isolated freshly from 265 HLA-typed normal individuals served as targets, TrJ14 killed cells expressing two TrJ14-positive HLA-A alleles, as well as the majority of cells having one TrJ14-positive and one TrJ14-negative HLA-A antigen. However, TrJ14 failed to recognize or reacted weakly with most HLA-A2 and -A3 heterozygous normal T cells when A2 or A3 was coexpressed together with a TrJ14-negative antigen. The serological reactivity of TrJ14 correlated with the amino acid valine and aspartic acid at positions 76 and 77 of the alpha 1-domain helix. These amino acids were shared exclusively by all the identified TrJ14+ alleles.

Vessel wall changes in the proximal non-treated segment after PTCA. An in vivo intracoronary ultrasound study

Intimal disruption is known to induce prolonged intimal functional disturbance and is thought to be one of the mechanisms contributing to restenosis after PTCA. Although such damage can be induced by minimal trauma, the inevitable far greater disruption caused by passage of the PTCA apparatus through the stenosis does not appear to induce significant angiographically documented intimal proliferation. Pathological studies, however, have suggested that such a process might occur. Intravascular ultrasound allows in vivo study of vessel wall shape and constitution and is a far more sensitive detector of coronary atheroma than angiography. In this study we sought to determine the frequency of such functional disturbances and to assess their significance with respect to restenosis. The study group comprised 18 patients who underwent IVUS examination immediately after PTCA and at 6-months follow-up. They were analysed for luminal dimensions and vessel wall changes at the site of PTCA and at the level of the proximal non-treated segment. Seven patients (38%) had restenosed at follow-up IVUS examination; two patients had angiographically demonstrated luminal narrowing proximal to the PTCA site whereas seven had new intimal thickening in the proximal non-treated segment demonstrated by IVUS. Six patients had no intimal changes in either PTCA treated or untreated segments. Proximal intimal thickening was seen more frequently in those in whom increased intimal thickening at the PTCA site was noted. A trend (P < 0.1) was found towards an increased rate of new proximal vessel disease in those patients who had angiographically restenosed. IVUS demonstrates new intimal thickening in proximal non-treated segments in a considerable number of or patients undergoing PTCA.(ABSTRACT TRUNCATED AT 250 WORDS)

Intravascular ultrasound imaging in acute aortic dissection

OBJECTIVES

This study was performed to determine the potential of intravascular ultrasound in the detection and delineation of aortic dissection.

BACKGROUND

Intravascular ultrasound is a new technique capable of displaying real-time cross-sectional images of arterial vasculature. Its clinical use has been explored mostly in coronary and peripheral arterial circulation.

METHODS

Intravascular ultrasound imaging of the aorta was performed using a 20-MHz ultrasound catheter in 28 patients with suspected aortic dissection. All patients underwent contrast angiography; 7 had computed tomography; and 22 had transesophageal echocardiography.

RESULTS

Imaging of the aorta from the root level to its bifurcation was performed in all patients in an average of 10 min. No complications occurred. Dissection was present in 23 patients and absent in 5. In the patients without dissection, intravascular ultrasound revealed normal aortic anatomy. In all 23 patients with dissection, intravascular ultrasound demonstrated the intimal flap and true and false lumena. The longitudinal and circumferential extent of aortic dissection, contents of the false lumen, involvement of branch vessels and the presence of intramural hematoma in the aortic wall could also be identified. In cases where aortography could not define the distal extent of the dissection, intravascular ultrasound did.

CONCLUSIONS

Our experience in this series of patients with aortic dissection indicates that intravascular ultrasound could be valuable in the identification and categorization of aortic dissection and in the description of associated pathologic changes that may be clinically important. It can be performed rapidly and safely and could serve as an alternative or adjunct diagnostic procedure in patients with aortic dissection.

Intravascular ultrasound imaging of angiographically normal coronary arteries: a prospective study in vivo

Intravascular ultrasound imaging (IVUS) was performed to elucidate the discrepancy between clinical history and angiographic findings and to measure the diameter and area of the lumen of the normal left coronary artery in 55 patients who presented with chest pain but had normal coronary angiograms. The left coronary artery (LCA) was scanned with a 4.8F, 20 MHz mechanically rotated ultrasound catheter at 413 sites. Atherosclerotic lesions were identified at 72 (17%) sites in 25 patients. The mean (SD) (range) plaque area was 5.55 (3.56) mm2 (2-26 mm2) and it occupied 28.8 (9.6)% (13-70%) of the coronary cross sectional area. Calcification was detected at 24 (33%) atherosclerotic sites in nine patients. The correlation coefficients for the lumen dimensions measured at normal sites by IVUS and by angiography were r = 0.93 (SEE = 0.43) mm for lumen diameter and r = 0.89 (SEE = 4.27) mm2 for lumen area (both p < 0.001). 16 of the 30 patients in whom no atherosclerotic plaques were detected in the LCA lumen by IVUS had no risk factors of coronary artery disease. The cross sectional area of 90 consecutive images of left main coronary artery (LMCA), proximal left anterior descending coronary artery (proximal LAD), and mid LAD was measured in these 16 subjects. The mean (SEM) areas at end diastole were LMCA 17.33 (7.98) mm2; proximal LAD 13.56 (5.85) mm2; mid LAD 9.75 (4.67) mm2. During the cardiac cycle the cross sectional area changed by 10.2 (4.0)% in the LMCA, by 8.3 (4.7)% in the proximal LAD, and by 9.8 (4.0)% in the mid LAD. In 11 patients with plagues the change in cross sectional area in plague segments (5.8(3.1)%) was significantly lower than in the segments from patients without plagues (p < 0.001). Lumen area reached a maximum in early diastole rather than in late diastole. IVUS can imagine atherosclerotic lesions that are angiographically silent; it also provides detailed information about plague characteristics. The variation in coronary cross sectional area during the cardiac cycle should not be ignored during quantitative analysis. Maximum dimensions in normal segments are reached in early diastole. Further studies are needed to clarify the clinical significance of atherosclerosis detected by IVUS in patients presenting with chest pain but normal coronary angiography.

Assessment of spontaneous coronary artery dissection by intravascular ultrasound in a patient with unstable angina

We describe a case of spontaneous coronary artery dissection that gave rise to post infarction unstable angina. An ambiguous angiographic appearance was shown by intracoronary ultrasound to arise from an extensive coronary dissection. The dissection membrane separating true and false lumina and features to suggest sluggish flow and early thrombosis in the false lumen were observed. No increase in lumen calibre was evident on ultrasound after PTCA (probably a consequence of the relatively large ultrasound catheter blank), but coronary flow reserve measured with intracoronary Doppler did improve and the patient remained stable and free of angina following the procedure.

Extent of atherosclerosis and remodeling of the left main coronary artery determined by intravascular ultrasound

This study used intravascular ultrasound (IU) to assess the incidence and extent of left main coronary artery (LMCA) disease and the effects of arterial remodeling. Sixty-nine patients undergoing cardiac catheterization were imaged with a 20 MHz rotational-tip IU device. Nine of the 69 studies (13%) could not be analyzed because of technical (n = 2) or anatomic (n = 7) reasons. Of the remaining 60 patients, 38 (63%) had at least 1 lesion in the left coronary artery perfusion territory by angiography; significant LMCA stenosis was present in 2 patients (3%). Intravascular ultrasonography demonstrated plaques in 27 of 60 LMCAs (45%), 6 of them in patients with normal angiograms. Twenty-four plaques (89%) were eccentric and calcium was present in 4 (15%). The mean minimal lumen diameter was 4.9 +/- 0.8 mm, the maximal lumen diameter was 5.6 +/- 0.8 mm, the planimetered lumen area was 22.6 +/- 6.0 mm2, the plaque area was 3.9 +/- 5.8 mm2, the vessel area was 26.5 +/- 5.9 mm2, and the area stenosis was 13 +/- 19%. In the 27 patients with plaque, plaque area was 8.7 +/- 5.7 mm2 and the area stenosis was 30 +/- 17%. The vessel area was significantly larger in diseased LMCAs (p < 0.001) and correlated with plaque area (r = 0.46). IU examination of the LMCA was feasible in 87% of patients and was more reliable for delineating plaques than angiography.

Comparison of intravascular ultrasound and angiography in the assessment of myocardial bridging

BACKGROUND

In autopsy, myocardial bridging is a common finding. With coronary angiography, a systolic compression, mainly of the left anterior descending coronary artery, is observed in 1% to 3% of the patients. Controversy exists concerning the functional importance of this finding. To obtain a functional insight into the myocardial bridging, intravascular ultrasound and intracoronary Doppler were performed.

METHODS AND RESULTS

Intracoronary ultrasound and Doppler were performed in 14 patients with angiographic evidence of systolic vessel compression ("milking effect") in the left anterior descending coronary artery. The 4.8F, 20-MHz ultrasound catheter could not be advanced through the entire myocardial bridge segment in 6 of the 14 patients studied because the lumen was < 1.6 mm. In these patients, only the proximal parts of the bridge segment were scanned. The changes in cross-sectional shape during the cardiac cycle were determined for both the normal proximal segment and the bridge segment by use of a semiautomatic computer program. Intracoronary Doppler (20 MHz) was performed in 7 patients with a 3F catheter. A highly characteristic systolic eccentric or concentric compression with delayed relaxation in diastole of the myocardial bridging segment was clearly visualized in all patients. The cross-sectional lumen area variation was 40 +/- 25% in the bridging segments and 9 +/- 7% in the normal segments (P < .01). No atherosclerotic lesions were detected in the bridge or the distal segment in the 8 patients in whom the IVUS catheter was successfully advanced through the entire myocardial bridge. However, atherosclerotic plaques were found in the segments proximal to the bridge in 12 of 14 patients (86%). The resting mean flow velocity was 6.4 +/- 1.2 cm/s; the maximal mean flow velocity after intracoronary administration of 10 mg papaverine was 14.1 +/- 3.4 cm/s. The coronary flow velocity reserve was 2.2 +/- 0.7. A highly characteristic pattern showing a prominent peak in coronary velocity in early diastole was observed in 86% of patients, and this pattern was enhanced after injection of intracoronary papaverine.

CONCLUSION

Intravascular ultrasound demonstrated a characteristic systolic compression of the bridge segments. The delayed compression release may explain the characteristic sharp early diastolic peak in coronary flow velocity found with intracoronary Doppler in vessels with myocardial bridging. Reduced coronary flow reserve may be related to this phenomenon, possibly explaining signs of ischemia detected in some of the patients, but may alternatively be a result of the presence of atherosclerosis in the segment proximal to the bridge in these patients.

A cytotoxic human hybridoma monoclonal antibody (TrJ6) defining an epitope expressed by HLA-DQ4 and -DQ5

We have generated a cytotoxic human hybridoma monoclonal IgM lambda antibody, designated TrJ6, that is specific for a new epitope shared by HLA-DQ4 and -DQ5. TrJ6 strongly killed all ten DQ4-bearing cells and weakly killed all four DQ5-bearing cell lines. In contrast, none of the 36 cell lines lacking DQ4 and DQ5 antigens was recognized by TrJ6. This was confirmed by fluorescence cytometry. The specific binding of TrJ6 to a DQ4-bearing line was efficiently blocked by IIB3 (murine anti-DQ8+9+4+5+6 mAb) and TrG6 (human IgG mAb against DQ4+5+6), confirming that TrJ6 is specific for a polymorphic DQ epitope. TrJ6 can be used to distinguish DQ5+ from DQ6+ B-lymphoblastoid cells. DQ4 beta and DQ5 beta chains share one unique residue (Ser-74) and one relatively unique residue (Val-75), which may therefore need to be coexpressed in order for the TrJ6 epitope to be formed. Alternatively, Ser-74 alone contributes critically to the allospecificity of this epitope. In addition, one or more of three residues unique for DQ4 (Leu-56, Glu-70, and Asp-71 on the DQ4 beta chain) could also contribute to the TrJ6 epitope because TrJ6 reacted stronger with DQ4- than with DQ5-bearing cell lines.

Spontaneous plaque rupture visualized by intravascular ultrasound

An intravascular ultrasound examination was performed in order to evaluate an angiographically complicated lesion. Intravascular ultrasound was able to demonstrate spontaneous plaque rupture in a patient with recent acute subendocardial infarction. The inconclusive angiographic appearance was clarified by the intravascular examination and led us to conclude that the myocardial infarction was due to plaque rupture with subsequent thrombotic occlusion, which had spontaneously resolved by the time of the study.

The profiles of interaction of yohimbine with anxiolytic and putative anxiolytic agents to modify 5-HT release in the frontal cortex of freely-moving rats

1. The interaction of yohimbine with anxiolytic and putative anxiolytic agents to modify 5-hydroxytryptamine (5-HT) release in the frontal cortex of the freely-moving rat was assessed using the microdialysis technique. 2. The alpha 2-adrenoceptor antagonist, yohimbine (5.0 mg kg-1, i.p.) increased maximally the extracellular levels of 5-HT in the rat frontal cortex by approximately 230% of the basal levels. 3. The alpha 2-adrenoceptor agonist, clonidine (30-100 micrograms kg-1, i.p.) decreased dose-dependently the extracellular levels of 5-HT in the rat frontal cortex by approximately 0-60% of the basal levels. A 5 min pretreatment with clonidine (50 micrograms kg-1, i.p.) prevented the yohimbine-induced increase in the extracellular 5-HT levels. 4. The benzodiazepine receptor agonist, diazepam (2.5 mg kg-1, i.p.) and the 5-HT3 receptor antagonist, ondansetron (100 micrograms kg-1, i.p.) (5 min pretreatment) completely prevented the yohimbine (5.0 mg kg-1, i.p.)-induced increases in the extracellular levels of 5-HT. The 5-HT1A receptor agonist, 8-OH-DPAT (0.32 mg kg-1, s.c.) partially antagonized the yohimbine response. 5. A 5 min pretreatment with the 5-HT3/5-HT4 receptor ligand R(+)-zacopride (10 micrograms kg-1, i.p.) reversed the yohimbine (5.0 mg kg-1, i.p.)-induced increase in the extracellular levels of 5-HT to approximately 30% below the basal levels. A 5 min pretreatment with S(-)-zacopride (100 micrograms kg-1, i.p.) failed to modify the response to yohimbine. 6. The present study provides evidence of the ability of the anxiogenic agent, yohimbine, to increase the activity of the central 5-hydroxytryptaminergic system and the ability of clonidine and various anxiolytic and putative anxiolytic agents to prevent the yohimbine response.

Coronary artery remodeling in atherosclerotic disease: an intravascular ultrasonic study in vivo

BACKGROUND

Pathologic studies have revealed that coronary arteries undergo compensatory enlargement in the presence of atherosclerosis.

METHODS

In order to assess coronary artery remodeling in vivo, we used intravascular ultrasound to examine 46 patients (36 men and 10 women; aged 58.2 +/- 6.8 years) with non-calcified plaques. The vessel, lumen, and plaque areas of the atherosclerotic and of normal proximal and distal segments were determined.

RESULTS

A total of 92 atherosclerotic segments were analyzed. The degree of stenosis ranged from 9.2 to 92.8% (mean 34.1 +/- 16.9%) and the plaque area from 2 to 19.6 mm2 (mean 6.3 +/- 3.6 mm2). The vessel area of the atherosclerotic segment (mean 20.4 +/- 7.3 mm2) was larger than that of the proximal segment (mean 18.7 +/- 7.3 mm2, P = 0.018). The vessel area increased in proportion to plaque area. This relationship can be described using the equation y = 23.5(1-e-0.35x). The difference between the vessel area in the atherosclerotic segment and that in the proximal normal segment correlated with the percentage of stenosis (r = 0.53, P < 0.005) until the degree of stenosis exceeded 45%.

CONCLUSION

This study indicates that coronary artery remodeling, previously observed in pathologic studies, can be evaluated using intravascular ultrasound in vivo. As a result of the compensatory enlargement of the vessel, coronary angiography cannot be used to detect or exclude the early signs of coronary atherosclerosis.

A cytotoxic human hybridoma monoclonal antibody (TrJ5) specific for HLA-B38(16) and -B39(16)

We have generated a cytotoxic IgM lambda human hybridoma mAb (TrJ5), that is specific for HLA-B38(16) and -B39(16). Among a panel of 42 HLA-defined cell lines, TrJ5 killed all five B38-positive and both B16-positive cell lines, as well as the single B39-positive cell line, but not any cell lines lacking these antigens. It could be ruled out that the TrJ5 epitope is located on the alpha 1 domain because TrJ5 did not react with cells bearing HLA-B14, the alpha 1 domain of which is identical to alpha 1 of B39. In the alpha 2 domain of B38 and B39, a unique threonine residue at position 158 (Thr-158) is not shared by any of 29 other HLA-B alleles. This suggests that Thr-158 of the alpha 2-domain helix is critical for the TrJ5 epitope.

The study of relationships between the damage of visual function and hemorrheology, ocular rheography, as well as other related factors in patients with primary open angle glaucoma (POAG)

Researches of glaucoma visual function damage, hemorheology, ocular rheography and other related multiplex factors, with computed multifactorial stepwise regression analysis, indicate that the elevation of intraocular pressure (IOP) is not the only factor to induce visual impairment. POAG patients are shown to have markedly reduced diastolic perfusion pressure in ophthalmic artery, besides prolonged filling time of the retinal artery and vein, diminished erythrocyte deformability and increased platelet adhesion rate. The characteristic of ocular rheographic changes in POAG patients of controlled IOP suggest that the abnormal changes of hemorheology be responsible for the damage of visual function. The abnormal changes of plasma viscosity, blood apparent viscosity, blood viscoelasticity, hematocrit, mean red cell volume etc could be found in addition to the reduction of PO2, SO2% and trace elements (Cr, Zn, Mg, Fe) in patients with POAG. Computed multiply stepwise regression analysis and Bayes discrimination were made among the deteriorate rate of quantitative visual field and 28 factors from the combined investigation. Only the hemorrheological index could be introduced into the multiply regression equations. The more the damage of visual function in POAG patients, the more accurate the discriminatory effect. Based upon the results, and the reports of articles published as well as the search of 1982-1989 Compact Combridge MEDLINE Medical data base, the new clinical concept could be presented that POAG might belong to the scope of blood hyperviscosity syndromes. When IOP elevation and the decrease of ocular artery pressure existed, the damage of visual function in POAG patients should be deteriorated.

A human monoclonal hybridoma antibody (TrJ1) specific for HLA-DQ2

TrJ1 is a cytotoxic human hybridoma mAb (IgM lambda). Its reaction pattern with a panel of 42 HLA-defined lymphoblastoid B-cell lines correlated precisely with expression of DQ2. By flow cytometry it was shown that the binding of TrJ1 to DQ2 was efficiently blocked by the murine anti-DQ2 mAb 358.4, indicating that the TrJ1 and 358.4 epitopes overlap. TrJ1 reacted much better with EBV-transformed B cells than with B cells freshly isolated from blood. TrJ1 seemed suitable for typing freshly isolated B cells provided the incubation with complement lasted for 115 min in Terasaki plates. One or more of the DQ2-specific polymorphic amino acids E46, F47, L52, L55, K71 or A74, situated on the alpha-helix of the DQ2 beta chain, are probably critical for the TrJ1 epitope.

Classification of morphologic effects of percutaneous transluminal coronary angioplasty assessed by intravascular ultrasound

The aim of this study was the assessment and classification of the morphologic effects of percutaneous transluminal angioplasty (PTCA) by intravascular ultrasound (IU). Fifty-eight patients were examined immediately after PTCA with a 4.8Fr, 20 MHz rotational tip IU system. In 10 patients (17%), IU images could not be analyzed due to failure of the imaging system or poor image quality. In 48 patients (83%; 40 men and 8 women, aged 55 +/- 9 years), IU images of 48 PTCA segments, as well as 41 distal and 44 proximal sites, were analyzed. The left anterior descending artery was studied in 30 patients, the right coronary artery in 17 and the left main coronary artery in 1. Calcium was present in 32 of 48 PTCA segments (67%). Plaque morphology was concentric in 18 patients (38%) and eccentric in 30 (62%). Seven distinct morphologic patterns were observed. In concentric plaques, plaque compression without significant wall alterations (type 1) was found in 2 patients (4%), superficial tears within the plaque (type 2) in 1 (2%) and deep tears (type 3) in 8 (17%). Deep tearing associated with submedial or subintimal dissection (type 4) was found in 2 patients (4%). Dissection between plaque and vessel wall without noticeable intimal tearing (type 5) was the most common morphology (n = 15; 31%) and occurred in concentric and eccentric plaques. In eccentric plaques, no significant tearing of the plaque (type 6) was found in 6 patients (13%), and tearing of the plaque close to its base with dissection (type 7) in 14 (29%).(ABSTRACT TRUNCATED AT 250 WORDS)

The interaction of R(+)- and S(-)-zacopride with PCPA to modify rodent aversive behaviour

The interaction of R(+)- and S(-)zacopride (0.00001-10 mg/kg i.p.) with parachlorophenylalanine (PCPA, 3 day treatment 100 mg/kg i.p.) to modify behaviour in an aversive situation was investigated in the mouse black and white test box and rat social interaction test. R(+)-Zacopride (but not S(-)zacopride) and PCPA had an anxiolytic profile of action to reduce aversive responding in both species. Their established anxiolytic profiles were abolished by a subsequent treatment with S(-)zacopride. In contrast, S(-)-zacopride was less or ineffective if administered simultaneously with R(+)-zacopride. A co-treatment of PCPA with R(+)-zacopride also inhibited the anxiolytic profiles observed to the individual treatments. It is concluded that there is a complex interaction between the isomers of zacopride to modify responding to an aversive situation that is dependent on the temporal sequence of drug administration, and which may be modified by changes in basal 5-hydroxytryptamine (5-HT) tone and agonist, partial agonist and antagonist effects at the 5-HT3 receptor.

[An analysis of the causes of glaucomatous visual function damage by computed multifactorial stepwise regression]

Computed multifactorial stepwise regression analysis of quantitative visual field deterioration in relation to 28 factors showed that only the hemorheological indices entered the multiplex regression equations, especially accurately for POAG patients with severe visual damages. Besides, the patients might also have lower antioxidant capability in the red cell membrane protein. Based on the present results and data abroad, POAG might pertain to the blood hyperviscosity syndrome, and with elevated intraocular pressure and decreased ocular arterial pressure, the visual function damage would be aggravated.

Intravascular ultrasound imaging of arterial wall architecture

Intravascular ultrasound (IVUS) is a promising new technique for assessing vascular morphology and structure. Controversy exists whether the three-layer appearance of the arterial wall correctly reflects the histologic structures of the intima, media, and adventitia. We performed an experimental study to clarify the three-layer appearance. The vessel wall architecture was analyzed by IVUS on eight different kinds of plastic cylinders, 24 normal blood vessels from pigs, and 59 human arterial segments. A distinct three-layer appearance was observed on all the plastic cylinders when the ultrasound beam was perpendicular to the wall. A three-layer appearance was also seen in the arterial wall, in the muscular (iliac, femoral artery) and elastic types (aorta), when the echo beam was perpendicular to the vessel wall. The three-layer pattern was even observed on the arterial wall when the intima was removed. Furthermore, the removed intima itself provided a three-layer image. Histologic examination showed that there was no correspondence between the IVUS three-layer appearance and the intima, media, and adventitia. Moreover, we also performed IVUS on nine patients who suffered from aortic dissection. Intravascular ultrasonic visualization of the dissected intima showed a distinct three-layer pattern. The pattern disappeared when: (1) the echo beam was not perpendicular to the vessel wall; (2) there was connective tissue around the vessel wall; (3) there was arterial wall calcification; or (4) the vessel wall was too thick or the distance between the ultrasound transducer and the vessel wall was too large.(ABSTRACT TRUNCATED AT 250 WORDS)

[The hemorheological features and other related factors in patients with primary open angle glaucoma (POAG)]

The second part of the investigation revealed that POAG patients manifested abnormalities in plasma viscosity, whole blood apparent viscosity and viscoelasticity, hematocrit, and mean red cell volume, with concurrent reduction in oxygen partial pressure degree of oxygen saturation, and levels of trace elements Cr, Zn, Mg, and Fe. The hemorheological factors should be taken into account in addition to intraocular pressure in the development of visual damages.

Differential modulation of extracellular levels of 5-hydroxytryptamine in the rat frontal cortex by (R)- and (S)-zacopride

1. The ability of various anxiolytic and potential anxiolytic agents to modify 5-hydroxytryptamine (5-HT) release in the frontal cortex of the rat was assessed by the microdialysis technique. 2. The benzodiazepine receptor agonist, diazepam (2.5 mg kg-1, i.p.), the 5-HT1A receptor agonist 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT, 0.32 mg kg-1, s.c.) and the 5-HT1A receptor partial agonist buspirone (4.0 mg kg-1, i.p.) maximally reduced extracellular levels of 5-HT in the rat frontal cortex by approximately 50-60%, 70-80% and 30-40%, respectively. 3. (R)-zacopride (1.0-100 micrograms kg-1, i.p.) dose-dependently reduced extracellular levels of 5-HT in the rat frontal cortex (approximately 80% maximal reduction) whereas the other 5-HT3 receptor antagonists ondansetron (10 micrograms kg-1, i.p.) and (S)-zacopride (10-100 micrograms kg-1, i.p.) were ineffective. 4. In contrast to (S)-zacopride (100 nM; administered via the microdialysis probe), (R)-zacopride (1.0-100 nM; administered via the microdialysis probe) induced a concentration-dependent reduction in extracellular levels of 5-HT in the rat frontal cortex (approximately 70% maximal reduction). 5. In contrast to ondansetron (100 micrograms kg-1, i.p.), (S)-zacopride (10-100 micrograms kg-1, i.p.) dose-dependently reversed the (R)-zacopride (10 micrograms kg-1, i.p.) induced reduction in extracellular levels of 5-HT in the rat frontal cortex. The highest dose of (S)-zacopride (100 micrograms kg-1, i.p.) completely prevented the (R)-zacopride response.In addition, (S)-zacopride (100 nM; administered via the microdialysis probe) attenuated the inhibitory action of (R)-zacopride (10 nM; administered via the microdialysis probe) on extracellular levels of 5-HT in the rat frontal cortex.6. In conclusion, the present study provides further evidence of the ability of diazepam, 8-OH-DPAT and buspirone to reduce the activity of the central 5-hydroxytryptaminergic system in vivo. Furthermore,the results indicate that the ability of (R)-zacopride to reduce the in vivo release of 5-HT in the rat frontal cortex does not correlate with its 5-HT3 receptor antagonism. However, the differential affinity of (R)- and (S)-zacopride for a (S)-zacopride-insensitive (R)-zacopride site in rat cerebral cortex mirrors the relative activity of the two zacopride stereoisomers to modify the in vivo release of 5-HT in the frontal cortex of the rat and their ability to release suppressed behaviour in animal models of anxiety.

Profiles of interaction of R(+)/S(-)-zacopride and anxiolytic agents in a mouse model

The mouse black and white test box was used to measure changes in behaviour in an aversive situation where the administration of R(+)-zacopride (but not S(-)-zacopride) alone decreased aversive responding to the white area. A similar anxiolytic profile of action was observed using parachlorophenylalanine (PCPA), whose effects were antagonised by a co-treatment with R(+)-zacopride and reversed by S(-)-zacopride to an exacerbation of the aversive response. An anxiolytic profile of action was also observed using ondansetron, granisetron, chlordiazepoxide, diazepam, ritanserin, 8-OH-DPAT (8-hydroxy-2-(di-n-propylamino)tetralin), E4424 (2-[4-[4-(4-chloro-l-pyrazoyl)butyl]-l-piperazinyl]-pyrimidine), umepsirone, DuP753 (2-n-butyl-4-chloro-5-hydroxy-methyl-1-[2(1H-tetrazol-5-yl) biphenyl-4-yl)methyl)]-imidazole), SQ29,852 ((S)-1-[6-amino-2[hydroxy)(4-phenyl-butyl)phosphinyl]-oxy)-1- nexy]-2-proline), devazepide and guanfacine, and this was retained following co-treatment with PCPA. The anxiolytic profile of action of PCPA was also retained following co-treatment with renzapride which when administered alone failed to modify behaviour. However, the ability of chlordiazepoxide, diazepam, ondansetron and E4424 (but not devazepide, DuP753 or SQ29,852) to reduce aversive responding was inhibited by co-treatment with R(+) and/or S(-)-zacopride. It is concluded that the reduction in aversive responding caused by pharmacological manipulation at the benzodiazepine, 5-HT receptor subtypes 5-HT1A, 5-HT1C/5-HT2 and 5-HT3 (but not at the cholecystokin CCKA or angiotensin receptors or inhibition of angiotensin converting enzyme) can be inhibited by R(+) and S(-)-zacopride. The data is discussed in terms of zacopride having an agonist or partial agonist effect at the 5-HT3 receptor.

[Visual function damage in primary open angle glaucoma (POAG) in relation to hemorheology, ocular rheograph and other factors]

Researches of glaucomatous visual damage, hemorheology, ocular rheograph and other multiplex factors, with computed multifactorial stepwise regression analysis, indicate that elevation of intraocular pressure (IOP) is not the only factor to induce visual impairment. POAG patients are shown to have markedly reduced diastolic perfusion pressure in the ophthalmic artery, besides prolonged filling time of the retinal artery and vein, diminished erythrocyte deformability and increased platelet adhesion rate. The characteristic ocular rheographic changes in POAG patients of controlled IOP suggest that hemorheological factors play a role in the visual function damage.

Dissection following balloon angioplasty of aortic coarctation: review of the literature

Balloon angioplasty of the coarctation of the aorta can result in intimal or medial or even adventitial dissections as demonstrated by in vitro studies and animal experiments. As a typical sign of stretching of the aortic wall, patients complain of pain during the angioplasty procedure. In the literature, aortic wall rupture and ventricular fibrillation during the procedure are reported. Additional sudden deaths can occur within 40 hours after the procedure. Mortality ranges from 0.1% to 2.5%. By transesophageal echocardiography, monitoring of balloon angioplasty, control of the positioning of the balloon, and control of the results and detection of complications are possible. Intimal as well as medial dissections can be detected with observed healing for intimal but also medial dissections. In order to avoid the patient's discomfort, intraaortic ultrasound will be used in the future, when major methodological improvements are done. Computed tomography demonstrates medial dissections but is not able to visualize intimal dissections. Using computed tomography and magnetic resonance after angioplasty of the coarctation of the aorta, irregularities are described in up to 17% of the patients. For angiography, a low detection rate of medial dissections has to be expected, when not biplane angiographies of the whole thoracic aorta are performed. Medial dissections can be seen, but intimal dissections are missed. In conclusion, a review of the literature demonstrates a high incidence of intimal and medial dissections after angioplasty of the coarctation of the aorta with spontaneous healing in most patients. As is the way with coronary angioplasty, aortic wall ruptures are rare, but stand-by surgery is necessary.

A cytotoxic monoclonal human hybridoma antibody (TrJ3) against HLA-B44(12) and -B45(12)

We have generated a human monoclonal cytotoxic IgM lambda antibody (TrJ3) that reacted specifically with all lymphoblastoid B-cell lines expressing HLA-B44(12) and B45(12). TrJ3 hybridoma supernatant was suitable for HLA-B12 typing of freshly isolated blood mononuclear cells. Analysis of available amino acid sequences of HLA-B molecules indicated that the alpha 1 domain does not contain the TrJ3 serological epitope. Since HLA-B44 is associated with a unique serine residue at position 167 that points towards the peptide binding groove, we propose that S167 of the alpha 2 domain helix is a critical part of the TrJ3 epitope.

[The correlation between measurements performed by intravascular echography and quantitative digital angiography in large- and small-caliber arteries]

Intravascular ultrasound is a new promising technique that appears as a very useful complement to standard angiography in the study of atherosclerosis. Specifically, intravascular ultrasound provides by itself, information of great value concerning vessel wall characteristics. Nevertheless, before taking any decision with the results provided by this new technique, we must validate this information with that provided by other more conventional techniques like standard angiography. Accordingly, we have analyzed in 25 patients, 50 images of the abdominal aorta and 77 images of the coronary arteries taken from arterial segments free of atherosclerotic involvement. With the use of a calibrated small grid located over the patient's thorax, we have analyzed "in the same points" the images obtained with intravascular ultrasound and those provided by contrast angiography using a quantitative angiographic analysis. In the abdominal aorta the vessel diameter measured by intravascular ultrasound and angiography was 17.8 +/- 0.39 mm vs 18.6 +/- 0.42 mm (NS), whereas in the coronary arteries it was 2.76 +/- 0.39 mm vs 2.98 +/- 0.37 mm (NS), respectively. The correlation between both techniques was good for both types of arteries (r = 0.93 in the abdominal aorta and r = 0.87 in the coronary arteries). We conclude, that in our experience and with the methodology used, there is a good correlation between the measurements of the vessel diameters obtained by both intravascular ultrasound and digital angiography in arteries of different sizes, being the correlation even better in large arteries.

[Intravascular ultrasound in patients with suspected aortic dissection: comparison with transesophageal echocardiography]

Thirteen patients with suspected aortic dissection (two women, 11 men, age 61 +/- 10.8 years) underwent transesophageal echocardiography (TEE), intravascular ultrasound (IVUS), angiography, and in part computed tomography (CT). TEE was performed using 3.5 or 3.75 MHz ultrasound transducers. IVUS examination was done using a 6F 20 MHz "rotational-tip" IVUS catheter (Boston Scientific) advanced over a guiding-wire positioned in the ascending aorta by the "side-saddle" technique. In two patients it was not possible to advance the catheter into the abdominal aorta. Of the remaining 11 patients, eight had aortic dissection (six Typ III, one Typ II, and one Typ I, de Bakey classification). Two patients had aortic aneurysms without dissection and one patient had a perforation of the ascending aorta. TEE, CT, and angiography led to the correct diagnosis in all patients, while IVUS failed to provide precise information within the ascending aorta and the aortic arch. Reasons were the limited scanfield of the 20 MHz transducer and the inability to steer and position the IVUS catheter. Contrary to the limited value in the ascending aorta, IVUS could successfully scan the entire descending aorta, including the dissection membrane and the originating vessels, if the max. diameter was less than 4 cm. No adverse effects occurred. Intravascular ultrasound allows to scan the entire aorta in patients with suspected aortic dissection. The current limitations can be solved only by the introduction of steerable and/or low frequency catheters.

[Experimental evaluation of the accuracy and safety of intraluminal ultrasound]

In this in vitro investigation, we studied the feasibility and accuracy as well as the safety of intravascular ultrasound imaging. Plastic cylinders were used in order to validate measurements of luminal area, perimeter, diameter, and wall thickness. Fifty-nine segments of human arteries were also examined by intravascular ultrasound; then the results regarding the luminal area, perimeter, and wall thickness were compared with the corresponding histopathologic section. Close correlations were found in plastic cylinder studies (r = 0.999, 0.999, 0.998, and 0.994 for area, perimeter, diameter, and wall thickness, respectively). There was also an excellent correlation between intravascular ultrasound imaging and pathologic measurements (r = 0.993, 0.994, and 0.915 for luminal area, perimeter, and wall thickness). Five different cylinders, with a volume of 2, 5, 10, 20, and 50 mls, were employed to evaluate the effect of ultrasound on temperature. Ten blood samples anticoagulated with EDTA were used to detect the effects of ultrasound on blood elements. In the course of time, the ultrasound caused a slight increase of solution temperature (from 23.9 degrees C to 24.6 degrees C after 1-h examination in a 2-ml cylinder) and the temperature change became less obvious as the solution volume increased (the temperature raised 0.3 degrees C in the 2-ml cylinder, 0.1 degrees C in the 20-ml cylinder, but no change was detectable in the 50-ml cylinder after 10 min). No significant differences about WBC, RBC, and platelet counts were found between test and control group (p greater than 0.1) before and 5, 10, 15, 30, and 60 min after ultrasound examination.(ABSTRACT TRUNCATED AT 250 WORDS)

A preliminary study of short-term efficacy of Nd:YAG laser peripheral iridotomy in patients with primary angle closed glaucoma

Q-switched Nd:YAG laser was used for the peripheral iridotomy in 68 cases (80 eyes) of primary angle closed glaucoma. The average number of laser shots is 20.5 (1-127 shots), and the average shot energy is 2.5 mJ (0.9-5.6 mJ). The successful rate of iris penetration is about 97.6%. The size of the iris hole is not smaller than 0.2 mm2. The kind of the iris is the most important factor that causes the marked variation in laser shots and in laser shot energy. The main complications of Nd:YAG laser iridotomy present as transient IOP elevation and iris bleeding. Increase in IOP most occurs within two hours after the laser therapy. The iris bleeding was seen in about 39% of the patients, but this iris bleeding is slight and very minor and tend to stop spontaneously. On the other hand, no correlation was found among the IOP elevation, laser shot, and laser shot energy. The causes and management of the IOP elevation after Nd:YAG laser iridotomy was discussed in detail. The authors believe that this newer treatment has immediate benefit for the patients with narrow-angle or angle-closure glaucoma, but many problems still remain to be investigated.

Successful replantation in ten-digit complete amputations

The authors report a case of successful replantation of all fingers in a ten-finger complete amputation. Among the factors responsible for the successful outcome were an adequate number of microsurgically-trained resident surgeons and staff, good organization and supervision by senior staff, emphasis on precision and perseverance in the operative procedures, and postoperative management. Follow-up is 15 months, and the patient now has a pair of functionally and cosmetically good hands.